A coastal saline field of 10.5 ha was selected as the study site and 122 bulk electrical conductivity (ECb) measurements were performed thrice in situ in the topsoil (0-20 cm) across the field using a hand held device...A coastal saline field of 10.5 ha was selected as the study site and 122 bulk electrical conductivity (ECb) measurements were performed thrice in situ in the topsoil (0-20 cm) across the field using a hand held device to assess the spatial variability and temporal stability of the distribution of soil electrical conductivity (EC), to identify the management zones using cluster analysis based on the spatiotemporal variability of soil EC, and to evaluate the probable potential for site-specific management in coastal regions with conventional statistics and geostatistical techniques. The results indicated high coefficients of variation for topsoil salinity over all the three samplings. The spatial structure of the salinity variability remained relatively stable with time. Kriged contour maps, drawn on the basis of spatial variance structure of the data, showed the spatial trend of the salinity distribution and revealed areas of consistently high or consistently low salinity, while a temporal stability map indicated stable and unstable regions. On the basis of the spatiotemporal characteristics, cluster analysis divided the site into three potential management zones, each with different characteristics that could have an impact on the way the field was managed. On the basis of the clearly defined management zones it was concluded that coastal saline land could be managed in a site-specific way.展开更多
In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1：5 soil/water extract （EC1：5）, the study focused on revealing the main chemical factors contributing to EC of s...In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1：5 soil/water extract （EC1：5）, the study focused on revealing the main chemical factors contributing to EC of soil extracts and their relative importance. The relationship between EC1：5 and the chemical properties of soil salinity in the delta oasis of Weigan and Kuqa rivers, China, were studied using path coefficient analysis, a path analysis method. We studied each key element affecting EC1：5 either directly or indirectly. The results obtained show that the salt content, total dissolved solids （TDS）, and the sum of the sodium ion concentration and the kalium ion concentration are the most influential factors on 1：5 soil/ water extract （EC1：5） in the 0-10 cm and the 30-50 cm soil layer. The results show that the sequence of direct path coefficients in the 0-10 cm and the 30-50 cm soil layers on soil conductivity is TDS→Na^＋ ＋ K^＋→Salt content→Ca^2＋→Cl-→the sodium dianion ratio （SDR）→pH→ SO4^2-→HCO3^-→Mg^2＋→the soluble sodium percentage （SSP） sodium absorption ratio （SAR） and TDS→Salt content→Na^＋ ＋ K^＋→Ca^2＋→SDR→Mg^2＋→HCO3^-→SSP→pH→SO4^2-→SAR→Cl^-. The salt content, chlorine ion, and SAR are the main factors affecting 1：5 soil/water extract （EC1：5） in the 10-30 centimeter soil layer. The order of direct path coefficients result is as follows： Salt content→Cl^-→SAR→SSP→TDS→Ca^2＋→Mg^2＋= SO4^2-→HCO3^-→pH→SDR→Na^- ＋ K^＋. Moreover, the effects of HCO3^-, pH were very weak. Though the direct path coefficients between EC1：5 and SAR, SO4^2- and Ca^2＋ were not high, influence of other chemical factors caused the coefficients to increase, making the summation of their direct and indirect path coefficients relatively high. The models of the different soil layers were structured separately. Evidences showed that multiple regression relations between EC1：5 and most of the primary factors had sound reliability and very good accuracy. The research results can serve as a reference to the scientific management amelioration and utilization of saline in the Delta Oasis of Weigan and Kuqa rivers.展开更多
Hydraulic conductivity is one of the most important parameters for flow and transport related phenomena in soil and also a criterion for measuring soil ability to transfer water. There is concern arising from the suit...Hydraulic conductivity is one of the most important parameters for flow and transport related phenomena in soil and also a criterion for measuring soil ability to transfer water. There is concern arising from the suitability, efficiency and ease of the different measuring methods use under different land management practices. The purpose of this paper is to determine and evaluate soil hydraulic conductivity under different land management practices which include forest land (teak and Melina plantation), grassland and maize cultivated land using the constant head method. The measurement is at different depth of 0 - 15 cm, 15 - 25 cm, 25 - 50 cm, 50 - 75 cm. The limited means of each land use were used to compare the result obtained through statistical means. All tests were carried out using SPSS at a significance level of 0.05. An ANOVA test was conducted to check if each of the land use is significantly different. The soil in forest zone (Teak plantation and Gmalina plantation) had a significantly high bulk density as 1.7533 cm<sup><span style="font-family:Verdana;">-3</span></sup><span style="font-family:Verdana;"> and 1.6967 cm</span><sup><span style="font-family:Verdana;">-3</span></sup><span style="font-family:Verdana;"> respectively at depth 50 - 75 cm compared to the low bulk density in the grass, maize cultivated land as 1.5000 cm</span><sup><span style="font-family:Verdana;">-3</span></sup><span style="font-family:Verdana;"> and 1.4833 cm</span><sup><span style="font-family:Verdana;">-3</span></sup><span style="font-family:Verdana;"> respectively at depth 50 - 75 cm. However, soil hydraulic conductivity was significantly high in the grass site or soil at the surface with 2.8833 cm·h</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">. Results obtained from the different land use serve as Knowledge of variability of soil that can assist in defining the best strategies for sustainable soil management through the provision of vital information for estimating soil susceptibility to erosion, hydrological modelling and efficient planning of irrigation projects.</span>展开更多
The study on soil thermal conductivity (STC) was an important side of research on ground source heat pump technique,geological disposal of high-level radioactive wastes,heat distribution of buried cable. Especially ow...The study on soil thermal conductivity (STC) was an important side of research on ground source heat pump technique,geological disposal of high-level radioactive wastes,heat distribution of buried cable. Especially owing to technical requirement for shallow terrestrial heat recently, it directly influenced the design and solution in engineering problems. The authors measured the STC in the studied area with QTM-D2 and discussed the effect of samples in size, the measurement error between the samples in lab and in site. The results indicate measuring STC by heat pole method with less influence upon the samples in size, and measuring results on the different geometry size approach very much. The STC is fit for the empirical relation between the temperature and TC under the condition of normal temperature. It is significance for understanding STC in northern China and simulation of temperature field.展开更多
Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductanc...Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductance to survey soil water profiles and comparing it with root distribution surveyed by soil coring and root harvesting in Changbai Mountain in 1999. The results were: (1) The profiles of soil water content were adjusted by root activity. The water content of the soil layer with abundant roots was higher. (2) When CO 2 concentration was doubled, water transport was more active at the root/soil interface and the roots were distributed into deeper layer. It was shown in this work that the method of measuring electric conductance is an inexpensive, non_destructive and relatively sensitive way for underground water transport process.展开更多
Continuous observation data collected over the whole year of 2004 on a cropland surtace m Tongyu, a senti-arid area of northeastern China （44°25＇N, 122°52＇E）, have been used to investigate the variations...Continuous observation data collected over the whole year of 2004 on a cropland surtace m Tongyu, a senti-arid area of northeastern China （44°25＇N, 122°52＇E）, have been used to investigate the variations of surface albedo and soil thermal parameters, including heat capacity, thermal conductivity and thermal diffusivity, and their relationships to soil moisture. The diurnal variation of surface albedo appears as a U shape curve on sunny days. Surface albedo decreases with the increase of solar elevation angle, and it tends to be a constant when solar elevation angle is larger than 40°. So the daily average surface albedo was computed using the data when solar elevation angle is larger than 40° Mean daily surface albedo is found to decrease with the increase of soil moisture, showing an exponential dependence on soil moisture. The variations of soil heat capacity are small during Julian days 90 300. Compared with the heat capacity, soil thermal conductivity has very gentle variations during this period, but the soil thermal diffusivity has wide variations during the same period. The soil thermal conductivity is found to increase as a power function of soil moisture. The soil thermal diffusivity increases firstly and then decreases with the increase of soil moisture.展开更多
Data from July 2006 to June 2008 observed at SACOL （Semi-Arid Climate and Environment Observatory of Lanzhou University, 35.946°N, 104.137°E, elev. 1961 m）, a semi-arid site in Northwest China, are used to...Data from July 2006 to June 2008 observed at SACOL （Semi-Arid Climate and Environment Observatory of Lanzhou University, 35.946°N, 104.137°E, elev. 1961 m）, a semi-arid site in Northwest China, are used to study seasonal variability of soil moisture, along with surface albedo and other soil thermal parameters, such as heat capacity, thermal conductivity and thermal diffusivity, and their relationships to soil moisture content. The results indicate that surface albedo decreases with increases in soil moisture content, showing a typical exponential relation between the surface albedo and the soil moisture. The heat capacity, the soil thermal diffusivity, and soil thermal conductivity show large variations between Julian day 90-212 and 450-578. The soil thermal conductivity is found to increase as a power function of soil moisture. Soil heat capacity and soil thermal diffusivity increase with increases in soil moisture. The SACOL observed soil moisture are also used to validate the AMSR-E/AQUA retrieved soil moisture and there is good agreement between them. The analysis of the relationship between satellite retrieved soil moisture and precipitation suggests that the variability of soil moisture depends on the variation of precipitation over the Loess Plateau.展开更多
The dynamics of water and salt in soil were monitored in the 2010 and 2011 growing seasons of cotton to evaluate the salinity risk of soil under drip irrigation in arid environments for different management practices ...The dynamics of water and salt in soil were monitored in the 2010 and 2011 growing seasons of cotton to evaluate the salinity risk of soil under drip irrigation in arid environments for different management practices of drip system uniformity and irrigation amount. In the experiments, three Christiansen uniformity coefficients （CU） of approximately 65, 80, and 95% （referred to as low, medium, and high uniformity, respectively） and three irrigation amounts of 50, 75, and 100% of full irrigation were used. The distribution of the soil water content and bulk electrical conductivity （ECb） was monitored continuously with approximately equally spaced frequency domain reflectometry （FDR） sensors located along a dripline. Gravimetric samples of soil were collected regularly to determine the distribution of soil salinity. A great fluctuation in CU of water content and ECb at 60 cm depth was observed for the low uniformity treatment during the irrigation season, while a relatively stable variation pattern was observed for the high uniformity treatment. The ECb CU was substantially lower than the water content CU and its value was greatly related to the water content CU and the initial ECb CU. The spatial variation of seasonal mean soil water content and seasonal mean soil bulk electrical conductivity showed a high dependence on the variation pattern of emitter discharge rate along a dripline for the low and medium uniformity treatments. A greater irrigation amount produced a significantly lower soil salinity at the end of the irrigation season, while the influence of the system uniformity on the soil salinity was insignificant at a probability level of 0.1. In arid regions, the determination of the target drip irrigation system uniformity should consider the potential salinity risk of soil caused by nonuniform water application as the influence of the system uniformity on the distribution of the soil salinity was progressively strengthened during the growing season of crop.展开更多
Using the Simple Biosphere Model （SiB2）, soil thermal properties （STP） were examined in a Tibetan prairie during the monsoon period to investigate ground surface temperature prediction. We improved the SiB2 model ...Using the Simple Biosphere Model （SiB2）, soil thermal properties （STP） were examined in a Tibetan prairie during the monsoon period to investigate ground surface temperature prediction. We improved the SiB2 model by incorporating a revised force-restore method （FRM） to take the vertical heterogeneity of soil thermal diffusivity （k） into account. The results indicate that （1） the revised FRM alleviates daytime overestimation and nighttime underestimation in modeled ground surface temperature （Tg）, and （2） its role in little rainfall events is significant because the vertical gradient of k increases with increasing surface evaporation. Since the original formula of thermal conductivity （A） in the SiB2 greatly underestimates soil thermal conductivity, we compared five Mgorithms of A involving soil moisture to investigate the cause of overestimation during the day and underestimation at night on the basis of the revised FRM. The results show that （1） the five algorithms significantly improve Tg prediction, especially in daytime, and （2） taking one of these five algorithms as an example, the simulated Tg values in the daytime are closer to the field measurements than those in the nighttime. The differences between modeled Tg and field measurements are mostly within the margin of error of -4-2 K during 3 August to 4 September 1998.展开更多
The infiltration of water into soil is one of the most important soil physical properties that affect soil erosion and the eco-environment, especially in the Pisha sandstone area on the Chinese Loess Plateau. We studi...The infiltration of water into soil is one of the most important soil physical properties that affect soil erosion and the eco-environment, especially in the Pisha sandstone area on the Chinese Loess Plateau. We studied the one-dimensional vertical infiltration of water in three experimental soils, created by mixing Pisha sandstone with sandy soil, irrigation-silted soil, and loessial soil, at mass ratios of 1：1, 1：2, 1：3, 1：4, and 1：5. Our objective was to compare water infiltration in the experimental soils and to evaluate the effect of Pisha sandstone on water infiltration. We assessed the effect by measuring soil bulk density（BD）, porosity, cumulative infiltration, infiltration rate and saturated hydraulic conductivity（Ks）. The results showed that Pisha sandstone decreased the infiltration rate and saturated hydraulic conductivity in the three experimental soils. Cumulative infiltration over time was well described by the Philip equation. Sandy soil mixed with the Pisha sandstone at a ratio of 1：3 had the best water-holding capacity. The results provided experimental evidence for the movement of soil water and a technical support for the reconstruction and reclamation of mining soils in the Pisha sandstone area.展开更多
Measurements of dielectric parameters followed by permeability tests are performed on soil samples of infiltration basin. The dielectric parameters are obtained by TDR （time domain reflectrometry） measurements from ...Measurements of dielectric parameters followed by permeability tests are performed on soil samples of infiltration basin. The dielectric parameters are obtained by TDR （time domain reflectrometry） measurements from which it is found that the measurement of the permittivity, the electrical conductivity and the relaxation time of compacted soil allows the mapping of the values of the coefficient of permeability at the surface of an infiltration basin. With the distribution of the coefficient of permeability, the areas of water stagnation can be detected before the basin filling. The study proves that the TDR measurements for the detection of these zones can be used for the management of infiltration basins for sustainable working and their remediation can be undertaken before the rainy seasons.展开更多
Developing water-saving irrigation regimes has important practical significance not only in alleviating the crucial water shortage,but also in controlling soil salinization for the protected cultivation in eastern Chi...Developing water-saving irrigation regimes has important practical significance not only in alleviating the crucial water shortage,but also in controlling soil salinization for the protected cultivation in eastern China.A field study with six treatments was conducted to evaluate the effects of different irrigation regimes with subdrainage systems on the soil nitrate nitrogen,salinity and moisture,also evaluate the effects on tomato growth,fruit yield and irrigation water use efficiency(IWUE).The treatments were distinguished by three different irrigation amounts of 310 mm,360 mm and 410 mm,and two irrigation frequencies of 7 and 11 times.Results showed that the irrigation amount had significant effects on the soil NO_(3)^(-)-N and electric conductivity(EC).A positive correlation was detected between soil NO_(3)^(-)-N(x)and EC(y)at 0-20 m depth after harvest,with a linear equation of y=0.063x-0.670.Soil volumetric moisture at 0.10 m and 0.20 m depth was increased as the irrigation amount increased.Moreover,a higher amount of irrigation increased the fruit yield but reduced the IWUE of tomato.It was also found that smaller irrigation amounts combined with frequent intervals could increase fruit yield and IWUE.However,the fruit quality of tomato had a significant(p<0.05)negative correlation with irrigation amount.Therefore,the parameters of irrigation regime including the irrigation amount and intervals should be considered comprehensively in order to find a compromise between salinity control and irrigation water use efficiency improvement.展开更多
A soil electrical conductivity(EC)measurement system based on direct digital synthesizer(DDS)and digital oscilloscope was developed.The system took the“current-voltage four-electrode method”as the design principal a...A soil electrical conductivity(EC)measurement system based on direct digital synthesizer(DDS)and digital oscilloscope was developed.The system took the“current-voltage four-electrode method”as the design principal and adopted a six-pin structure of the probe,two center pins to measure the soil EC in shallow layer,two outside pins to measure the soil EC in deep layer,and two middle pins for inputting the driving current.A signal generating circuit using DDS technology was adopted to generate sine signals,which was connected with the two middle pins.A digital oscilloscope was used to record and store the two soil output signals with noises in microseconds,which were from the two center pins and two outside pins,respectively.Then a digital bandpass filter was used to filter the soil output signals recorded by the digital oscilloscope.Compared with the traditional analog filter circuit,the digital filter could filter out the noises of all frequency except for the frequency of the excitation source.It could improve the effect of filtering and the accuracy of the soil EC measurement system.The DDS circuit could provide more stable sine signals with larger amplitudes.The use of digital oscilloscope enables us to analyze the soil output signals in microseconds and measure the soil EC more accurately.The new soil EC measurement system based on DDS and digital oscilloscope can provide a new effective tool for soil sensing in precision agriculture.展开更多
A utility equipment used in soil science is designed and installed.The equipment can be used in research pro- grams of soil water and solute transport.Pressure in pressure chamber of the equipment in which a tested so...A utility equipment used in soil science is designed and installed.The equipment can be used in research pro- grams of soil water and solute transport.Pressure in pressure chamber of the equipment in which a tested soil sam- ple is laid can be adjusted exactly so that we can determine the water content of soil sample.With the equipment we can not only study the problems related water movement in soil but also measure some solute,such as cadmi- um,plumbum and so on,adsorption on surface of soil in saturated and unsaturated state.As an illustration of the use of the equipment,we give the isothermal of cupric ion adsorption in soil.This equipment can be used in the re- search work and application of soil science.展开更多
Understanding the influence of collapsing gully management restoration on soil quality and function is essential to the protection of the regional ecological environment in the collapsing gully erosion area.The primar...Understanding the influence of collapsing gully management restoration on soil quality and function is essential to the protection of the regional ecological environment in the collapsing gully erosion area.The primary objective of this study was to construct soil quality index(SQI)to assess the influence of different vegetation restoration types on soil quality in collapsing gully restoration.The influence of five vegetation restoration types on soil properties was investigated by using a path analysis,a comprehensive soil quality index(SQI),and a general linear model(GLM).Vegetation restoration was shown to significantly increase the saturated hydraulic conductivity(Ks),mainly due to the effect of the physical parameters of bulk density,soil cohesion,and soil water content.Meanwhile,pH,Ks,soil organic matter(OM),and sand content were revealed as reasonable indicators to evaluate the influence of vegetation restoration on soil quality.Moreover,vegetation restoration was found to significantly improve the soil quality,with the highest SQI value for natural restoration mixed forest(NF),followed by replanted arboreal forest(RA)and replanted scrubland(RS),which were all significantly higher than the SQI value of the erosion area(EA)in the collapsing gully.Additionally,vegetation type explained the most substantial proportion of total variability(46.41%),and restoration time showed a positive correlation with SQI.The results of this study can provide a reference for the restoration and protection of the regional ecological environment in the collapsing gully area.展开更多
Knowledge of the spatial distribution of soil textural properties is important for determining soil moisture storage and soil hydraulic transport properties.Capturing field heterogeneity without exhaustive sampling an...Knowledge of the spatial distribution of soil textural properties is important for determining soil moisture storage and soil hydraulic transport properties.Capturing field heterogeneity without exhaustive sampling and costly sample analysis is difficult. Our objective was to employ electromagnetic induction(EMI) mapping in low apparent electrical conductivity(EC_a) soils at varying soil water contents to capture time invariant properties such as soil texture. Georeferenced EC_ameasurements were taken using a ground conductivity meter on six different days where volumetric water content(θ_v) varied from 0.11 to 0.23. The 50 m × 50 m field included a subsurface gravelly patch in an otherwise homogeneous silt-loam alluvial soil.Ordinary block kriging predicted EC_aat unsampled areas to produce 1-m resolution maps. Temporal stability analysis was used to divide the field into three distinct EC_a regions. Subsequent ground-truthing confirmed the lowest conductivity region correlated with coarse textured soil parent materials associated with a former high-energy alluvial depositional area. Combining maps using temporal stability analysis gives the clearest image of the textural difference. These maps could be informative for modeling,experimental design, sensor placement and targeted zone management strategies in soil science, ecology, hydrology,and agricultural applications.展开更多
Borehole thermal energy storage(BTES)systems have garnered significant attention owing to their efficacy in storing thermal energy for heating and cooling applications.Accurate modeling is paramount for ensuring the p...Borehole thermal energy storage(BTES)systems have garnered significant attention owing to their efficacy in storing thermal energy for heating and cooling applications.Accurate modeling is paramount for ensuring the precise design and operation of BTES systems.This study conducts a sensitivity analysis of BTES modeling by employing a comparative investigation of five distinct parameters on a wedge-shaped model,with implications extendable to a cylindrical configuration.The parameters examined included two design factors(well spacing and grout thermal conductivity),two operational variables(charging and discharging rates),and one geological attribute(soil thermal conductivity).Finite element simulations were carried out for the sensitivity analysis to evaluate the round-trip efficiency,both on a per-cycle basis and cumulatively over three years of operation,serving as performance metrics.The results showed varying degrees of sensitivity across different models to changes in these parameters.In particular,the round-trip efficiency exhibited a greater sensitivity to changes in spacing and volumetric flow rate.Furthermore,this study underscores the importance of considering the impact of the soil and grout-material thermal conductivities on the BTES-system performance over time.An optimized scenario is modelled and compared with the base case,over a comparative assessment based on a 10-year simulation.The analysis revealed that,at the end of the 10-year period,the optimized BTES model achieved a cycle efficiency of 83.4%.This sensitivity analysis provides valuable insights into the merits and constraints of diverse BTES modeling methodologies,aiding in the selection of appropriate modeling tools for BTES system design and operation.展开更多
This paper demonstrates that we should use two different hierarchic composition methods for the two different types of levels in the AHP. The first method is using the weighted geometric mean to synthesize the judgmen...This paper demonstrates that we should use two different hierarchic composition methods for the two different types of levels in the AHP. The first method is using the weighted geometric mean to synthesize the judgments of alternative-type-level elements, which is the only hierarchic composition method for the alternative-type level in an AHP hierarchy, and the rank is preserved automatically. The second one is using the weighted arithmetic mean to synthesize the priorities of the criteria-type-level elements, which is the only hierarchic composition method for all the criteria-type levels, and rank reversals are allowed.展开更多
No-tillage and soil mulching with pruning residues,applied in olive groves of the semi-arid Mediter-ranean environment,as erosion control practices still practice not fully studied.This study has evaluated the saturat...No-tillage and soil mulching with pruning residues,applied in olive groves of the semi-arid Mediter-ranean environment,as erosion control practices still practice not fully studied.This study has evaluated the saturated hydraulic conductivity(Ksat),surface runoff(SR)and soil erosion(SL)under rainfall at plot scale throughout two years in four different management practices,total soil cover with a net(SP),mechanical tillage(MT)and mulching by vegetal residues at 3,5·10^(3) and 17,5·10^(3) kg ha^(-1) of dry matter(NTR350 and NTR1750),in an olive grove of Southern Italy.Ksat varied between 1.6(MT)and 25.1(NTR1750)mm/h.A clear reduction in runoff and soil losses was detected for the mulch-based practices when compared to MT,from 20 to 32%in the runoff coefficient and 75-80%in SL,with higher reductions in the NTR1750.This reduction in SL can be mainly explained by the reduction in SR and rain-splash,interrill and rill erosion,due to protection by mulch residues,which increased the vegetal cover and organic matter content of mulched plots.The vegetal cover was on average higher in SP(33%),NTR1750(25%)and NTR350(22%),and lower in MT(12%).The mean organic matter content of soil was 2.01%,1.69%,1.34%and 0.82%for NTR1750,NTR350,SP and MT respectively.Overall,the results quantify the impact of soil mulching with pruning residues at different doses,which will provide guidelines to control and mitigate the hydrological response of clayey and steep soils in Mediterranean olive groves,analysing the associated environmental and economic benefits.展开更多
The objective of this study was to explore the effects of different degrees of water and salt stress on the actual water consumption and soil salt accumulation of tomatoes and the salt tolerance characteristics of tom...The objective of this study was to explore the effects of different degrees of water and salt stress on the actual water consumption and soil salt accumulation of tomatoes and the salt tolerance characteristics of tomatoes under brackish water combined with regulated deficit irrigation mode.The greenhouse pot experiment was used to set three influencing factors,the irrigation water salinity S1 was 1.1 g/L(local shallow groundwater),S2 was 2.0 g/L,and S3 was 4.0 g/L,respectively,and different degrees of water deficit(W1 ranged from 65%-75%Field Capacity(FC),W2 ranged from 55%-65%FC,W3 ranged from 45%-55%FC)and seedling stage(T1),blossoming and bearing fruits stage(T2)and mature picking stage(T3).The response of fresh fruit weight,stems and leaves weight,yield and water use efficiency of tomato under water and salt stress were monitored and analyzed.The results showed the coordinated regulation of water and salt can significantly reduce the electrical conductivity of the 0-30 cm soil of the tomato root system.The higher the salinity of irrigation water,the better the salt control effects of the coordinated regulation of water and salt;the coordinated regulation of water and salt at different growth stages had significant effects on the weight of fresh tomato fruits,the weight of stems and leaves and the yield.The salinity of irrigation water was in inverse proportion to the yield of tomatoes;In S1 treatment irrigation(irrigation water salinity was 1.1 g/L)under the mildly regulated deficit in the seedling stage(irrigation water was 55%-65%of the field water capacity)can effectively reduce the irrigation water volume during the whole growth stage while ensuring that there was no significant reduction in yield.The research results provided a scientific and reliable theoretical basis for the increase of local tomato production,the improvement of water use efficiency and the formulation of suitable irrigation patterns.展开更多
基金Project supported by the National Natural Science Foundation of China (Nos. 40001008 and 40571066)German Federal Ministry of Education and Research (BMBF) (No. AZ39742)the Postdoctoral Science Foundation o China (No. 20060401048).
文摘A coastal saline field of 10.5 ha was selected as the study site and 122 bulk electrical conductivity (ECb) measurements were performed thrice in situ in the topsoil (0-20 cm) across the field using a hand held device to assess the spatial variability and temporal stability of the distribution of soil electrical conductivity (EC), to identify the management zones using cluster analysis based on the spatiotemporal variability of soil EC, and to evaluate the probable potential for site-specific management in coastal regions with conventional statistics and geostatistical techniques. The results indicated high coefficients of variation for topsoil salinity over all the three samplings. The spatial structure of the salinity variability remained relatively stable with time. Kriged contour maps, drawn on the basis of spatial variance structure of the data, showed the spatial trend of the salinity distribution and revealed areas of consistently high or consistently low salinity, while a temporal stability map indicated stable and unstable regions. On the basis of the spatiotemporal characteristics, cluster analysis divided the site into three potential management zones, each with different characteristics that could have an impact on the way the field was managed. On the basis of the clearly defined management zones it was concluded that coastal saline land could be managed in a site-specific way.
基金supported by the National Natural Science Foundation of China(40861020)the Natural Science Foundation of Xinjiang(200821128)+1 种基金the Key Laboratory of Oasis Ecology in Xinjiang University(XJDX0201-2008-03)the Fund of Young Teachers Scientific Research in Xinjiang University(QN070122),China
文摘In order to assess the effects of chemical properties of soil salinity on electrical conductivity of 1：5 soil/water extract （EC1：5）, the study focused on revealing the main chemical factors contributing to EC of soil extracts and their relative importance. The relationship between EC1：5 and the chemical properties of soil salinity in the delta oasis of Weigan and Kuqa rivers, China, were studied using path coefficient analysis, a path analysis method. We studied each key element affecting EC1：5 either directly or indirectly. The results obtained show that the salt content, total dissolved solids （TDS）, and the sum of the sodium ion concentration and the kalium ion concentration are the most influential factors on 1：5 soil/ water extract （EC1：5） in the 0-10 cm and the 30-50 cm soil layer. The results show that the sequence of direct path coefficients in the 0-10 cm and the 30-50 cm soil layers on soil conductivity is TDS→Na^＋ ＋ K^＋→Salt content→Ca^2＋→Cl-→the sodium dianion ratio （SDR）→pH→ SO4^2-→HCO3^-→Mg^2＋→the soluble sodium percentage （SSP） sodium absorption ratio （SAR） and TDS→Salt content→Na^＋ ＋ K^＋→Ca^2＋→SDR→Mg^2＋→HCO3^-→SSP→pH→SO4^2-→SAR→Cl^-. The salt content, chlorine ion, and SAR are the main factors affecting 1：5 soil/water extract （EC1：5） in the 10-30 centimeter soil layer. The order of direct path coefficients result is as follows： Salt content→Cl^-→SAR→SSP→TDS→Ca^2＋→Mg^2＋= SO4^2-→HCO3^-→pH→SDR→Na^- ＋ K^＋. Moreover, the effects of HCO3^-, pH were very weak. Though the direct path coefficients between EC1：5 and SAR, SO4^2- and Ca^2＋ were not high, influence of other chemical factors caused the coefficients to increase, making the summation of their direct and indirect path coefficients relatively high. The models of the different soil layers were structured separately. Evidences showed that multiple regression relations between EC1：5 and most of the primary factors had sound reliability and very good accuracy. The research results can serve as a reference to the scientific management amelioration and utilization of saline in the Delta Oasis of Weigan and Kuqa rivers.
文摘Hydraulic conductivity is one of the most important parameters for flow and transport related phenomena in soil and also a criterion for measuring soil ability to transfer water. There is concern arising from the suitability, efficiency and ease of the different measuring methods use under different land management practices. The purpose of this paper is to determine and evaluate soil hydraulic conductivity under different land management practices which include forest land (teak and Melina plantation), grassland and maize cultivated land using the constant head method. The measurement is at different depth of 0 - 15 cm, 15 - 25 cm, 25 - 50 cm, 50 - 75 cm. The limited means of each land use were used to compare the result obtained through statistical means. All tests were carried out using SPSS at a significance level of 0.05. An ANOVA test was conducted to check if each of the land use is significantly different. The soil in forest zone (Teak plantation and Gmalina plantation) had a significantly high bulk density as 1.7533 cm<sup><span style="font-family:Verdana;">-3</span></sup><span style="font-family:Verdana;"> and 1.6967 cm</span><sup><span style="font-family:Verdana;">-3</span></sup><span style="font-family:Verdana;"> respectively at depth 50 - 75 cm compared to the low bulk density in the grass, maize cultivated land as 1.5000 cm</span><sup><span style="font-family:Verdana;">-3</span></sup><span style="font-family:Verdana;"> and 1.4833 cm</span><sup><span style="font-family:Verdana;">-3</span></sup><span style="font-family:Verdana;"> respectively at depth 50 - 75 cm. However, soil hydraulic conductivity was significantly high in the grass site or soil at the surface with 2.8833 cm·h</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">. Results obtained from the different land use serve as Knowledge of variability of soil that can assist in defining the best strategies for sustainable soil management through the provision of vital information for estimating soil susceptibility to erosion, hydrological modelling and efficient planning of irrigation projects.</span>
文摘The study on soil thermal conductivity (STC) was an important side of research on ground source heat pump technique,geological disposal of high-level radioactive wastes,heat distribution of buried cable. Especially owing to technical requirement for shallow terrestrial heat recently, it directly influenced the design and solution in engineering problems. The authors measured the STC in the studied area with QTM-D2 and discussed the effect of samples in size, the measurement error between the samples in lab and in site. The results indicate measuring STC by heat pole method with less influence upon the samples in size, and measuring results on the different geometry size approach very much. The STC is fit for the empirical relation between the temperature and TC under the condition of normal temperature. It is significance for understanding STC in northern China and simulation of temperature field.
文摘Water transport at the root/soil interface of 1 year old Pinus sylvestris Linn. var. sylvestriformis (Takenouchi) Cheng et C. D. Chu seedlings under CO 2 doubling was studied by measuring soil electric conductance to survey soil water profiles and comparing it with root distribution surveyed by soil coring and root harvesting in Changbai Mountain in 1999. The results were: (1) The profiles of soil water content were adjusted by root activity. The water content of the soil layer with abundant roots was higher. (2) When CO 2 concentration was doubled, water transport was more active at the root/soil interface and the roots were distributed into deeper layer. It was shown in this work that the method of measuring electric conductance is an inexpensive, non_destructive and relatively sensitive way for underground water transport process.
基金the National Basic Research Program of China (973Program, 2006CB500401).
文摘Continuous observation data collected over the whole year of 2004 on a cropland surtace m Tongyu, a senti-arid area of northeastern China （44°25＇N, 122°52＇E）, have been used to investigate the variations of surface albedo and soil thermal parameters, including heat capacity, thermal conductivity and thermal diffusivity, and their relationships to soil moisture. The diurnal variation of surface albedo appears as a U shape curve on sunny days. Surface albedo decreases with the increase of solar elevation angle, and it tends to be a constant when solar elevation angle is larger than 40°. So the daily average surface albedo was computed using the data when solar elevation angle is larger than 40° Mean daily surface albedo is found to decrease with the increase of soil moisture, showing an exponential dependence on soil moisture. The variations of soil heat capacity are small during Julian days 90 300. Compared with the heat capacity, soil thermal conductivity has very gentle variations during this period, but the soil thermal diffusivity has wide variations during the same period. The soil thermal conductivity is found to increase as a power function of soil moisture. The soil thermal diffusivity increases firstly and then decreases with the increase of soil moisture.
基金supported bythe National Natural Science Foundation of China un-der Grants Nos40725015 and 40633017the Na-tional Basic Research Program of China under Grant No2006CB400501
文摘Data from July 2006 to June 2008 observed at SACOL （Semi-Arid Climate and Environment Observatory of Lanzhou University, 35.946°N, 104.137°E, elev. 1961 m）, a semi-arid site in Northwest China, are used to study seasonal variability of soil moisture, along with surface albedo and other soil thermal parameters, such as heat capacity, thermal conductivity and thermal diffusivity, and their relationships to soil moisture content. The results indicate that surface albedo decreases with increases in soil moisture content, showing a typical exponential relation between the surface albedo and the soil moisture. The heat capacity, the soil thermal diffusivity, and soil thermal conductivity show large variations between Julian day 90-212 and 450-578. The soil thermal conductivity is found to increase as a power function of soil moisture. Soil heat capacity and soil thermal diffusivity increase with increases in soil moisture. The SACOL observed soil moisture are also used to validate the AMSR-E/AQUA retrieved soil moisture and there is good agreement between them. The analysis of the relationship between satellite retrieved soil moisture and precipitation suggests that the variability of soil moisture depends on the variation of precipitation over the Loess Plateau.
基金supported by the National Natural Science Foundation of China (50979115)
文摘The dynamics of water and salt in soil were monitored in the 2010 and 2011 growing seasons of cotton to evaluate the salinity risk of soil under drip irrigation in arid environments for different management practices of drip system uniformity and irrigation amount. In the experiments, three Christiansen uniformity coefficients （CU） of approximately 65, 80, and 95% （referred to as low, medium, and high uniformity, respectively） and three irrigation amounts of 50, 75, and 100% of full irrigation were used. The distribution of the soil water content and bulk electrical conductivity （ECb） was monitored continuously with approximately equally spaced frequency domain reflectometry （FDR） sensors located along a dripline. Gravimetric samples of soil were collected regularly to determine the distribution of soil salinity. A great fluctuation in CU of water content and ECb at 60 cm depth was observed for the low uniformity treatment during the irrigation season, while a relatively stable variation pattern was observed for the high uniformity treatment. The ECb CU was substantially lower than the water content CU and its value was greatly related to the water content CU and the initial ECb CU. The spatial variation of seasonal mean soil water content and seasonal mean soil bulk electrical conductivity showed a high dependence on the variation pattern of emitter discharge rate along a dripline for the low and medium uniformity treatments. A greater irrigation amount produced a significantly lower soil salinity at the end of the irrigation season, while the influence of the system uniformity on the soil salinity was insignificant at a probability level of 0.1. In arid regions, the determination of the target drip irrigation system uniformity should consider the potential salinity risk of soil caused by nonuniform water application as the influence of the system uniformity on the distribution of the soil salinity was progressively strengthened during the growing season of crop.
基金supported by National Natural Science Foundation of China (Grant No.40874047)supported by National Natural Science Foundation of China (Grant No.40975009)supported by the National Key Basic Research Program (Grant No. 2012CB417203)
文摘Using the Simple Biosphere Model （SiB2）, soil thermal properties （STP） were examined in a Tibetan prairie during the monsoon period to investigate ground surface temperature prediction. We improved the SiB2 model by incorporating a revised force-restore method （FRM） to take the vertical heterogeneity of soil thermal diffusivity （k） into account. The results indicate that （1） the revised FRM alleviates daytime overestimation and nighttime underestimation in modeled ground surface temperature （Tg）, and （2） its role in little rainfall events is significant because the vertical gradient of k increases with increasing surface evaporation. Since the original formula of thermal conductivity （A） in the SiB2 greatly underestimates soil thermal conductivity, we compared five Mgorithms of A involving soil moisture to investigate the cause of overestimation during the day and underestimation at night on the basis of the revised FRM. The results show that （1） the five algorithms significantly improve Tg prediction, especially in daytime, and （2） taking one of these five algorithms as an example, the simulated Tg values in the daytime are closer to the field measurements than those in the nighttime. The differences between modeled Tg and field measurements are mostly within the margin of error of -4-2 K during 3 August to 4 September 1998.
基金supported by the Key Technology and Demonstration of Damaged Ecosystem Restoration and Reconstruction in Shanxi–Shaanxi–Inner Mongolia Energy Base Location (KZCX2-XB3-13-02)
文摘The infiltration of water into soil is one of the most important soil physical properties that affect soil erosion and the eco-environment, especially in the Pisha sandstone area on the Chinese Loess Plateau. We studied the one-dimensional vertical infiltration of water in three experimental soils, created by mixing Pisha sandstone with sandy soil, irrigation-silted soil, and loessial soil, at mass ratios of 1：1, 1：2, 1：3, 1：4, and 1：5. Our objective was to compare water infiltration in the experimental soils and to evaluate the effect of Pisha sandstone on water infiltration. We assessed the effect by measuring soil bulk density（BD）, porosity, cumulative infiltration, infiltration rate and saturated hydraulic conductivity（Ks）. The results showed that Pisha sandstone decreased the infiltration rate and saturated hydraulic conductivity in the three experimental soils. Cumulative infiltration over time was well described by the Philip equation. Sandy soil mixed with the Pisha sandstone at a ratio of 1：3 had the best water-holding capacity. The results provided experimental evidence for the movement of soil water and a technical support for the reconstruction and reclamation of mining soils in the Pisha sandstone area.
文摘Measurements of dielectric parameters followed by permeability tests are performed on soil samples of infiltration basin. The dielectric parameters are obtained by TDR （time domain reflectrometry） measurements from which it is found that the measurement of the permittivity, the electrical conductivity and the relaxation time of compacted soil allows the mapping of the values of the coefficient of permeability at the surface of an infiltration basin. With the distribution of the coefficient of permeability, the areas of water stagnation can be detected before the basin filling. The study proves that the TDR measurements for the detection of these zones can be used for the management of infiltration basins for sustainable working and their remediation can be undertaken before the rainy seasons.
基金This work was financially supported by the National Natural Science Foundation of China(51509068)the China Postdoctoral Science Foundation(2015M581716)the Fundamental Research Funds for the Central Universities(2018B00314).
文摘Developing water-saving irrigation regimes has important practical significance not only in alleviating the crucial water shortage,but also in controlling soil salinization for the protected cultivation in eastern China.A field study with six treatments was conducted to evaluate the effects of different irrigation regimes with subdrainage systems on the soil nitrate nitrogen,salinity and moisture,also evaluate the effects on tomato growth,fruit yield and irrigation water use efficiency(IWUE).The treatments were distinguished by three different irrigation amounts of 310 mm,360 mm and 410 mm,and two irrigation frequencies of 7 and 11 times.Results showed that the irrigation amount had significant effects on the soil NO_(3)^(-)-N and electric conductivity(EC).A positive correlation was detected between soil NO_(3)^(-)-N(x)and EC(y)at 0-20 m depth after harvest,with a linear equation of y=0.063x-0.670.Soil volumetric moisture at 0.10 m and 0.20 m depth was increased as the irrigation amount increased.Moreover,a higher amount of irrigation increased the fruit yield but reduced the IWUE of tomato.It was also found that smaller irrigation amounts combined with frequent intervals could increase fruit yield and IWUE.However,the fruit quality of tomato had a significant(p<0.05)negative correlation with irrigation amount.Therefore,the parameters of irrigation regime including the irrigation amount and intervals should be considered comprehensively in order to find a compromise between salinity control and irrigation water use efficiency improvement.
基金This study was supported by the Chinese National Key Research and Development Plan(2016YFD0700300-2016YFD0700304)the National Natural Science Foundation of China(31801265).
文摘A soil electrical conductivity(EC)measurement system based on direct digital synthesizer(DDS)and digital oscilloscope was developed.The system took the“current-voltage four-electrode method”as the design principal and adopted a six-pin structure of the probe,two center pins to measure the soil EC in shallow layer,two outside pins to measure the soil EC in deep layer,and two middle pins for inputting the driving current.A signal generating circuit using DDS technology was adopted to generate sine signals,which was connected with the two middle pins.A digital oscilloscope was used to record and store the two soil output signals with noises in microseconds,which were from the two center pins and two outside pins,respectively.Then a digital bandpass filter was used to filter the soil output signals recorded by the digital oscilloscope.Compared with the traditional analog filter circuit,the digital filter could filter out the noises of all frequency except for the frequency of the excitation source.It could improve the effect of filtering and the accuracy of the soil EC measurement system.The DDS circuit could provide more stable sine signals with larger amplitudes.The use of digital oscilloscope enables us to analyze the soil output signals in microseconds and measure the soil EC more accurately.The new soil EC measurement system based on DDS and digital oscilloscope can provide a new effective tool for soil sensing in precision agriculture.
文摘A utility equipment used in soil science is designed and installed.The equipment can be used in research pro- grams of soil water and solute transport.Pressure in pressure chamber of the equipment in which a tested soil sam- ple is laid can be adjusted exactly so that we can determine the water content of soil sample.With the equipment we can not only study the problems related water movement in soil but also measure some solute,such as cadmi- um,plumbum and so on,adsorption on surface of soil in saturated and unsaturated state.As an illustration of the use of the equipment,we give the isothermal of cupric ion adsorption in soil.This equipment can be used in the re- search work and application of soil science.
基金the National Natural Science Foundation of China(41630858)the National Key Research and Development Program of China(2017YFC0505404)the National Natural Science Foundation of China(41771304).
文摘Understanding the influence of collapsing gully management restoration on soil quality and function is essential to the protection of the regional ecological environment in the collapsing gully erosion area.The primary objective of this study was to construct soil quality index(SQI)to assess the influence of different vegetation restoration types on soil quality in collapsing gully restoration.The influence of five vegetation restoration types on soil properties was investigated by using a path analysis,a comprehensive soil quality index(SQI),and a general linear model(GLM).Vegetation restoration was shown to significantly increase the saturated hydraulic conductivity(Ks),mainly due to the effect of the physical parameters of bulk density,soil cohesion,and soil water content.Meanwhile,pH,Ks,soil organic matter(OM),and sand content were revealed as reasonable indicators to evaluate the influence of vegetation restoration on soil quality.Moreover,vegetation restoration was found to significantly improve the soil quality,with the highest SQI value for natural restoration mixed forest(NF),followed by replanted arboreal forest(RA)and replanted scrubland(RS),which were all significantly higher than the SQI value of the erosion area(EA)in the collapsing gully.Additionally,vegetation type explained the most substantial proportion of total variability(46.41%),and restoration time showed a positive correlation with SQI.The results of this study can provide a reference for the restoration and protection of the regional ecological environment in the collapsing gully area.
基金supported by an INRA SSGP Doctoral Fellowship from the Inland North-west Research Alliance (INRA)by the Utah Agricultural Experiment Station, Utah State University, Logan, Utah, approved as journal paper 8952
文摘Knowledge of the spatial distribution of soil textural properties is important for determining soil moisture storage and soil hydraulic transport properties.Capturing field heterogeneity without exhaustive sampling and costly sample analysis is difficult. Our objective was to employ electromagnetic induction(EMI) mapping in low apparent electrical conductivity(EC_a) soils at varying soil water contents to capture time invariant properties such as soil texture. Georeferenced EC_ameasurements were taken using a ground conductivity meter on six different days where volumetric water content(θ_v) varied from 0.11 to 0.23. The 50 m × 50 m field included a subsurface gravelly patch in an otherwise homogeneous silt-loam alluvial soil.Ordinary block kriging predicted EC_aat unsampled areas to produce 1-m resolution maps. Temporal stability analysis was used to divide the field into three distinct EC_a regions. Subsequent ground-truthing confirmed the lowest conductivity region correlated with coarse textured soil parent materials associated with a former high-energy alluvial depositional area. Combining maps using temporal stability analysis gives the clearest image of the textural difference. These maps could be informative for modeling,experimental design, sensor placement and targeted zone management strategies in soil science, ecology, hydrology,and agricultural applications.
文摘Borehole thermal energy storage(BTES)systems have garnered significant attention owing to their efficacy in storing thermal energy for heating and cooling applications.Accurate modeling is paramount for ensuring the precise design and operation of BTES systems.This study conducts a sensitivity analysis of BTES modeling by employing a comparative investigation of five distinct parameters on a wedge-shaped model,with implications extendable to a cylindrical configuration.The parameters examined included two design factors(well spacing and grout thermal conductivity),two operational variables(charging and discharging rates),and one geological attribute(soil thermal conductivity).Finite element simulations were carried out for the sensitivity analysis to evaluate the round-trip efficiency,both on a per-cycle basis and cumulatively over three years of operation,serving as performance metrics.The results showed varying degrees of sensitivity across different models to changes in these parameters.In particular,the round-trip efficiency exhibited a greater sensitivity to changes in spacing and volumetric flow rate.Furthermore,this study underscores the importance of considering the impact of the soil and grout-material thermal conductivities on the BTES-system performance over time.An optimized scenario is modelled and compared with the base case,over a comparative assessment based on a 10-year simulation.The analysis revealed that,at the end of the 10-year period,the optimized BTES model achieved a cycle efficiency of 83.4%.This sensitivity analysis provides valuable insights into the merits and constraints of diverse BTES modeling methodologies,aiding in the selection of appropriate modeling tools for BTES system design and operation.
文摘This paper demonstrates that we should use two different hierarchic composition methods for the two different types of levels in the AHP. The first method is using the weighted geometric mean to synthesize the judgments of alternative-type-level elements, which is the only hierarchic composition method for the alternative-type level in an AHP hierarchy, and the rank is preserved automatically. The second one is using the weighted arithmetic mean to synthesize the priorities of the criteria-type-level elements, which is the only hierarchic composition method for all the criteria-type levels, and rank reversals are allowed.
基金funded by the Italian minister of education and research in the framework of the project PON"Modelli Sostenibili e Nuove tecnologie per la Valorizzazione delle Olive e dell'Olio Extravergine di Oliva Prodotto in Calabria".Grant ID.:PON03 PE 00090_2。
文摘No-tillage and soil mulching with pruning residues,applied in olive groves of the semi-arid Mediter-ranean environment,as erosion control practices still practice not fully studied.This study has evaluated the saturated hydraulic conductivity(Ksat),surface runoff(SR)and soil erosion(SL)under rainfall at plot scale throughout two years in four different management practices,total soil cover with a net(SP),mechanical tillage(MT)and mulching by vegetal residues at 3,5·10^(3) and 17,5·10^(3) kg ha^(-1) of dry matter(NTR350 and NTR1750),in an olive grove of Southern Italy.Ksat varied between 1.6(MT)and 25.1(NTR1750)mm/h.A clear reduction in runoff and soil losses was detected for the mulch-based practices when compared to MT,from 20 to 32%in the runoff coefficient and 75-80%in SL,with higher reductions in the NTR1750.This reduction in SL can be mainly explained by the reduction in SR and rain-splash,interrill and rill erosion,due to protection by mulch residues,which increased the vegetal cover and organic matter content of mulched plots.The vegetal cover was on average higher in SP(33%),NTR1750(25%)and NTR350(22%),and lower in MT(12%).The mean organic matter content of soil was 2.01%,1.69%,1.34%and 0.82%for NTR1750,NTR350,SP and MT respectively.Overall,the results quantify the impact of soil mulching with pruning residues at different doses,which will provide guidelines to control and mitigate the hydrological response of clayey and steep soils in Mediterranean olive groves,analysing the associated environmental and economic benefits.
基金This work was financially supported by the Applied Basic Research General Project of Yunnan Science and Technology Department(Grant No.2019FB075).[References][1]Siddiqui M N,Mostofa M G,Akter M M,Srivastava A K,Sayed M A,。
文摘The objective of this study was to explore the effects of different degrees of water and salt stress on the actual water consumption and soil salt accumulation of tomatoes and the salt tolerance characteristics of tomatoes under brackish water combined with regulated deficit irrigation mode.The greenhouse pot experiment was used to set three influencing factors,the irrigation water salinity S1 was 1.1 g/L(local shallow groundwater),S2 was 2.0 g/L,and S3 was 4.0 g/L,respectively,and different degrees of water deficit(W1 ranged from 65%-75%Field Capacity(FC),W2 ranged from 55%-65%FC,W3 ranged from 45%-55%FC)and seedling stage(T1),blossoming and bearing fruits stage(T2)and mature picking stage(T3).The response of fresh fruit weight,stems and leaves weight,yield and water use efficiency of tomato under water and salt stress were monitored and analyzed.The results showed the coordinated regulation of water and salt can significantly reduce the electrical conductivity of the 0-30 cm soil of the tomato root system.The higher the salinity of irrigation water,the better the salt control effects of the coordinated regulation of water and salt;the coordinated regulation of water and salt at different growth stages had significant effects on the weight of fresh tomato fruits,the weight of stems and leaves and the yield.The salinity of irrigation water was in inverse proportion to the yield of tomatoes;In S1 treatment irrigation(irrigation water salinity was 1.1 g/L)under the mildly regulated deficit in the seedling stage(irrigation water was 55%-65%of the field water capacity)can effectively reduce the irrigation water volume during the whole growth stage while ensuring that there was no significant reduction in yield.The research results provided a scientific and reliable theoretical basis for the increase of local tomato production,the improvement of water use efficiency and the formulation of suitable irrigation patterns.
