Pai, an arid forest in Sindh Province of Pakistan, is important for the environmental, social, economic development and conservation of ecosystems of the province. Considering the significance of the forest for Sindh ...Pai, an arid forest in Sindh Province of Pakistan, is important for the environmental, social, economic development and conservation of ecosystems of the province. Considering the significance of the forest for Sindh and the calls from the local population for its deforestation, we quantified the spatial and temporal variation in the vegetation of the forest and land surface temperature （LST） using optical and thermal Landsat satellite data. Our analysis of temporal （1987-2014） images with ArcGIS 10.1 revealed that the dense forest area was greatest at 725 ha （37 % of the total forest area） during 2013 while it was smallest at 217 ha （11%） in 1992. The sparse forest area peaked during 1987 at 1115 ha （58 %） under shrubs whereas it was smallest at 840 ha （43 %） in 1992, and the maximum deforestation of Pai forest occurred during 1992. Spatial change in vegetation over a period of about 27 years （1987-2014） revealed that vegetation increased on an area of 735 ha （37 %）, decreased on 427 ha （22 %）, and there was no change on 808 ha （41%） of the forest. Variation in temperature between shaded （dense forest） and unshaded areas （bare land） of the forest was from 6 to 10 ℃. While the temperature difference between areas with sparse forest and bare land ranged from 4 to 6℃. An inverse relationship between LST and NDVI of Pai forest with coefficients of determination of 0.944 and 0.917 was observed when NDVI was plotted against minimum and maximum LST, respectively. The vegetation in the forest increased with time and the areas of more dense Pai forest supported lower surface temperature and thus air temperature.展开更多
The increasing demand of water in the country highlights the need to introduce low-input and water saving technologies for agricultural sustainability and crop production,mainly in semi-arid region.A study was conduct...The increasing demand of water in the country highlights the need to introduce low-input and water saving technologies for agricultural sustainability and crop production,mainly in semi-arid region.A study was conducted to minimize deep percolation losses from the furrow bottom under two different irrigation treatments viz.(1)furrow bottom with plastic sheet(T1)and(2)furrow bottom without plastic Sheet(T0).The physical and chemical analyses of soil profile were taken at a depth of 0-80 cm before and after crop harvesting.The dry density of soil slightly increased(0.01 g/cm^(3))under both treatments,while soil pH decreased under T1.The average yield was 8332 kg/hm^(2) and 7575 kg/hm^(2),with 21.56 m^(3) and 31.09 m^(3) total volume of irrigation water applied under T1and T0,respectively.The saving percentages of water under treatments were 52.22% and 31.00% under T1 and T0 respectively as compared to the saving of water under traditional irrigation practice.Overall,better performance,in terms of crop production and water saving,was obtained with use of plastic sheet integrated with bottom of furrows.Hence,it is suggested that the furrow irrigation method with plastic sheet may be used to preventing moisture and minimize deep percolation losses from furrow bottom.展开更多
文摘Pai, an arid forest in Sindh Province of Pakistan, is important for the environmental, social, economic development and conservation of ecosystems of the province. Considering the significance of the forest for Sindh and the calls from the local population for its deforestation, we quantified the spatial and temporal variation in the vegetation of the forest and land surface temperature （LST） using optical and thermal Landsat satellite data. Our analysis of temporal （1987-2014） images with ArcGIS 10.1 revealed that the dense forest area was greatest at 725 ha （37 % of the total forest area） during 2013 while it was smallest at 217 ha （11%） in 1992. The sparse forest area peaked during 1987 at 1115 ha （58 %） under shrubs whereas it was smallest at 840 ha （43 %） in 1992, and the maximum deforestation of Pai forest occurred during 1992. Spatial change in vegetation over a period of about 27 years （1987-2014） revealed that vegetation increased on an area of 735 ha （37 %）, decreased on 427 ha （22 %）, and there was no change on 808 ha （41%） of the forest. Variation in temperature between shaded （dense forest） and unshaded areas （bare land） of the forest was from 6 to 10 ℃. While the temperature difference between areas with sparse forest and bare land ranged from 4 to 6℃. An inverse relationship between LST and NDVI of Pai forest with coefficients of determination of 0.944 and 0.917 was observed when NDVI was plotted against minimum and maximum LST, respectively. The vegetation in the forest increased with time and the areas of more dense Pai forest supported lower surface temperature and thus air temperature.
基金Authors wish to thank the National Natural Science Foundation of China(Grant No.51275250)for supporting.
文摘The increasing demand of water in the country highlights the need to introduce low-input and water saving technologies for agricultural sustainability and crop production,mainly in semi-arid region.A study was conducted to minimize deep percolation losses from the furrow bottom under two different irrigation treatments viz.(1)furrow bottom with plastic sheet(T1)and(2)furrow bottom without plastic Sheet(T0).The physical and chemical analyses of soil profile were taken at a depth of 0-80 cm before and after crop harvesting.The dry density of soil slightly increased(0.01 g/cm^(3))under both treatments,while soil pH decreased under T1.The average yield was 8332 kg/hm^(2) and 7575 kg/hm^(2),with 21.56 m^(3) and 31.09 m^(3) total volume of irrigation water applied under T1and T0,respectively.The saving percentages of water under treatments were 52.22% and 31.00% under T1 and T0 respectively as compared to the saving of water under traditional irrigation practice.Overall,better performance,in terms of crop production and water saving,was obtained with use of plastic sheet integrated with bottom of furrows.Hence,it is suggested that the furrow irrigation method with plastic sheet may be used to preventing moisture and minimize deep percolation losses from furrow bottom.
