Over the past five decades, increased pressure caused by the rapidly growing population has resulted in a reclamation of agricultural and urban buffer zones along China's coastline. However, information about the ...Over the past five decades, increased pressure caused by the rapidly growing population has resulted in a reclamation of agricultural and urban buffer zones along China's coastline. However, information about the spatio–temporal variation of soil salinity in these reclaimed regions is limited. As such, obtaining this information is crucial for mapping the variation in saline areas and to identify suitable salinity management strategies. In this study, we employed EM38 data to conduct digital soil mapping of spatio–temporal variation and map these variations of different site-specific zones. The results indicated that the distribution of soil salinity was heterogeneous in the middle of, and that the leaching of salts was significant at the edges of, the study field. Afterwards, fuzzy-k means algorithm was used to divide the site-specific management zones within the time series apparent soil electrical conductivity(ECa) data and the spatial correlations of variation. We concluded that two management zones are optimal to guide precision management. Zone A had an average salinity level of about 165 mS m–1, in which salt-tolerant crops, such as cotton and barley can grow normally, while crops such as soybean and cowpeas may be planted using leaching and increasing the mulching film methods to reduce the accumulation of salt in surface soil. In Zone B, there was a low salinity level with a mean of 89 mS m–1 for ECa, which allows for rice, wheat, and a wide range of vegetables to be grown normally. In such situations, measures such as an optimized combination of irrigation and drainage, as well as soil amendment can be taken to adjust and control the salt content. Particularly, flattening the land with a large-scale machine was used to improve the ability of micro-topography to influence salt migration; rice and other dry, land crops were planted in rotation in combination with utilizing salt-leaching multiple times to speed up desalinization.展开更多
Soil salinization is a major problem affecting soils and threatening agricultural sustainability in arid and semi-arid regions,which makes it necessary to establish an efficient strategy to manage soil salinity and co...Soil salinization is a major problem affecting soils and threatening agricultural sustainability in arid and semi-arid regions,which makes it necessary to establish an efficient strategy to manage soil salinity and confront economic challenges that arise from it.Saline soil recovery involving drainage of shallow saline groundwater and the removal of soil salts by natural rainfall or by irrigation are good strategies for the reclamation of salty soil.To develop suitable management strategies for salty soil reclamation,it is essential to improve soil salinity assessment pro cess/mechanism and to adopt new approaches and techniques.T his study mapped a recovered area of 7200 m2 to assess and verify variations in soil salinity in space and time in K airouan region in Central Tunisia,taking into account the thickness of soil materials.Two electromagnetic conductivity meters(EM38 and EM31)were used to measure the electrical conductivity of saturated soil-paste extract(ECe)and apparent electrical conductivity(E Ca).Multiple linear regression was established between ECe and ECa,and it was revealed that ECa-EM38 is optimal for E Ce prediction in the surface soils.Salinity maps demonstrated that the spatial structure of soil salinity in the region of interest was relatively unchanged but varied temporally.Variation in salinity at the soil surface was greater than that at a depth.These findings can not only be used to track soil salinity variations and their significance in the field but also help to identify the spatial and temporal features of soil salinity,thus improving the efficiency of soil management.展开更多
根据土壤盐渍化空间异质性对南疆干旱区绿洲农田进行精准管理分区,对农业种植结构调整和精细化管理具有重要意义。以典型干旱区绿洲农田为研究对象,以电磁感应数据、地形数据和卫星遥感数据为数据源,通过地统计学方法分析研究区土壤盐...根据土壤盐渍化空间异质性对南疆干旱区绿洲农田进行精准管理分区,对农业种植结构调整和精细化管理具有重要意义。以典型干旱区绿洲农田为研究对象,以电磁感应数据、地形数据和卫星遥感数据为数据源,通过地统计学方法分析研究区土壤盐渍化的空间异质性,利用相关分析筛选出不同时期的植被指数和盐分指数。以农田表层表观电导率(EC_(h0.375))为主变量,深层表观电导率(EC_(h0.75)、EC_(v0.75)、EC_(v1.5))、植被指数(RVI、GRVI、EVI)、土壤盐分指数(NDSI、S5、SI-T)为辅助变量,采用面向对象多尺度分割算法对研究区进行分区,并用分区内平均变异系数(C_(V),Coefficient of Variation)和莫兰指数(Moran’s I)对分区结果进行评价。结果表明:(1)研究区各土层表观电导率都存在明显空间异质性,且各辅助变量与主变量均存在极显著相关。(2)各分区的平均变异系数较整个研究区的变异系数下降了60%,且基于多源数据分区的区间异质性均高于单一数据分区的区间异质性。(3)从农田耕作角度、分割效果及分区评价原则出发,综合利用表层和深层土壤盐渍化信息的管理分区效果最佳,该分区结果既符合当地农田管理又符合机械化作业要求。研究结果可为南疆干旱区绿洲农田的精准管理分区提供一定的技术和方法借鉴。展开更多
基金funded by the National Natural Science Foundation of China (41601213)the National Key Research and Development Program of China (2017YFD0700501)the Major Science and Technology Projects of Henan, China (171100110600)
文摘Over the past five decades, increased pressure caused by the rapidly growing population has resulted in a reclamation of agricultural and urban buffer zones along China's coastline. However, information about the spatio–temporal variation of soil salinity in these reclaimed regions is limited. As such, obtaining this information is crucial for mapping the variation in saline areas and to identify suitable salinity management strategies. In this study, we employed EM38 data to conduct digital soil mapping of spatio–temporal variation and map these variations of different site-specific zones. The results indicated that the distribution of soil salinity was heterogeneous in the middle of, and that the leaching of salts was significant at the edges of, the study field. Afterwards, fuzzy-k means algorithm was used to divide the site-specific management zones within the time series apparent soil electrical conductivity(ECa) data and the spatial correlations of variation. We concluded that two management zones are optimal to guide precision management. Zone A had an average salinity level of about 165 mS m–1, in which salt-tolerant crops, such as cotton and barley can grow normally, while crops such as soybean and cowpeas may be planted using leaching and increasing the mulching film methods to reduce the accumulation of salt in surface soil. In Zone B, there was a low salinity level with a mean of 89 mS m–1 for ECa, which allows for rice, wheat, and a wide range of vegetables to be grown normally. In such situations, measures such as an optimized combination of irrigation and drainage, as well as soil amendment can be taken to adjust and control the salt content. Particularly, flattening the land with a large-scale machine was used to improve the ability of micro-topography to influence salt migration; rice and other dry, land crops were planted in rotation in combination with utilizing salt-leaching multiple times to speed up desalinization.
文摘Soil salinization is a major problem affecting soils and threatening agricultural sustainability in arid and semi-arid regions,which makes it necessary to establish an efficient strategy to manage soil salinity and confront economic challenges that arise from it.Saline soil recovery involving drainage of shallow saline groundwater and the removal of soil salts by natural rainfall or by irrigation are good strategies for the reclamation of salty soil.To develop suitable management strategies for salty soil reclamation,it is essential to improve soil salinity assessment pro cess/mechanism and to adopt new approaches and techniques.T his study mapped a recovered area of 7200 m2 to assess and verify variations in soil salinity in space and time in K airouan region in Central Tunisia,taking into account the thickness of soil materials.Two electromagnetic conductivity meters(EM38 and EM31)were used to measure the electrical conductivity of saturated soil-paste extract(ECe)and apparent electrical conductivity(E Ca).Multiple linear regression was established between ECe and ECa,and it was revealed that ECa-EM38 is optimal for E Ce prediction in the surface soils.Salinity maps demonstrated that the spatial structure of soil salinity in the region of interest was relatively unchanged but varied temporally.Variation in salinity at the soil surface was greater than that at a depth.These findings can not only be used to track soil salinity variations and their significance in the field but also help to identify the spatial and temporal features of soil salinity,thus improving the efficiency of soil management.
文摘根据土壤盐渍化空间异质性对南疆干旱区绿洲农田进行精准管理分区,对农业种植结构调整和精细化管理具有重要意义。以典型干旱区绿洲农田为研究对象,以电磁感应数据、地形数据和卫星遥感数据为数据源,通过地统计学方法分析研究区土壤盐渍化的空间异质性,利用相关分析筛选出不同时期的植被指数和盐分指数。以农田表层表观电导率(EC_(h0.375))为主变量,深层表观电导率(EC_(h0.75)、EC_(v0.75)、EC_(v1.5))、植被指数(RVI、GRVI、EVI)、土壤盐分指数(NDSI、S5、SI-T)为辅助变量,采用面向对象多尺度分割算法对研究区进行分区,并用分区内平均变异系数(C_(V),Coefficient of Variation)和莫兰指数(Moran’s I)对分区结果进行评价。结果表明:(1)研究区各土层表观电导率都存在明显空间异质性,且各辅助变量与主变量均存在极显著相关。(2)各分区的平均变异系数较整个研究区的变异系数下降了60%,且基于多源数据分区的区间异质性均高于单一数据分区的区间异质性。(3)从农田耕作角度、分割效果及分区评价原则出发,综合利用表层和深层土壤盐渍化信息的管理分区效果最佳,该分区结果既符合当地农田管理又符合机械化作业要求。研究结果可为南疆干旱区绿洲农田的精准管理分区提供一定的技术和方法借鉴。
