| The arid and semi-arid regions of northwestern China have large land areas and sufficient sunlight,and are the main reserves for grain production.However,this area is mostly coarsetextured soil,with high content of sand and low content of clay and silt,lack of organic matter and difficult to accumulate,and scarcity of water resources.In order to improve soil and rapidly increase land productivity,this study selected the Shanxi-Shaanxi-Mongolian border area in this area,and studied the effects of different exogenous organic matter and clay mineral additions on soil physicochemical properties and crop growth through indoor pot experiments and field in-situ experiments.The following research conclusions were obtained:1 Adding exogenous organic matter and clay minerals was an effective measure to improve the physical properties of coarse sandy loess soil and enhance soil fertility.Compared with the control,under different crops in this study,the soil electricity conductivity of woody peat and lignite material with single application of exogenous organic matter increased by 33.8%and 24.2%,respectively,and the soil bulk density decreased by 4.6% and 2.5%,respectively,the content of organic(carbon)matter was significantly increased by 117.3% and 138.9%,respectively,the soil total nitrogen was increased by 9.0% and 5.2%,and the soil p H was decreased by 0.11 and 0.09 units,respectively.In addition,soil porosity,clay silt content and total phosphorus content also increased to a certain extent.Relatively speaking,single application of woody peat can improve soil structure and physicochemical properties better than lignite.The single application of the clay mineral bentonite also had a certain improvement effect on soil structure and physical and chemical properties,but the differences in each index did not reach a significant level.2 Adding exogenous organic matter and clay minerals was an effective way to promote the growth and yield of coarse sandy loess crops.This study investigated the effects of adding different exogenous organic matter and clay minerals on crop growth and yield by planting three crops of indoor potted spinach and field pepper,spinach and corn.The results showed that single application of exogenous organic matter woody peat and lignite material can significantly promote crop growth and yield.The yields of potted spinach and field pepper increased by 65.9% and 53.0%,respectively,under the single application of lignite,while the yields of single application of woody peat increased by 18.6% and 31.0%,respectively.In addition,single application of clay mineral bentonite also had a certain degree of promotion effect on crop growth and yield,but the difference did not reach a significant level.While,exogenous organic matter combined with clay mineral treatment has the most significant effect on promoting crop growth and yield improvement.From the perspective of long-term benefits,woody peat combined with bentonite treatment has the best effect.Compared with the control,the average yield of different crops in the field increased significantly by 53.4%.3 Supplementing clay minerals on the basis of adding exogenous organic matter has a certain protective effect on soil organic(carbon)matter,and was an effective measure for rapid improvement and maintenance of soil fertility in coarse sandy loess.The results of this study showed that compared with single application of woody peat,woody peat combined with bentonite treatment increased soil organic(carbon)matter by 4.4%-29.8% under different crops.Compared with the single application of lignite,the soil organic(carbon)content of lignite and bentonite increased in the range of-0.3% to 13.7 under different crops.With the increased of planting years,the soil organic matter content of each treatment showed a downward trend as a whole.From the perspective of long-term benefits,woody peat combined with bentonite treatment was the best fertilization scheme for rapid improvement and fertility maintenance of sandy loess in the interlaced area of wind and water erosion. |
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