Response of soil structure and crop yield to soft rock in Mu Us sandy land, China

The sandy land leaks water and fertilizer, and is seriously degraded, while the soft rock has a special depression structure, which plays a role in retaining water and fertilizer. The application of soft rock new material to sand reclamation can improve the ecological environment and ensure the quality of basic cultivated land. The soft rock and sand were mixed in different volume ratios (1:0, 11:1, 5:1, 4:1, 3:1, 2:1, 7:5, 1:1, 5:7, 1:2, 1:3, 1:4, 1:5, 1:11, 0:1) to prepare the composite soil, and its Raman spectrum characteristics, microstructure, texture composition and potato yield were studied. The results show that there are more silt and clay particles in the soft rock and more coarse particles in the sand. The peak position of the sand is 464.5 cm−1. With the increase of the content of the soft rock, the peak position decreases gradually. When the content of the soft rock accounts for more than 50%, the soil structure collapses and also becomes compact, at the same time the compressive stress is generated between the soil particles. When the ratio of soft rock to sand is 1:1, the soil texture is loam. The potato yield of the soil with the ratio of 1:5 of soft rock and sand cover increases significantly by 4.89–37.31% and 4.08–35.95% compared with that of 1:1 and 1:2 compound soils. Under the condition of 1:1 and 1:2 compounded ratio of soft rock and sand, there are more cementitious materials between the soil particles generated. The compounded ratio 1:5 is most suitable ratio for potato growth of local economic crop. The results confirmed that the Raman spectroscopy characteristics of SiO2 molecules can be used to study the cementation force between composite soil particles. When the compound ratio is 1:5, the soil improvement of Mu Us sandy land and the high yield of potatoes can be achieved, which could also provides a theoretical basis for sandy land remediation.