Abstract:

To fully understand the effect of different amendments on the physical properties of newly cultivated land, a greenhouse culture experiment was carried out on three kinds of newly cultivated land soil with different texture. The effects of 14 amendments, including polyacrylamide, β-cyclodextrin, potassium fulvic acid, bentonite, kaolin, vermiculite, zeolite, diatomite, limestone powder, commercial organic fertilizer, rice straw, Chinese milk vetch, and biochar and peat, on soil structure, water retention and water permeability of the three kinds of soil were compared. The results showed that most of the amendments could improve the soil water stability aggregates, bulk density, saturated water holding capacity, wilting water content, saturated water conductivity and effective water range. And the effect of applying polyacrylamide, β-cyclodextrin, potassium fulvic acid on the physical properties was the most obvious, while the application of peat and commercial organic fertilizer also had a better effect on the physical properties of the soil. Compared with the control, the water stability aggregates of the soil with the application of polyacrylamide, β-cyclodextrin, potassium fulvic acid increased by 42.88%-299.38%, 41.15%-239.69% and 55.39%-207.70%, respectively. The application of peat and commercial organic fertilizer had better improving effects on the soil of newly reclaimed land in low hilly region, the water stability aggregates increased by 31.90%-119.69% and 35.19%-71.05%, respectively. Bentonite, Chinese milk vetch and rice straw could obviously improve the water stability aggregates of sandy soil and loamy soil. The application of kaolin and vermiculite could obviously improve the water stability aggregates of sandy soil, but they had little effect on the water stability aggregates of clay and loamy soil. Biochar had little effect on the content of water stable aggregates, but it could increase the saturated water holding capacity, saturated hydraulic conductivity and effective water range, and reduce the wilting water content. In general, the organic amendments, such as polyacrylamide, β-cyclodextrin, potassium fulvic acid, peat and commercial organic fertilizer, can effectively improve the overall physical properties of the soil, and are more suitable for being applied to the newly reclaimed land in low hilly regions.

Key words: amendment, cultivated land, physical properties, improvement effect, organic carbon, soil structure