Abstract:
Objective Effects of practices of tillage and green manure utilization on fertility and enzyme activity of soil and yield of sugarcane crop under a continuous cultivation were evaluated.
Method On a sugarcane field, the traditional rotary tillage (TCK), Fenlong tillage (FLCK), Fenlong tillage with sugarcane and soybean discards returned to sugarcane roots (FLG), and soybean discards returned to wide rows (FLK) were applied with a random block design. Contents of organic matter and available nutrients and activities of urease, saccharase, acid phosphatase, and catalase as well as yield and quality of sugarcane crop under treatments were compared.
Result (1) The treatments induced significantly varied effects on the fertility and enzyme activity of the soil. The 40.6% to 76.7% organic matter contents in the soil around the roots and wide rows were significantly higher than that of TCK (P<0.05). FLG, FLK, and FLCK significantly raised the available N and P in the soil around the roots with an increase of 16.1%–41.8%. (2) The activities of urease (except under FLG), sucrase, acid phosphatase, and catalase in the soil under FLG, FLK, and FLCK were 0.7-166.7% higher than those under TCK. (3) The 2-year average sugarcane yields under FLG, FLK, and FLCK were 13.1%–30.5% higher than under TCK. Those of FLG and FLK were significantly higher than that of FLCK by 9.9%–15.3% with FLG showing the highest average of 86 043 kg·hm−2. The sucrose content, brix, gravity purity, apparent purity, and pol of sugarcane grown under FLG, FLK, and FLCK were higher than those under TCK. (4) The sugarcane yield significantly correlated with soil urease activity, and extremely significantly correlated with soil sucrase, acid phosphatase, catalase activity, organic matter, available N, and available P.
Conclusion Fenlong tillage with green manure returned to the land significantly improved the nutrient contents and enzyme activities in the soil as well as the sugarcane yield and quality on a continuous cropping field. Ease for field operation, Fenlong tillage using green manure on wide rows was recommended for local farming.