Abstract:
objective The aims were to investigate the effects of long-term rotation and fertilization on rice yield, plant nutrient uptake and utilization, and soil nutrient content, so as to provide reference for rational rotation selection in yellow soil area.
Methods Based on the 25-year yellow soil (paddy field) long-term located experiments, four crop rotation patterns were selected: rice monoculture (RM), rice-wheat rotation (RWR), rice-canola rotation (RRR), and rice-green manure rotation (RMR). The differences in crop yield, plant nitrogen (N), phosphorus (P) and potassium (K) nutrient uptake and soil nutrients were compared among different crop rotation patterns.
Result The average rice yield of different rotations from 2016 to 2020 was RWR > RRR > RM > RMR, but there was no significant difference among treatments. Compared to RM processing, RWR, RRR and RMR treatments increased the average N, P and K contents of rice straw and grain by 10.9%-37.0%, 63.6%-101.6%, 11.9%-17.6% and 7.1%-20.4%, 19.7%-37.6%, 6.0%-8.1%, respectively. The average N, P and K uptake of straw and grain were increased by 15.0%-45.4%, 69.7%-113.9%, 16.1%-24.8% and 3.7%-22.6%, 15.9%-40%, 2.6%-10.1%, respectively. The total uptake amounts of N, P and K were increased by 8.0%-30.2%, 22.3%-44.8% and 12.9%-21.3%, respectively. The N, P and K nutrient content, absorption amount and absorption efficiencies of rice straw and grain in each rotation treatment showed the following order: RWR > RRR > RMR. Compared with RM treatment, soil organic matter was increased by 37.0%-41.1%, total N by 1.7%-28.6%, alkali-hydrolyzed N by 24.4%-47.5%, and available P by 2.2%-54.8%.
Conclusion Under the current cropping system and fertilization conditions, various cropping rotations could maintain rice yield without decreasing, increase land productivity per unit area, increase N, P and K uptake of rice plants, and improve soil fertility.