Objective Effects of various types of crop rotation and fertilization on the yield and nutrient absorption of the vegetables and rice grown on the land were studied.
Method Seasonal yields of the vegetables/rice were obtained from same assigned test lots for 6 consecutive years to determine the variation coefficient and yield stability of the vegetable-vegetable-rice (V-V-R) and vegetable-vegetable-vegetable (V-V-V) rotations on soil applied with either the recommended fertilization (RF) or conventional fertilization (CF). Efficiencies on nitrogen (N), phosphorus (P), and potassium (K) utilization by the vegetables/rice under the treatments were analyzed based on the nutrient contents in the leaves, stems, or grains of the plants.
Result In V-V-R, the yields on the sequential plantings of kidney beans, mustard, and rice increased under RF by 9.07%, 7.77%, and 8.43%, respectively, over CF. Whereas in V-V-V the yield increases or reduction on kidney beans, mustard, and cowpeas were 7.24%, −0.88%, and 7.54%, respectively. On the other hand, the varied crop rotations and fertilizations appeared to mainly affect the nutrient utilization of kidney beans and cowpeas. The N, P, and K uptakes of the kidney beans were 13.50%, 10.43%, and 12.16%, respectively, higher with RF than CF in V-V-R; and that of the cowpea on K at 12.84% was the only significant difference found between RF and CF under V-V-V. The annual nutrient accumulation by the crops was significantly higher under RF than CF under V-V-R but not under V-V-V.
Conclusion Planting vegetables and/or rice in the sequence of V-V-R combined with RF application could result in high and stable annual yields of all crops involved. Consequently, besides the significant improvements on NPK absorption, utilization, and accumulation of the crops, V-V-R rotation with RF was recommended for the farming where applicable.
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