Long term effects of crop rotation and fertilization on crop yield stability in southeast China

The objective of this study was to determine the effects of different fertilizer treatments and crop rotations on crop yield stability. A 9 years field experiment was conducted from 2013 to 2021 to evaluate the effects of combinations of two annual crop rotations and two methods of applying fertilizer on crop yield stability. Crop rotations were kidney bean-mustard-rice (P-B-O) and kidney bean-mustard-cowpea (P-B-V) each year. Fertilization methods were recommended fertilization (RF) and conventional fertilization (CF). The indexes Wi² (Wricke's ecovalance), coefficient of variation (CV), and sustainable yield index (SYI) were used to quantify the long term effects of crop rotation and fertilization on crop yield stability, and a yield change trend model was used to predict future production. For fertilization program RF, average kidney bean and mustard yields in rotation P-B-O increased respectively by 7.47% and 19.37% over P-B-V in the 9 years of the project. For CF, average kidney bean and mustard yields for P-B-O increased respectively by 14.99% and 18.33% over P-B-V. Wi² indexes of kidney bean and mustard for P-B-O (respectively 116 and 956) were significantly less than for P-B-V (respectively 147.87 and 1259.67). SYI for kidney beans and mustard in P-B-O (respectively 0.63 and 0.57) were significantly greater than for P-B-V (respectively 0.50 and 0.42). The trends of crop average yields for RF and CF show that the average yield trends of kidney bean in P-B-O (respectively 32.41 and 32.34) were greater than in P-B-V (respectively 29.56 and 27.45). The trends of average yields of mustard for RF and CF in P-B-O (respectively 64.18 and 60.87) were greater than in P-B-V (respectively 51.74 and 51.87). The preceding results led to the conclusion that long term annual P-B-O rotation combined with RF considerably increased yield and maintained yield stability, thus establishing the sustainability of this cropping system.