Better nutrient management strategy for rice-wheat, rice-rapeseed and rice-rice cropping systems

In 2016, supported by the government and IPNI China program, project cooperators in Wuhan Botanical Garden collected and summarized 101 field experimental results from rice-maize, rice-wheat, and rice-rapeseed crop rotation systems, which came from 54 experimental sites in six provinces of Yangtze River Valley. Comparison of the balanced fertilization rates and annual fertilizer management in three different rotation systems indicated that the fertilizer input for rice was about half of the annual system input (48%, 51%, and 55% of N, P, and K). The net economic benefit from rice was much higher in the annual system benefit (52%, 79%, and 68%, respectively).

In these three rotation systems, the rice-maize system produced an annual average grain yield of 20,040 kg/ha that was 42% and 66% higher than in the rice-wheat and rice-rapeseed systems, respectively. The annual gross average income of the rice-maize system was US$7,670/ha, which was 52% and 57% higher than the rice-wheat and rice-rapeseed systems, respectively. The rice-maize system produced an average annual net income of $6,920/ha and it was 51% and 61% higher than that in rice-wheat and rice-rapeseed systems, respectively. Under the rice-maize rotation, maize average partial factor productivity of nitrogen (PFP-N) and phosphorus (PFP-P) fertilizers was 39 and 105, respectively. They were 26% and 9% higher than the corresponding PFP-N and PFP-P for wheat in rice-wheat system, and 3 and 3.5 times higher than that for rapeseed in rice-rapeseed system, respectively. Therefore, as maize has become the second largest grain crop in China, and has extended quickly in south China in recent years, it seems that the rice-maize rotation system will have a wide application in the region in near future. This research have been published in a Chinese scientific journal named Chinese Agricultural Science Bulletin, 2016, 32(36):198-204.