30 Sep 2018
Spatial variation of attainable yield and fertilizer requirements for maize at the regional scale in China
Xu XP, He P*, Zhang JJ, Pampolino MF, Johnston AM, Zhou W. Spatial variation of attainable yield and fertilizer requirements for maize at the regional scale in China. Field Crops Research, 2017, 203: 8-15
Nutrient Expert field validation at Liufangzi, Jilin Province
Understanding attainable yield, soil nutrient supply capacity and fertilizer requirements in current inten-sive maize (Zea mays L.) production at regional and national scales in China is essential in making informed decisions on policy, research and investment. In this study, results of a large number of on-farm experiments (n = 5893) were collected for the period 2001–2015 from the main maize production areas in China to study the spatial variability of attainable yield, relative yield (RY) and fertilizer requirements by coupling geographical information system with the Nutrient Expert for Hybrid Maize system. We found strong spatial variation in attainable yield across all sites, with a coefficient of variation (CV) of 25.5%.Mapping the spatial variability of RY indicated that 85.3%, 79.3% and 72.5% of RY for nitrogen (N), phosphorus (P) and potassium (K) of the study areas ranged from 0.68 to 0.87, from 0.83 to 0.95 and from 0.84 to 0.94, respectively. The RY was higher in North Central China than other regions. The RY can reveal the spatial heterogeneity of soil nutrient supply capacity, and has been integrated into crop management strategies for calculating fertilizer requirements using the Nutrient Expert for Hybrid Maize decision sup-port system. Overall, there were large variations in N, P and K fertilizer requirements across all sites with CVs of 19.5%, 31.6% and 35.0%, respectively, and the ranges of 150–210 kg N/ha, 50–90 kg P2O5/ha and 50–110 kg K2O/ha accounted for 72.0%, 81.7% and 81.5% of the study areas, respectively. The results of 605 field experiments in 10 provinces during 2010–2014 showed that the Nutrient Expert for Hybrid Maize system not only reduced N and P fertilizer application rates by 31.6% and 15.5%, respectively, but also increased maize yield by 3.3% compared with farmers’ current practices. The combination of the fertilizer recommendation system and geographical information system with a large database of field trials provides a useful tool to identify spatial variation in fertilizer requirements in fields and regions, and contributes towards more efficient and effective fertilizer management.
