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An Optimized Model For Simulating Grain-filling Of Maize And Regulating Nitrogen Application Rates Under Different Film Mulching And Nitrogen Fertilizer Regimes On The Loess Plateau, China
Published 2020 · Mathematics
Abstract Grain-filling is a key stage allowing for the achievement of high grain yield. The ridge-furrow film mulching (RFFM) farming system has been widely adopted as a water saving and yield-improving planting pattern on the Loess Plateau of China. However, there is no convenient and effective model to understand the mechanism of maize grain-filling and effective nitrogen (N) management to obtain high grain yield under RFFM and N fertilizer. A two-year (2017–2018) field experiment was conducted on summer maize under RFFM (biodegradable film mulching (BM) and PE film mulching (PM)) and nitrogen fertilizer (0 (N0), 90 (N1), 180 (N2) and 270 (N3) kg N ha−1). The results showed that the 100-kernel dry weight was successfully simulated by the proposed model. After optimizing parameters, the model not only achieved minimum input requirements, but also successfully regulated N application. Moreover, characteristic parameters of grain-filling were significantly affected by the interaction of RFFM and N. N was beneficial for the improvement of the final 100-kernel dry weight ( a ) and grain-filling rate ( V m a x , V ¯ ) and was more improved under BM. The N1 with PM treatment reached the maximum grain-filling rate ( V m a x ) earlier. The maximum grain-filling rate ( V m a x ) and average rate of grain-filling ( V ¯ ) of PM was more sensitive to high N than BM. Parameters of the gradual-growing period were significantly affected by RFFM or N, but the interaction between RFFM and N had extremely significant effects on parameters of the fast-growing and slow-growing periods. For BM, N could improve the rate of three periods of grain-filling, and the N2 treatment was the best in the fast-growing and slow-growing periods. For PM, N could improve the rate of the gradual-growing period. According to the optimized model, the optimal nitrogen application rate of BM and PM was 205 kg ha−1 and 196 kg ha−1, respectively. Based on this optimized model, we could better understand the grain-filling process and achieve the appropriate nitrogen application rate.