EFFECT OF CONTROLLED-RELEASE FERTILIZER ON MAIZE YIELD AND NUTRIENT UPTAKE UNDER A FERTILIZER ONE-TIME POINT-APPLIED SYSTEM

Currently, maize production in China suffers from many problems, such as excessive fertilizer application, inefficient fertilizer use, and insufficient agricultural labour. The effect of one-time mechanical point-applied fertilization of controlled-release compound fertilizer in the root-zone on yield and nutrient uptake was investigated to explore efficient fertilization patterns for fertilizer decrease and yield increase in maize. The selected fertilizer was a controlled-release granular fertilizer (24-6-10 for N-P2O5-K2O) with six treatments in the application program: 1) no fertilizer (CK); 2) application of a one-time banding fertilizer (BDP) 5 cm off the seeds between rows and 10 cm deep; 3) application of a one-time point-applied fertilization (RZF) 5 cm off seed in the row and 10 cm deep; 4) application of a one-time point-applied fertilization (90% RZF) 10% fertilizer reduction 5 cm off seed in the row and 10 cm deep; 5) application of a one-time point-applied fertilization (80% RZF) 20% fertilizer reduction 5 cm off seed in the row and 10 cm deep; 6) application of a one-time pointapplied fertilization (70% RZF) 30% fertilizer reduction 5 cm off seed in the row and 10 cm deep. The results showed that RZF increased yield by 5.84% over BDP, and the difference was significant, indicating that mechanized point-applied fertilization of fertilizer can replace manual point-applied fertilization application operations and achieve increased crop yield. The agronomic utilization rate of fertilizer of 12.35% and the bias productivity of 5.31% were higher in RZF than in BDP, and the differences were significant, indicating that onetime mechanical point-applied fertilization in the root zone significantly improved fertilizer utilization and reduced fertilizer loss.