关键词: 夏玉米, 滴灌施肥, 肥料利用率, 作物产量, 干物质积累量

Abstract:

【Objective】 The experiment was carried out to study the fertilizer effects of different nitrogen, phosphorus and potassium fertilizer application rates on summer maize under low-yield soil conditions in North China, and provided a theoretical basis for high-efficiency drip fertigation of summer maize, in order to optimize drip fertigation system and promote the technology of water and fertilizer integration. 【Method】 Maize variety “Zhengdan 958” was used as materials in the two-year field experiment. Under the condition of one tube with two rows of drip fertigation belts, the experiment was subjected to four treatments for nitrogen, phosphorus and potassium respectively, of which nitrogen fertilizer treatments were 0, 144, 180, and 216 kg·hm ^-2(denoted as N0, N1, N2, and N3, respectively), phosphate fertilizer treatments were 0, 72, 90, and 108 kg·hm ^-2(denoted as P0, P1, P2, and P3, respectively) and potassium fertilizer treatments were 0, 72, 90, and 108 kg·hm ^-2 (denoted as K0, K1, K2, and K3, respectively). The nitrogen, phosphorus and potassium fertilizers were divided into four times by drip fertigation. The study analyzed the effects of different nitrogen, phosphate and potassium application rates on crop yield and the dry matter in different growing stages of summer maize, and analyzed the fertilizer use efficiency. 【Result】 (1) The yield of summer maize under the conditions of low-yield field in North China showed a parabolic linear change with the rates of nitrogen and phosphorus fertilizer. The crop yield was the highest when the nitrogen application was 180 kg·hm ^-2 and the phosphorus application was 90 kg·hm ^-2. When the nitrogen and phosphorus fertilizer application exceeded the maximum yield fertilization amount, the crop yield decreased with the increase of nitrogen and phosphorus application, but the difference of nitrogen fertilizer treatment was not significant. And when the application rate of phosphate fertilizer exceeded 90 kg·hm ^-2, the yield of crop decreased significantly with the increase of phosphorus application (P＜0.05). In this treatment, the yield of summer maize increased with the amount of potassium applied. (2) Different fertilization treatments had little effect on the dry matter accumulation of summer maize in the early growth stage. The change of crop yield and the dry matter accumulation showed the same parabolic linear change along with the increase of nitrogen application rate and phosphorus application rate in the filling period and harvesting period. (3) The use efficiencies of nitrogen, phosphorus and potassium fertilizers were 33.39%-58.44%, 14.15%-28.88% and 54.70%-65.75%, respectively. The nitrogen, phosphorus and potassium fertilizer average use efficiencies were 51.21%, 28.88% and 65.75%, respectively, when the yield of summer maize was the highest. The average agronomic efficiency of nitrogen, phosphorus and potassium fertilizers were 8.08 kg·kg ^-1, 11.41 kg·kg ^-1 and 8.83 kg·kg ^-1, respectively, under the highest yield conditions. At this point, the average partial factor productivity of nitrogen, phosphorus and potassium fertilizers were 59.88 kg·kg ^-1, 119.75 kg·kg ^-1 and 100.65 kg·kg ^-1, respectively. 【Conclusion】 Under the conditions of drip fertigation in low-yield soil in North China, the optimum nitrogen and phosphorus application were 180 kg·hm ^-2 and 90 kg·hm ^-2, respectively. The yield of summer maize would decrease when nitrogen application exceeded 180 kg·hm ^-2or phosphorus application rate surpassed 90 kg·hm ^-2, but the yield of summer maize would increase along with the increase of potassium application. Drip fertigation could obtain higher nitrogen, phosphorus and potassium fertilizer use efficiency, which was 51.21%, 28.88% and 65.75%, respectively.

Key words: summer maize, drip fertigation, fertilizer use efficiency, crop yield, dry matter accumulation