东北春玉米滴灌施肥的适宜种植密度和施钾量研究

Optimal plant density and potassium application rate for spring maize under drip-fertigation in Northeast China

【目的】适宜的种植密度和施肥量是实现春玉米高产和高肥料利用效率的重要因素。研究东北半干旱区滴灌水肥一体化条件下种植密度和施钾量对春玉米产量、效益、养分转运及吸收利用的影响,为进一步挖掘东北玉米产量潜力提供科学依据。【方法】田间试验于2018—2019年在吉林省半干旱区乾安县赞字乡父字村进行,供试玉米品种为‘富民985’。试验采用完全区组设计,设置60000、75000、90000株/hm^(2)3个种植密度(分别记作D1、D2和D3)和0、60、90、120、150 kg/hm^(2)和5个施钾(K_(2)O)量(分别记作K0、K1、K2、K3和K4)。分析玉米氮磷钾积累、分配与转运特征及产量、效益和钾素利用率。【结果】同一施钾量下,玉米产量和效益均以D2密度下最高,该密度下两年的玉米平均产量较D1和D3密度下分别提高了8.1%和5.3%,效益分别提高了10.3%和9.4%。在这3个密度下,玉米产量均随施钾量的增加而增加。D1密度下,当K_(2)O量≥90 kg/hm^(2)时,产量和效益的增幅不再明显;而D2和D3密度下,当K_(2)O量≥120 kg/hm^(2)时,产量和效益增幅不再明显。随施钾量的增加,不同种植密度下钾素吸收利用率、农学利用率和偏生产力均呈下降趋势,但同一钾量下的钾素利用率均以D2密度下的处理最高。种植密度和施钾量对玉米吐丝前后氮、磷、钾素累积量有显著的交互作用,D2K3处理促进了吐丝前氮、磷、钾养分的积累及向籽粒的转运,提高了吐丝后氮、磷、钾同化量及对籽粒的贡献率,进而提高了籽粒氮、磷、钾积累量。相关分析结果表明,玉米吐丝前后氮、磷、钾素积累量与籽粒产量均呈极显著正相关(r=0.636~0.971),其中吐丝后的相关性高于吐丝前。【结论】在东北半干旱区,滴灌水肥一体化条件下,密度和钾肥互作显著影响玉米产量、养分吸收、转运和钾素利用率。最佳密度和施钾量组合是75000株/hm^(2)配合K_(2)O 120 kg/hm^(2)。

【Objectives】Appropriate plant density and fertilizer application rate are important factors to achieve high yield and fertilizer efficiency of crop production.We studied the suitable combination of plant density and potash application rate for the spring maize production in Northeast China under semiarid climate area.【Methods】A field experiment was conducted from 2018 to 2019 in Qian'an County,Jilin Province,with maize cultivar‘Fumin 985’as tested material.A complete block design was used,including plant densities of 60000 plants/hm^(2)(D1),75000 plants/hm^(2)(D2)and 90000 plants/hm^(2)(D3),and potassium application rates of K_(2)O 0,60,90,120 and 150 kg/hm^(2)(recorded as K0,K1,K2,K3 and K4,respectively).The accumulation,distribution and translocation of NPK,yield,benefit and K utilization efficiency of maize were investigated.【Results】Under the same K_(2)O application rate,the highest maize yield and benefit were recorded in D2 treatment.Compared to D1 and D3,D2 increased the average maize yield by 8.1%and 5.3%,and increased the benefit by 10.3%and 9.4%.Regardless of plant densities,the maize yield increased with the increase of K_(2)O rate;however,the yield and benefit increase were similar under D1 when K_(2)O was≥90 kg/hm^(2),and under D2 and D3 when K_(2)O was≥120 kg/hm^(2).The K recovery efficiency,agronomic efficiency and partial factor productivity decreased with increasing K_(2)O application rate,but they remained higher in D2 than in D1 and D3 in the same K rate.The planting density and K_(2)O rate had significant interaction on the accumulation of N,P and K before and after silking stage.D2K3 increased the accumulation and transfer of N,P and K to the grains before silking stage,and increased the assimilation of N,P and K and their contribution rates to grains after silking stage.The correlation analysis showed that the accumulation of N,P and K before and after silking stage and the grain yield were highly significantly correlated(r=0.636-0.971),and the correlation coefficients after silking stage were higher than those before silking stage.【Conclusions】Planting density and K fertilizer interactions significantly affected maize yield,nutrient uptake,translocation and K-use-efficiency under drip irrigation with integration of water and fertilizer in the semi-arid region of Northeast China.The best combination was planting density of 75000 plants/hm^(2)and K_(2)O rate of 120 kg/hm^(2)under fertigation.