滴灌量对耐密宜机收玉米干物质积累分配及产量形成的影响

Influence of Drip Irrigation on Dry Matter Distribution and Yield Formation of the Grains of Densely Planted Maize

【目的】探究增密种植条件下滴灌量对籽粒机收玉米干物质积累分配规律及产量形成的影响。【方法】以2018年在内蒙古自治区农牧业科学院试验田开始的长期定位滴灌灌溉试验为基础,设置W1(415m^(3)/hm^(2))、W2(645m^(3)/hm^(2))、W3(945 m^(3)/hm^(2))、W4(1275 m^(3)/hm^(2))、W5(1605 m^(3)/hm^(2))5个滴灌量,以自然雨养为对照(CK),定量分析籽粒机收玉米地上部干物质积累分配规律,构建Logistic模型拟合玉米干物质积累动态,探究不同滴灌水平下干物质积累分配规律及灌水量与产量的关系和差异性。【结果】灌水可显著提高玉米单株地上部干物质积累量,不同处理玉米干物质积累过程符合Logistic模型,拟合度R^(2)均在0.8880以上,2 a干物质积累量的最大增长速率均表现为随灌水量增加而增加,以CK最低,W5处理最高。2020、2021年生物产量均以W5处理最高,收获指数分别以W4处理和W3处理最高,分别为0.51和0.50。与CK相比,灌水处理降低成熟期干物质在营养器官中的分配比例,但提高了籽粒干物质分配比例。随着灌水量增加,2020年经济产量呈先升高后降低趋势,W4处理最大为14282.42kg/hm^(2);2021年经济产量呈随灌水量增加而升高趋势,W4(15480.33 kg/hm^(2))处理和W5(15892.52 kg/hm^(2))处理显著高于其余处理。【结论】适宜的灌水量能够显著提高干物质积累速率,增加籽粒机收玉米地上部干物质积累量并促进干物质向籽粒分配,在年自然降水量364.2~390.7 mm范围的干旱年,种植密度为7.5×104株/hm^(2)的情况下,内蒙古中西部干旱、半干旱地区以每年1275 m^(3)/hm^(2)的滴灌灌水量进行灌溉为最佳。

【Objective】The purpose of this paper is to investigate the effect of drip irrigation amount on dry matter accumulation and distribution,as well as the yield formation of the grain machine harvest maize.【Method】The study was based on the drip irrigation experiment established in 2018 in the Experimental Field of Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences.The experiment consisted of five irrigation treatments by irrigating 415 m^(3)/hm^(2)(W1),645 m^(3)/hm^(2)(W2),945 m^(3)/hm^(2)(W3),1275 m^(3)/hm^(2)(W4)and 1605 m^(3)/hm^(2)(W5),respectively.A rain-fed plot was taken as the control(CK).In each treatment,we measured the accumulation and distribution of above-ground dry matter in 2020 and 2021.Logistic model was used to describe the temporal change in dry matter accumulation,from which we further analyze the characteristics of dry matter accumulation and distribution,as well as the relationship of drip irrigation amount and yield under different treatments.【Result】Irrigation significantly increased the dry matter accumulation in the upper part of the plant;temporal change in the dry matter accumulation is well described by the logistic model,with R^(2)>0.888.In 2020 and 2021,the maximum growth rate of the dry matter accumulation increased as the irrigation amount increased,with the increase in the CK being the least and the increase in W5 being the highest.The biological yield in W5 was the highest in both 2020 and 2021;the harvest index in W4 and W3 was the highest,being 0.51 and 0.50 respectively.Compared with CK,irrigation reduced dry matter distribution in the vegetative organs at maturity stage but increased dry matter accumulation in the grains.With the increase in irrigation amount,the economic yield in 2020 first increased,followed by a decline,maximizing in W4,reaching 14282.42 kg/hm^(2)in 2021.The yield in W4(15480.33 kg/hm^(2))and W5(15892.52 kg/hm^(2))was significantly higher than that in other treatments.【Conclusion】Optimizing irrigation amount can significantly increase dry matter accumulation in the aboveground part,and promote distribution of dry matter in the grain.In drought years with average annual natural precipitation between 364.2 and 390.7 mm,the optimum drip irrigation amount is 1275 m^(3)/hm^(2)for grain machine harvest maize(planting density is 7.5×104 plants/hm^(2))in the arid and semi-arid areas in central and western Inner Mongolia.