滴灌水肥调控对苹果-大豆间作系统光合特性和水分利用的影响

为探究适于晋西黄土区果农间作系统滴灌水肥一体化管理制度,以典型的苹果-大豆间作系统为研究对象,设置灌水和施肥两因素,分析不同水肥调控措施对土壤含水量分布、苹果和大豆光合生理特征、大豆生长和产量以及间作系统水分利用等指标的影响。试验在大豆4个关键需水期进行灌水,肥料随灌溉水施入,每次设置不同灌水上限和施肥水平,4个灌水量上限水平分别为:田间持水量(Fc)的60%(W1),70%(W2),80%(W3)和90%(W4),3个施氮水平:纯N 59.40 kg/hm^2(F1),92.00 kg/hm^2(F2),124.32 kg/hm^2(F3),对照处理(CK)整个生育期不灌水不施肥,仅在播种前施入基肥。结果表明:各水肥处理土壤含水量在水平和垂直方向上具有显著差异,灌水量对土壤含水量的影响程度高于施肥量和水肥交互作用。苹果和大豆的净光合速率(Pn)和蒸腾速率(Tr)的日变化特征相似,均为单峰型曲线,最大值均为W3F2处理。各处理大豆株高、茎粗和叶面积指数(LAI)分别较对照组提高了1.3%~32.3%,2.8%~33.9%和3.4%~125.9%,其中最大值均出现在W3F2处理,该处理大豆产量和间作系统水分利用效率(WUE)也最优,较其他处理分别提高了10.9%~99.3%和8.0%~70.0%。在播种至出苗期、幼苗期至分枝期、开花结荚期和鼓粒期可以设置80%Fc的灌水上限,同时在大豆幼苗期至分枝期、结荚期和鼓粒期分别施加92.00 kg/hm^2的氮肥,该水肥管理方式使苹果—大豆间作系统获得较高的作物产量及水分利用效率,可为该地区间作系统滴灌水肥一体化管理提供参考。

Effects of Water and Fertilizer Regulation on Photosynthetic Characteristics, Yield and Water Use of Apple-soybean Intercropping System Under Drip Irrigation

In order to explore the optimal integrated management system of water and fertilizer under drip irrigation in a fruit-crop intercropping system in the loess area of Shanxi Province,a one-year experiment was carried out in the typical apple (Malus pumila)-soybean (Glycine max) intercropping system, and two factors of irrigation and fertilization were set up to analyze the influence of different water and fertilizer control measures on soil water content distribution, photosynthetic characteristics of apple and soybean, soybean growth and yield, and water use of intercropping system. In the experiment, irrigation was conducted in four key water demand periods of soybean. Fertilizer was applied with irrigation water, and different upper limit of irrigation and fertilization level were set each time. The four levels of maximum irrigation were 60% (W1), 70% (W2), 80% (W3) and 90% (W3) of field capacity (Fc), and the three different nitrogen fertilization levels were pure nitrogen 59.40 kg/hm²(F1),92.00 kg/hm²(F2) and 124.32 kg/hm²(F3). In addition, the rain-fed crop (neither irrigation nor fertilization during the whole growth period, only basal fertilizer was applied before sowing) was taken as the control (CK).The results indicated that the soil water content for each water and fertilizer treatment had significant differences in both horizontal and vertical directions. The influence of irrigation amount on soil water content was more significant than that of fertilization amount and interaction of water and fertilizer.The diurnal variation characteristics of net photosynthetic rate (P_n) and transpiration rate (T_r) for apple and soybean were similar, both of which were unimodal curves and the maximum values were obtained in W3F2.The plant height, stem diameter and leaf area index (LAI) of each water and fertilizer treatment for soybean increased by 1.3%~32.3%, 2.8%~33.9% and 3.4%~125.9%,compared with CK, respectively. Moreover, all the maximum value of growth indexes appeared in W3F2. The soybean yield and water use efficiency (WUE) for intercropping system were also optimal in W3F2, which increased by 10.9%~99.3% and 8.0%~70.0%,compared with other treatments, respectively. The irrigation upper limit of 80% Fc could be set from sowing to emergence stage, from seedling to branching stage, from flowering to pod and blast stage. Meanwhile, 92.00 kg/hm² nitrogen fertilizer could be applied at seedling to branching stage,at pod and drum stage of soybean, respectively. This water and fertilizer management under drip irrigation could make the apple-soybean intercropping system obtain higher crop yield and water use efficiency, which could provide reference for integrated management of water and fertilizer under drip irrigation for the intercropping system in this area.