In order to investigate the effects of water and fertilizer coupling on physiological index of leaves,yield and economic benefit in an apple-maize intercropping system,an experiment of water and fertilizer coupling was carried out in the Loess Plateau of Shanxi Province.The irrigation regimes were established by three threshold levels of soil moisture as follows:W1,50％ field capacity (50％ Fc);W2,65％ field capacity (65％ Fc);W3,85％ field capacity (85％ Fc).Meanwhile,three fertilizer levels were also set up in this experiment,including F1,N(289 kg· hm-2) + P2O5(118 kg·hm-2) +K2O(118 kg·hm-2),F2,N (412.4 kg·hm-2) + P2O5(168.8 kg·hm-2) + K2O (168.8 kg·hm-2),and F3,N(537 kg·hm-2) + P2O5(219 kg·hm-2) + K2O(219 kg·hm-2).The results are summarized as follows:Irrigation and fertilization had no significant effect on chlorophyll content while significant effects were found on leaf water potential.The leaf water potential,leaf area index,maize yield all decreased with the increasing of fertilizer rate;while chlorophyll content increased with the increasing of the distance from the tree line.Different irrigation levels had considerable influences on the horizontal distributions of leaf water potential.According to the analysis of multiple regression,the maximum maize yield could obtained when 289kg· hm-2 nitrogen fertilizer,118 kg· hm-2 phosphorus fertilizer,118 kg· hm-2 potassium fertilizer was applied during the whole stages.The theoretical maximum yield can be 10 133.50 kg· hm-2,10 205.90 kg· hm-2.According to the results of economic benefit analysis,the maximum economic benefit could obtained when no fertilizer applied at jointing stage,262.5 kg· hm-2 fertilizer applied at tasseling stage and filling stage and irrigating water upper limits (about 85％ field capacity).The net income can be 10 470.38 yuan· hm-2.Therefore,the treatment with relatively low amount of irrigation water and applied fertilizer can not only obtain the maximum economic benefit but also can avoid the pollution to soil and underground water and resource waste caused by unreasonable fertilization and irrigation.Accordingly,it was the most economical and environmental irrigation and fertilizer regulation method for the apple-maize intercropping system.%为了探求适用于晋西黄土区果粮间作系统的水肥管理制度,以当地典型的苹果-玉米间作系统为研究对象,通过设置二因素三水平水肥耦合试验,分析不同水肥调控下玉米灌浆期穗位叶叶绿素和叶水势相对含量及水平分布特征,从而建立灌水量、施肥量与各叶片生理指标及产量的回归关系,进一步分析各处理投入产出值及经济收益.试验设置灌水量上限三水平分别为:田间持水量(Fc)的50％(W1)、65％ (W2)和85％ (W3),施肥量分别为:N 289 kg·hm-2+P2O5 118 kg·hm-2+ K2O 118 kg· hm-2(F1,70％经验施肥量)、N 412.4 kg·hm-2+ P2O5 168.8 kg·hm-2+ K2O 168.8 kg·hm-2(F2,100％经验施肥量)、N 537 kg·hm-2+ P2O5 219 kg·hm-2+ K2O 219 kg·hm-2(F3,130％经验施肥量).结果表明:水肥调控对植物叶绿素含量影响较小,对叶水势影响较大;随着施肥量的增加,植物叶水势、叶面积指数及产量均逐渐减小;不同水肥调控措施通过种间竞争对叶片生理参数产生的影响不同.玉米叶绿素随着距树行距离的增加而逐渐递增,不同灌溉水平对距树不同距离处玉米叶水势影响差异较大.多元回归分析结果显示:当全生育期氮肥施用量为289 kg· hm-2、磷肥施用量为118 kg·hm-2、钾肥施用量为118 kg·hm-2,间作系统可获得较高的产量,理论最大值分别为10 133.50 kg·hm-2、10 205.90 kg·hm-2.在本次试验设计范围内采用全生育期灌水上限设定值为田间持水量的50％,总施肥量为525 kg·hm-2(F1,70％经验施肥量)的水肥管理制度可使间作系统净收益最高,可达10 470.38元·hm-2.因此,低量灌水和施肥不仅可使系统净收益最大,还可避免盲目施肥和灌溉造成的环境污染和资源浪费,是最有利于晋西黄土区果粮间作系统的水肥管理制度.
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