施磷对间套作玉米叶面积指数、干物质积累分配及磷肥利用效率的影响

通过2011、2012年连续两年田间试验, 研究了“小麦/玉米/大豆”间套作体系中不同施磷处理（小麦0、45、90、135、180 kg P₂O₅·hm^-2, 记为WP₀、WP₁、WP₂、WP₃、WP₄; 玉米0、37.5、75、112.5、150 kg P₂O₅·hm^-2, 记为MP₀、MP₁、MP₂、MP₃、MP₄）对玉米叶面积指数、干物质积累动态和磷肥利用效率的影响.结果表明: 在玉米与小麦共生期, 施磷明显增加了玉米叶面积指数（LAI）和群体光合势（LAD）, 促进了茎、叶干物质的积累（DMA）; 玉米拔节以后LAI、LAD、生长率（CGR）和DMA均随磷肥施用量的增加呈先增加后减少的趋势, 最大值都出现在MP₂或MP₃处理; 玉米生殖生长期营养器官的干物质输出随着磷肥施用量的增加而增加.玉米籽粒产量和体系总产量均随磷肥施用量的增加先增大后减少，都以P₃处理为最高，分别为6588和11955 kg·hm^-2.玉米磷肥表观利用率（PARE）以MP₂处理最高（26.3%）,分别比MP₁（14.4%）、MP₃（19.0%）、MP₄（10.4%）处理高82.6%、38.4%和152.9%.综上,在麦/玉/豆间套作体系中,适量施用磷肥可促进玉米的生长、减轻小麦对玉米的影响,同时可提高玉米当季磷肥利用率,玉米的磷肥施用量在75～112.5 kg P₂O₅·hm^-2为宜.

Effects of phosphorus fertilization on leaf area index,biomass accumulation and allocation,and phosphorus use efficiency of intercropped maize.

A 2 year field experiment was conducted in 2011 and 2012 to investigate the effects of phosphorus (P) fertilization on the leaf area index (LAI), dry matter accumulation (DMA), and P use efficiency (PUE) of maize in wheat/maize/soybean intercropping system. Five P fertilization rates were installed, i.e., 0, 45, 90, 135, and 180 kg P2O5·hm-2 for wheat, marked as WP0, WP1, WP2, WP3, and WP4, respectively, and 0, 37.5, 75, 112.5, and 150 kg P2O5·hm-2 for maize, marked as MP0, MP1, MP2, MP3, and MP4, respectively. During the coexisted growth periods of wheat and maize, P fertilization increased the LAI, leaf area duration (LAD), and stem and leaf DMA of maize significantly. After the jointing stage of maize, the maize LAI, LAD, DMA, and crop growth rate (CGR) all decreased after an initial increase with the increasing P rate, with the maximum growth in treatment MP2 or MP3. During the reproductive stage of maize, the maize dry mass translocation from vegetative to reproductive organ increased with increasing P fertilization rate, and the grain yield of both maize and whole cropping system increased firstly and decreased then, with the maximum grain yield of maize and whole cropping system being 6588 and 11955 kg·hm-2 in treatment P3, respectively. The P apparent recovery efficiency of maize was the highest (26.3%) in treatment MP2, being 82.6%, 38.4%, and 152.9% higher than that in MP1 (14.4%), MP3 (19.0%), and MP4 (10.4%), respectively. In sum, for the wheat/maize/soybean intercropping system, applying appropriate amount of P fertilizer could promote maize growth, alleviate the impact of wheat on maize, and consequently, increase the P apparent recovery efficiency of maize. In this study, the appropriate P fertilization rate was 75-112.5 kg P2O5·hm-2.