间套作和施磷对玉米籽粒磷质量分数和体内磷素分配及利用效率的影响

为明确间套作和施磷对玉米籽粒磷质量分数、收获指数、磷素收获指数和体内磷素利用效率的影响,进行为期3年(2009—2011年)的田间定位试验。试验为裂区设计,主区为不同施磷水平,分别为0、40和80kg/hm2施磷量,副区为油菜、蚕豆、鹰嘴豆和大豆与玉米间套作及单作玉米。结果表明:1)间套作显著提高玉米籽粒磷质量分数,与油菜、蚕豆、鹰嘴豆和大豆间套作的玉米平均籽粒磷质量分数比单作玉米分别高出19.8%、13.0%、17.2%和12.0%;而间套作玉米相对于单作玉米收获指数和磷素收获指数均无显著变化;间套作明显降低玉米体内磷素利用效率,与油菜、蚕豆、鹰嘴豆和大豆间套作玉米的平均体内磷素利用效率比单作玉米分别降低15.9%、9.6%、14.9%和8.5%。2)施磷对玉米收获指数无显著影响;2009年施磷量对玉米籽粒磷质量分数没有显著影响,后2年40和80kg/hm2施磷量时玉米籽粒磷质量分数显著高于不施磷,2年平均提高12.5%和15.9%;40kg/hm2施磷量时(2010年)和80kg/hm2施磷量时(2010和2011年)平均体内磷素利用效率显著低于不施磷,2年平均分别降低8.8%和10.4%;施磷只对2011年磷素收获指数有增加趋势,这可能与土壤基础磷肥肥力较好,施磷在第2年和第3年才产生梯度效应有关。综上,间套作和施磷均能提高玉米籽粒磷质量分数,对收获指数均无影响,但却降低体内磷素利用效率,磷素存在奢侈吸收现象;间套作对磷素收获指数无影响;施磷有提高磷素收获指数的趋势。

Grain P concentrations, P allocation and internal use efficiency of maize affected by P application and intercropping

The aim of this study was to investigate the influences of phosphorus (P) fertilizer application and intercropping on maize grain P concentrations, harvest indexes, P harvest indexes and internal P use efficiency of maize plants.Field experiments were carried out in 2009, 2010 and 2011.The main plots received pure P applications of 0, 40 and 80 kg/hm², and the sub-plots comprised maize monoculture and maize (Zea mays L.cv.Zhengdan no.958) intercropping with oilseed rape (Brassica napus L.cv.Longyou no.1) in 2009 or turnip (Brassica campestris L.cv.Gannan no.4) in 2010 and 2011, faba bean (Vicia faba L.cv.Lincan no.5), chickpea (Cicer arietinum L.cv.Longying no.1) and soybean (Glycine max L.cv.Huaxia no.1 in 2009 and cv.Wuke no.2 in 2010 and 2011), respectively.1) Intercropping significantly enhanced maize grain P concentrations compared to monocropped maize, the average grain P concentrations of maize intercropped with Brassica, faba bean, chickpea and soybean were increased by 19.8%, 13.0%, 17.2% and 12.0%, respectively.However, neither the harvest indexes nor the P harvest indexes of maize were influenced by intercropping.This indicates that the allocation of dry matter and P in vegetative tissues and grains at maize harvest were not influenced by intercropping.Further studies showed that internal P use efficiency of maize plants intercropped with Brassica, faba bean, chickpea and soybean were significantly reduced by 15.9%, 9.6%, 14.9% and 8.5%, respectively.2) No responses of harvest index of maize to P were found in all the three years.In 2009, there were no significant effects of fertilizer P application rates on the average maize grain P concentrations.Afterwards, the average grain P concentrations in 2010 and 2011 were all significantly increased by average of 12.5% at P 40 kg/hm² and 15.9% at P 80 kg/hm² compared to no P application;meanwhile, the internal P use efficiency of maize plants at P 40 kg/hm² in 2010 and at P 80 kg/hm² in both 2010 and 2011 were significantly decreased by 8.8% and 10.4%, respectively;the P harvest indexes were enhanced by P only in 2011.In general, both intercropping and P application increased maize grain P concentrations while decreased internal P use efficiency with luxury absorption of P and P application enhanced the P harvest index of maize.