施氮量对稻茬麦土壤速效磷质量分数及磷素平衡的影响

以宁麦9号和豫麦34为材料,研究施氮量(0、75、150、225、300kg·hm-2)对土壤速效磷质量分数变化、植株磷素吸收、土壤磷素平衡的影响。结果表明,各处理植株磷素吸收均以拔节至开花期为积累高峰期,且随施氮量增加,磷素吸收呈先增后降的趋势,以N225处理最高。磷肥施用显著提高0~40cm土层速效磷质量分数,随施氮量的增加,土壤速效磷质量分数呈降低趋势。土壤-小麦系统磷素平衡呈明显的阶段性,播种至拔节期磷素出现大量的盈余,拔节至成熟期磷素出现不同程度的表观亏缺。在全生育期,2品种磷素表观盈余量均以N225处理最低,N0处理最高。综合考虑小麦产量和磷素平衡特征,宁麦9号和豫麦34在105kg·hm-2的施磷量基础上可分别再降低P2O5用量7kg·hm-2和10kg·hm-2,配施225kg·hm-2施氮量,能够获得较高的小麦产量并减少磷素损失。

Effects of Nitrogen Rates on the Distribution of Soil Available Phosphorus and Phosphorus Balance under Rice-wheat Rotation

Field experiments with two cultivars of wheat (Triticum aestivum L. cv Ningmai 9 & cv Yumai 34) were conducted to investigate the effects of nitrogen rates (0, 75, 150, 225, 300 kg·hm^-2) on temporal-spatial distribution of soil available phosphorus(P) mass fraction, P uptake and soil P apparent surplus amount. The results showed that P uptake peak was from jointing to anthesis, and the treatment N225 reached the highest. P fertilizer application enhanced soil available P mass fraction of 0-40 cm soil layer, soil available P mass fraction decreased with the increase of nitrogen fertilizer application rates. Soil P surpluses and deficits were obviously linked to growth-stage features owing to a difference in P supply and crop P demand. P surplus occurred from sowing to jointing, and P deficit occurred from jointing to maturity. During the whole growing season, P apparent surplus was the lowest at N225, and the highest at N0. It can be concluded that the N rate to 225 kg·hm^-2, Ninmai 9 and Yumai 34 reduced P₂O₅ rate 7 and 10 kg·hm^-2 on the basis of phosphorus application rate 105 kg·hm^-2 which could improve grain yield and reduce loss of P in wheat production.