[目的]汛前储水灌溉是陕西关中地区雨洪资源高效利用的重要方式.研究不同深蓄储水灌溉量对农田土壤磷素利用、累积与流失状况的影响,以实现农田的"高"磷吸收和"低"磷淋溶.[方法]在陕西宝鸡峡灌区进行小麦田间试验,供试小麦品种为'小偃 22'.设置储水灌溉量分别为 0、80、120、140、160 和 180 cm,分别记为CK、D80、D120、D140、D160、D180,共 6 个处理.在小麦拔节期、开花期和成熟期,测定冬小麦植株各营养器官生物量、磷素含量及农田 0-200 cm土层土壤速效磷含量,计算冬小麦吸磷量、磷肥利用效率和磷素盈亏.[结果]与CK处理相比,D80、D120、D140、D160、D180 处理冬小麦产量分别提高了 8.85%、24.71%、30.99%、17.91%、9.90%,成熟期籽粒磷素累积量分别提高了 37.55%、46.34%、38.09%、28.23%、22.11%,小麦植株磷素吸收效率分别增加 10.10%、12.47%、10.25%、7.59%、5.95%,有效磷表观盈余量分别降低了 13.82%、17.05%、14.02%、10.39%、8.13%.随着储水灌溉量的增加,成熟期小麦植株磷素累积量呈先增加后降低的趋势,以D120 处理磷素累积量最高,显著高于D160 和D180 处理,因此其磷素表观盈余量最低(78.83 kg/hm2),显著低于D160、D180 处理.D120 处理相较D160 和D180 有助于小麦花前磷素转运和花后磷素累积;D80 处理相较D120 处理小麦花前磷素转运有所降低,但在花后磷素累积上表现出补偿作用;D140 处理虽然降低了花后的磷素累积,但通过提高花前磷素转运实现了平衡.值得注意的是,D80、D120 和D140 处理之间的成熟期植株磷素累积量与籽粒磷素累积量差异不显著.另外,由于土壤中 20-100 cm土层速效磷含量远低于该地磷素淋溶的环境阈值(39.9 mg/kg),尽管存在高水平的磷盈余,在适宜储水灌溉量下也不会引发磷淋失.然而,当储水深度大于 160 cm时,对深层土壤中速效磷产生了明显的影响,导致土壤磷素发生淋失.[结论]在西北地区,适宜的储水灌溉量为 80～140 cm,既可以提高小麦磷素吸收,又可以控制土壤中速效磷含量处于适宜范围,降低土壤磷素盈余,进而获得较低的土壤磷素环境风险.
[Objectives]Deep storage water irrigation before rain season is an efficient utilization way of rainwater and flood resources in central Shaanxi Province.As the potential risks of nutrient leaching,and reduced fertilizer utilization efficiency due to large irrigation water volume,we studied the effect of storage water irrigation volumes on wheat P utilization,apparent P balance,and leaching risks down to deep soil.[Methods]A field experiment on wheat was conducted in the Baojixia Irrigation Area of the Guanzhong Plain(Caoxinzhuang Farm,Yangling Demonstration Zone),with winter wheat cultivar'Xiaoyan 22'as the test material.The treated storage irrigation water volumes were 0,80,120,140,160,and 180 cm,denoted as CK,D80,D120,D140,D160,and D180,respectively.The biomass and P contents in various organs of winter wheat were analyzed for the calculation of wheat phosphorus uptake,phosphorus fertilizer utilization efficiency,and apparent P surplus.The available phosphorus content in 0-200 cm soil layers were measured for the assessment of P leaching down to deep soil.[Results]Compared with CK,treatment D80,D120,D140,D160,and D180 increased winter wheat yield by 8.85%,24.71%,30.99%,17.91%,and 9.90%,increased the grain P accumulation at maturity stage by 37.55%,46.34%,38.09%,28.23%,and 22.11%,enhanced phosphorus absorption efficiency of wheat plants by 10.10%,12.47%,10.25%,7.59%,5.95%,and decreased phosphorus apparent surplus by 13.82%,17.05%,14.02%,10.39%,and 8.13%,respectively.With the increase of water storage irrigation volume,the P accumulation in wheat showed a trend of first increasing and then decreasing,reaching the highest value at D120.And the apparent P surplus showed a trend of declining first and then rising,the lowest P surplus(78.83 kg/hm2)was recorded at D120,which was significantly lower than that at D160 and D180 treatments.Compared with D160 and D180,D120 treatment was more conducive to pre flowering phosphorus transport and post flowering phosphorus assimilation in wheat.D80 treatment showed lower phosphorus transport before flowering compared to D120 wheat,but showed a compensatory effect on phosphorus accumulation after flowering.Although D140 treatment reduced phosphorus accumulation after flowering,it achieved balance by increasing phosphorus transport before flowering.It was worth noting that there was no significant differences in plant and grain phosphorus accumulation between D80,D120,and D140 treatments.In addition,due to the fact that the available phosphorus content in the 20-100 cm soil layer was much lower than the environmental threshold for phosphorus leaching in the area(39.9 mg/kg),the high level of phosphorus surplus did not cause phosphorus leaching when the water storage water irrigation amounts was less than 140 cm,however,it did when the water storage depth was greater than 160 cm.[Conclusions]Appropriate storage water irrigation volume significantly improves the efficiency of wheat phosphorus absorption and utilization,and controls the soil available phosphorus content within threshold of P leaching,and reduces phosphorus surplus in soil.The suitable irrigation volume for water storage is 80-140 cm in the Northwest area.
庞耀悦;胡笑涛;王芳;查晴;范晓懂;王文娥
西北农林科技大学/旱区农业水土工程教育部重点实验室,陕西杨凌 712100
储水灌溉深度;磷素利用效率;磷素淋失;磷素盈余
storage water irrigation volume;phosphorus use efficiency;phosphorus leaching;phosphorus surplus
《植物营养与肥料学报》 2024 (003)
493-504 / 12
陕西水利科技计划项目(2022slkj-6).
10.11674/zwyf.2023424
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