磷肥滴施对膜下滴灌棉田土壤磷形态及磷肥利用率的影响

Effects of drip application of phosphorus fertilizer on soil phosphorus morphology and use efficiency in cotton field with drip-irrigation under plastic-film mulch

【目的】基于水肥一体化技术,研究不同施磷方式的效果,为膜下滴灌棉田合理施用磷肥提供依据。【方法】2021年在新疆棉田以新陆早63号为试验对象,设置不施磷(CK)、基施磷酸一铵(MAP-B,折合P2O5用量100 kg·hm^(-2),下同)、基施+滴施磷酸一铵(基施50%,蕾期和花铃前期分别滴施25%,MAP-D)、基施+滴施磷酸一铵和聚谷氨酸(基施50%磷酸一铵,蕾期和花铃前期分别滴施25%磷酸一铵和50%聚谷氨酸,MAP-DS)共4个处理,比较分析棉田土壤磷含量、不同形态无机磷含量、土壤磷吸附-解吸特征、磷肥利用率和籽棉产量。【结果】施磷能够增加苗期和花铃期0~40 cm土层有效磷和全磷含量,花铃期MAP-D和MAP-DS处理的土壤有效磷含量明显高于其余处理。与基施相比,磷肥滴施显著提高了花铃期10~20 cm土层二钙磷、八钙磷和铝结合态磷的含量占比,降低了十钙磷的含量占比。苗期和花铃期不同施磷处理下0~40 cm土层磷的等温吸附曲线和解吸曲线呈现相似的变化趋势,即随着平衡溶液磷浓度的增加,土壤磷吸附量呈先快速增加后缓慢上升的趋势;随着标准溶液磷浓度的增加,土壤磷解吸率呈先快速降低后趋于稳定的趋势。各施磷处理的籽棉产量均高于对照处理,磷肥滴施处理的磷肥利用率和籽棉产量均高于基施处理,MAP-DS处理的磷肥利用率最大,籽棉产量也最高(6829.75 kg·hm^(-2))。【结论】在新疆棉区水肥一体化模式下,滴施磷肥和聚谷氨酸更有利于新陆早63号对土壤磷素的吸收与利用,可进一步提高磷肥利用率与籽棉产量。

[Objective]Based on the integrated technology of water and fertilizer,the effects of different phosphorus(P)application methods were studied,so as to provide a basis for the rational application of P fertilizer in cotton field with drip-irrigation under plastic-film.[Method]The experiment was carried out in Xinjiang cotton field in 2021.Xinluzao 63 was used as the object,and four treatments were set up,CK:no P application;MAP-B:basal application of monoammonium phosphate(MAP),total amount of P2O5 was 100 kg·hm^(-2)(same as below);MAP-D:basal application of 50%MAP+drip application of 25%MAP at bud stage and 25%at early flowering and boll development stage;MAP-DS:MAP-D+drip application of polyglutamic acid of 50%at bud stage and 50%at early flowering and boll development stage.Soil P content,inorganic P content in different forms,soil P adsorption-desorption characteristics,P use efficiency,and seed cotton yield of different treatments were compared and analyzed.[Result]P application could increase the available P content and total P content in 0-40 cm soil layer at the seedling stage and flowering and boll development stage,and the content of available soil P under MAP-D and MAP-DS treatment was significantly higher than that of other treatments at flowering and boll development stage.Compared with basal application of P(MAP-B),drip application significantly increased the content proportion of dicalcium phosphate(Ca2-P),octa-calcium phosphate(Ca8-P)and aluminum bounded phosphate(Al-P),and reduced the proportion of apatite(Ca10-P)at the flowering and boll development stage.The isothermal adsorption and desorption curves of P in 0-40 cm soil layers under different treatments at the seedling stage and flowering and boll development stage showed similar trend,that is,with the increase of P concentration in equilibrium solution,the soil P adsorption increased rapidly at first and then slowly,and with the increase of P concentration in standard solution,the P desorption rate decreased rapidly at first and then tended to be stable.Compared with CK,the seed cotton yield of P application treatments increased.The P use efficiency and seed cotton yield under drip application of P were higher than that of basal application of P(MAP-B).MAP-DS treatment showed the highest P use efficiency and the highest seed cotton yield(6829.75 kg·hm^(-2)).[Conclusion]Drip application of P fertilizer combined with polyglutamic acid under the integration of water and fertilizer in Xinjiang cotton planting region is more conducive to the absorption and utilization of soil P for Xinluzao 63,and further improves the P use efficiency and seed cotton yield.