秸秆覆盖与施磷显著提高丘陵旱地小麦花后根尖质子动力势

Straw mulching and phosphorus fertilization increase the proton motive force of wheat root tips after anthesis in dry land area

【目的】西南丘陵旱地气候冬干春旱,土壤速效磷缺乏,施磷可有效提高小麦的抗旱能力和产量。我们研究了秸秆覆盖与施磷量对旱地小麦花后根尖质子吸收能力(PMF)的影响,为小麦高产稳产提供理论和技术依据。【方法】试验于2020—2022年在四川仁寿进行,采用二因素裂区设计,以秸秆覆盖和不覆盖为主区;3个磷(P2O5)水平0(P0)、75(P75)和120(P120)kg/hm2为裂区,分析了小麦花后20天根尖质子动力势(质子吸收速率、净吸收速率),测定了小麦干物质积累量、产量及其构成因素。【结果】花后20天,P75和P120处理的质子净吸收速率秸秆覆盖下较P0分别提高了37.7%和32.4%,秸秆不覆盖下分别提高了20.3%和36.5%。与不覆盖相比,秸秆覆盖下小麦根尖质子净吸收速率平均提升了29.4%,氮、磷和钾积累量分别提高了23.2%、32.7%和31.9%,开花期和成熟期营养器官干物质积累量分别提高了30.9%和38.5%。秸秆覆盖显著提高了有效穗、穗粒数和产量,且增加幅度表现为P120>P75>P0。无论是否进行秸秆覆盖,P75、P120处理较P0显著提高了小麦氮、磷和钾吸收效率,P75与P0的氮、钾素籽粒生产效率无显著差异,而P120处理显著降低了氮、钾素籽粒生产效率。秸秆覆盖和磷肥配合的6个处理中,秸秆覆盖+P75处理所获得的小麦产量和磷素利用效率显著高于无秸秆覆盖+P120处理。【结论】秸秆覆盖与施用磷肥均可显著提高小麦花后根尖质子动力势,促进养分吸收和地上部干物质的积累,增加有效穗和穗粒数,进而实现增产。施磷75 kg/hm2可提高小麦的氮、钾吸收率,不影响氮、钾素籽粒生产效率,而施磷120 kg/hm2显著降低了氮、钾素籽粒生产效率,因此,采用秸秆覆盖配施75 kg/hm2的磷肥(P2O5)可实现小麦高产高效和绿色生产。

【Objectives】The hilly area in southwest China is drought in winter and spring,and the soil is deficient in phosphorus.Phosphorous application could effectively alleviate the water and nutrient limitation of wheat.We studied the effect of straw mulching combined with different rates of phosphorus fertilizers on increasing the nutrient uptake capacity.【Methods】A two-year experiment with split design was conducted in Renshou,Sichuan Province from 2020 to 2022.The main factor was straw mulching and no-mulch,and the subfactor was P application rate(0,75 and 120 kg/hm2,denoted as P0,P75 and P120).The proton motive force of wheat root tips at anthesis stage(PMF)was determined.The nutrient uptake,dry matter accumulation and grain yield of wheat were investigated.【Results】After 20 days anthesis,the PMF of P75 and P120 increased by 37.7%and 32.4%compared to P0 under straw mulching(SM),and increased by 20.3%and 36.5%under no-mulch(NSM).The average PMF of root tips in SM treatment increased by 29.4%compared to NSM wheat treatment.Compared with no-mulch,the accumulation of N,P,and K in wheat under straw mulching increased by 23.2%,32.7%,and 31.9%,respectively,and the dry matter accumulation in nutrient organs during flowering and maturity stages increased by 30.9%and 38.5%,respectively.Straw mulching significantly increased the effective spike,grain number per spike,and yield,with an increase range of P120>P75>P0.Regardless of straw mulching,P75 and P120 achieved significantly higher N and K uptake efficiency than P0,P75 was recorded similar but P120 led to significantly lower N and K grain production efficiency than P0.Among the whole six treatments,straw mulching+P75 achieved the highest P utilization efficiency.【Conclusions】Both straw mulching and P application could increase the proton motive force of wheat root tip after anthesis,so promote the nutrient uptake and dry matter accumulation,and increase the yield through improved effective spike number and grain number per spike.Considering the nutrient use efficiency and grain production efficiency,straw mulching combined with 75 kg/hm2 of P application rate is an environmental friendly and cost effective measurement for wheat production in drought and hilly area of southwest China.