等养分条件下稻草还田替代双季早稻氮钾肥比例的研究

Replacement ratio of nitrogen and potassium fertilizer by straw incorporation in early rice under the same nitrogen, phosphorus and potassium input

【目的】研究等量氮磷钾养分投入条件下,长期稻草原位全量还田配施化肥对双季早稻氮(N)、磷(P)、钾(K)养分吸收累积、转运及养分利用的影响,为南方稻区稻草资源有效利用,维持并提高土壤肥力及水稻合理施肥提供理论依据。【方法】以江西温圳国家级耕地质量监测点长期定位试验为研究对象,陆两优996为供试材料,在不施化肥和施用化肥基础上设稻草还田、稻草烧灰还田和稻草不还田共6个处理,除空白对照外,所有处理养分投入量相等。于2015年在早稻移栽期、分蘖期、幼穗分化期、抽穗期和成熟期取地上部植株样,分析水稻植株不同部位的N、P、K含量和累积量以及转运比例,并计算N、P、K养分利用效率。【结果】稻草还田提高了水稻产量,施肥条件下稻草还田处理比稻草烧灰还田和稻草不还田处理平均增产2.9%~6.4%,比不施肥区产量增幅高达23.8%~26.0%,且差异达显著水平。无论是施肥区处理,还是无肥区处理,与稻草烧灰还田和稻草不还田处理相比,稻草还田植株中K含量及N、P、K积累量在整个生育期均较高,而N、P含量在生育后期较高,N、P、K积累量以施肥区处理大于相应的无肥区处理;稻草还田提高水稻N、P、K养分农学效率、回收率和养分偏生产力,且N、K差异达显著水平,同时显著增加K的收获指数;稻草还田还提高了抽穗至成熟期茎鞘中N、P、K的转运量、转运率及转移养分对籽粒的贡献率,而叶片各处理间差异不显著。【结论】稻草还田配施化肥能提高水稻产量,同时还可以调节N、P、K养分的积累和转运,提高养分的吸收利用效率。本试验条件下,稻草还田可替代化肥氮肥(N)29.5%、磷肥(P_2O_5)4.0%和钾肥(K_2O)50.0%。综合考虑,稻草还田相比稻草烧灰还田而言是南方稻区土壤养分管理实现高效利用的有效途径之一。

[ Objectives ] Effects of total straw incorporation with chemical fertilizers in situ on the N, P and K use efficiencies of early rice of double cropping were studied under the same N, P and K input in the long run to provide base support for effective utilization of the southern straw resource and sustainable soil fertility, and rational application fertilizers. [ Methods ] A long-term field experiment located in the cultivated land quality monitoring system on straw incorporation and soil fertility （Wenzhen Town, Jiangxi Province） was carried out, and early rice cultivar, Luliangyou 996, was selected as tested material. Plant samples were collected from six treatments： total straw incorporation （TS）, straw burning and straw no-incorporation, containing application chemical fertilizer and no chemical fertilizer, respectively, all the treatments, except blank control, were input the same amount of N, P and k nutrients. The N, P and K accumulation, translocation and use efficiencies were analyzed at the transplanting, tillering, panicle initiation, heading and maturity stages of early rice in 2015. [ Results ] With supplement of chemical fertilizer, the total straw incorporation treatment could stably increase grain yields of early rice within six years, and the yields were 2.9% and 6.4% higher than those in treatments of the straw burning and pure chemical fertilizer treatments, and compared with no chemical fertilizer and no straw treatment, the increments were from 23.8% to 26.0%. Compared with the straw burning and straw no- incorporation, no matter the fertilization treatments and blank, the straw incorporation had the higher K content and N, P and K accumulation at the growth stages, but the N and P contents were higher at the later growth stages. The N, P and K accumulation amounts in the fertilization treatments were higher than those in the no fertilization treatments. The straw incorporation enhanced the N, P and K fertilizer agronomy efficiencies （AE）, recovery efficiencies （RE） and partial factor productivity （PFP）, and increased the K harvest index significantly, while the N and K use efficiencies were significantly different among the treatments. Meanwhile, the straw incorporation increased the N, P and K transfer amounts, transfer rates and contribution to grain nutrient of the stems and sheaths, but no differences were observed in the leaves among treatments. [ Conclusions ] The straw incorporation with application fertilizers could increase the grain yield, and improve the accumulation and translocation of applied N, P and K, and their use efficiencies in the long-run. Replacing of N 29.5%, P205 4.0% and K20 50.0% with straw for fertilizer N, P and K in the straw incorporation is proved to be a feasible way to realize soil nutrient management in the southern rice zone contrast to the straw burning.