【作者】 许有尊；

【导师】 彭少兵；

【作者基本信息】 华中农业大学 ， 作物栽培学与耕作学， 2009， 博士

【摘要】 目前我国化肥消费总量占世界总用量的近三分之一,而单位面积化肥用量远远超过世界平均水平,大量施用化肥而忽视有机肥的施用是我国目前水稻生产中的突出问题。由于化肥的大量使用导致的生产成本上升、产出／投入比低、肥料利用率尤其是氮肥利用率低下、环境污染等现象已经越来越明显。如果能将农业生产中现有的有机肥资源合理利用,使有机肥和化肥配合施用对提高农业的可持续生产能力具有十分重要的作用。本研究目的在于：(1)探明耕作方式和稻草还田对水稻生长和产量的影响；(2)研究耕作方式和稻草还田对肥料吸收和氮肥利用率的影响；(3)探讨稻草还田与氮肥管理模式对水稻生长、产量以及氮肥利用率的影响；(4)探讨耕作方式／稻草还田和氮肥管理模式结合对水稻产量及氮肥利用率的影响；(5)探讨有机肥和化肥配合施用对水稻产量及氮肥利用率的影响。利用大田和盆栽试验结合的方式进行了相关研究,取得的主要研究结果如下：(1)结合实地氮肥管理模式可以使免耕处理获得与传统翻耕方式相当的产量。本试验比较研究了不同耕作方式对水稻生长发育和产量的影响机理,结果表明,与传统翻耕方式相比,免耕处理水稻幼苗期根系长度和茎蘖数略低,但分蘖成穗率提高,最终获得的有效穗数于翻耕处理相当；免耕处理的叶面积指数、叶片含氮量(SAPD值)与传统翻耕方式相当,但是中后期伤流量增加了14.3%,成熟期吸收的氮、磷、钾与传统翻耕相当,氮肥利用率并没有降低。(2)不施氮肥时,稻草还田可以显著提高水稻的产量,但当氮肥用量在100 kgN ha-1-150kg N ha-1之间时,稻草还田的增产效应被施用氮肥引起的增产效应所掩盖,因此还田处理和不还田处理的产量差异不显著。无论是稻草全部还田还是半量,结合实地氮肥管理模式和合理的水分管理,水稻产量并没有降低甚至略有增加。本研究结果表明,不施氮肥的条件下,稻草还田处理的水稻产量比不还田的高10.3%-16.7%,其增产的机理主要是：稻草还田后,由于短时间内氮的固定作用,在生育前期水稻叶片SPAD值低于不还田处理,但在生育中后期,随着稻草的腐烂,被微生物固定的养分逐渐释放到土壤中供植株吸收利用,所以后期水稻叶片SPAD值高于不还田处理,同时提高了根系活力,因此,稻草还田处理的干物质积累速度高于不还田处理,有利于提高单位面积的颖花数,形成较高的干物质积累量和较大的库容,从而提高产量。但施用适量氮肥后,稻草还田引起的促进效应不显著,所以还田处理与不还田处理之间产量也没有显著差异。(3)在本试验条件下,与农民习惯施肥(FFP)相比,实地氮肥管理(SSNM)的氮肥用量降低了16.7%-32.0%,但是在不同年份产量的表现不完全相同,2004和2005年增产效应不显著,但在2006年产量显著增加了5%。SSNM处理在2006年增产的主要原因是穗粒数、单位面积颖花数和收获指数比FFP处理显著增加。(4)稻草还田有利于促进水稻对氮素的吸收。本试验中,在施用氮肥的条件下,与不还田处理相比,秸秆还田处理的植株氮素积累量三年分别增加12.1%、11.1%和5.6%,而在不施氮肥的条件下,三年中秸秆还田处理的植株氮素积累量分别增加了14.4%,25.7%和25.8%。(5)与不还田处理相比,秸秆还田处理的水稻氮肥利用率有显著的提高,其中氮肥农学利用率增加了14.8%-20.6%,偏生产力提高了1.9%-8.4%,生理利用率也提高了4.3%-36.3%。本试验中,通过比较SSNM和FFP处理对氮肥利用率的影响发现,在不同的耕作方式和稻草还田方式下,SSNM的氮肥农学利用率提高幅度达40.5%-54.2%,氮肥偏生产力提高26.5%-50.1%,回收利用率提高了27.7%-62.0%,氮肥利用率提高原因的主要是,SSNM比FFP的氮肥用量大幅下降,但产量与其相当或显著增加。(6)有机肥和化学氮肥配合施用可使水稻产量显著提高12.5%-22.3%,增产的原因主要是干物质积累量和库容(单位面积穗数、穗粒数、单位面积颖花数)显著增加,其次是收获指数的提高。施用有机肥后,水稻顶三叶长度和宽度增加,叶面积和叶面积指数增大,整个生育期叶片含氮量(SPAD值)较高,中后期伤流量较大,生育中后期干物质积累较多,这些均为产量提高的基础。经过分析产量对有机肥和氮肥的反应曲线,结果表明,随着有机肥用量的增加,达到最高产量时的氮肥的用量减少,因此,在有机无机肥配合施用时,应对化学氮肥的用量做出相应调整,以同步提高有机肥和化肥的施肥效应。在本试验条件下,早稻施用的有机肥和化学肥料对晚稻有一定的残效,早稻有机肥用量和氮肥用量高的处理早稻,其后季作物(晚稻)产量显著高于肥料用量较低的处理。更多还原

【Abstract】 At present, the total consumption of chemical fertilizers in China has accounted for about one third of the world’s total consumption, while the consumption per unit field has far exceeded the world’s average level, furthermore, applying chemical fertilizers massively and ignoring organic fertilizers have been the outstanding problems in rice production in China. Low fertilizer-N Use Efficiency, low ratio of output/input and environment pollution, etc, are the new problems need to solve. It’s very useful if we can mixed the organic fertilizer which from agricultural production system and inorganic fertilizer to maintain the long term sustainability of rice production.The objectives of this dissertation were:(1) Prove the effects of tillage and straw return on the growth and rice grain yield; (2) Study the effects of tillage and straw return on fertilizer absorption and fertilizer-N use efficiency; (3) Investigate the effects of site-specific nitrogen management on the growth, grain yield and fertilizer-N use efficiency of rice; (4) Explore the effects of combining tillage and straw return with nitrogen management on the yield and fertilizer-N use efficiency of rice; (5) Study the effects of the mixed application of chemical fertilizers and organic fertilizers on the yield and fertilizer-N use efficiency of rice. In this study, field and pot experiments were conducted, and the following results were obtained:(1) Compared with conventional tillage, zero tillage had the comparable rice yield in our experiment. Influence mechanism of rice growth and yield under different tillage model were studied, the results suggested that, compared with conventional tillage, although the maximum root length and tiller number were litlle lower at early growth stage under zero tillage treatment, however, it had comparable leaf area index, leaf N content (SPAD value) and effective panicles at maturity stage through increased spike rate, moreover, the root bleeding sap increased by 14.3% compared with conventional tillage, and the N, P, K accumulation at maturity stage were no difference between them too.(2) Grain yield was increased after straw returned when no N fertilizer applied, however, yield increasing effect of rice straw return was covered by the increasing effect of fertilizer-N when the amount of N fertilizer applied between 100 kg N ha-1 to 150 kg N ha-1 in our experiment, so no difference was found between straw returned treatment and removed treatment. All straw return and half straw return treatments were not decreased grain yield through site-specific nitrogen management and reasonable water management. In our experiment, compared with no straw return treatment, grain yield of straw return treatment increased from 10.3% to 16.7% when no N-fertilizer applied. That’s because the straw has high C:N ratio, the inorganic N of soil was immobilized by microorganism in shot-term after returned, the leaf SPAD value was lower compared with no return treatment in early growth stage, while with the plant growth, roots can absorb much more nutrient from soil after straw decomposed, so the leaf SPAD was higher compared with no straw return at middle and late growth stage, and increased root activity, so the rate of dry matter accumulation was higer, it benefit to increase the biomass and spikelets per m2, and lead to yield increasing. However, the increasing effect was not significant after straw return under N-fertilizer treatment, that’s the reason of no yield difference between straw returned and no returned treatment.(3) In our experiment, compared with farmers’N-fertilizer practice (FFP), the amount of applied N-fertilizer was dcreased by 16.7%-32.0%, but grain yield of site-specific nitrogen management (SSNM) showed difference trend in different year, no difference was found in 2004 and 2005, however grain yield increased significantly in 2006, the reasons were spikelets per panicle, spikelets per m2 and harvest index increased significantly.(4) Straw return improved the N uptake of rice plant. In our expertiment, compared with straw removed treatment, N uptake was increased by 12.1%,11.1% and 5.6% in three years, respectively, moreover, N uptake was increased more significantly under no fertilizer-N application, and increased by 14.4%,25.7% and 25.8% comparing with no straw return, respectively.(5) Compared with no straw returned treatment, fertilizer-N use efficiency was increased significantly under the straw returned treatment, agronomic use efficiency of fertilizer-N (AE) increased from 14.8% to 20.6%, partial fator productivity (PFP) increased from 1.9% to 8.4%, and physiology use efficiency (PE) increased from 4.3% to 36.3%. Under the different tillage and straw return treatment, we compared the fertilize N use efficiency between SSNM and FFP, the results showed that, AE, PE and recovery efficiency (RE) of SSNM were all significantly higher than that of FFP treatment, 40.5%-54.2%,26.5%-50.1% and 27.7%-62.0% increased, respectively, because compared with FFP treatment, the yield of SSNM treatment is comparable or increased significantly, however, its nitrogen application amount was decreased greatly.(6) Mixed application of organic and inorganic fertilizer increased the rice yield from 12.5% to 22.3% in our experiment, the reasons were significant higher dry matter accumulation and larger sink (panciles per m2, spikelets per panicle and spikelets per m2). After organic fertilizer applied, the length, width and leaf area of rice top three leaves increased, that lead to the leaf area index increased, leaf N content (SPAD value) was higher in whole growth stage, and the root bleeding sap at middle and late growing stage was larger, meanwhile the dry matter accumulation stage was higher, that’s all the basis of the yield increase. After analyzed the response curve of grain yield, the results showed that, with the increase of organic fertilizer applied, fertilizer N amount was decreased when got the highest grain yield, so, we need adjust the amount of fertilizer N when we mixed application of organic and inorganic, to improve the organic and inorganic fertilizer effect together. In our experiment, residual effect of organic and inorganic fertilizer applied in early season was found, grain yield of late season rice was significantly higher when the amount of organic and inorganic fertilizer applied higher in early season.更多还原