稻草还田和合理的氮肥运筹不仅可以改良土壤和培肥地力,提高农作物产量和品质,还可以减少因过量施用氮肥带来的环境污染。随着水稻机械化收割的快速发展,稻草全量原位还田面积迅速扩大。因此,研究稻草全量还田后合理施用氮肥十分必要。本文通过早稻机收稻草切碎全量还田后晚稻氮肥运筹试验,探索该条件下晚稻氮肥的合理施用技术。以超级晚稻品种淦鑫688为试验材料,设计4个施氮(N)水平(0、120、180、240 kg/hm2)基蘖穗肥比例为5：2：3,并在180 kg/hm2水平下增设稻草不还田对照处理和稻草全量还田下基蘖穗肥不同施氮比例处理(5：0：5、5：1：4、5：2：3、5：3：2、5：4：1、5：5：0)。旨在分析不同处理间水稻产量、产量构成和氮素吸收利用的差异。稻草全量还田下,施氮量在180 kg/hm2以下时产量随施氮量的增加而增加,之后则下降,处理间差异极显著。随施氮量的增加,有效穗数显著增加,而结实率则显著下降,施氮处理每穗粒数和千粒重显著高于不施氮处理。在相同施氮水平下,因为有效穗数、结实率和千粒重显著提高,所以稻草全量还田产量极显著高于不还田处理,增幅8.83%。稻草全量还田同一施氮水平下,施氮比例为5：2：3处理产量极显著高于其他处理,其每穗粒数和千粒重均为最高,有效穗数随分蘖肥比例的增加而减少,处理间结实率差异不显著。稻草全量还田后,随着施氮量增加,其氮素总积累量、氮肥表观利用率、氮素的吸收率和百公斤籽粒的需氮量也显著提高,且与施氮量呈极显著正相关。但氮素收获指数和氮肥生理利用率均随施氮量的增加而降低。同一施氮水平下,全量还田处理水稻氮肥农学利用率和生理利用率均显著高于不还田处理。相关分析表明,氮素总积累量与产量呈二次抛物线极显著正相关,氮肥表观利用率、氮素吸收率与产量呈极显著正相关。稻草全量还田相同施氮水平下,随着穗肥施氮比例降低,其氮素总积累量、中期的积累量和比率下降,其氮肥的表观利用率、收获指数和氮素的吸收率也随之降低,但前期的氮素积累量和比率则升高。氮素的农学利用率和生理利用率均表现为随着穗肥比例的减少呈先增加后降低趋势,均以施氮比例为5：2：3处理处理最高,不施穗肥处理最低。各施氮比例处理中,穗肥的施氮量与氮素的总积累量、中期积累量、氮肥的表观利用率、收获指数和氮素吸收率呈极显著正相关,氮肥的农学利用率和生理利用率与产量显著正相关。稻草全量还田后配施适量的氮肥可以提高晚稻产量,本试验以配施N 180 kg/hm2产量最高；在施纯N 240 kg/hm2以内,施氮越多,氮素积累量越多,相应的氮肥表观利用率、氮素的吸收率和百公斤籽粒的需氮量也越大。总施氮量相同条件下,以基肥：分蘖肥：穗肥为5：2：3的施氮比例水稻产量,氮肥农学、生理利用率均为最高,此结果可作为双季稻区稻草全量还田后的推荐施氮比例。
稻草還田和閤理的氮肥運籌不僅可以改良土壤和培肥地力,提高農作物產量和品質,還可以減少因過量施用氮肥帶來的環境汙染。隨著水稻機械化收割的快速髮展,稻草全量原位還田麵積迅速擴大。因此,研究稻草全量還田後閤理施用氮肥十分必要。本文通過早稻機收稻草切碎全量還田後晚稻氮肥運籌試驗,探索該條件下晚稻氮肥的閤理施用技術。以超級晚稻品種淦鑫688為試驗材料,設計4箇施氮(N)水平(0、120、180、240 kg/hm2)基蘗穗肥比例為5：2：3,併在180 kg/hm2水平下增設稻草不還田對照處理和稻草全量還田下基蘗穗肥不同施氮比例處理(5：0：5、5：1：4、5：2：3、5：3：2、5：4：1、5：5：0)。旨在分析不同處理間水稻產量、產量構成和氮素吸收利用的差異。稻草全量還田下,施氮量在180 kg/hm2以下時產量隨施氮量的增加而增加,之後則下降,處理間差異極顯著。隨施氮量的增加,有效穗數顯著增加,而結實率則顯著下降,施氮處理每穗粒數和韆粒重顯著高于不施氮處理。在相同施氮水平下,因為有效穗數、結實率和韆粒重顯著提高,所以稻草全量還田產量極顯著高于不還田處理,增幅8.83%。稻草全量還田同一施氮水平下,施氮比例為5：2：3處理產量極顯著高于其他處理,其每穗粒數和韆粒重均為最高,有效穗數隨分蘗肥比例的增加而減少,處理間結實率差異不顯著。稻草全量還田後,隨著施氮量增加,其氮素總積纍量、氮肥錶觀利用率、氮素的吸收率和百公斤籽粒的需氮量也顯著提高,且與施氮量呈極顯著正相關。但氮素收穫指數和氮肥生理利用率均隨施氮量的增加而降低。同一施氮水平下,全量還田處理水稻氮肥農學利用率和生理利用率均顯著高于不還田處理。相關分析錶明,氮素總積纍量與產量呈二次拋物線極顯著正相關,氮肥錶觀利用率、氮素吸收率與產量呈極顯著正相關。稻草全量還田相同施氮水平下,隨著穗肥施氮比例降低,其氮素總積纍量、中期的積纍量和比率下降,其氮肥的錶觀利用率、收穫指數和氮素的吸收率也隨之降低,但前期的氮素積纍量和比率則升高。氮素的農學利用率和生理利用率均錶現為隨著穗肥比例的減少呈先增加後降低趨勢,均以施氮比例為5：2：3處理處理最高,不施穗肥處理最低。各施氮比例處理中,穗肥的施氮量與氮素的總積纍量、中期積纍量、氮肥的錶觀利用率、收穫指數和氮素吸收率呈極顯著正相關,氮肥的農學利用率和生理利用率與產量顯著正相關。稻草全量還田後配施適量的氮肥可以提高晚稻產量,本試驗以配施N 180 kg/hm2產量最高；在施純N 240 kg/hm2以內,施氮越多,氮素積纍量越多,相應的氮肥錶觀利用率、氮素的吸收率和百公斤籽粒的需氮量也越大。總施氮量相同條件下,以基肥：分蘗肥：穗肥為5：2：3的施氮比例水稻產量,氮肥農學、生理利用率均為最高,此結果可作為雙季稻區稻草全量還田後的推薦施氮比例。
도초환전화합리적담비운주불부가이개량토양화배비지력,제고농작물산량화품질,환가이감소인과량시용담비대래적배경오염。수착수도궤계화수할적쾌속발전,도초전량원위환전면적신속확대。인차,연구도초전량환전후합리시용담비십분필요。본문통과조도궤수도초절쇄전량환전후만도담비운주시험,탐색해조건하만도담비적합리시용기술。이초급만도품충감흠688위시험재료,설계4개시담(N)수평(0、120、180、240 kg/hm2)기얼수비비례위5：2：3,병재180 kg/hm2수평하증설도초불환전대조처리화도초전량환전하기얼수비불동시담비례처리(5：0：5、5：1：4、5：2：3、5：3：2、5：4：1、5：5：0)。지재분석불동처리간수도산량、산량구성화담소흡수이용적차이。도초전량환전하,시담량재180 kg/hm2이하시산량수시담량적증가이증가,지후칙하강,처리간차이겁현저。수시담량적증가,유효수수현저증가,이결실솔칙현저하강,시담처리매수립수화천립중현저고우불시담처리。재상동시담수평하,인위유효수수、결실솔화천립중현저제고,소이도초전량환전산량겁현저고우불환전처리,증폭8.83%。도초전량환전동일시담수평하,시담비례위5：2：3처리산량겁현저고우기타처리,기매수립수화천립중균위최고,유효수수수분얼비비례적증가이감소,처리간결실솔차이불현저。도초전량환전후,수착시담량증가,기담소총적루량、담비표관이용솔、담소적흡수솔화백공근자립적수담량야현저제고,차여시담량정겁현저정상관。단담소수획지수화담비생리이용솔균수시담량적증가이강저。동일시담수평하,전량환전처리수도담비농학이용솔화생리이용솔균현저고우불환전처리。상관분석표명,담소총적루량여산량정이차포물선겁현저정상관,담비표관이용솔、담소흡수솔여산량정겁현저정상관。도초전량환전상동시담수평하,수착수비시담비례강저,기담소총적루량、중기적적루량화비솔하강,기담비적표관이용솔、수획지수화담소적흡수솔야수지강저,단전기적담소적루량화비솔칙승고。담소적농학이용솔화생리이용솔균표현위수착수비비례적감소정선증가후강저추세,균이시담비례위5：2：3처리처리최고,불시수비처리최저。각시담비례처리중,수비적시담량여담소적총적루량、중기적루량、담비적표관이용솔、수획지수화담소흡수솔정겁현저정상관,담비적농학이용솔화생리이용솔여산량현저정상관。도초전량환전후배시괄량적담비가이제고만도산량,본시험이배시N 180 kg/hm2산량최고；재시순N 240 kg/hm2이내,시담월다,담소적루량월다,상응적담비표관이용솔、담소적흡수솔화백공근자립적수담량야월대。총시담량상동조건하,이기비：분얼비：수비위5：2：3적시담비례수도산량,담비농학、생리이용솔균위최고,차결과가작위쌍계도구도초전량환전후적추천시담비례。
Objectives Rice straw incorporation and appropriate nitrogen ( N ) management can not only improve soil fertility and crop yield, but also reduce environmental pollution. With the rapid development of mechanized harvest, the area of in situ total incorporation of rice straw is expanded rapidly. Thus, it is important to determine reasonable N fertilization regimes under the total incorporation of rice straw. The objective of this study is to investigate the proper management for late rice under total incorporation of chopped early rice straw by a combine harvester. [Methods]Using a late rice variety ( Ganxin 688 ) as materials the experiment included four N rates (0, 120, 180 and 240 kg/hm2) with a ratio of 5:2:3 for basal, tillering, and panicle initiation, respectively. At the same time, under the N rate of 180 kg/hm2 , a control treatment without straw return and different N application ratios (5:0:5, 5:1:4, 5:2:3, 5:3:2, 5:4:1, 5:5:0 for basal, tillering, and panicle initiation, respectively) under total incorporation of rice straw were arranged. Rice yield, yield components, N absorption and utilization in different treatments were investigated. [Results]The yield increased with increasing N application rates, and was highest at the N rate of 180 kg/hm2 under total incorporation of rice straw. The number of effective panicles increased with increasing application rates, while the percentage of filled grains showed the opposite trend. In comparison with no straw retention, the higher yield under straw retention mainly attributed to the higher number of effective panicles, percentage of filled grains and 1000-grain weights, with an increase of 8. 83% in yield. Under the same N rate, the yield, number of grains per panicle, and 1000-grain weight were the highest at the N ratio of 5:2:3. The number of effective panicles decreased with increasing N proportions at the tillering stage, while the percentage of filled grains showed no significant differences among treatments. Under straw incorporation, the N accumulation, N recovery efficiency (NRE), N uptake rate (NUR) and N requirement for producing 100-kg grain increased with increasing N application rates. However, N harvest index ( NHI ) and nitrogen physiological efficiency ( NPE) decreased with increasing N application rates. Under the same N rate, the nitrogen agronomic efficiency ( NAE ) and NPE under total incorporation of rice straw were significantly higher than those under no straw incorporation. The correlation between yield and N accumulation was quadratic. NRE and NUR were significantly positively correlated with yield. Under the same nitrogen rate with total incorporation of rice straw, total N accumulation ( TNA) , N accumulation ratio in middle stage, NRE, NHI, and NUR were decreased with decreasing N proportions at panicle initiation, whereas N accumulation and ratio in early stage were increased. Both NAE and NPE were increased at first, but then decreased with decreasing N proportions at panicle initiation with the highest at the ratio of 5:2:3. The N application rate at panicle initiation was significantly positively correlated with TNA, N accumulation in middle stage, NRE, NHI and NUR, while NAE and NPE were positively correlated with yield. [Conclusion]The highest yield achieved when the N application rate is 180 kg/hm2. The N accumulation, NRE, NUR and N requirement for producing 100-kg grain increased with increasing N application rates from 0 to 240 kg/hm2. Under the same N application rate, the highest yield, the highest NAE and NPE can be achieved with the N application ratio of 5:2:3 for basal, tillering, and panicle initiation, respectively.
