Yield performance and optimal nitrogen and phosphorus application rates in wheat and faba bean intercropping

Yield performance in cereal and legume intercropping is related to nutrient management,however,the yield response of companion crops to nitrogen(N)input is inconclusive and only limited efforts have focused on rationed phosphorous(P)fertilization.In this study,two multi-year field experiments were implemented from 2014-2019 under identical conditions.Two factors in a randomized complete block design were adopted in both experiments.In field experiment 1,the two factors included three planting patterns(mono-cropped wheat(MW),mono-cropped faba bean(MF),and wheat and faba bean intercropping(W//F))and four N application rates(N0,0 kg N ha^(-1);N1,90 and 45 kg N ha^(-1) for wheat and faba beans,respectively;N2,180 and 90 kg N ha^(-1) for wheat and faba beans,respectively;and N3,270 and 135 kg N ha^(-1) for wheat and faba beans,respectively).In field experiment 2,the two factors included three P application rates(P0,0 kg P_(2)O_(5) ha^(-1);P1,45 kg P_(2)O_(5) ha^(-1);and P2,90 kg P_(2)O_(5) ha^(-1))and the same three planting patterns(MW,MF,and W//F).The yield performances of inter-and mono-cropped wheat and faba beans under different N and P application rates were analyzed and the optimal N and P rates for intercropped wheat(IW)and MW were estimated.The results revealed that intercropping favored wheat yield and was adverse to faba bean yield.Wheat yield increased by 18-26%,but faba bean yield decreased by 5-21% in W//F compared to MW and MF,respectively.The stimulated IW yield drove the yield advantage in W//F with an average land equivalent ratio(LER)of 1.12.N and P fertilization benefited IW yield,but reduced intercropped faba bean(IF)yield.Nevertheless,the partial LER of wheat(pLER_(wheat))decreased with increasing N application rates,and the partial LER of faba bean(pLER_(faba bean))decreased with increasing P application rates.Thus,LER decreased as N input increased and tended to decline as P rates increased.IW maintained a similar yield as MW,even under reduced 40-50% N fertilizer and 30-40% P fertilizer conditions.The estimated optimum N application rates for IW and MW were 150 and 168 kg ha^(-1),respectively,and 63 and 62 kg ha^(-1) for P_(2)O_(5),respectively.In conclusion,W//F exhibited yield advantages due to stimulated IW yield,but the intercropping yield benefit decreased as N and P inputs increased.Thus,it was concluded that modulated N and P rates could maximize the economic and ecological functions of intercropping.Based on the results,rates of 150 kg N ha^(-1) and 60 kg P_(2)O_(5) ha^(-1) are recommended for IW production in southwestern China and places with similar conditions.

Optimum Application Rate of Nitrogen in Summer Peanut in Southern Shandong Area

[Objectives]To study the effect of nitrogen(N)on the growth demand of summer peanuts under a certain level of phosphorus and potassium fertilizers,and to carry out experiments on nitrogen fertilizer control of summer peanuts.[Methods]Four treatments were set up in the experiment:no-nitrogen plot(N 0P_(4)K_(4)),optimized nitrogen plot(N_(7)P_(4)K_(4)),70%optimized nitrogen plot(N_(5)P_(4)K_(4)),130%optimized nitrogen plot(N 9P 4K 4),repeated 3 times,and arranged in random blocks.The area of the plot was 42 m^(2),ridges were set between the plots,and protective rows of more than 1 m were set around the experimental site.The types of fertilizers were urea,superphosphate,and imported potassium chloride,and the variety of peanuts was Linhua 5.Except for the level of fertilization,other agricultural operations were the same,and soil sampling tests,field records,and yield testing were carried out according to the requirements of the plan.[Results]On the basis of 60 kg/ha of phosphorus and potassium fertilizer application,the optimum economical fertilizer application rate and the highest application rate of pure nitrogen were about 115.20 and 131.25 kg/ha,respectively.[Conclusions]This study is expected to provide a certain basis for the high-quality and high-yield summer peanuts in southern Shandong area.

Effect Models of Nitrogen,Phosphorus and Potassium Fertilizer Formulation in Banana

[Objective] The aim was to modify the application amount of N,P and K fertilizer so as to provide a reference for establishing balanced fertilization index system of banana.[Method]The N,P and K fertilizer ＂3414＂ test was carried out on banana,and then regression analysis was performed on the fertilizer effect.Ternary quadratic,binary quadric and one-variable quadratic regression equations for the fertilizer effect on the banana yield were constructed.[Result]Suitable amount of N,P and K fertilizer had significant yield improving effect,whereas overdose of fertilizer application led to decreasing of utilization rate of fertilizer.Therefore,suitable amount of N,P and K fertilizer should be selected in production.It could be concluded that one-variable quadratic regression equations was the best model to calculate the suitable fertilizer amount.The best yield range of banana in the tested field was 44.193-45.904 t/hm2,while the corresponding optimum application amount of N,P2O5 and K2O was 795.1,262.3 and 1 236.9 kg/hm2 respectively,and the ratio among nitrogen,phosphorus and potassium are 1∶0.33∶1.55.[Conclusion]The result in this study could provide references for the soil types similar to the tested field.

Effects of Increased Planting Density with ReducedNitrogen Application on Yield Formation and NitrogenUtilization of Autumn Maize

With the change of cropping system in the middle reaches of the Yangtze River,the planting area of autumn maize is gradually increasing.However,the cultivation techniques are still under improvement for higher yield and nitrogen efficiency of autumn maize.Increase in planting density with reduced nitrogen fertilizer application is one of the important paths to achieve high yield and high nitrogen utilization efficiency.Meanwhile,the effect needs to be verified for autumn maize.The semi-compact autumn maize variety Qinyu 58 was planted under different planting densities and nitrogen fertilizer amounts with the split plot design.Different nitrogen application rates were arranged in the main plots,including the conventional nitrogen application(N300,300 kg/hm^2),30%reduction from the conventional treatment(N210,210 kg/hm^2)and no nitrogen application(N0).Different planting densities were arranged in the sub-split plots,including the conventional planting density(D60,60000 plants/hm2),medium density(D78,78000 plants/hm^2)and high density(D93,93000 plants/hm2).The effects of nitrogen fertilizer,planting density and their interaction effects on canopy structure,dry matter accumulation,yield and nitrogen use efficiency of autumn maize were studied.The nitrogen application rate and planting density had obvious interaction effects on the yield formation of autumn maize.Compared with the conventional cultivation(N300D60),increasing the planting density with 30%reduction in nitrogen application(N210)can obviously increase the canopy light interception rate,LAI,dry matter accumulation and yield.However,there was no significant change in canopy light interception rate,LAI,dry matter accumulation,grain weight and yield between D93 and D78.Compared with N300D60,nitrogen translocation efficiency and nitrogen contribution proportion to grain nitrogen did not change significantly in autumn maize grown under N210 and D78 treatments,whereas nitrogen partial productivity,nitrogen agronomic efficiency and recovery and utilization efficiency of nitrogen fertilizer increased significantly.Moreover,high density(D93)planting at N210 plots significantly improved nitrogen transport efficiency and utilization efficiency in autumn maize.Therefore,the suitable planting density of the autumn maize variety Qinyu 58 in Hubei Province is recommended a value of 78000 plants/hm^2,with the nitrogen application rate of 210 kg/hm2,which can achieve the target of higher yield by increasing density and reducing nitrogen.

推荐施肥量下控释肥替代普通尿素提高高粱产量和氮肥生产力

【目的】高粱生产中氮肥施用不合理,氮肥利用效率低,研究适宜重庆地区高粱种植的控释氮肥减施比例,在减少氮肥用量的同时,确保高粱稳产高产,提高肥料利用效率。【方法】田间定位试验于2021、2022年在重庆永川进行,供试高粱品种为晋渝糯3号和金糯粱1号。设置6个处理,分别为不施氮肥(CK);习惯尿素施肥量(U,N 180 kg/hm^(2));尿素推荐施用量(U1,减N 20%,N 144 kg/hm^(2));控释氮肥减施氮量20%(C1,N144 kg/hm^(2));控释氮肥减施氮量30%(C2,N 126 kg/hm^(2));控释氮肥减施氮量40%(C3,N 108 kg/hm^(2))。在高粱开花期和成熟期,调查干物质积累量和转运量,成熟期调查植株和籽粒氮素含量、生物量、产量及产量构成因素。【结果】开花期和成熟期高粱干物质积累量均以C1和U1处理最高,C1处理成熟期干物质积累量又显著高于U1。C1处理叶片花前干物质转运量显著高于U。花后干物质积累量C1处理显著高于其他处理,U1和C2处理显著高于U处理。C1处理晋渝糯3号和金糯粱1号花后干物质积累量对籽粒的贡献率较U分别显著提高了11.54%和12.41%。C1处理的高粱产量最高(晋渝糯3号6611 kg/hm^(2),金糯粱1号5690 kg/hm^(2)),较其他施氮处理显著提高了5.40%~18.66%;其次为C2和U1处理,二者的产量均显著高于U和C3处理。各施氮处理的氮肥生理利用率(NPE)差异不显著;减氮处理间氮肥农学利用率(NAE)无显著差异,氮肥偏生产力(NPFP)差异显著,其NAE和NPFP均显著高于习惯施氮处理U;控释肥各减氮处理的NPFP显著高于普通氮肥推荐量处理U1。C1处理较U处理大幅提高了NAE、NPFP和氮肥利用率(NUE),晋渝糯3号分别提高了58.54%、39.61%和59.28%,金糯粱1号分别提高了80.97%、48.30%和63.08%;与U1处理相比,晋渝糯3号的NPFP、NUE分别提高了5.38%和22.19%,金糯粱1号分别提高了5.82%和4.42%。【结论】推荐施氮量下,用控释肥替代普通氮肥增加了高粱开花期和成熟期干物质积累量,提高了叶片花前干物质转运量和花后干物质积累量及其对籽粒的贡献率,提升了高粱产量和氮肥利用效率,可作为西南地区高粱生产的推荐氮肥施用方式。

水肥一体化下施氮量对土壤有机氮组分及玉米产量的影响

为进一步优化玉米水肥一体化施肥技术,促进氮肥有效转化利用,研究不同施氮量对土壤有机氮组分及玉米产量的影响。结果表明,随施氮量的增加,土壤酸解总氮、酸解铵态氮、酸解氨基酸态氮和酸解氨基糖态氮含量呈先上升后下降趋势,当施氮量为210 kg·hm^(-2)(N2处理)时,以上4种有机氮组分含量最高。酸解铵态氮是影响玉米产量的关键因素,N2处理下酸解铵态氮含量较N3(252 kg·hm^(-2))、N4(273 kg·hm^(-2))、N1(147 kg·hm^(-2))和N0(0 kg·hm^(-2))分别显著提高3.55%、9.86%、20.37%和170.21%;产量分别显著提高1.58%、2.97%、18.43%和112.89%。综上,N2处理(施氮肥210 kg·hm^(-2))具有更高的供氮潜力,是较为理想的施氮量。

稻麦复种模式下氮肥与稻秸互作对小麦产量和N_(2)O排放影响及推荐施肥研究

优化氮肥施用和秸秆还田技术为途径的农业管理措施被认为是提升农业可持续性的有效手段,然而当前关于氮肥和秸秆还田对小麦产量和N_(2)O排放影响的研究仍十分有限。为此,本研究基于2000—2022年发表的关于长江中下游流域氮肥和秸秆投入下小麦产量和N_(2)O排放变化的文献,运用随机森林建模,定量分析氮肥和秸秆还田对小麦产量和N_(2)O排放的影响,并结合情景设置进行了特定地点的小麦产量和N_(2)O排放模拟,同时评估了碳排放强度(CEE)和净生态系统经济效益(NEEB)。结果表明,建立的区域尺度小麦产量与N_(2)O排放对氮秸互作响应的随机森林模型,验证结果R^(2)分别为0.66和0.65,RMSE分别为0.70和1.11。结果表明施氮量和土壤有机质是影响小麦产量和N_(2)O排放的重要因素。综合来看,达到最大产量所需的氮肥量为208~212 kg hm^(-2),达到最小CEE所需的氮肥量为113~130 kg hm^(-2),达到最高的NEEB所需的氮肥量为202~205 kg hm^(-2),其中在6.75 t hm^(-2)的秸秆投入下施用202 kg hm^(-2)的氮肥可以获得最高的生态收益1.37万元。优化氮肥和秸秆投入具备减少作物碳排放强度并获得最大净生态环境效益的潜力。

不同秸秆还田方式下黑土玉米田肥料氮素去向

探究不同秸秆还田方式下肥料氮在连续两季作物系统中的去向,为黑土地保护下的氮肥管理提供重要依据。于2020—2021年在吉林梨树开展大田微区试验,设置无秸秆还田(CK)、深翻还田(DTS)、免耕覆盖还田(NTS)3种秸秆还田方式,每种方式下设置2个施氮水平:180 kg·hm^(-2)(N1)和270 kg·hm^(-2)(N2)。结果表明:当季和第二季玉米成熟期植株氮分别有38.0%~46.8%和12.9%~18.6%来源于^(15)N标记氮肥。肥料氮当季平均利用、残留和损失率分别为32.4%~43.9%、32.8%~51.4%和13.2%~32.7%,秸秆覆盖配施适量氮肥(180 kg·hm^(-2))处理下肥料氮当季利用率显著提高29.5%,而秸秆深翻还田则使肥料氮在土壤中的残留率显著增加18.6%。当季施用肥料氮仍有8.5%~14.9%被第二季玉米吸收利用,两季累积利用率达40.9%~58.8%,在高氮(270 kg·hm^(-2))下秸秆深翻还田显著提高肥料氮的第二季利用率及累积利用效率。综上,秸秆覆盖还田配施适量氮肥有利于提高肥料利用效率,而秸秆深翻还田更有利于高施氮量下土壤对肥料氮的保持,增加其被下季作物利用的机会,两者均能显著减少氮的损失。

宁夏六盘山区芹菜栽培对氮肥施用量的响应差异

为解决宁夏六盘山区芹菜生产过程中由于氮肥施用不当引起的一系列问题,以芹菜品种皇后为供试材料,通过单因素多水平随机区组试验设计,研究不同供氮水平(0、150、300、450、600 kg‧hm^(-2))对芹菜产量和品质等方面的影响。结果表明,适量的氮肥施用有助于芹菜对钾素和磷素的吸收,在增施氮肥后,能够提高芹菜的植株高度、植株周长、叶柄长、干物质积累和产量,且增产范围在15.65%~33.28%。通过对产量进行回归分析得出,芹菜取得最高产量时氮肥用量为394.75 kg·hm^(-2),最佳经济效益氮肥用量为287.07 kg·hm^(-2)。此外,在一定范围内增施氮肥,会提高芹菜的硝酸盐、粗纤维、维生素C和可溶性固形物含量。采用TOPSIS法对芹菜的多项指标进行评价,N450处理的评分最高,N0处理最低。综上,为减少土壤环境污染,提高氮肥利用率,推荐宁夏六盘山区种植芹菜时氮肥施用量为287.07~394.75 kg·hm^(-2)。

Effects of different ration of NPK fertilizer on the grain yield and protein content in forage rice

Different ratios of NPK were adopted in this research to study its effects on the objective traits of 2 early forage-rice varieties, and to obtain the optimum ratio to further improve the application technique in theory. At the same time, the possibility of increasing yield and protein content in the grain through cultivation technique was also studied. The conclusions were：

施氮量和穴苗数对中籼稻钵苗有序机抛产量和氮肥利用率的影响

为了筛选杂交中籼水稻钵苗有序机抛穴苗数和氮肥用量,本试验以玮两优8612为材料,研究了穴苗数(1、2和3苗/穴)和不同氮肥用量(0、90、180、270和360 kg/hm^(2))对水稻钵苗有序抛栽产量及氮肥利用率的影响。结果表明,水稻群体结构及生育期均受大田施氮量和穴苗数的协同影响。产量以N18D1处理时最高,为13315.54 kg/hm^(2)。氮肥利用率方面,在中低氮水平下,随着施氮量和基本苗的提高,氮肥农学利用率呈增加趋势,而在高氮水平下,其随着施氮量及基本苗的增加而下降;氮肥偏生产力随着氮量及基本苗的增加而降低。综合来看,适宜的氮素水平(270 kg/hm^(2))和基本苗数(穴苗数为1~2苗)有利于促进水稻分蘖、提高氮肥利用效率,进而获得水稻高产。

低肥力土壤不同施氮量及配施有机肥对烤烟生长发育及产质量的影响

以‘云烟87’为供试品种,采用大田试验方法研究低肥力土壤不同施氮量及配施有机肥对烤烟生长发育及产质量的影响。结果表明,在一定范围内施氮量的增加促进了烟株的生长发育,有利于烤烟产量和质量的形成,但是纯氮量增加到126 kg/hm^(2)时病害加重,烤烟质量有降低趋势,增施腐熟农家肥处理农艺性状、经济性状优于增施商品有机肥处理。从田间表现、农艺性状、抗逆性及经济指标综合分析T4处理(处理1的施肥量+腐熟农家肥16500 kg/hm^(2))表现最好,其次是T5处理(处理1的施肥量+商品有机肥1500 kg/hm^(2)),T2处理(按当地常规肥量增加10%施用烟草专用复合肥,施氮量115.5 kg/hm^(2))次之,T3处理(按当地常规肥量增加20%施用烟草专用复合肥,施氮量126 kg/hm^(2))和T1处理(常规对照,施氮量105 kg/hm^(2))表现较差,T6处理(无肥对照)表现最差。

氮肥优化对凤头姜产量和养分吸收利用的影响

通过2年田间试验,研究了来凤县凤头姜最佳施氮量及优化施肥对凤头姜产量和养分吸收利用的影响。结果表明,随着施氮量的增加,凤头姜产量、干物质量和氮素累积量均呈先增加后降低的变化趋势,且以450~495 kg/hm2施氮量为最佳。不同施氮量对凤头姜氮素利用效率和氮素农学利用率的影响不显著,但是增加施氮量却降低了氮肥偏生产力。与常规施肥(CF)相比,专用肥(SF)和缓控释肥(SRF)处理凤头姜产量分别增加了25.23%和13.96%,专用肥能够获得更高的干物质量和氮素累积量。较常规施肥而言,专用肥处理氮素利用效率、氮素农学利用率和氮肥偏生产力分别增加了19.33%、62.58%和25.23%,而缓控释肥处理则分别增加了13.33%、34.66%和13.96%。

氮肥减量调优对优良食味粳稻产量与品质的影响

2021年进行了氮肥减量、比例调优试验,结果表明:在减氮10%的情况下,控制基蘖肥与穗肥的比例在6∶4,减产幅度降低至3.3%左右,稻米食味值提高3.5分,整精米率提高4.31个百分点;控制基蘖肥与穗肥的比例在7∶3,稻米的食味值提高7分,整精米率提高3.04个百分点,减产幅度控制在5.9%左右。

不同地力条件下施氮量对杂交籼稻干物质积累、氮肥利用率和产量的影响

在大田试验条件下,以宜香优2115为试验材料,设地力(高、较高、中、低)和施氮量(0、75、150和225kg/hm^(2))两因素处理,探明不同地力条件下施氮量对杂交籼稻干物质积累、转运和产量及氮肥利用率的影响。结果表明,随着施氮量增加,穗前和成熟期干物质积累量有增加趋势;抽穗期至成熟期,随着施氮量的增加,茎叶干物质转运量和茎叶干物质转运对穗部贡献率均呈先增加后降低的趋势;随着施氮量的增加,氮肥吸收利用率、农学利用率和偏生产力,以及千粒重和结实率逐渐降低,每穗粒数和产量先增加后降低,而有效穗数逐渐升高。随着地力条件的降低,穗前、成熟期和穗后干物质积累量、茎叶干物质转运量和茎叶干物质对穗部的贡献率及穗部干物质增加量均呈逐渐下降趋势,氮肥吸收利用率和生理利用率亦有降低趋势,而偏生产力呈先增后降的趋势。水稻有效穗数和产量均随土壤地力的提高而增加,而每穗粒数表现为下降。回归分析表明,在高、较高、中、低地力条件下,水稻可获得的最高产量分别为10829.94、10107.20、9757.30和9112.37 kg/hm^(2),其对应的适宜施氮量分别为141.96、165.47、154.86和152.98 kg/hm^(2)。综上所述,中等施氮量能够使杂交籼稻在不同地力条件下获得较高的干物质积累量和转运能力,及较高的氮肥利用率,实现高产稳产。

施氮量和磷肥运筹对青贮玉米产量及养分利用的影响

【目的】探讨不同施氮量和磷肥运筹对青贮玉米产量及养分吸收利用的影响,为青贮玉米的绿色高效栽培提供理论依据。【方法】2021—2022年,以青贮玉米品种桥单6号为试验材料进行田间试验,设N1(减氮20%,240 kg/ha)和N2(常规施氮,300 kg/ha)2个施氮处理,每个施氮水平下分别设3种磷肥施用方式:P1(100%基肥)、P2(50%基肥,50%穗肥)、P3(50%拔节肥,50%穗肥),共6个施肥处理。测定不同施氮量和磷肥施用方式下青贮玉米的干物质积累量、鲜草产量、养分吸收利用量及土壤养分含量和酶活性。【结果】施氮量影响青贮玉米生物量,总体表现为N1处理低于N2处理。磷肥追施可提高青贮玉米生物产量,在N1水平下,P2处理显著高于P3和P1处理(P<0.05,下同);N2水平下,P3处理显著高于P2和P1处理。在各处理组合中,N1P2和N2P3处理的鲜草产量较N2P1处理(常规施肥)增产显著。氮磷素的吸收量也表现为N2处理高于N1处理,同时,追施磷肥可显著提高氮磷养分吸收利用量。在N1水平下,乳熟期的氮磷素吸收量均表现P2>P3>P1;N2水平下则表现为P3>P2>P1。在各处理中,N2P3处理在乳熟期的氮磷素吸收量显著高于N1P2和N2P1处理;与N2P1处理相比,N1P2处理2021年和2022年氮素吸收量分别提高9.52%和9.03%,磷素吸收量分别提高4.69%和9.45%,且玉米磷素与氮素吸收在吐丝期和乳熟期表现出极显著正相关关系(P<0.01)。此外,减氮20%总体会降低磷肥偏生产力,但能提高氮肥偏生产力。与N2P1处理相比,N1P2处理的氮肥偏生产力2021和2022年分别显著提高36.91%和39.62%。N2P3处理磷肥偏生产力显著高于N2P1和N1P2处理;N1P2较N2P1处理,2021和2022年分别提高4.71%和9.51%。减氮20%总体会降低碱解氮和速效磷含量及脲酶和酸性磷酸酶活性,而磷肥追施可提高酶活性,增加土壤速效养分,基本表现为P2和P3处理高于P1处理。在各处理中,N1P2和N2P3较N2P1处理能保持较高的土壤脲酶和酸性磷酸酶活性,促进碱解氮和速效磷的积累,增加植株干物质积累量和氮磷素吸收利用量。【结论】磷肥作追肥提高了土壤酶活性和土壤速效养分,促进了玉米对养分的吸收利用,从而缓解减氮造成的产量损失。从施氮量和磷肥施用方式看,N1P2和N2P3处理表现出氮磷养分资源的高效利用和产量的提高。

施氮方式与添加脲酶/硝化抑制剂对稻季NH_(3)挥发和N_(2)O排放的影响

【目的】分析施肥方式及添加脲酶/硝化抑制剂对稻田NH3挥发和N_(2)O排放的影响,基于稻田NH_(3)和N_(2)O减排的效果评价优化施肥措施的可行性。【方法】在太湖地区开展为期两年的稻季田间小区试验,供试脲酶抑制剂为N-丁基硫代磷酰三胺(NBPT),硝化抑制剂为对羟基苯丙酸甲酯(MHPP),用量为施氮量的1%。设置6个处理:1)不施氮肥对照(CK);2)表施尿素N 300 kg/hm^(2)(当地常规施肥,CN);3)表施尿素N 225 kg/hm2(RNB);4)尿素N 225 kg/hm^(2),50%表施,50%深施(RND);5)表施尿素N 225 kg/hm^(2)+NBPT+MHPP(RNB+DI);6)尿素N 225 kg/hm^(2)+NBPT+MHPP,50%表施,50%深施(RND+DI)。每次施肥后两周内,用密闭式抽气法监测稻田NH3挥发,在水稻生育期内用静态箱—气相色谱法监测稻田N2O排放。【结果】1) NH_(3)挥发主要发生在每次施氮后7天内,CN、RNB和RNB+DI处理基肥和分蘖肥施用后的NH3挥发量占总挥发量的86.63%~91.76%;稻季N_(2)O排放峰期主要出现在每次施肥后一周内和中期烤田期。2) RNB比CN处理可减少NH3挥发总量29.69%~39.41%和N_(2)O排放总量13.43%~23.37%。3) RND比RNB处理可减少NH_(3)挥发总量53.50%~72.05%和N2O排放总量16.66%~23.43%。4) RNB+DI比RNB处理可减少NH3挥发总量9.57%~22.27%和N_(2)O排放总量8.77%~15.67%。5) RND+DI比CN处理可减少NH3挥发总量76.89%~82.29%和N_(2)O排放总量37.98%~48.71%。【结论】尿素总氮投入减少25%,50%由撒施改为基肥深施,并添加脲酶/硝化抑制剂,可显著减少稻季NH3挥发和N2O总排放,特别是降低NH3挥发的效果更佳;将这3种措施组合集成的RND+DI处理减排效果最佳。该综合集成措施的实际操作性强,为在水稻生产上推广应用提供了技术支撑。

基于^(15)N标记的干旱区滴灌肥料氮的去向和效益研究

【目的】采用^(15)N示踪法,研究滴灌肥料氮与土壤氮素的转化和去向以及在土壤中的残留分布,为新疆滴灌春小麦氮肥优化管理提供科学依据。【方法】试验于2019年在石河子大学农学院试验站进行,供试春小麦材料为强筋型‘新春38’(XC38)和中筋型‘新春49’(XC49)。试验设7个施氮(N)水平:300、285、270、255、240、225和0 kg/hm^(2),分别记作N300、N285、N270、N255、N240、N225和N0处理。每个试验小区内,安装未封底的PVC管(直径11 cm,高65 cm),管内施用与该处理等量的^(15)N标记尿素。于小麦成熟期,测定PVC管内植株样品与土壤样品中的^(15)N丰度,同时在小区内测定产量,计算氮素利用效率。【结果】两品种春小麦吸收的氮素来自肥料的比例为30.49%~36.06%,对土壤氮的依赖程度在60%以上。随着氮肥施用量的降低,对土壤氮的依赖程度逐渐增加。^(15)N标记氮肥在土壤中的总残留率为24.05%~31.60%,主要集中在0—40 cm土层,土壤^(15)N残留量与^(15)N总回收率随施氮量的降低而逐渐降低,^(15)N吸收利用率随施氮量的降低呈先升高后降低趋势。XC38强筋小麦各器官对肥料氮的吸收量为43.1~61.3 kg/hm^(2),占总吸氮量的30.94%~36.06%,高于中筋小麦XC49的42.3~54.5 kg/hm^(2)和30.81%~34.39%。XC38小麦在N270处理下产量最高,为7384.0 kg/hm2;XC49小麦在N255处理下氮肥农学利用效率最高,为7236.1 kg/hm^(2)。【结论】在滴灌施肥条件下,作物当季肥料氮吸收量占比平均为19.79%,0—60 cm土层中的平均残留率为27.86%,平均总回收率为47.64%。提高施氮量可提高小麦对肥料氮的吸收及其比例,且增加土壤中氮素的残留率,有效补充土壤氮库。虽然强筋型小麦XC38对肥料氮素的吸收强于中筋型小麦XC49,但对肥料氮的基本去向没有显著影响。综合考虑产量和氮肥利用效益,春小麦XC38和XC49适宜的施氮量分别为N 270 kg/hm^(2)和225 kg/hm^(2)。

中国桃土壤氮素丰缺指标与适宜施氮量研究

为了给国内桃测土施氮提供科学依据,采用“零散实验数据整合法”和“养分平衡—地力差减法”新应用公式,对中国桃土壤的氮素丰缺指标以及适宜的施氮量进行了初步研究。结果表明:中国桃土壤碱解氮第1~6级丰缺指标依次为:≥206、125~206、76~125、46~76、28~46和<28 mg/kg;土壤有机质第1~4级丰缺指标依次为:≥53、32~53、12~32和<12 g/kg。当桃目标产量为15~60 t/hm^(2),氮肥利用率为40%时,氮素丰缺级别第1~6级土壤的适宜施氮量范围依次为0~0、20~80、40~159、60~239、80~318和99~398 kg/hm^(2)。本研究初步建立了桃土壤碱解氮和有机质丰缺指标推荐施氮系统,为桃测土施氮提供了相应的科学依据。

红壤稻田不同肥力水平和施氮量对早晚季甲烷排放的互作效应

土壤肥力和施氮量是影响稻田甲烷(CH_(4))排放的重要因子,但二者的互作效应尚不明晰。明确不同土壤肥力下施氮量对稻田CH_(4)排放的影响,对提高稻田CH_(4)排放清单的准确性和改进稻田CH_(4)排放模型具有重要意义。以土壤有机质含量为标准,选择3个不同土壤肥力梯度(低、中、高)的红壤性双季稻田,设置4个施氮水平(N_(0)、N_(90)、N_(150)和N_(210)分别代表纯氮施用量为0、90、150和210 kg/hm^(2)),研究了土壤肥力和施氮量对稻田CH_(4)排放的互作效应。结果表明,在早稻季,与低肥力稻田相比,中、高肥力稻田CH_(4)排放量分别显著减少115.7%和32.4%;与N_(0)处理相比,N_(90)处理的CH_(4)排放量显著增加36.0%,而N_(150)和N_(210)处理分别显著减少32.9%和55.0%。在晚稻季,与低肥力稻田相比,中肥力稻田CH_(4)排放量显著增加40.0%,而高肥力稻田CH_(4)排放量有增加趋势,但两者差异不显著;与N_(0)处理相比,N_(90)处理CH_(4)排放量显著增加46.4%,而N_(150)、N_(210)处理无显著差异。从周年CH_(4)排放量来看,低肥力条件下,N_(90)处理比N_(0)处理显著增加82.8%,N_(150)和N_(210)处理与N_(0)处理相比无显著差异;中、高肥力条件下,各施氮量处理间CH_(4)排放无显著差异。土壤肥力和施氮量对早稻季和周年CH_(4)排放量有显著的互作效应,但对晚稻季CH_(4)排放量无显著互作效应。