渍害条件下有机肥替代化肥对小麦产量、产量构成因素及氮素吸收的影响

小麦在渍害条件下,通过研究花后进行有机肥替代化肥对其产量、产量构成因素以及氮素吸收的影响,以期筛选出最适宜小麦的施肥配比.结果表明:有机肥替代化肥30％且进行追肥的处理4在渍害和正常环境下产量、产量构成因素等指标都起到了促进作用.其中,有机肥替代化肥50％且进行追肥的处理6也可以适用于渍害条件下小麦的生长,但没有处理4的效果突出.试验确定了2种环境下最适宜小麦生长的有机肥与化肥配施比例,为小麦的抗渍害栽培和肥料的合理配施提供了理论依据.     

有机肥替代部分化肥对稻麦轮作系统产量及土壤微生物区系的影响

[目的]本文旨在研究不同有机肥替代部分化肥对稻麦轮作系统产量及其构成因素、土壤微生物区系的影响,为找到合适的施肥措施来提高作物产量,培育高产土壤微生物区系提供理论依据。[方法]以江苏省金坛市的长期肥料试验点为研究对象,设置6个施肥处理:不施肥(CK),常规氮、磷、钾化肥(NPK),3 000 kg·hm~(-2)猪粪有机肥替代30%常规化肥施用量(NPKM1),6 000 kg·hm~(-2)猪粪有机肥替代50%常规化肥施用量(NPKM2),1 800 kg·hm~(-2)猪粪有机无机复合肥替代50%常规化肥施用量(NPKMOI1),3 600 kg·hm~(-2)猪粪有机无机复合肥替代70%常规化肥施用量(NPKMOI2)。测定水稻、小麦的有效穗数、每穗粒数、千粒质量、理论产量和实际产量;并利用氯仿熏蒸-硫酸钾浸提法和高通量测序测定土壤微生物生物量及微生物群落结构。[结果]与NPK处理相比,猪粪有机肥(NPKM1、NPKM2)和猪粪有机无机复合肥(NPKMOI1、NPKMOI2)替代部分化肥对水稻和小麦的产量构成因素、理论产量和实际产量无显著降低,且均能提高土壤微生物生物量碳、氮。NPKMOI1和NPKMOI2处理能够增加土壤细菌丰富度、多样性和均匀度指数,显著改变土壤细菌区系,且这种改变随着化肥替代量的增加而变大。[结论]3 600 kg·hm~(-2)猪粪有机无机复合肥替代70%常规化肥施用量处理能够提高作物产量,是一种具有培育高产土壤微生物区系潜力的施肥措施。     

玉米/大豆套作系统下不同品种与根系分隔对大豆根瘤固氮及氮素吸收的影响

【目的】研究玉米/大豆套作系统下不同品种与根系分隔处理对大豆生物固氮酶活性和吸氮量的影响,为完善间套作系统下氮高效理论提供借鉴。【方法】通过根系分隔盆栽试验,研究了3种根系分隔方式(根系不分隔、尼龙网分隔、塑料膜分隔)对强结瘤大豆品种‘NTS1007’和弱结瘤大豆品种‘南豆12’的根瘤固氮酶活性、地上部生物量及氮素吸收的影响。【结果】‘NTS1007’的地上部植株总生物量与吸氮量、根瘤固氮酶活性均显著高于‘南豆12’,但籽粒的产量和吸氮量比‘南豆12’低48.9%、55.3%。根系不分隔下大豆根瘤固氮酶活性、地上部生物量及植株吸氮量显著高于完全分隔,在R1时期不分隔较完全分隔分别高26.11%、43.4%、18.5%;在R3时期较完全分隔分别高32.2%、46%、25.5%。     

Increasing soil microbial biomass nitrogen in crop rotation systems by improving nitrogen resources under nitrogen application

Soil microbial biomass nitrogen(MBN) contains the largest proportion of biologically active nitrogen(N) in soil,and is considered as a crucial participant in soil N cycling.Agronomic management practices such as crop rotation and monocropping systems,dramatically affect MBN in agroecosystems.However,the influence of crop rotation and monocropping in agroecosystems on MBN remains unclear.A meta-analysis based on 203 published studies was conducted to quantify the effect of crop rotation and mono-...     

牛粪化肥最优配比条件下不同轮作方式对稻田氮磷流失的影响

为探讨牛粪化肥最优配比条件下不同轮作方式对稻田氮磷流失的影响,通过田间小区试验设置Y-OL（70%化肥+30%牛粪-黑麦草-水稻）、Y-OV（70%化肥+30%牛粪-紫花苕-水稻）、Y-ON（70%化肥+30%牛粪-冬闲-水稻）3种轮作处理,以C-ON（100%化肥-冬闲-水稻）为对照,研究不同轮作模式下水稻产量及稻田田面水、下渗水、径流中的总氮（TN）和总磷（TP）浓度变化特征。结果表明：不同处理田面水TN浓度在施穗肥后第2 d达到峰值,TP浓度在施基肥第2 d达到峰值,且最高值均出现在Y-ON处理; C-ON和Y-ON处理下渗水TN浓度在施基肥第2 d出现峰值,Y-OL和Y-OV处理下渗水TN浓度在施穗肥后第2 d出现峰值,在整个水稻生育期Y-OV处理下渗水TP浓度整体低于其他处理;不同处理间稻田氮磷径流流失量无显著差异,稻田氮磷径流流失量与降雨量极显著相关,且降雨量最大时,各处理TN径流流失量占径流流失总量的70.24%~73.42%,TP径流流失量占径流流失总量的35.12%~42.42%; Y-OV、Y-OL、Y-ON处理TN总流失量与C-ON相比分别降低43.92%、25.21%、35.74%,Y-OL、Y-ON处理TP总流失量与C-ON相比分别显著上升66.67%、13.13%,Y-OV处理TP总流失量与C-ON无显著差异; Y-OV、Y-OL、Y-ON各处理水稻产量与C-ON相比无显著差异。研究表明,70%化肥+30%牛粪施肥条件下,紫花苕-水稻的轮作方式可保证水稻产量,有效降低下渗水和径流中氮素流失量且维持较低水平的磷素流失量,是一种有效减少氮磷面源污染、增加土地利用效率的种植模式。     

江汉平原稻虾轮作模式地表径流氮、磷流失特征

为明确江汉平原地区典型稻虾轮作模式的农田地表径流流失特征,推动稻虾综合生态种养模式的可持续发展,从2018年9月至2021年9月,采用原位监测的方法,对稻虾轮作模式典型田块地表径流发生过程进行了研究。结果表明：该模式稻田年产生径流10次,产流量（1270±287）mm,产流系数44.7%。总氮年均流失量（24.59±4...     

Transfer characteristics of nitrogen fixed by leguminous green manure crops when intercropped with maize in northwestern China

To ascertain the possibility of cultivating maize using biological nitrogen fixation (BNF) by leguminous green manure crops in maize/leguminous green manure intercropping systems, BNF and nitrogen (N) transfer were studied in Xining and Wuwei, two typical northwestern Chinese cities. The experimental treatments included monocultured maize, monocultured green manures (hairy vetch and common vetch), and their intercropping systems. The proportions of N derived from the atmosphere (%N_dfa) in intercropping systems were not significantly different from that in monocultured green manure systems at either experimental site, except for that in hairy vetch (HV) in Xining. The amount of N derived from the atmosphere (N_dfa) of common vetch (CV) significantly decreased from 1.16 and 1.10 g/pot in monoculture to 0.77 and 0.55 g/pot when intercropped with maize, in Xining and Wuwei, respectively, and the N_dfa of HV when intercropped significantly decreased from 1.02 to 0.48 g/pot in Xining. In the intercropping systems in Xining and Wuwei, the amounts of N transferred (N_transfer) from CV to maize were 21.54 and 26.81 mg/pot, accounting for 32.9 and 5.9% respectively of the N accumulation in maize, and the values of N_transfer from HV to maize were 39.61 and 46.22 mg/pot, accounting for 37.0 and 23.3%, respectively, of the N accumulation in maize. Path analysis showed that soil nutrient and green manure biomass were mainly related to N_dfa, and that δ¹⁵N had a primary relationship with N_transfer. We found that 5.9–37.0% of N accumulation in maize was transferred from green manures, and that the N transfer ability to maize of HV was higher than that of CV. In conclusion, intercropping with leguminous green manures provided a feasible way for maize to effectively utilize biologically fixed N.     

华北平原不同轮作模式固碳减排模拟研究

为探索解决长期冬小麦-夏玉米(麦-玉)单一轮作两熟模式导致农田温室气体排放加剧的问题,基于Denitrification-Decomposition(DNDC)模型分析当前气侯环境下华北地区不同轮作模式对土壤耕层有机碳储量及温室气体排放的影响。结果表明:2003—2014年各轮作模式碳汇速率整体表现为麦-玉麦-豆麦-玉-春玉米麦-玉-大豆春-玉米连作;长期模拟发现,一年两熟制两年三熟制一年一熟制轮作模式,麦玉轮作模式碳汇速率最高,有利于有机碳的长期积累,春玉米连作有机碳储量短期内有所增加,长期则表现出负增长趋势。全球增温潜势(GWP)研究发现,各轮作模式增温潜势整体表现为麦-玉麦-玉-春玉米麦-豆麦-玉-大豆春-玉米连作;从长远角度看,各模式增温潜势短期内都呈增加趋势,15年后维持稳定,稳定后麦玉模式排放量最大,而春玉米连作模式排放最低,禾豆轮作相比禾本科轮作具有很好的固碳减排效应。因此,在华北地区农田管理方面,可考虑推行禾豆轮作模式,最终达到提高土壤有机碳库和减少温室气体排放的目标。     

华北平原不同施氮量与施肥模式对作物产量与氮肥利用率的影响

合理施肥是保证作物高产、减少面源污染的重要措施,以华北平原为研究区域,基于7个长期施肥试验,探讨不同施氮量及施肥模式（不施肥CK、化肥NPK、有机肥M、有机无机配施NPKM）对作物产量及氮肥利用率的影响。结果表明,作物产量与施肥量之间整体呈抛物线趋势,作物产量最高值均出现在NPKM处理。不同施肥模式对作物产量有一定影响,NPKM与NPK处理小麦产量无显著差异,且显著高于M、CK处理;NPKM、NPK、M处理玉米产量无显著差异,均显著高于CK处理。氮肥利用率随着施氮量增加呈下降趋势,不同施肥模式对氮肥利用率有一定影响,小麦季NPKM与NPK处理氮肥利用率无显著差异,且高于M处理,玉米季NPKM、NPK、M处理之间氮肥利用率均无显著差异。综合分析施氮量与有机肥替代率两因素对小麦产量的影响,在华北平原,利用有机肥替代化肥潜力可观,且不会显著降低作物产量,甚至增产,但为避免显著减产,在考虑提高有机肥替代率时,需要满足总施氮量的需求。     

Estimation of USLE crop and management factor values for crop rotation systems in China

Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss assessments using the Universal Soil Loss Equation(USLE) would supply a scientific basis for soil conservation planning. However, a lack of information on the cover and management(C) factor for cropland, one of the most important factors in the USLE, has limited accurate regional assessments in China due to the large number of crops grown and their complicated rotation systems. In this study, single crop soil loss ratios(SLRs) were collected and quantified for 10 primary crops from past studies or reports. The mean annual C values for 88 crop rotation systems in 12 cropping system regions were estimated based on the combined effects of single crop SLRs and the percentage of annual rainfall erosivity(R) during the corresponding periods for each system. The C values in different cropping system regions were compared and discussed. The results indicated that the SLRs of the 10 primary crops ranged from 0.15 to 0.74. The mean annual C value for all 88 crop rotation systems was 0.34, with a standard deviation of 0.12. The mean C values in the single, double and triple cropping zones were 0.37, 0.36 and 0.28, respectively, and the C value in the triple zone was significantly different from those in single and double zones. The C values of dryland crop systems exhibited significant differences in the single and triple cropping system regions but the differences in the double regions were not significant. This study is the first report of the C values of crop rotation systems in China at the national scale. It will provide necessary and practical parameters for accurately assessing regional soil losses from cropland to guide soil conservation plans and to optimize crop rotation systems.     

Nitrate leaching of winter wheat grown in lysimeters as affected by fertilizers and irrigation on the North China Plain

Proper application of nitrogen(N) fertilizers and irrigation management are important production practices that can reduce nitrate leaching into groundwater and improve the N use efficiency(NUE). A lysimeter/rain shelter facility was used to study effects of the rate of N fertilization, type of N fertilizer, and irrigation level on key aspects of winter wheat production over three growing seasons(response variables were nitrate transport, N leaching, and NUE). Results indicated that nitrate concentration in the soil profile and N leaching increased with the rate of N fertilization. At the end of the third season, nitrate concentration in the top 0–75 cm layer of soil was higher with manure treatment while urea treatments resulted in higher concentrations in the 100–200 cm layer. With normal irrigation, 3.4 to 15.3% of N from applied fertilizer was leached from the soil, yet no leaching occurred under a stress irrigation treatment. The manure treatment experienced less N leaching than the urea treatment in all cases except for the 180 kg N ha-1 rate in 2011–2012(season 3). In terms of grain yield(GY), dry matter(DM) or NUE parameters, values for the manure treatment were lower than for the urea treatment in 2009–2010(season 1), yet were otherwise higher for urea treatment in season 3. GY and crop nitrogen uptake(NU) were elevated when the rate of N fertilizer increased, while the NUE decreased; GY, DM, and NU increased with the amount of irrigation. Data indicated that reduced rates of N fertilization combined with increased manure application and proper irrigation management can lower nitrate levels in the subsoil and reduce potential N leaching into groundwater.     

化肥减量替代对华北平原小麦-玉米轮作产量及氮流失影响

为降低氮素流失风险,提高肥料利用效率,在华北平原采用田间定位试验研究了不同施肥措施对小麦-玉米产量、周年氮素淋溶和径流损失的影响。结果表明,相比当地常规施肥处理(CON),减施氮肥150 kg·hm~(-2)的条件下,单施化肥(RF)和10%比例沼液替代(RFM)不会降低小麦和玉米产量。相较于CON处理的氮素年均盈余量218.1 kg·hm~(-2),RF和RFM处理氮盈余量分别显著降低了66.7%和55.9%。CON处理总氮平均淋失浓度和年均淋失量分别为33.70 mg·L~(-1)和22.01 kg·hm~(-2),与之相比,RF处理总氮平均淋失浓度和年均淋失量分别降低了31.45%和30.58%,而RFM处理分别降低了40.65%和43.39%。试验期间径流产流只发生2次,氮素淋溶发生次数和氮损失量远高于径流损失,因此淋溶是氮素流失的主要途径。CON处理总氮平均径流浓度和年均径流流失量分别为23.0 mg·L~(-1)和0.095 kg·hm~(-2),与之相比,RF处理总氮平均径流浓度和年均径流流失量分别降低了32.9%和30.5%,而RFM处理分别降低了45.5%和50.5%。由于施肥量较高,CON处理氮淋溶表观流失率为4.19%,而RF和RFM处理氮淋溶表观流失率分别降低了2.86%和20.76%。NO_3~--N是氮素流失的主要形态,分别占淋溶和径流总氮流失量的66.3%和73.3%,其与总氮流失变化趋势一致。综上,化肥减量配施沼液在保证作物产量的情况下,是降低氮素流失的有效措施。     

不同形态猪粪储用过程的气态氮损失特征

为探讨不同形态猪粪短期存储和施用全过程的气态氮(N)损失特征,优化猪粪清储模式,以猪粪生浆液(PS)、固液分离液态组分(LF)、固液分离固态组分(SF)和风干猪粪(DM)为研究对象,利用原位气体采集法和盆栽试验,针对粪肥气态氮损失主要形式——NH_3挥发和N_2O排放,开展了不同形态猪粪存储及施用过程中的气态氮损失特征研究,并比较了4种形态猪粪施用后生菜产量和氮素利用效率(NUE)。结果表明:存储和施用全过程中,各形态猪粪的总气态氮损失达12.4%～20.9%,其中PS最高,SF最低;气态氮损失主要发生在存储/风干过程,占总气态氮损失的58.6%～76.3%。不同形态猪粪存储/施用过程的气态氮损失形态差异显著,在存储过程,LF和DM以NH_3挥发为主,分别占存储过程气态氮损失的71.5%和49.8%,而PS(38.0%)和SF(31.4%)的NH_3挥发占比相对较低;在施用过程,LF的气态氮损失依然以NH_3挥发为主,排放系数达到9.7%,其他形态猪粪NH_3挥发排放系数仅为3.3%～3.9%。SF经存储初级发酵后施用的资源化利用模式效果最优,其生菜产量(33.2 t·hm~(-2))及NUE最高,而等N施用下LF和PS对作物生长具有抑制作用。猪粪施用后N_2O排放带来的增温潜势达2.01～4.26 t CO_2e·hm~(-2),具有较高的温室效应。综上,猪粪的清储模式宜选择干清粪或者固液分离模式,液态部分可通过酸化等方式降低NH_3挥发损失,而固态组分可在简单堆肥发酵处理后进行农田资源化利用。