Effect of Different Fertilization Practices on Yield of a Wheat-Maize Rotation and Soil Fertility

A 15-year field experiment was carried out in Henan Province, China, to study the effects of different fertilization practices on yield of a wheat-maize rotation. Fertilizers tested contained N alone (N), N plus P (NP) or plus P and K (NPK), all with or without manure (M). Different long-term fertilization practices affected the yields under the rotation system of wheat and maize differently and the effects on yields was in a general trend of MNPK＞MNP＞MN＞NPK＞NP＞M＞N＞the control. The average contribution rate of soil fertility to the highest yield was 37.9%, and the rest 62.1% came from fertilizer applications. The yield effects of the chemical fertilizers were in the order of N＞P＞K and were increased by application of manure.Balanced fertilization with multielement chemical fertilizers and manure can be effective in maintaining growth in agricultural production. Combined application of chemical fertilizer and organic manure also increased the content of soil organic matter.

Effects of Continuous Nitrogen Application on Grain Yield and Nitrogen Uptake and Utilization in Winter Wheat-Summer Maize Rotation System

[Objective] This study aimed to achieve high yield and stable yield of win- ter wheat-summer maize rotation system and provide basis for rational application of nitrogen fertilizer. [Method] Effects of continuous nitrogen application on grain yield, economic profit, nitrogen uptake and utilization efficiency, and soil inorganic nitrogen accumulation in winter wheat-summer maize rotation system were investigated. [Re- sult] Nitrogen application could significantly increase the y（eld of the winter wheat- summer maize rotation system, which increased by 17.76%-30.32% and 22.24%- 46.63% in two rotation cycles, respectively. The yield of the winter wheat-summer maize rotation system was the maximum in two rotation cycles with nitrogen appli- cation amount of 660.0 kg/hm2, which reached respectively 23 391.19 and 23 444.35 kg/hm2, the yield and economic benefit were the highest, the nitrogen fertilizer use efficiency was 22.2% and 30.7%, the agronomic efficiency was 8.3 and 11.3 kg/kg. However, the nitrogen fertilizer use efficiency and agronomic efficiency between ni- trogen application amount of 540.0 and 660.0 kg/hm2 showed no significant differ- ence. After two rotation cycles, inorganic nitrogen accumulation in 0-40 cm soil with nitrogen application amount of 540.0 kg/hm2 was almost equal to that before experi- ment. [Conclusion] Under the experimental conditions, comprehensively considering the grain yield, economic profit, nitrogen fertilizer efficiency and soil inorganic nitro- gen balance, the optimal nitrogen application amount was 625.3-660.0 kg/hm2 in high-yield winter wheat-summer maize rotation system.

Fate of ^(15)N-Labeled Urea Under a Winter Wheat-Summer Maize Rotation on the North China Plain

A field experiment was conducted to investigate the fate of ^15N-labeled urea and its residual effect under the winter wheat （Triticum aestivum L.） and summer maize （Zea mays L.） rotation system on the North China Plain. Compared to a conventional application rate of 360 kg N ha^-1 （N360）, a reduced rate of 120 kg N ha^-1 （N120） led to a significant increase （P 〈 0.05） in wheat yield and no significant differences were found for maize. However, in the 0-100 cm soil profile at harvest, compared with N360, N120 led to significant decreases （P 〈 0.05） of percent residual N and percent unaccounted-for N, which possibly reflected losses from the managed system. Of the residual fertilizer N in the soil profile, 25.6%-44.7% and 20.7%-38.2% for N120 and N360, respectively, were in the organic N pool, whereas 0.3%-3.0% and 11.2%-24.4%, correspondingly, were in the nitrate pool, indicating a higher potential for leaching loss associated with application at the conventional rate. Recovery of residual N in the soil profile by succeeding crops was less than 7.5% of the applied N. For N120, total soil N balance was negative; however, there was still considerable mineral N （NH4^＋-N and NO3^--N） in the soil profile after harvest. Therefore, N120 could be considered ngronomically acceptable in the short run, but for long-term sustainability, the N rate should be recommended based on a soil mineral N test and a plant tissue nitrate test to maintain the soil fertility.

Effects of mulches on water use in a winter wheat/summer maize rotation system in Loess Plateau, China

Limited water resources often result in reduced crop yield and low water productivity（WP）. In northwestern China, crop production is generally dependent on precipitation. Therefore, a variety of agricultural rainwater harvesting（ARH） techniques have been used for conserving soil moisture, ameliorating soil environment, increasing crop yield, and improving water use efficiency. A two-year（2013–2015） field experiment was conducted under a typical sub-humid drought-prone climate in Yangling（108°24′E, 34°20′N; 521 m a.s.l.）, Shaanxi Province, China, to explore the effects of mulching（same for summer maize and winter wheat） on soil moisture, soil temperature, crop water consumption, and crop yield with a winter wheat/summer maize rotation. Crops were planted in a ridge-furrow pattern and the treatments consisted of a transparent film mulch over the ridges（M1）, a crop straw mulch in the furrows（M2）, a transparent film mulch over the ridges and a crop straw mulch in the furrows（M3）, a black film mulch over the ridges and a crop straw mulch in the furrows（M4）, and a control with no mulch（CK）. Results showed that M4 was the best treatment for improving soil water storage and content, and decreasing crop water consumption during the summer maize and winter wheat rotation. In both maize and wheat seasons, M1 had a higher soil temperature than M2 and CK, and M3 had a higher soil temperature than M4. In the maize seasons, M4 had the highest yield, WP, and precipitation productivity（PP）, with the average values for these parameters increasing by 30.9%, 39.0%, and 31.0%, respectively, compared to those in CK. In the wheat seasons, however, M3 had the highest yield, WP, and PP, with the average values for these parameters being 23.7%, 26.7%, and 23.8% higher, respectively, than those in CK. Annual yield（maize and wheat yields combined） and WP did not differ significantly between M3 and M4. These results suggested that M3 and M4 may thus be the optimal ARH practices for the production of winter wheat and summer maize, respectively, in arid and semi-arid areas.

Effect of various crop rotations on rice yield and nitrogen use efficiency in paddy–upland systems in southeastern China

To evaluate the effects of various rotation systems on rice grain yield and N use efficiency, a paddy–upland cropping experiment(2013–2016) was conducted in southeastern China. The experiment was designed using six different rice––winter crop rotations: rice–fallow(RF),rice–wheat(RW), rice–potato with rice straw mulch(RP), rice–green manure(Chinese milk vetch; RC–G), rice–oilseed rape(RO), and rice–green manure crop(oilseed rape with fresh straw incorporated into soil at flowering; RO–G) and three N rates, N0(0 kg N ha-1), N1(142.5 kg N ha-1), and N2(202.5 kg N ha-1). Average rice yields in the RF(5.93 t ha-1) rotation were significantly lower than those in the rotations with winter crops(7.20–7.48 t ha-1)under the N0 treatment, suggesting that incorporation of straw might be more effective for increasing soil N than winter fallow. The rice yield differences among the rotations varied by year with the N input. In general, the grain yields in the RP and RO–G rotations –were respectively 11.6–28.5% and 14.80–37.19% higher than those in the RF in plots with N applied. Increasing the N rate may have tended to minimize the average yield gap between the RF and the other rotations; the yield gaps were 18.55%, 4.14%, and 0.23% in N0, N1, and N2, respectively. However, the N recovery efficiency in the RF was significantly lower than that in other rotations, except for 2015 under both N1 and N2 rates, a finding that implies a large amount of chemical N loss. No significant differences in nitrogen agronomic efficiency(NAE) and physiological efficiency(NPE) were found between the rotations with legume(RC–G) and non–legume(RO and RW) winter crops, a result that may be due partly to straw incorporation. For this reason, we concluded that the return of straw could reduce differences in N use efficiency between rotations with and without legume crops. The degree of synchrony between the crop N demand and the N supply was evaluated by comparison of nitrogen balance degree(NBD) values. The NBD values in the RP and RW were significantly lower than those in the other rotations under both N1 and N2 rates. Thus,in view of the higher grain yield in the RP compared to the RW under the N1 rate, the RP rotation might be a promising practice with comparable grain yield and greater N use efficiency under reduced N input relative to the other rotations. The primary yield components of the RF and RP were identified as number of panicles m-2 and numbers of kernels panicle-1, respectively. The NAE and NPE were positively correlated with harvest index, possibly providing a useful indicator for evaluating N use efficiency.

Using the DSSAT model to simulate wheat yield and soil organic carbon under a wheat-maize cropping system in the North China Plain

Crop modelling can facilitate researchers＇ ability to understand and interpret experimental results, and to diagnose yield gaps. In this paper, the Decision Support Systems for Agrotechnology Transfer 4.6 （DSSAT） model together with the CENTURT soil model were employed to investigate the effect of low nitrogen （N） input on wheat （Triticum aestivum L.） yield, grain N concentration and soil organic carbon （SOC） in a long-term experiment （19 years） under a wheat-maize （Zea mays L.） rotation at Changping, Beijing, China. There were two treatments including NO （no N application） and N150 （150 kg N ha-1） before wheat and maize planting, with phosphorus （P） and potassium （K） basal fertilizers applied as 75 kg P205 ha-1 and 37.5 kg K^O ha-~, respectively. The DSSAT-CENTURY model was able to satisfactorily simulate measured wheat grain yield and grain N concentration at NO, but could not simulate these parameters at N150, or SOC in either N treatment, Model simulation and field measurement showed that N application （N150） increased wheat yield compared to no N application （NO）. The results indicated that inorganic fertilizer application at the rates used did not maintain crop yield and SOC levels. It is suggested that if the DSSAT is calibrated carefully, it can be a useful tool for assessing and predicting wheat yield, grain N concentration, and SOC trends under wheat-maize cropping systems.

不同绿肥作物周年搭配种植下土壤微生物养分限制与土壤质量指数

【目的】绿肥作物种类多,对土壤理化性状和微生物活性的影响存在差异。我们从土壤微生物代谢与养分限制的角度探讨周年覆盖不同绿肥作物对土壤质量的影响,以期为周年覆盖绿肥的土壤生态效应提供理论依据,为果园、休耕地、撂荒地等空间闲置性土地的绿肥应用提供技术支撑。【方法】3年连续田间定位试验在贵州省农业科学院土壤肥料研究所进行,设置4个冬季和夏季绿肥组合处理:二月兰-小葵子(O-G)、二月兰-饭豆(O-P)、箭筈豌豆-小葵子(V-G)、箭筈豌豆-饭豆(V-P)。在第3年冬季绿肥盛花期采集0—20 cm耕层土样,测定土壤胞外酶活性、土壤微生物量碳(MBC)、氮(MBN)、磷(MBP)含量,以及土壤pH及全量氮磷含量,计算土壤胞外酶化学计量比,并分析各土壤因子对土壤质量指数的贡献。【结果】不同绿肥作物轮作模式下土壤的pH、全氮(TN)、MBN、MBP、β-葡萄糖苷酶(BG)和酸性磷酸酶(ACP)活性差异显著。基于土壤胞外酶化学计量特征,所有处理受土壤微生物碳限制和磷限制,碳限制差异不显著,以O-G处理土壤的磷限制最低,较V-P处理低2%(P<0.05)。土壤pH、有效磷(AP)、可溶性有机碳(DOC)是驱动土壤胞外酶活性和微生物养分限制变化的关键因子,pH对土壤胞外酶活性有显著负效应,土壤全量碳、氮、磷含量对土壤胞外酶活性有显著正效应,对微生物碳限制有显著负效应。土壤胞外酶活性对微生物碳利用效率有显著正效应,主要受ACP活性调控。【结论】不同冬季与夏季绿肥作物组合覆盖的土壤,其pH值、全氮、微生物量氮、微生物量磷、β-葡萄糖苷酶活性、酸性磷酸酶活性具有显著差异,冬季绿肥对土壤微生物磷限制、土壤微生物碳利用效率产生显著影响,冬季绿肥与夏季绿肥的交互效应对土壤质量指数具有显著影响。箭筈豌豆-小葵子(V-G)处理的土壤微生物代谢受磷限制较小,且土壤微生物碳利用率和土壤质量指数最高,最利于调节微生物代谢,维持生态功能,提高土壤质量指数,可优选为土壤快速培肥的绿肥组合。

增施铵态氮肥诱导滨海盐渍土作物根际降碱抑钠可实现以种适地增产增效

通过改变栽培种植模式激发作物自身抗盐碱的潜力,实现作物以种适地增产增效的目标,对盐碱地绿色产能提升具有重要意义。本试验以滨海盐渍土冬小麦-夏玉米轮作体系为研究对象,采用田间定位试验,设置AS0(100%尿素,磷肥减量)、AS50(50%尿素+50%硫酸铵,磷肥减量)、AS75(25%尿素+75%硫酸铵,磷肥减量)、AS100(100%硫酸铵,磷肥减量)和FP(农民过量施氮磷肥,100%尿素,对照1)、P0(不施磷肥,100%尿素,对照2)6个处理,分析了不同硫酸铵替代尿素比例处理下冬小麦和夏玉米的产量、养分吸收量、氮磷肥利用效率、根际土壤pH、根际土壤盐度和钠吸附比(sodiumadsorptionratio,SAR)的变化。2年田间试验结果表明:P0处理下盐碱地小麦、玉米产量最低,作物生长受到土壤缺磷限制;与FP处理相比,所有减磷处理的作物产量无显著差异。等氮等磷条件下,与全部施用尿素(AS0)处理相比,AS50处理冬小麦平均增产5.4%,夏玉米平均增产1.5%。增施硫酸铵(AS50、AS75、AS100)处理与AS0处理相比小麦根际土壤pH降低0.08~0.24个单位,玉米根际pH降低0.06~0.35个单位。随硫酸铵比例增加,根际土壤速效磷含量呈先增后减的趋势,其中AS50处理速效磷含量最高;根际土壤Ca^(2+)、Na^(+)含量和SAR降低。与FP处理相比,AS50和AS75处理的根际pH、SAR和Na^(+)含量均显著降低,氮磷肥利用效率显著提高;并且玉米季的处理效应比小麦季更显著。在滨海盐渍土区,与FP处理相比,硫酸铵替代50%的尿素能够在磷肥减施的情况下通过诱导根际pH的下降促进SAR和Na^(+)含量降低、提高有效磷和Ca^(2+)含量,营造更适宜作物生长的根际低盐低碱高营养环境,从而提高产量和肥料利用效率。基于以上结果提出了增铵降碱解磷增钙的措施,诱导根土界面肥盐分布区隔化、实现以种适地的轻-中度盐碱地作物增产增效。

Yielding of Winter Triticale Varieties in Different Protection Levels in Two Sequence Systems

Five-year trials （2011-2015） were accomplished in a continuous field experiment conducted at the Production and Research Station in Balcyny. The experiment was set up on a luvisol medium soil, derived from light loam with the objective of evaluating the response of two winter triticale varieties （Pigmej and Cyrkon） to cultivation without protection （O）, chemical weed control （H） and combined protection against weeds and fungi （HF）. Comparisons were made in two crop sequence systems： cultivation of winter triticale varieties in a 6-field crop rotation and cultivation in a 19-23-year-long monoculture. The results showed that the plant sequence system significantly differentiated the response of winter triticale varieties to the applied levels of field protection. Significantly higher grain yield gains of the winter triticale varieties in response to the application of herbicides or herbicides with fungicides were obtained in the monoculture than in the crop rotation. In the crop rotation, a higher increase in yields induced by the applied plant protection treatments was achieved by the variety Cyrkon. In the monoculture, the response of both varieties to the herbicides applied was nearly identical, while the combined application of herbicides and fungicides raised the yields of var. Pigmej higher than those of var. Cyrkon. Overall for the plant protection levels, var. Cyrkon yielded higher than var. Pigmej by 18.1% more in the crop rotation and by 26.9% in the monoculture. At the same time, var. Cyrkon demonstrated a weaker response to being grown in the monoculture than var. Pigmej did. The average yield of the former was reduced by 21.1%, whereas the latter yielded 26.6% less grain.

冬小麦-夏玉米轮作田沟金针虫垂直活动特征

基于河北固城农业气象国家野外科学观测研究站2019—2020年、2021—2022年冬小麦-夏玉米轮作田沟金针虫在土壤中分层调查数据,引入虫口重量指标,结合虫口密度指标,揭示沟金针虫在冬小麦-夏玉米轮作田为害-休眠动态变化,讨论沟金针虫在土壤中垂直活动特征、气象条件与其相关性以及对冬小麦产量影响。结果表明:沟金针虫在冬小麦-夏玉米轮作田存在3个为害期和3个休眠期,且交替出现。3个为害期出现在冬小麦返青-拔节期、夏玉米幼苗期、冬小麦秋苗期,3个休眠期出现在冬小麦越冬期、冬小麦成熟-收获期、夏玉米灌浆-成熟期,3个为害期中以冬小麦返青-拔节期最为严重。冬季偏暖及春季回暖早,沟金针虫表现出晚下早上特征,使得沟金针虫冬季休眠期缩短而为害活动期延长;土壤温度、湿度以及食源关系共同影响沟金针虫为害、休眠以及取食活动,其为害适宜土壤重量含水率约为15%~18%,适宜土壤温度为14~18℃。分析沟金针虫为害与冬小麦减产率可知,虫口密度每增加10 m^(-2)或虫口重量每增加1.0 g·m^(-2),可导致减产率增加5.1%。

西北旱塬免耕的产量效应受降水特征和施肥显著影响

【目的】在冬小麦-夏春玉米轮作体系,研究不同降水年型条件下西北雨养农业区耕作与施肥对作物产量的影响,为西北旱塬作物高产稳产提供理论依据。【方法】基于2005年甘肃陇东旱塬设置的土壤耕作与培肥长期定位试验(3年冬小麦—1年春玉米),主处理为传统耕作和免耕,副处理为不施肥(CK)、单施氮肥(N)、单施磷肥(P)、单施农家肥(M)、氮磷配施(NP)和氮磷配施农家肥(NPM)。结合对冬小麦和玉米产量的分析,探究不同耕作与施肥处理下作物产量在不同降水年型的差异机制。【结果】降水年型、耕作和施肥方式显著影响冬小麦和玉米产量。无论何种降水年型或耕作方式,配施有机肥的NPM处理作物产量(冬小麦3441 kg/hm^(2),春玉米8991 kg/hm^(2))均显著高于其他施肥处理,并且NPM处理对作物的增产效果在丰水年型更为明显。在丰水年型,相对于传统耕作,免耕处理的作物产量无明显差异,但在干旱及平水年型下,免耕冬小麦平均产量分别下降了15.6%和25.7%,玉米平均产量分别下降了17.9%和4.6%;与传统耕作相比,免耕处理下的冬小麦和玉米水分利用效率在干旱年型分别下降了6.7%和17.0%,冬小麦水分利用效率在平水年型下降了24.0%。免耕处理下土壤有机质、全氮、全钾、速效氮、速效磷和速效钾含量显著高于传统耕作。【结论】在西北半干旱雨养农业区,干旱及平水年型免耕虽然提高了土壤养分含量,但降低了作物水分利用效率,这是导致作物产量降低的主要原因。因此,需要根据降水情况选择耕作方式,提高西北黄土旱塬作物产量的稳定性。

覆土种植杏鲍菇营养评价与效益分析

以工厂化种植杏鲍菇为对照,检测覆土种植不同采收期杏鲍菇的蛋白质、氨基酸、脂肪等营养成分和种植前后土壤养分含量,根据覆土种植投入产出计算效益,探讨冬闲田杏鲍菇覆土种植-菌渣还田-粮食/水果/蔬菜轮作种植模式的可行性。结果表明,不同采收期覆土种植杏鲍菇鲜品子实体蛋白质、脂肪、氨基酸等含量均高于工厂化种植,采收期对覆土种植杏鲍菇蛋白质含量影响较大,成熟初期含量最高,达4.19 g/100 g,是成熟期的1.3倍、孢子释放期的1.6倍、工厂化种植的1.9倍。覆土种植杏鲍菇必需氨基酸、呈味氨基酸含量均高于工厂化种植,E/T值接近FAO/WHO提出的优质蛋白质氨基酸组成值。菌渣还田后土壤有机质含量提高了116%,杏鲍菇从覆土到采收完毕共34 d,生物转化率可达136%,投入产出比达1:1.8。冬闲田覆土种植杏鲍菇子实体营养丰富,味道鲜美,经济效益好,菌渣还田可提高土壤有机质含量,适合在南方水稻主产区、荔枝等果园的林下冬春季推广应用。

施用生物炭和秸秆还田对农田温室气体排放及增温潜势的影响

【目的】农业生态系统增温潜势是影响全球气候变化的重要部分。本研究通过田间试验明确施用生物炭和秸秆还田对农田增温潜势的影响,以期为减缓气候变化和农业废弃物资源化利用提供理论依据。【方法】在山东省桓台县农业生态系统试验站的冬小麦-夏玉米轮作农田中开展了3年田间定位试验,试验共设置4个处理:①对照(CK);②施用生物炭9.0t·hm^(-2)·a^(-1)(C);③全量秸秆还田(S);④秸秆还田配施9.0 t·hm^(-2)·a^(-1)生物炭(CS)。4个处理均施等量的氮磷钾化肥,其中氮肥为尿素,用量为200 kg·hm^(-2)·a^(-1),磷肥为过磷酸钙,用量为55 kg·hm^(-2)·a^(-1),钾肥为硫酸钾,用量为40 kg·hm^(-2)·a^(-1)。采用静态暗箱-气相色谱法测定各处理温室气体(CO_(2)、N_(2)O和CH_4)的排放通量并计算净全球增温潜势(NGWP)和温室气体排放强度(GHGI),分析连续施用生物炭和秸秆还田对农田温室气体排放及增温潜势的影响。【结果】(1)综合3年的温室气体排放情况,与CK处理相比,S和CS处理的年平均生态呼吸排放量(Re)分别增加了47.8%和67.9%(P<0.05);C处理的年平均N_(2)O累积排放量降低了20.3%(P<0.05),而S和CS处理的N_(2)O年平均累积排放量分别增加了23.6%和41.4%(P<0.05)。(2)与CK处理相比,C、S和CS处理的土壤有机碳年平均变化量(ΔSOC)均有显著增加,其中CS处理增幅最大,增加了150.6%(P<0.05)。与第1年相比,C、S和CS处理第3年的ΔSOC均有显著增加(P<0.05),分别增加了21.7%、20.8%和17.8%。各处理的NGWP和GHGI均存在显著差异,与CK相比,C、S和CS处理的年平均NGWP分别降低了163.5%、171.7%和273.0%(P<0.05),与第1年相比,C、S和CS处理第3年的NGWP均有显著降低(P<0.05),分别降低了73.4%、58.8%和54.7%。与CK相比,C、S和CS处理的年平均GHGI分别降低了236.2%、253.3%和388.9%(P<0.05),C、S和CS处理第3年的GHGI较第1年分别降低了126.3%、98.2%和108.6%(P<0.05)。就产量而言,C、S和CS处理的作物产量保持相对稳定,有轻微增长,但与CK相比无显著差异。【结论】与单施化肥相比,在施化肥的基础上添加生物炭、秸秆还田、秸秆还田配施生物炭的措施均能够在不影响作物产量的前提下抑制增温潜势,其中秸秆还田配施生物炭能够最大程度地降低农田增温潜势,因此秸秆还田配施生物炭是增加农田固碳、缓解气候变化的一项有效措施。

秸秆还田和施肥对冬小麦-夏大豆轮作系统培肥与生产效益的影响

为探明秸秆还田和化肥施用对冬小麦-夏大豆轮作系统土壤培肥和生产效益的影响,于2020-2022年在关中平原开展田间定位试验,设置秸秆不还田不施肥(S0F0)、秸秆不还田常规施肥(S0F1)、秸秆还田配合常规施肥(S1F1)和秸秆还田配合减量施肥(S1F0.8)4个处理。利用静态暗箱-气相色谱法监测土壤N_(2)O排放通量,综合分析土壤养分、作物产量和土壤N_(2)O排放,明确秸秆还田配施化肥在土壤培肥、增产减排方面的效应。结果表明,秸秆还田和施肥通过显著提高土壤有机质(SOM)、全氮(TN)、全磷(TP)、硝态氮(NO_(3)^(-)-N)、铵态氮(NH_(4)^(+)-N)、速效磷(AP)含量来促进土壤培肥。与S0F0相比,S1F0.8和S1F1处理提高土壤综合肥力314.24%~317.12%、330.58%~384.98%;S1F0.8和S1F1处理显著提高冬小麦产量80.29%~101.25%、82.50%~107.66%,提高夏大豆产量25.31%~34.72%、36.93%~45.20%;S0F1、S1F0.8、S1F1均显著增加土壤N_(2)O累积排放量和种植系统温室气体排放强度,但S1F0.8较S0F1、S1F1处理显著降低土壤N_(2)O累积排放量和种植系统温室气体排放强度;S1F0.8和S1F1处理提高生产效益75.09%~75.88%、67.54%~114.23%。综上,秸秆还田配合常规施肥(S1F1)是关中平原麦-豆轮作系统土壤培肥的有效方式;但依照国家降低化肥施用量的要求来说,秸秆还田配合减量施肥(S1F0.8)是关中平原麦-豆轮作系统增产、减排、提高收益的推荐方式。

复合轴旋转影响青少年冰雪运动员空间认知的ERP研究

运用ERP技术记录青少年短道速滑和自由式滑雪雪上技巧运动员在心理旋转任务中的行为绩效及大脑活动差异,解释旋转性运动经验影响青少年冰雪运动员的具体特征及其神经机制。采用专家—新手范式,选取雪上技巧和短道速滑运动员各15人,以包含不同身体复合旋转轴向以及角度的3D动作图像为实验刺激进行心理旋转测试,记录并分析行为和ERP数据。结果发现:(1)运动员在进行小角度心理旋转时的判断速度比大角度旋转的判断速度更快,正确率更高。(2)运动员在进行小角度旋转时,横轴的反应速度快于竖轴和纵轴;大角度旋转时,纵轴的判断比其他两轴向更快更准。(3)雪上技巧运动员在进行竖轴大角度旋转时的反应时较短道速滑运动员更快。(4)雪上技巧运动员与短道速滑运动员相比,在进行竖轴大角度心理旋转时的N1潜伏期更短,进行横轴大角度心理旋转的P1峰波幅更小,RRN平均波幅更小。与只具备竖轴旋转经验的短道速滑运动员相比,具备横、竖、纵轴身体旋转经验的雪上技巧运动员能够将身体各轴具身化地描绘至任务目标以提升任务绩效。

轮作及减氮对绿洲灌区农田温室气体排放及土壤酶活性的影响

基于2018年在武威绿洲农业试验站布设的田间定位试验,设春小麦-冬油菜-箭筈豌豆(WRV)、春小麦-冬小麦-箭筈豌豆(WWV)、春小麦-箭筈豌豆-春小麦-箭筈豌豆(WV)、春小麦连作(W)4种种植模式,减氮25%(270 kg·hm^(-2),N 1)、传统施氮(360 kg·hm^(-2),N 2)两个施氮水平,共8个处理,于2020—2021年测定并分析不同轮作模式结合减氮对农田CO 2、N 2O排放的影响及其与春小麦产量和土壤酶活性的关系,以期为当地农业绿色高效发展提供理论依据。结果表明:轮作结合减氮处理可显著降低温室气体排放,增加作物产量,以WRVN 1处理增产减排效果最佳,其CO 2、N 2O排放总量分别较WN 2处理降低了15.2%、28.0%,全球增温潜势(GWP)、温室气体排放强度(GHGI)分别降低15.7%和30.4%,作物产量增加16.7%。土壤脲酶和过氧化氢酶活性均表现为0~10 cm高于10~30 cm土层,轮作降低了小麦开花期土壤酶活性,以WRVN 1处理土壤酶活性最低;在N 1处理下土壤脲酶、过氧化氢酶活性较N 2处理分别降低20.1%~28.7%、8.3%~12.2%,且CO 2、N 2O排放速率与土壤脲酶、过氧化氢酶活性均呈显著正相关关系。综上,春小麦-冬油菜-箭筈豌豆轮作模式结合减氮25%可作为实现绿洲灌区农业增效减排的合理种植模式与施氮制度。

汉中地区4种冬绿肥还田腐解和养分释放特征

研究汉中地区水稻(Oryza sativa)-绿肥轮作制下翻压还田绿肥的腐解动态变化及养分释放特征,可为水稻-绿肥轮作生产中的水稻科学施肥提供理论依据。以紫云英(Astragalus sinicus)、毛叶苕子(Vicia villosa)、山黧豆(Lathyrus cicera)和箭筈豌豆(Vicia sativa)为供试材料,进行145 d的田间原位埋袋腐解试验,并定期观测4种豆科绿肥腐解变化及养分释放特征。结果表明,绿肥腐解及养分释放均表现为前期(0~14 d)快、后期(41~145 d)慢。经过145 d,紫云英、毛叶苕子、山黧豆和箭筈豌豆的累计腐解率分别为74.58%、74.17%、72.14%和72.57%,而氮、磷、钾平均累计释放率分别为85.64%、75.23%和96.22%。翻压量为22500 kg·hm^(-2)的紫云英、毛叶苕子、山黧豆和箭筈豌豆腐解145 d后,氮素累计释放量分别为82.27、134.73、144.73和94.17 kg·hm^(-2),磷素累计释放量分别为14.68、21.39、21.21和17.25 kg·hm^(-2),钾素累计释放量分别为70.90、93.72、85.23和82.13 kg·hm^(-2)。4种绿肥的氮、磷、钾平均累计释放量分别为113.99、18.63和83.02 kg·hm^(-2),可为后茬水稻提供63.33%N、20.70%P2O5和79.07%K2O。综上,紫云英、毛叶苕子、山黧豆和箭筈豌豆均适于汉中地区冬闲稻田种植,且理论化肥减量顺序为毛叶苕子≈山黧豆>箭筈豌豆>紫云英,此外,水稻生育前期氮和钾减施潜力较大,建议水稻季氮肥和钾肥后移施用。

Soil physical properties,nutrients,and crop yield with two-year tillage rotations under a winter wheat-summer maize double cropping system

Winter wheat and summer maize were planted from 2015-2017 to study the effects of different rotational tillage patterns on soil physicochemical properties,crop yield,water content,and fertilizer utilization.The tillage treatments were designed as wheat subsoiling-maize no tillage(WS-MN),wheat rotary tillage-maize subsoiling(WR-MS),wheat subsoiling-maize subsoiling(WS-MS),and conventional wheat rotary tillage-maize no tillage(WR-MN)as a control.Among the four treatments,WS-MN and WR-MS were single-season subsoiling treatments,and WS-MS was a two-season subsoiling treatment.The average soil bulk density decreased by 7.6%in the single-and double-season subsoiling groups compared to the WR-MN group,and the total porosity and noncapillary porosity increased by 10.7%and 12.2%,respectively.Single-or double-season subsoiling treatment was not conducive to water storage in the 0-20 cm soil layer but increased the water content of the 20-140 cm soil layer,and the average soil water content of the 0-140 cm layer was increased by 11.6%in the two-growing season treatment groups compared with the WR-MN group.In WS-MS and WS-MN groups compared with the WR-MN group,the soil ammonium nitrogen content was increased by an average of 18.6%in 0-20 cm soil and 16.8%in 20-100 cm soil;soil nitrate-nitrogen content was decreased by 13.5%in 0-100 cm soil;total organic carbon and microbial carbon contents in the 15-30 cm soil were increased by 18.1%and 12.7%,respectively;and soil urease,catalase,and alkaline phosphatase activities were increased by 46.1%,15.2%,and 23.1%,respectively.Annual crop yield and water use efficiency increased by 8.9%and 15.0%,respectively,in both the single-and double-season subsoiling treatment groups.This study demonstrated the advantages of subsoiling tillage and suggested that it is suitable for crop cultivation in the Haihe Plain,China.

改进密闭室抽气法以准确定量旱地土壤氨挥发

密闭室抽气法被认为是定量土壤NH_(3)挥发较为可靠的方法,具有灵敏度高且成本低的优点。然而,大部分研究忽略了密闭室抽气法大气进气口NH_(3)浓度,可能会高估土壤NH_(3)挥发量,目前尚缺乏相关定量研究。本研究以华北冬小麦-夏玉米轮作为对象,对比分析了2019——2021年间冬小麦基肥(2次)、追肥(1次)、夏玉米四叶肥(2次)、夏玉米十叶肥(2次)共7次施肥后,改进密闭室抽气法前后测定农田土壤NH_(3)挥发的结果。改进前为包含大气背景NH_(3)的测定方法,为常规测定方法;改进后为扣除大气背景NH_(3)的测定方法,通过在田间加装3套采集距地面2.5 m高度大气的装置实现。结果表明:改进后的NH_(3)挥发通量(以N计)比改进前低0~0.23 kg·hm^(-2)·d^(-1)(0%~100%),平均值为0.06 kg·hm^(-2)·d^(-1)(33%),且37%的样本存在显著性差异(P<0.05,n=931)。改进后的NH_(3)挥发累积量比改进前低0.53~2.66 kg·hm^(2)(3%~53%),平均值为1.15 kg·hm^(-2)(29%),且47%的样本存在显著性差异(P<0.05,n=49)。改进前后NH_(3)挥发量(包括通量和累积量)存在显著差异的样本占比随着NH_(3)挥发量降低而升高。回归分析表明,改进前的NH_(3)挥发累积排放量可以用算式校正得到真实的NH_(3)累积排放量,校正式为y=0.94x-0.78(R2=0.99,P<0.01,n=49),其中y和x分别为校正后和校正前的NH_(3)挥发累积量,该算式可应用于华北土壤-作物体系NH_(3)挥发累积量的校正。综上,利用抽气法定量农田土壤NH_(3)挥发需要扣除大气背景NH_(3)以得到准确的测定结果,对于未扣除大气背景的旱地NH_(3)挥发累积量,可采用校正算式进行校正。

轮耕对土壤物理性状和冬小麦产量的影响

针对华北地区土壤连续单一耕作存在的主要问题,进行了土壤轮耕效应的研究。试验选择冬小麦夏玉米玉两熟区连续5a免耕田,设置免耕、翻耕和旋耕3种轮耕处理(即免耕一免耕,免耕一翻耕和免耕一旋耕),冬小麦播种前进行耕作处理。研究结果表明:多年免耕后进行土壤耕作(翻耕、旋耕)可以显著降低土壤体积质量;旋耕显著降低0～10cm土壤体积质量,翻耕则降低0～20cm体积质量;随时间变化各处理土壤体积质量差异逐渐降低。翻耕、旋耕均显著增加了0～10cm土壤总孔隙,同时翻耕显著增加了10～20cm土壤总孔隙;翻耕、旋耕显著提高了5～10cm毛管孔隙。0～10cm土壤饱和导水率表现为旋耕>翻耕>免耕,翻耕、旋耕在5%水平上显著高于免耕;10～20、20～30cm土层均表现为翻耕>旋耕>免耕,且10～20cm翻耕5%水平上显著高于免耕;饱和导水率与体积质量呈显著线性负相关。翻耕、旋耕有效穗数与免耕相比分别提高了24.1%、22.3%;冬小麦的实际产量表现为:旋耕>翻耕>免耕,翻耕、旋耕分别比免耕增产11.8%、16.9%。总之,长期免耕后进行土壤耕作有利于改善土壤物理性状,提高作物产量。