Farm size significantly affects the yield, nutrient use efficiency, and environmental effects of wheat–maize systems. A case study of a wheat–maize rotation system in the North China Plain (Henan Province) was conducted to enhance large-scale farm size. The study area included numerous differently sized wheat–maize crop systems in different ecological zones, representing 596 farming households. The average yield, resource use efficiency, and environmental indicators of the wheat–maize systems were analyzed. Combining our parameter-based analysis with field irrigation experiments, we conclude that in the wheat–maize rotation areas of the North China Plain, a farm size of 10.0–16.7 ha optimizes yield, resource use efficiency, and economic and environmental benefits. Moreover, improving irrigation efficiency, such as switching from flood to drip irrigation, significantly enhances the system yield (15.5%–17.5%) and output-to-input ratio (33.5%–44.4%). This study offers recommendations for optimizing farm size and achieving multi-objective sustainability in wheat–maize double-cropping areas.

In light of the issue concerning excessive fertilization that prevails in the Huang-Huai-Hai Plain, through conducting a 13-year long-term positioning experiment, the sustainability of a wheat and maize double-cropping soil system under different fertilization strategies is evaluated using the triangular area method. The objective is to establish a theoretical basis for the development and implementation of appropriate fertilization practices in the Huang-Huai-Hai Plain. In the protracted long-term experiment, chemical fertilizer (F) was taken as the control (CK) and three distinct treatments combining organic and inorganic fertilizers were used: chemical fertilizer with straw mulching (FS), chemical fertilizer with cow dung (FM), and chemical fertilizer with cow dung and straw mulching (FMS). Between 2018 and 2019, a non-fertilization treatment was concurrently incorporated in parallel on the foundation of each existing fertilization treatment. The results indicated that following prolonged fertilization, the soil nutrient content, enzyme activity, and crop yield of each organic fertilizer treatment were significantly greater than those of the chemical fertilizer treatment alone, resulting in a more stable yield. After two years of discontinuation of fertilizer cultivation, the soil fertility indexes of each treatment exhibited a notable decline. However, the rate of decrease in soil fertility indexes for the three organic fertilizer treatments was lower compared to that of the single application of chemical fertilizer treatment, suggesting that long-term allocation of organic + inorganic fertilizers contributes to better preservation of soil fertility. Through an assessment of the soil system’s sustainability under various treatments, it becomes evident that following a two-year cessation of fertilization, the sustainability indexes of the soils subjected to three long-term organic + inorganic fertilizer treatments (1.26, 1.29, and 1.27) exceeded that of the soil treated solely with chemical fertilizer (1.00). These findings provide further evidence supporting the notion that the combined application of organic and inorganic fertilizers can enhance the soil system’s capacity for sustainable production in wheat–maize farmland within the Huang-Huai-Hai Plain.

Globally, agricultural soils are considered as one of the most important sources of greenhouse gas (GHG) emissions. No-tillage (NT), one of the most admired ways of climate-smart agriculture, has been deemed to have co-benefit to mitigation of GHG emissions and sustainability for crop yield, however, the effect of NT on GHG emissions is controversial. This study analyzed the overall effects of NT on GHG emissions, as well as the moderators that significantly influenced the overall effects, of the wheat-based rotation cropping systems in China through meta-analysis. The results showed that the overall effect size of NT on methane (CH 4 ) uptake, nitrous oxide (N 2 O) emission, and global warming potential (GWP) was 0.70 (95% Confidence Interval (CI): 0.21–1.19), −0.27 (95%CI: −0.72–0.18), and −0.39 (95%CI: −1.01–0.23), respectively. In temperate climate zones with alkaline soils, the nitrogen application rate of 120–240 kg/ha, NT could significantly reduce GHG emissions and GWP. However, the mitigation effect will be weakened along with NT duration, except for proper straw addition. Overall, NT has the potential to reduce GHG emissions from wheat-based rotation systems in China, but it is necessary to implement NT depending on local conditions, soil characteristics, and field management.

以华北平原南部两熟作物的搭配为研究对象,在玉米、大豆和花生 3 种前茬作物的磷常规施用水平基础上,同时设置不施磷肥的磷匮乏水平,同期检测收获后土壤的养分含量及后茬小麦产量及籽粒养分累积量,为华北平原一年两熟制的作物搭配提供理论依据.结果表明,对前茬作物收获后土壤养分而言,在不施磷肥情况下土壤全磷含量表现为大豆前茬处理较高,花生前茬处理与常规施肥处理含量相近;土壤速效磷含量整体表现为花生前茬处理较高;土壤硝态氮和铵态氮含量均表现为大豆前茬处理最高.对后茬小麦而言,小麦千粒质量和产量及小麦籽粒氮、磷累积量和氮肥偏生产力在不施磷肥下均表现为花生前茬处理较高,分别较玉米前茬处理提高 0.60％,6.19％,15.46％,18.11％和6.21％,较大豆前茬处理提高2.18％,7.30％,17.66％,13.40％和7.30％.综上,在低磷水平下,为了保证土壤养分平衡,选择花生作为小麦前茬作物是华北平原南部两熟区作物搭配的较优模式.

为探究不同施肥处理对黄淮海平原农田土壤养分和小麦籽粒产量及品质的影响,在2007年开始的长期培肥试验基础上,于2018年至2020年设置6个处理:在原有常规化肥(+F),化肥和秸秆配施(+FS),化肥和牛粪配施(+FM),以及3种长期施肥处理的基础上各增一个不施肥处理,分别记为-F,-FS,-FM.在小麦成熟期对土壤养分、产量以及籽粒品质进行综合分析,结果表明:+FS和+FM的土壤养分质量分数和籽粒产量以及品质显著高于+F组;连续两年不施肥处理后,与+FS和+FM处理相比,-FS和-FM处理的速效磷质量分数分别下降15％和16％,土壤有机碳质量分数分别下降9.3％和9.9％,产量分别下降3.4％和4.2％,但-FS和-FM处理籽粒蛋白质量分数、湿面筋质量分数和淀粉质量分数并未出现显著下降;-FS和-FM处理的速效磷质量分数、有机碳质量分数、籽粒蛋白质量分数、湿面筋质量分数、淀粉质量分数下降幅度均小于-F处理.因此,在长期培肥基础上,无机有机肥配施的土壤-小麦系统的稳定性更高.

NAC transcription factors play critical roles in regulating drought stress. However, the drought-responsive NAC transcription factors are largely unexplored in wheat. In this study, we isolated a NAC gene, TaNAC5D-2, and characterized the function of TaNAC5D-2 as a positive regulator of drought tolerance. The expression level of TaNAC5D-2 was induced under drought or abscisic acid treatment. Transient expression and transcriptional activity assays showed that TaNAC5D-2 is localized to the nucleus, and the C-terminal region exhibited transcriptional activity. Overexpression of TaNAC5D-2 in Arabidopsis thaliana led to greater drought tolerance, fresh weight and dry weight than wild-type plants, and the water loss was significant inhibited in the leaves of overexpression lines. Conversely, silencing of TaNAC5D-2 in wheat seedlings led to increased water loss and decreased growth compared to control and negative control plants under drought stress. RNA-Seq and RT-qPCR revealed that many Group A PP2C genes were upregulated in the TaNAC5D-2 silenced plants compared to negative control. And silencing TaNAC5D-2 negatively regulate ABA-induced stomatal closure that led to higher water loss. These data suggest that TaNAC5D-2 acts as a drought-responsive regulator, possibly by an abscisic acid-mediated stomatal closure to control water loss under drought condition.

The NAC genes, a large plant-specific family of transcription factors, regulate a wide range of pathways involved in development and response to biotic and abiotic stress. In this study, the NAC transcription factors were identified in 27 green plants, and the results showed that NAC transcription factors in plants undergo an appearance stage from water to land and a number expansion stage from gymnosperm to angiosperm. Investigating the evolutionary process of the NAC transcription factors from diploid species to hexaploid wheat revealed that tandem replications during the polyploidization process is an important event for increasing the number of NAC transcription factors in wheat. Then, the molecular characteristics, phylogenetic relationships, and expression patterns of 462 NAC transcription factors of hexaploid wheat (TaNACs) were analyzed. The protein structure results showed that TaNAC was relatively conservative at the N-terminal that contains five subdomains. All these TaNACs were divided into Group I and Group II by phylogenetic analysis, and the TaNACs in Group I should undergo strong artificial selection based on single nucleotide polymorphism (SNP) analysis. Through genome synteny and phylogenetic analysis, these TaNACs were classified into 88 groups and 9 clusters. The biased expression results of these TaNACs showed that there are 24 groups and 67 groups of neofunctionalization genes under biotic and abiotic stress, respectively, and 16 groups and 59 groups of subfunctionalization genes. This shows that neofunctionalization plays an important role in coping with different stresses. Our study provides new insights into the evolution of NAC transcription factors in hexaploid wheat.

Wheat bran is abundant in dietary fiber, and an important indicator for evaluating the dietary fiber is the soluble dietary fiber (SDF) content. In this study, we analyzed the effect of steam explosion (SE) treatment on the SDF content of wheat bran. The parameters, including steam pressure, residence time, and mesh size were optimized, and it was found that the content of total SDF in wheat bran after SE treatment could be increased from 18.88 % to 40.32 %. The SDF characteristics from raw wheat bran and SE-treated wheat bran were investigated. The results show that the molecular weight of SDF decreased after SE treatment, and the SDF surface became disintegrated. In addition, the thermodynamic characteristic of SDF was improved after SE treatment, and similar functional groups were found to those SDF from raw wheat bran. These effects could potentially improve the physicochemical properties of SDF and increase the application value of wheat bran.

为了探寻华北平原南部一年两熟制中较适宜的搭配模式,研究了该区域广泛应用的:小麦-玉米、小麦-大豆、小麦-花生、小麦-甘薯4种搭配模式,分析了不同模式光合性能的变化规律,计算了其光资源利用效率及产量与产值.结果表明:小麦-甘薯模式在两季的总光资源积累量中表现出最高;但由于小麦-甘薯模式价格最低,所以其两季的总产值最低.另一方面,小麦-玉米、小麦-大豆、小麦-花生3种搭配模式由于生育期基本一致使得其光能积累几乎相等;而小麦-甘薯模式在除小麦-玉米模式的其他3种模式中光合作用强度较高,光能利用效率仅次于小麦-玉米模式,加之产品价格较高,故两季的总产值最高;此外,小麦-花生模式在光资源利用效率以及总产值方面也具有相对的优势.因此选择小麦-玉米模式作为华北平原南部两熟区最适宜的搭配模式,而小麦-花生模式可作为该地区的替代搭配模式.

为了更好地利用华北平原南部的自然资源,充分发挥该区域光、温、水、土资源的优势,于2016年6月—2019年6月以玉米-小麦→玉米-小麦→玉米-小麦(T1)、大豆-小麦→大豆-小麦→玉米-小麦(T2)、花生-小麦→花生-小麦→玉米-小麦(T3)、甘薯-小麦→甘薯-小麦→玉米-小麦(T4)4种轮作模式为研究对象,以经济价值为考核依据,用等价代换法对不同作物产量进行等价转换,并运用相关分析和灰色关联分析法对这几种模式光、温、水、土资源利用效率及作物等价产量(E GY)进行分析.结果表明,T3模式的光能利用率(RUE)、积温生产效率(PE GDD)、水分利用效率(WUE)皆为最高,分别为0.78％、5.37 kg/(hm2·℃)、28.05 kg/mm;T1模式仅次于T3模式,RUE、PE GDD、WUE分别为0.61％、4.82 kg/(hm2·℃)、25.28 kg/mm.对作物E GY及自然资源的相关分析可知,E GY与PE GDD、WUE呈极显著正相关,与土地利用率(LUE)呈显著正相关;进而以E GY为母系列,自然资源利用率为子系列进行灰色关联度分析可知,各种资源利用效率关系为PE GDD>WUE>LUE>RUE.综上所述,积温生产效率与水分利用效率对产量的影响较大,而T3模式与T1模式的整体自然资源利用率较高.

两熟种植模式一直是华北平原的主要种植模式,冬季作物以小麦为主,夏季则以玉米、大豆、棉花和薯类等作物为主.为研究不同夏播前茬作物对后茬小麦产量和品质的影响,选用玉米(T1)、大豆(T2)、花生(T3)和甘薯(T4)四种夏播作物,在播种前和收获后检测田间土壤养分变化,以及后茬小麦的籽粒产量和品质.结果 表明,大豆收获后,15～30 cm土层土壤碱解氮和速效磷含量分别提高129.75％和43.93％,远高于其他前茬处理;花生收获后,15～30 cm土层土壤碱解氮和速效磷含量与播前相比基本保持平衡;四种前茬处理下土壤速效钾和有机质含量均显著增加.玉米前茬和花生前茬处理下,小麦产量和籽粒中氮、磷、钾的积累量显著高于大豆前茬和甘薯前茬处理,小麦产量比甘薯前茬处理分别提高38.15％和31.13％％.花生前茬能够有效提高后茬小麦籽粒干基蛋白、湿面筋含量和籽粒容重,大豆前茬能够提高后茬小麦籽粒的干基淀粉含量,甘薯前茬能够提高后茬小麦的出粉率.总的来看,选择花生做前茬,在保持后茬小麦产量较高的同时,能够提高小麦籽粒的品质性状.

为探讨土壤Pb污染的治理方法,通过盆栽试验,比较了离子交换纤维的两种不同放置方式(分层放置与混匀放置)对麦田土壤Pb污染的修复效果.结果 表明,在土壤1 000 mg· kg-1 Pb污染水平下,Pb污染处理(T1:Pb胁迫;T2:Pb+在土壤中分三层放置纤维;T3:Pb+在土壤中混匀剪碎的纤维)的土壤pH值、总有机碳含量较对照(CK:未添加Pb和离子交换纤维)有所降低.在小麦成熟期,T2、T3处理下土壤和植株各部位的Pb含量均低于T1处理,其中T3处理变化显著;T2、T3处理中纤维吸附的Pb含量则分别达到115.01和128.26 mg· kg-1.T2、T3处理的Pb富集系数低于T1处理及CK.由此说明,离子交换纤维能够有效吸附土壤中的Pb,降低Pb从土壤向植株的转运能力,且离子交换纤维混匀放置方式的修复效果较好.

为研究不同有机物料还田与减施氮肥处理对农田碳氮水足迹及经济效益的影响,本试验以单施化肥处理(CK,纯氮270 kg·hm-2)为对照,设置了秸秆(J)、秸秆+牛粪(JF)、秸秆+菌渣(JZ)3种有机物料还田方式,耦合减施氮肥10％(N1,243 kg·hm-2)、20％(N2,216 kg·hm-2)、30％(N3,189 kg·hm-2)3个施氮水平,共计10个处理.结果表明:与单施化肥相比,有机物料还田与减施氮肥处理能够显著提高作物产量及农田经济效益,且JZN1、JN2和JFN3处理对农田经济效益的提高效果最显著;JN1、JN2、JFN2、JFN3和JZN3处理均可以有效增加农田的净碳值及碳效率,降低农田的生产氮足迹,增加其输出氮足迹,提高氮投入有效利用水平,同时降低农田水足迹.其中JFN3处理可以在保证农田经济效益的同时,显著提高其碳效率、降低生产氮足迹、提高氮投入有效利用水平、降低农田的水足迹.因此建议豫北地区采用秸秆+牛粪还田、配施纯氮189 kg·hm-2的施肥方式.

为探讨微量元素在农业生产中的作用,研究不同轮作模式下土壤-作物系统内Fe、Mn含量变化,为基于轮作模式的土壤-作物系统中Fe、Mn养分管理提供理论依据和生产指导.采用根箱试验方法,设置了小麦-玉米(W-M)、小麦-大豆(W-B)、小麦-花生(W-P)和小麦-甘薯(W-S)4种轮作模式,使用电感耦合等离子体质谱法(ICP-MS)测定不同处理土壤与作物体内Fe、Mn含量,计算作物地上部Fe、Mn累积量和成熟期Fe、Mn富集系数.结果表明,W-M、W-B模式下小麦和夏季作物地上部Fe、Mn含量均随生育时期的推进而逐渐增加,而W-P模式小麦地上部分Fe含量则逐渐递减;W-P模式夏季作物地上部分Fe、Mn累积量随生育时期的推进呈先增加后减少的趋势,W-S模式小麦地上部分Fe、Mn累积量均随生育时期的推进而逐渐增加,但是夏季作物地上部分Fe、Mn累积量均随生育时期的推进先增加后减少.在不同轮作模式下,土壤中Fe、Mn含量均逐渐减少;在0～20、20～50 cm土层深度,W-M模式在2018年10月Fe、Mn含量均最高,在50～80 cm土层深度,W-B、W-S模式在2018年10月Fe、Mn含量较高;不同作物在表层土壤中的Fe富集系数均小于Mn;小麦Fe、Mn富集系数均为W-S模式最高;夏季作物W-M模式Fe富集系数最高,W-B模式Mn富集系数最高.

为了探讨不同前茬作物与小麦轮作的生化关系,以大豆、花生、玉米、甘薯为供试材料,以小麦为受体材料,研究了4种作物根系分泌物对小麦种子萌发、幼苗形态及生理指标的影响.结果 表明,大豆、花生、玉米和甘薯根系分泌物对小麦种子萌发率、胚根长、株高、根长、叶绿素含量、丙二醛(MDA)含量、超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性均产生不同程度的影响,这4种作物根系分泌物对供试小麦的萌发率均表现出抑制作用,对小麦的胚根长、幼苗株高及根长则表现为低浓度促进、高浓度抑制的作用,且小麦幼苗的叶绿素含量整体上随着根系分泌物浓度的增加而降低.此外,小麦幼苗的POD、CAT活性总体上均随着根系分泌物浓度的增加而增加,大豆和甘薯根系分泌物处理下的MDA含量随着根系分泌物浓度的增加而降低.

运用相关分析和通径分析方法,研究麦玉两熟制农田土壤因子与玉米产量的关系,测定麦玉周年成熟期土壤养分、微生物量碳氮、酶活性和玉米产量等指标.结果 表明,土壤有机质、全氮、全磷、速效钾、速效磷、土壤微生物量碳氮和脲酶活性均与玉米产量有极显著或显著相关关系.土壤有机质对玉米产量的直接作用最大(直接通径系数P1y=0.422),其次是微生物量氮(P6y=0.381)和全氮(P2y=0.254),三者的通径系数均为正值,表明对提高玉米产量起到促进作用.从决策系数绝对值大小可以得出,土壤有机质、全氮和微生物量氮对玉米产量的综合排序为土壤有机质＞微生物量氮＞全氮,土壤有机质的决策系数最大且为正值,说明土壤有机质是影响麦玉两熟制农田玉米产量的主要决策指标.

Exploring the impact of returning organic materials to the soil on greenhouse gas emission characteristics of winter wheat fields can help to improve economic and environmental consequences. Based on 3 modes of organic material return (JF: straw return and cow dung; J: straw return; JZ: straw return and mushroom dregs) and 2 nitrogen levels (N1: 243 kg·hm; N2: 216 kg·hm), the fluxes of N2O, CO2, and CH4 in winter wheat fields were monitored using the static chamber method and gas chromatography, and 816 中国生态农业学报(中英文) 2019 第 27卷 http://www.ecoagri.ac.cn the effects of the different fertilization measures on cumulative greenhouse gas emissions and warming potential of wheat fields were studied. During the experimental period, the amount of fuel consumed by farm machines and the power consumed during irrigation and fertilizer application were recorded and transformed to their carbon equivalents using a transformation coefficient. In addition, crop yield and aboveground biomasses were measured and carbon sequestration calculated. The total GWP under each of the 6 treatments were estimated based on the identified parameters of the greenhouse effect. The results indicated that wheat fields served as sources of N2O and CO2 and sinks of CH4. Nitrogen application and adequate irrigation increased CO2 and N2O in the soil, but weakened the characteristics of CH4 as an atmospheric absorption sink. The total amounts of N2O and CO2 emitted were highest in the JF treatment, at 3.5 kg (N2O-N)·hm and 19 689.67 kg (CO2-C) hm respectively, and the absorption value of CH4 in this treatment was 5.33 kg (CH4-C) hm, significantly higher than in both of the JZ and J treatments. The total amounts of N2O and CO2 in each treatment increased, and the total amount of CH4 decreased, with an increase in the nitrogen application rate. The GWP of JFN2, JN2, and JZN2 treatments were all negative, which indicated that the farmland ecosystem is an atmospheric carbon sink when organic materials were returned to the field; nitrogen was reduced by 20%, and the carbon interception by wheat was 1 0382 024 kg·hm. The GWP values were positive and the JZN2 treatment-treated wheat yield was 8 061 kg·hm, significantly higher than that of the JFN2 treatment. In summary, JZN2 treatment could ensure wheat yield and had the most favorable environmental effects, and thus was the best fertilization management model for winter wheat in this region

新乡地区是河南省重要的粮食产区,其农田土壤微生物的群落结构和多样性目前仍不清楚.以新乡市获嘉县长期免耕和传统耕作的农田土壤为材料,测定其土壤理化特征,并且采用高通量测序技术分析其土壤微生物的群落特征.结果显示,该区域农田土壤的基本理化性质为:含水量9.37％～13.39％,pH值8.55～8.65,全氮和全磷质量分数分别为0.91～0.96 mg/g和4.06～5.34 mg/g.土壤中优势细菌菌群为变形菌门(～30％)、浮霉菌门(～20％)、酸杆菌门(～16％)和放线菌门(～8％),优势真菌菌群为子囊菌门的粪壳菌纲(～50％)、散囊菌纲(3％～10％)和座囊菌纲(～10％).免耕处理的土壤微生物丰富度和多样性要高于常规耕作的土壤微生物,而且轮作处理的土壤微生物数量要高于同等条件下单一种植模式的对照处理.本研究有助于了解该地区不同种植模式下的土壤微生物群落结构,可为进一步改良土壤和防治土传病害提供理论依据.

为了研究不同有机物料还田对麦田土壤酶活性与土壤养分的影响,通过田间试验比较单施氮肥(CK,施纯氮270kg/hm2)、秸秆还田(J,较CK减氮20％)、秸秆还田+牛粪(JF,较CK减氮20％)、秸秆还田+菌渣(JZ,较CK减氮20％)4种不同培肥处理,对麦田0～60cm土层脲酶、蔗糖酶活性与土壤有机碳、全氮含量变化进行研究.结果 表明,在小麦季0～20cm土层各处理在拔节期脲酶活性最大,20～40cm土层JF处理在拔节期和开花期脲酶活性最大;在0～20和20～40cm土层JF处理在拔节期蔗糖酶活性显著高于CK处理.除J处理外,其他处理在0～20cm土层拔节期有机碳含量最大,且有机碳含量均表现为JF处理最大,其次是JZ处理;在0～20cm土层各生育时期JF处理的全氮含量均最大,且显著高于CK处理.减氮条件下有机物料还田能有效提高土壤脲酶、蔗糖酶活性,有机碳和全氮含量,并且土壤脲酶活性、蔗糖酶活性与有机碳和全氮含量均呈极显著正相关关系.综上,在减施氮肥条件下有机物料还田可以提高土壤质量.