The first factor affecting dryland winter wheat grain yield under various mulching measures: Spike number

Water is the key factor limiting dryland wheat grain yield.Mulching affects crop yield and yield components by affecting soil moisture.Further research is needed to determine the relationships between yield components and soil moisture with yield,and to identify the most important factor affecting grain yield under various mulching measures.A long-term 9-yearifeld experiment in the Loess Plateau of Northwest China was carried out with three treatments:no mulch (CK),plastic mulch (M_(P)) and straw mulch (M_(S)).Yield factors and soil moisture were measured,and the relationships between them were explored by correlation analysis,structural equation modeling and significance analysis.The results showed that compared with CK,the average grain yields of M_(P) and M_(S) increased by 13.0and 10.6%,respectively.The average annual grain yield of the M_(P) treatment was 134 kg ha^(–1) higher than the M_(S) treatment.There were no significant differences in yield components among the three treatments (P<0.05).Soil water storage of the M_(S) treatment was greater than the M_(P) treatment,although the differences were not statistically signifiant.Soil water storage during the summer fallow period (SWSSF) and soil water storage before sowing (SWSS) of M_(S) were significantly higher than in CK,which increased by 38.5 and 13.6%,respectively.The relationship between M_(P) and CK was not statistically significant for SWSSF,but the SWSS in M_(P) was significantly higher than in CK.In terms of soil water storage after harvest (SWSH) and water consumption in the growth period(ET),there were no signi?cant differences among the three treatments.Based on the three analysis methods,we found that spike number and ET were positively correlated with grain yield.However,the relative importance of spike number to yield was the greatest in the M_(P )and M_(S) treatments,while that of ET was the greatest in CK.Suifcient SWSSF could indirectly increase spike number and ET in the three treatments.Based on these results,mulch can improve yield and soil water storage.The most important factor affecting the grain yield of dryland wheat was spike number under mulching,and ET with CK.These findings may help us to understand the main factors influencing dryland wheat grain yield under mulching conditions compared to CK.

Plastic mulch increases dryland wheat yield and water-use productivity,while straw mulch increases soil water storage

Amplifying drought stress and high precipitation variability impair dryland wheat production.These problems can potentially be minimized by using plastic mulch(PM)or straw mulch(SM).Therefore,wheat grain yield,soil water storage,soil temperature and water-use productivity of PM and SM treatments were compared with no mulch(CK)treatment on dryland wheat over a period of eight seasons.Compared to the CK treatment,PM and SM treatments on average significantly increased grain yield by 12.6 and 10.5%,respectively.Compared to the CK treatment,SM treatment significantly decreased soil daily temperature by 0.57,0.60 and 0.48℃ for the whole seasons,growing periods and summer fallow periods,respectively.In contrast,compared to the CK treatment,PM treatment increased soil daily temperature by 0.44,0.51 and 0.27℃ for the whole seasons,growing periods and summer fallow periods,respectively.Lower soil temperature under SM allowed greater soil water storage than under PM.Soil water storage pre-seeding was 17%greater under the SM than under the PM treatment.Soil water storage post-harvest was similar for the PM and SM treatments,but evapotranspiration was 4.5%higher in the SM than in the PM treatment.Consequently,water-use productivity was 6.6%greater under PM than under the SM treatment.Therefore,PM treatment increased dryland wheat yield and water-use productivity,while straw mulch increased soil water storage.

Buried straw layer and plastic mulching increase microflora diversity in salinized soil

Salt stress has been increasingly constraining crop productivity in arid lands of the world. In our recent study, salt stress was aleviated and crop productivity was improved remarkably by straw layer burial plus plastic iflm mulching in a saline soil. However, its impact on the microlfora diversity is not wel documented. Field micro-plot experiments were conducted from 2010 to 2011 using four tilage methods： （i） deep tilage with plastic iflm mulching （CK）, （i） straw layer burial at 40 cm （S）, （ii） straw layer burial plus surface soil mulching with straw material （S＋S）, and （iv） plastic iflm mulching plus buried straw layer （P＋S）. Culturable microbes and predominant bacterial communities were studied; based on 16S rDNA, bacterial com-munity structure and abundance were characterized using denaturing gradient gel electrophoresis （DGGE） and polymerase chain reaction （PCR）. Results showed that P＋S was the most favorable for culturable bacteria, actinomyces and fungi and induced the most diverse genera of bacteria compared to other tilage methods. Soil temperature had signiifcant positive correlations with the number of bacteria, actinomyces and fungi （P〈0.01）. However, soil water was poorly correlated with any of the microbes. Salt content had a signiifcant negative correlation with the number of microbers, especialy for bacteria and fungi （P〈0.01）. DGGE analysis showed that the P＋S exhibited the highest diversity of bacteria with 20 visible bands folowed by S＋S, S and CK. Moreover, P＋S had the highest similarity （68%） of bacterial communities with CK. The major bacterial genera in al soil samples wereFirmicutes,Proteobacteria andActinobacteria. Given the considerable increase in microbial growth, the combined use of straw layer burial and plastic iflm mulching could be a practical option for aleviating salt stress effects on soil microbial community and thereby improving crop production in arid saline soils.

Growth Characteristics and Yield of Late-Season Rice under No-tillage and Non-flooded Cultivation with Straw Mulching

A long-term field experiment （started at 2003） was conducted to determine the effects of different dce cultivation methods on growth characteristics and grain yield of late-season rice under double-rice cropping system in seasonal drought region of southeast China （Yujiang County, Jiangxi Province）. The rice cultivation methods included no-tillage and flooded rice cultivation （N-F）, no-tillage and non-flooded rice cultivation with straw mulching （N-SM）, and no-tillage and non-flooded rice cultivation without straw mulching （N-ZM）. There was no significant difference in rice grain yield between the N-SM and N-F treatments. However, the rice grain yields in the N-SM and N-F treatments were significantly higher than that in the N-ZM treatment. The late-season rice plants in the N-SM treatment had significantly higher numbers of effective panicles and total grains per hill compared with those in the N-ZM treatment. The above-ground dry matter of late-season rice was similar between the N-SM and N-F treatments. Compared with the N-F treatment, the N-ZM and N-SM treatments significantly decreased the leaf area at the heading stage. Moreover, the N-SM treatment could significantly increase total root length and root tip number at the grain-filling stage compared with the N-ZM treatment.

Effects of Non-flooded Cultivation with Straw Mulching on Rice Agronomic Traits and Water Use Efficiency

A field experiment was conducted to study water use efficiency and agronomic traits in rice cultivated in flooded soil and non-flooded soils with and without straw mulching. The total amount of water used by rice under flooded cultivation （FC） was 2.42 and 3.31 times as much as that by rice under the non-flooded cultivation with and without straw mulching, respectively. The average water seepage was 13 560 m^3/ha under the flooded cultivation, 4 750 m^3/ha under the non-flooded cultivation without straw mulching （ZM） and 4 680 m^3/ha under non-flooded cultivation with straw mulching （SM）. The evapotranspiration in the SM treatment was only 38.2% and 63.6% of the FC treatment and ZM treatment, respectively. Compared with the ZM treatment, straw mulching significantly increased leaf area per plant, main root length, gross root length and root dry weight per plant of rice. The highest grain yield under the SM treatment （6 747 kg/ha） was close to the rice cultivated in flooded soil （6 811.5 kg / ha）. However, the yield under the ZM treatment （4 716 kg/ha） was much lower than that under the FS treatment and SM treatment. The order of water use efficiency and irrigation water use efficiency were both as follows： SM〉 ZM〉 FC.

Research on the effect of straw mulching on the soil moisture by field experiment in the piedmont plain of the Taihang Mountains

To reveal the influencing effect of the long-term straw mulching on the soil moisture, this paper employed the field experiment data in 2010 of a typical area of Taihang Mountains plain, observed the soil moisture dynamic regularities under different mulching patterns by virtue of depressimeter and neutron probe, analyzed the characteristics of soil water content and storage in different depths and seasons under the long-term straw mulching. The results showed that the long-term straw mulching can keep the soil moisture conservation of the deep, while decreased the shallow.(1) The long-term straw mulching can changed the type of soil water movement. If no straw mulching, the type is mainly evaporation-infiltration. And with straw mantle the type would change into infiltration. The number of zero flux plane would be reduced or absent.(2) The long-term straw mulching can increase the soil water reserves of the whole soil profile with the depth between 0 cm and 220 cm. But the soil water content of the layer from 30 cm to 80 cm decreased and the soil water content of the layer from 80 cm to 220 cm increased instead., The effect of soil moisture conservation on winter wheat is not obvious;(3) With no straw mulching, the depth of infiltration recharge by rainfall or irrigation is shallower than 80 cm. In a straw mulching, the influence depth is can extend to 120 cm;(4) With no straw mulching, there is a deep layer on the depth of 220 cm between March and June, while this layer will disappear with a long-term straw mulching.

The ecological effects of rice straw mulching on vineyard

Yongzhou often encounters drought condition in July and August. Sometimes no rainfall lasts for 20 to 40 days, causes a great damage to grape production Our four-year rice straw mulching test on vineyard indicates that if favorable mulching is supplied properly, it reduces soil temperature and conserves soil moisture in summer, increases soil temperature in winter, keeps soil loose and mellow, depresses weeds, and increases soil organic matter content in vineyard to secure good quality and higher yield even under drought condition.

Effect of Straw Mulching on Vineyard Ecology and Fruit Quality of Southern Jiangsu Province

[Objectives] The ecological environment of orchard has a direct impact on fruit quality,and straw mulching can effectively improve the physicochemical indicators of orchard soil,so as to achieve environmental protection and yield increase.[Methods]Tests were carried out for 3 consecutive years of mulching straw in vineyard of southern Jiangsu Province.[Results]The results showed that mulching straw continuously could effectively improve soil physicochemical properties,weed controlling effect,and the photosynthetic rate of leaves,as well as the yield and quality of grapes.The contents of total nitrogen,available phosphorus,quickacting potassium and organic matter increased up to 91.67%,259.76%,442.39% and 34.30%,respectively.Soil bulk density decreased by 7.15%,and the weed plant control effect reached 87.45%.The increased of fresh weight was up to 93.55%,and the increase of the leaf parenthetical rate was up to 18.24%.The increases of soluble solids content and single grain weight reached up to 8.82% and 12.75%.The rate of dehiscent fruit was decreased by 50.89%.The grape could pick for sale 3 days ahead,and the increase of unit area yield reached up to 13.16%.[Conclusions]Straw mulching cultivation in vineyard is a good model for efficient recycling of crop straw and safe production of quality grape,and it provides a new technical approach for straw utilization,promising with good economic and ecological benefits.

Study on the Agricultural Fuel Consumption Subsidy Policy for Wheat Straw Low Stubble——Taking the Investigation of Wheat Combine Harvester as an Example in Xushui District of Hebei Province

With the improvement of agricultural mechanization equipment levels, the mechanized wheat harvesting level has been above 80% and the rate of wheat straw returned has increased significantly in the main wheat production of wheat of northern countryside in China. Chinese government popularized the beneficial agronomic measures in the process of wheat straw returned field by mechanization. The agronomic measure was reducing the wheat straw stubble height(WSSH) not more than 20 cm.However, local government didn't apply and disseminate the measure, because in practice the cost of fuel consumption was high, and the operation time of harvesting was longer than ever. The machinery operators and farmers needed to support extra fuel cost and time if they took government's advice. In fact, the objective subsidy policy of fuel cost on reducing WSSH was not been formulated by all levels of government. Therefore, the set of agronomic measure couldn't be popularized in main wheat production area of North China. Our research addressed to master the changing feature of fuel cost and mechanical efficiency,seeking suitable subsidy standard, providing some useful and constructive suggestions to improve subsidy policy of fuel consumption cost for national government department. The study carried out the tracking experiments of the operation efficiency and fuel costs of farm harvester in the situation of different WSSH in 2010 in Xushui District of Hebei Province. In conclusion, the operation time of harvesting decline and machinery fuel consumption cost increased along with the decreasing of WSSH. First for the older harvester, the operation efficiency would decline by 18.7% when the WSSH changed from 20 cm to 10 cm, the cost would increase 4.7%, exact cost was 152.2CNY per hectare. For the new harvester, the operation efficiency would decline by 39.9% when the WSSH changed from 20 cm to 15 cm, the cost would increase 4.6%, exact cost was 368.4CNY per hectare. We provided about 375 CNY per hectare to the mechanical operators and farmer who attended this project, and they were willing to accept the subsidies. We also put forwards some policy suggestions on promoting agronomic measures of reducing WSSH including strengthen the construction of agricultural machinery service system, practise a special fuel consumption subsidies of agricultural machinery and open up new paths for combine sales and circulation.

玉米秸秆还田下深松年限对土壤有机碳含量及胡敏酸结构特征的影响

为明确不同秸秆还田结合耕作措施下土壤有机碳组分的变化特征,基于6 a秸秆还田长期定位试验,利用三维荧光光谱技术,对CK(不深松+不秸秆还田)、NFG(不深松+每年秸秆还田)、EFG(隔一年深松+每年秸秆还田)、TFG(隔两年深松+每年秸秆还田)和SFG(连年深松+每年秸秆还田)处理下土壤有机碳(SOC)含量及胡敏酸(HA)结构特征进行分析。结果表明:与CK相比,EFG处理0~10 cm土层的SOC、HA含量和PQ值分别显著增加25.23%、16.19%和4.27%,FA含量降低4.55%。10~20 cm土层,EFG处理的SOC含量最高,较CK增加13.18%;SFG处理的HA和FA含量较CK提高最多,增幅分别为13.27%和32.74%。通过HA三维荧光图谱发现,与CK(Ex/Em=270/455,270/460)相比,EFG(Ex/Em=280/455,270/465)处理下0~10 cm和10~20 cm土层中的HA荧光峰波长均有红移现象。土壤胡敏酸中包含两个组分,C1(Ex/Em=270/280)和C2(Ex/Em=440/515)同为类腐殖酸物质,胡敏酸整体腐殖化程度较高,结构较为复杂;其中EFG和TFG处理的C2组分所占比例最高,分别为28.59%和31.38%。各处理的C1和C2组分F_(max)值均较CK有所增加,即腐殖化程度增加。综上所述,EFG处理(隔一年深松+每年秸秆还田)通过提升土壤有机碳及腐殖酸类物质含量,增加腐殖化程度,加强了土壤的供肥能力,为黑龙江黑土区较佳的耕作技术措施。

秸秆覆盖量和施氮量对陇中春小麦的产量效应模拟

为量化分析秸秆覆盖量和施氮量对旱地春小麦的产量效应和协同作用,在APSIM模型中,设置秸秆覆盖量和施氮量2因素5个变化梯度,组合交叉设计25个处理,利用模型模拟25个处理的春小麦产量;于2016—2018年在甘肃省定西市安定区开展小麦大田试验,得到早播(ESW)、正常播(NSW)、晚播(LSW)春小麦产量的实测值,利用APSIM模型模拟2016—2018年春小麦的产量,将模拟值与实测值进行对比,对模型的适用性和模拟精度进行分析;对春小麦产量与秸秆覆盖量、施氮量的耦合关系进行二次多项回归和通径分析,利用Matlab计算春小麦的最大产量及对应的秸秆覆盖量和施氮量。结果表明:不同处理下产量的模拟值与实测值均位于15%置信带内,模型模拟精度较高,归一化均方根误差值为4.64%~12.22%,表明该模型在研究区具有良好的适用性;秸秆覆盖量和施氮量的增长对春小麦的产量效应为正效应,相应关系表现为开口向下的二次抛物线变化关系;ESW、NSW和LSW模拟情景下,春小麦最大产量分别为3548.64、3149.59、2507.58 kg/hm^(2);ESW模式下,最佳秸秆覆盖量和施氮量分别为7062.04、194.91 kg/hm^(2);NSW模式下,最佳秸秆覆盖量和施氮量分别为8211.31、218.81 kg/hm^(2);LSW模式下,最佳秸秆覆盖量和施氮量分别为6215.15、162.01 kg/hm^(2)。

南方双季稻区水田高留茬秸秆还田机作业效果研究

为考察自行研制的南方双季稻区水田高留茬秸秆还田机大田作业效果,以原谷珍香为供试品种进行大田试验,并设置现有的常规秸秆还田机作业进行对照,通过对早稻不同高度的留茬秸秆进行还田作业,考察了该机具的耕作效果,并研究了对后茬晚稻机插质量、群体质量构建及产量和产量构成等指标的影响。结果显示,较对照,同一留茬高度时,经自行研制的南方双季稻区水田高留茬秸秆还田机处理的效果显著,其耕深、耕深稳定性、埋茬深度、耕后地面平整度和植被覆盖率分别平均提升5.18%、4.64%、20.85%、21.61%和4.43%,漏插率、漂秧率、伤秧率和翻倒率分别平均降低28.79%、23.17%、29.84%和45.02%,均匀度合格率和插秧深度合格率分别平均提高1.40%和1.65%,茎蘖数平均提高2.52%~6.62%,SPAD值(移栽后27d始)平均提高3.59%~6.53%,地上部干物质重(插秧后34 d始)平均提高1.78%~4.81%,穗干重和收获指数分别平均提高3.39%和2.16%,有效穗、穗粒数、千粒重、结实率和理论产量分别平均提高2.52%、1.34%、0.08%、1.41%和5.47%,实际产量平均增产268.86 kg·hm^(-2),平均增产率4.09%。该机具对秸秆的留茬高度适应性强,作业效果好,适宜在南方双季稻区水田进行推广应用。

水分及秸秆覆盖对夏玉米土壤呼吸及碳平衡的影响

【目的】充分发挥秸秆覆盖与适宜灌溉对作物增产及土壤固碳减排的各自优势及二者协同效应,建立减排增产节水的高效农田管理模式。【方法】以豫东地区夏玉米为研究对象,设置覆盖方式(秸秆覆盖(S)和无覆盖(N))和灌水控制下限(田间持水率(FC)的50%(W1)、60%(W2)、70%(W3)、80%(W4))两因素试验,系统研究水分及秸秆覆盖对土壤碳排放总量、土壤微生物异氧呼吸碳释放量和农田净初级生产力固碳量影响。【结果】秸秆覆盖和灌水增加了土壤呼吸、农田净初级生产力固碳量和土壤微生物异氧呼吸碳释放量,其中SW4处理均最高,与SW3、NW4处理差异不显著。SW3处理净生态系统生产力(NEP)和碳排放效率均最高,分别较其他处理高3.99%~245.74%和2.35%~138.80%。与SW4处理相比,SW3处理在节约灌水的前提下,农田净生态系统生产力提高2.99%,碳排放效率提高2.35%。【结论】综合考虑农田净生态系统生产力和碳排放效率,SW3处理(灌水控制下限为70%FC+秸秆覆盖)可以作为节水、减排、增产的农田管理模式。

调亏灌溉和秸秆覆盖对苦荞生物学特性和水分利用效率的影响

为探讨调亏灌溉和秸秆覆盖对苦荞生物学特性和水分调亏利用效率的影响,设置秸秆覆盖(裸地S_(1)、秸秆覆盖S_(2))和灌溉方式(常规灌溉M_(1)、轻度调亏灌溉M_(2)、重度调亏灌溉M3)组合共6个处理,比较各处理的土壤含水量、农艺性状、产量和水分调亏利用效率等差异。结果表明:与裸地处理相比,秸秆覆盖处理的产量和水分调亏利用效率分别提高了13.5%和32.9%。与全灌处理相比,轻度调亏灌溉处理的产量、水分调亏利用效率分别提高了5.3%和52.8%。调亏灌溉和秸秆覆盖互作后,M_(2)S_(2)处理下产量和水分调亏利用效率最高。M_(2)S_(2)的产量、水分调亏利用效率较M_(1)S_(1)分别增加16.1%,95.7%,主要是因为M_(2)S_(2)处理的净光合速率、单株分枝数、生物量及结实率较M_(1)S_(1)分别显著增加13.0%,12.1%,12.5%和8.3%。综上所述,轻度调亏灌溉和秸秆覆盖能显著提高苦荞产量和水分调亏利用效率,可为苦荞的节水高效栽培提供理论依据和技术支撑。

玉米秸秆覆盖还田技术

玉米秸秆覆盖还田是一种环保、节能的农业技术,它利用玉米秸秆来覆盖田地,起到保水保肥、改良土壤、减少土壤侵蚀等作用。该文设置了秸秆覆盖还田(RF)和秸秆不还田(CK)两种方式,探究不同方式对土壤理化性质、土壤肥力及玉米产量的影响,为高效利用秸秆还田资源、提升土壤肥力提供科学依据。结果表明,RF可以显著提高土壤含水量和土壤呼吸速率,提升土壤肥力,玉米产量提高20.5%。因此,秸秆覆盖还田技术利于指导农田管理、提升土壤肥力、增加农作物产量。此外,有效利用农作物的残余部分,减少了对化肥、农药等化学品的依赖,降低了环境污染,有利于农田生态环境的改善,符合可持续发展的理念。

热带作物秸秆覆盖对土壤质量及玉米产量和品质的影响

【目的】探究甘蔗叶、菠萝茎叶等热带作物秸秆作为农业覆盖材料对土壤质量及玉米生长的影响,为热带作物秸秆废弃物资源化利用提供参考依据。【方法】以玉米为种植对象,采用田间小区对比试验,设置甘蔗叶覆盖(SLM)、腐熟甘蔗叶覆盖(RSLM)、菠萝茎叶覆盖(PLM)和富贵竹茎叶覆盖(FLM)4个处理,以塑料地膜覆盖(CK1)和无覆盖(CK2)为对照,研究不同秸秆覆盖对土壤pH、有机质、全氮、有效磷和速效钾的影响,以及对玉米产量和品质的影响。【结果】热带作物秸秆覆盖,与无覆盖相比,可以有效提升土壤pH、有机质、全氮、有效磷和速效钾含量,对提升土壤质量具有积极作用。富贵竹茎叶覆盖效果最显著,与塑料地膜覆盖相比,土壤pH提高9.01%,有机质提高6.42%,全氮提高17.59%,速效钾提高477.79%,有效磷含量低于塑料地膜覆盖,但差异不显著;与无覆盖相比,土壤pH提高22.22%,有机质提高21.63%,全氮提高24.51%,有效磷提高2.74%,速效钾提高389.38%。腐熟甘蔗叶和富贵竹茎叶覆盖可以显著提升玉米产量,其他秸秆覆盖对玉米产量和品质的影响均不显著。【结论】热带作物秸秆覆盖可以提升土壤质量、促进玉米增产,富贵竹茎叶覆盖在改良土壤方面的效果显著,腐熟甘蔗叶覆盖对于玉米增产有较好的促进作用。

航拍多光谱田间秸秆覆盖量反演模型的建立与优化

保护性耕作是农业耕地可持续性发展的重要方法,已被世界多地采用,秸秆覆盖量实现从“有无”到“多少”的进一步判定,是秸秆还田检测的重要指标。通过无人机搭载多光谱相机航拍研究区内春秋两季遥感数据,并同步测定玉米秸秆覆盖量。首先,通过遥感数据提取光谱反射率并构建光谱指数,采用相关系数法筛选出对秸秆覆盖量敏感的波段变量和光谱变量,作为模型输入变量;然后,采用支持向量机(Support Vector Machine,SVM)、随机森林(Random Forest,RF)、BP神经网络(Back Propagation Neural Network,BPNN)和极限学习机(Extreme Learning Machine,ELM)4种机器学习算法,建立玉米秸秆覆盖量的反演模型,比较不同时期和不同研究区域的模型精度;最后,为解决预测性能受其模型参数影响较大问题,引入遗传算法(Genetic Algorithm,GA)和粒子群算法(Particle Swarm Optimization,PSO),并提出遗传-粒子群混合算法(Genetic-Particle Swarm Optimization,GA-PSO),利用它们的互补性提高模型的性能,完成区域内秸秆覆盖量的估算。实验结果表明,基于GA-PSO优化的RF算法玉米秸秆覆盖量反演模型取得了最佳的反演效果,其中R^(2)达到了0.74。同时,对比分析不同数据的反演结果,均较为真实地反映了区域内秸秆覆盖量,估测准确率达到91.36%,说明可以通过优化模型实现结果估算。研究为保护性耕作秸秆还田量检测提供科学参考,亦为其他作物秸秆覆盖量估测提供了可靠的模型反演方法。

旱作农田覆膜和秸秆碳投入对土壤团聚特性及作物产量的影响

研究秸秆还田形式对旱作覆膜农田土壤团聚特性、有机碳含量及玉米产量的影响,为优化覆膜耕作措施,实现旱作覆膜农田可持续性生产提供理论依据。以长期定位旱作玉米覆膜农田(始于2012年)为研究对象,设置双垄沟覆膜(P)和传统平作(T),分别施加秸秆(S)和生物质炭(C),以不还田为对照(N),共形成6个处理:覆膜秸秆还田(PS)、覆膜生物质炭还田(PC)、覆膜不还田(PN)、平作秸秆还田(TS)、平作生物质炭还田(TC)和平作不还田(TN)。测定土壤团聚体组成及团聚体有机碳含量,并分析了双垄沟覆膜和不同秸秆碳投入对土壤有机碳含量、团聚体稳定性及玉米产量的影响。研究结果表明,各秸秆还田处理较不还田处理均可显著(P<0.05)改善各粒级团聚体分布及其稳定性,其中>0.25mm团聚体含量平均显著(P<0.05)提高47.32%,各双垄沟覆膜处理MWD和GMD较平作处理分别平均提高9.19%和4.15%;各还田处理可显著(P<0.05)提高0~60 cm土层土壤有机碳含量,其中PC和TC处理分别较对应PS和TS处理土壤有机碳含量提高2.60%和2.73%;各处理团聚体有机碳含量均随粒径增大而增大,秸秆碳投入可显著(P<0.05)提高各粒级团聚体有机碳含量,而双垄沟覆膜处理则降低了土壤有机碳及团聚体有机碳含量;还田方式、种植方式及土壤有机碳对玉米产量有促进作用,施加秸秆及生物质炭均能显著(P<0.05)提高旱作覆膜农田玉米产量,平均提高14.6%,而秸秆直接还田处理与生物质炭还田处理的增产效果无显著差异。综合分析,在双垄沟覆膜条件下投入秸秆碳能够明显提高土壤稳定性、土壤有机碳含量和作物产量,其中,双垄沟覆膜与生物质炭还田的耦合效应对改善农田土壤质量及地力提升有积极作用。

覆盖栽培对旱地春玉米耗水特性的影响

【目的】探讨覆盖方式对旱地春玉米产量及耗水特性的影响,以期为半干旱区玉米高效及绿色生产提供理论支撑。【方法】在陇中旱作区设置秸秆带状覆盖(SM)、白膜双垄沟覆盖(BM)和黑膜双垄沟覆盖(HM)和露地平作(CK)4种栽培方式。【结果】与CK相比,SM、BM和HM处理下春玉米播种~成熟期0~200 cm土壤水分增加2.6%~20.9%;各生育时期间,增墒幅度SM以抽雄吐丝期最大,BM和HM均以苗期最大;不同土层间,SM、BM和HM增墒幅度分别以60~120、60~120和120~200 cm土层最大。覆盖处理较对照降低了春玉米全生育期耗水量5.1%,其中SM处理均降低了春玉米生育前期(播种期-拔节期)、中期(拔节期-灌浆期)和后期(灌浆期-收获期)耗水,降幅为2.4%~50.0%,而地膜覆盖(BM和HM)降低了生育前期和后期的耗水量,而增加了中期的耗水。与CK相比,覆盖均能显著增加春玉米籽粒产量22.9%~34.9%和水分利用效率33.1%~39.7%,增幅分别以BM和SM处理最大。相关分析发现,春玉米籽粒产量与穗粒数(r=0.922**)和百粒质量(r=0.833**)高度相关。【结论】在西北旱作区,应用秸秆带状覆盖能明显增墒、增产,显著降低耗水而增加水分利用效率,是适宜旱地玉米生产的可行措施。

秋闲期秸秆覆盖与施磷对冬小麦氮素吸收利用的影响

西南冬麦区气候冬干春旱频发、土壤速效磷缺乏,限制冬小麦氮素吸收。本研究探究秋闲期秸秆覆盖与施磷对小麦根系NO3-吸收动力势、氮素吸收利用、叶绿素含量和籽粒产量的影响,以期为小麦高产稳产及养分的高效利用提供理论依据。试验于2020—2022年在四川仁寿进行,采用二因素裂区设计,以秸秆覆盖(SM)和不覆盖(NSM)为主区;3个磷水平0(P0)、75(P75)和120(P120) kg hm-2为裂区。结果表明:秸秆覆盖与施磷显著提高地上部磷素积累量, SM较NSM的小麦根尖NO3-净吸收速率、籽粒氮积累量、氮素转运量、氮素同化量、氮肥偏生产力和籽粒产量分别增加28.2%、8.4%、9.0%、41.9%、23.3%和21.9%。与P0相比, P75和P120增加幅度分别达到35.1%~37.6%、12.6%~19.0%、7.1%~9.3%、35.7%~60.5%、17.6%~23.8%、17.2%~23.6%。与NSM相比, SM的小麦旗叶灌浆期叶绿素含量上升,进而提高籽粒产量。综上所述,秸秆覆盖与施磷可促进小麦根尖NO3-吸收,提高叶绿素含量,从而显著增加花后氮素的吸收及营养器官临时贮存氮素向籽粒的再分配,最终提高籽粒产量。考虑经济效益和产量回报,西南地区小麦高产高效栽培时,推荐采用秋闲期秸秆覆盖配施磷肥75 kg hm-2。