Effect of Direct-seeding with Non-flooding and Wheat Residue Returning Patterns on Greenhouse Gas Emission from Rice Paddy

[Objective] This study aimed to investigate the effect of direct-seeding with non-flooding and wheat residue returning patterns on greenhouse gas emission from rice paddy. [Method] Two rice cultivars currently used in the production, Yangdao 6 （an indica） and Yangjing 4038 （a japonica）, were field grown using a direct-seeding method, and four treatments, wheat straw incorporation into soil and traditional flooding （SlF）, non-flooding and wheat straw mulching （NSM）, non-flooding and wheat straw incorporation into soil （NSl） and traditional flooding （no straw returned, Control, TF）, were imposed after sowing to maturity. Effects of direct-seeding with non-flooding and wheat residue returning patterns on CH4, N20 and CO2 emissions were investigated by using the method of static chamber-gas chromatographic tech- niques. [Result] Grain yield showed no significant difference between non-flooding and flooding treatments, but was significantly higher under the SlF than under any other treatments. The emission flux of CH4 and CO2 under TF and SlF exhibited a single peak curve, while changed little under the NSl and NSM The emission flux of N2Oshowed multiple perk curves for all the treatments. Compared with TF, SlF significantly increased mean emission flux of CH4 or N2O, decreased emission of N20, while NSl and NSM significantly decreased the mean emission flux of OH4, and increased emission flux of N2O and CO2. SIF also increased Green Warm Potential （GWP） of CH4, N2O and CO2 and the GWP per unit grain yield by 47.3%- 53.7% and 32.2%-39.4%, respectively. Both NSl and NSM decreased GWP by 24.2%-29.6% and 30.1%-35.5%, and the GWP per unit grain yield was decreased by 21.7-27.2% and 25.6%-31.1%, respectively. [Conelusion] both NSl and NSM could significantly reduce greenhouse effect of CH4, N2O and CO2 meanwhile maintain a high grain yield.

Increasing the appropriate seedling density for higher yield in dry direct-seeded rice sown by a multifunctional seeder after wheatstraw return

Dry direct-seeded rice(DDR) sown using a multifunctional seeder that performs synchronous rotary tillage and sowing has received increased attention because it is highly efficient,relatively cheap,and environmentally friendly.However,this method of rice production may produce lower yields in a rice–wheat rotation system because of its poor seedling establishment.To address this problem,we performed field experiments to determine the rice yield at five seedling density levels(B1,B2,B3,B4,and B5=100,190,280,370,and 460 seedlings m-2,respectively) and clarify the physiological basis of yield formation.We selected a representative high-quality rice variety and a multifunctional seeder that used in a typical rice–wheat rotation area in 2016 and 2018.The proportion of main stem panicle increased with increasing seedling density.There was a parabolic relationship between yield and seedling density,and the maximum yield(9.34-9.47 t ha-1) was obtained under B3.The maximum yield was associated with a higher total spikelet number m-2 and greater biomass accumulation from heading to maturity.The higher total spikelet number m-2 under B3 was attributed to an increase in panicle number m-2 compared with B1 and B2.Although the panicle numbers also increased under B4 and B5,these increases were insufficient to compensate for the reduced spikelet numbers per panicle.Lower biomass,smaller leaf area,and lower N uptake per plant from the stem elongation stage to the heading stage were partially responsible for the smaller panicle size at higher seedling density levels such as B5.The higher biomass accumulation under B3 was ascribed to the increases in the photosynthetic rate of the top three leaves m-2 of land,crop growth rate,net assimilation rate,and leaf area index.Furthermore,the B3 rice population was marked by a higher grain–leaf ratio,as well as a lower export ratio and transport ratio of biomass per stem-sheath.A quadratic function predicted that 260-290 seedlings m-2 is the optimum seedling density for achieving maximum yield.Together,these results suggested that appropriately increasing the seedling density,and thereby increasing the proportion of panicles formed by the main stem,is an effective approach for obtaining a higher yield in DDR sown using a multifunctional seeder in a rice–wheat rotation system.

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.

豫中烟区不同接茬种植模式对烤烟生长发育及综合效益的影响

为明确豫中烟区不同接茬种植模式对烟株生长发育及综合效益的影响,以常规移栽为对照,安排了大麦接茬和小麦接茬种植烤烟大田试验。结果表明,大麦接茬移栽期较常规移栽晚8~10 d,大田生育期较常规移栽长8~9 d,小麦接茬移栽期较常规移栽晚31 d,大田生育期较常规移栽短4~9 d。不同种植模式各生育期光温水资源分配不同,大麦接茬还苗伸根期和旺长期雨热同期,成熟期日均温和日照时数与常规移栽差异较小;与常规移栽相比,小麦接茬还苗伸根期和旺长期日均温较高、昼夜温差较小,成熟期日均温较低、日照时数较少。栽后90 d时,小麦接茬干物质积累量明显低于常规移栽和大麦接茬。与常规移栽相比,大麦接茬增加了烤后烟叶还原糖含量,糖碱比协调性较好,但烤后烟叶氯含量受前茬施用含氯肥料影响较大,前茬施用含氯肥料明显增加烤后烟叶氯含量。大麦接茬烤后烟叶收益与常规移栽相当,但增加1季大麦收益,小麦接茬较常规移栽增加1季小麦收益,但烤后烟叶收益明显低于常规移栽,综合收益表现为大麦接茬>小麦接茬>常规移栽。综上,豫中烟区大麦-烤烟接茬种植模式烤后烟叶质量较好,综合效益较高,但大麦前茬需施用不含氯肥料,以避免前茬土壤氯过量残留和烤后烟叶氯含量较高。

大豆和玉米茬口对冬小麦根际土壤细菌群落结构和功能的影响

为探明黄淮海地区玉米茬口和大豆茬口微生物遗留效应的差异,于2023年在长达4 a(2019—2023年)的长期定位试验田中采集冬小麦拔节期的根际土壤样品,采用16S高通量测序技术并结合Tax4Fun2功能预测分析,研究玉米茬口(M)和大豆茬口(S)下冬小麦拔节期根际土壤细菌群落结构及功能对不施氮(N0)和常规施氮(N240,纯氮240 kg/hm2)共4个处理(MN0、SN0、MN240、SN240)的响应。结果表明,门水平下,变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、拟杆菌门(Bacteroidetes)和放线菌门(Actinobacteriota)为冬小麦拔节期根际优势菌门,优势菌门相对丰度为66.66%~69.56%。N0施氮量S茬口的拟杆菌门相对丰度比M茬口显著增加了19.10%(P<0.05);N240施氮量S茬口的变形菌门相对丰度比M茬口显著增加了11.90%(P<0.05)。目水平下,Vicinamibacterales与伯克氏菌目(Burkholderiales)为优势菌目,优势菌目相对丰度为18.42%~19.68%。N0施氮量S茬口的Vicinamibacterales相对丰度比M茬口显著减少了13.69%(P<0.05),伯克氏菌目相对丰度显著增加了11.31%(P<0.05)。通过Tax4Fun2功能预测,与KEGG数据库对比发现,N0施氮量下新陈代谢分类中的7个二级功能途径相对丰度存在显著差异(P<0.05);进一步通过相关性分析发现,Vicinamibacterales和伯克氏菌目与氨基酸代谢途径存在极显著相关关系(P<0.01)。冬小麦土壤细菌有26个功能基因参与土壤氮循环途径,其中反硝化功能基因相对丰度最高。N0施氮量M茬口的norB、norC、nirS型反硝化功能基因相对丰度显著高于S茬口(P<0.05)。综上,不同施氮量下茬口均造成冬小麦拔节期根际土壤细菌群落结构发生变化,不同茬口通过改变根际土壤细菌群落结构进一步影响细菌群落氮代谢功能。

缓释掺混肥配比对稻茬小麦产量、氮素利用和籽粒品质的影响

为探究不同缓释掺混肥配比对稻茬小麦生产的影响,在沿淮下游地区,以淮麦52和淮麦920为材料,通过随机区组试验,以缓释掺混肥(SRF,N∶P2O5∶K_(2)O=26∶12∶12)和丰卉尿素(U,46%N)为供试肥料,设置U四次分施(M_(1))、SRF一次基施(M_(2))、60%SRF基施+40%U拔节期追施(M_(3))、60%SRF基施+40%SRF返青期追施(M_(4))、M_(3)模式减氮15%(M_(5))和M_(4)模式减氮15%(M_(6))6种施肥模式,分析了不同处理下小麦产量、氮素积累及利用、干物质转运和品质等的差异。结果表明,缓释掺混肥一次基施(M_(2))和减氮15%条件下两次分施(M_(5)和M_(6))较常规肥料处理(M_(1))均能实现稳产。缓释掺混肥两次分施(M_(4))可有效促进稻茬小麦花后光合物质生产和氮素向籽粒运转,增加籽粒氮素积累量,提高氮肥利用率,氮肥农学效率、氮肥表观利用率、氮素生理效率和氮收获指数分别较M_(1)处理增加16.49%、11.09%、4.86%和4.72%,较M_(2)处理增加21.31%、15.19%、5.32%和18.60%;M_(4)处理较M_(1)处理增产9.01%和6.78%,较M_(2)处理增产11.43%和12.10%,实现产量提升的同时显著改善小麦籽粒蛋白品质。综上,60%缓释掺混肥基施和40%缓释掺混肥返青期追施有助于实现小麦的高产优质高效生产,适宜在沿淮下游稻茬麦区推广应用。

水分与秸秆处理对玉米苗期素质及产量的影响

为了缓解因气候变化产生的播种期干旱对夏玉米幼苗发育的不利影响,以‘郑单958’为试验材料,在河南省许昌市灌溉试验站,采用不同底墒条件和麦茬处理方式,研究不同处理组合对播种层土壤水分和玉米苗期生长发育的差异。结果表明:土壤含水量随着土层的变深而增大,表现为偏湿平茬>正常平茬>偏湿除茬>偏干平茬>正常除茬>偏干除茬。SPAD值、光合速率及产量变化趋势一致,均表现为正常平茬>偏湿平茬>偏湿除茬>正常除茬>偏干平茬>偏干除茬。因此,平茬相比除茬可以更好地改善土壤水分环境,提高玉米的出苗率、光合速率和产量,可以在生产中进行广泛推广应用。

基于PLC的稻茬湿地小麦播控系统开发

目的:针对长江中下游稻茬田小麦播种过程中由于地轮打滑导致的播种量不均及效率低等问题,基于PLC技术开发一套精量播种控制系统,以提升播种效果。方法:通过采集稻茬湿地小麦播种机作业速度,结合预设播种量和实时播种量数据,计算并调整外槽轮转速,实现精准播种控制。结果:在预设播种量参数下利用MATLAB进行仿真试验,播量误差均控制在5%以内,验证了控制系统的可行性。结论:基于PLC的精量播种控制系统通过建立排种器转速的数学模型,为稻茬田小麦的智能播种提供理论参考。

2023年皖西南地区麦茬稻品种比较试验

为筛选适合皖西南地区推广种植的优质、丰产麦茬水稻品种,本研究选择隆两优8612、隆两优1377和隆两优5438等12个引进水稻品种与1个对照品种(丰两优四号)进行品种比较试验,从生育期、农艺性状、抗性和产量及产量构成因子等方面进行比较分析。筛选出在试验田当年气候条件下,生育期适中、抗倒伏能力强、产量较高且产量构成因子协调的4个品种,分别为荃优1606(产量:9758.3 kg/hm^(2))、荃优822(产量:9586.2 kg/hm^(2))、徽两优898(产量:9568.9 kg/hm^(2))和银两优606(产量:9368.9 kg/hm^(2)),可作为麦茬稻品种在研究区推广种植。

2023年单季晚粳品种筛选

为鉴定单季晚粳品种的丰产性、稳产性、适应性、抗性、米质及其他重要特征特性表现,进一步筛选适宜当地推广种植的麦茬粳稻品种,满足种植需求,本研究选取10个水稻新品种,以嘉优5号作为对照,开展2023年单季晚粳品种筛选试验。每个品种重复种植3个小区,每个小区面积13.3 m^(2),田间完全随机区组排列,对10个品种及对照的产量、米质、抗病性及其他性状进行综合分析。结果表明,适宜在研究区及周边地区种植的高产粳稻新品种有5个,分别是W214176、W217682、W097、W227962和W098;抗性品种3个,分别是申优531、W220096和W220130;优质稻品种1个(W222509)。

Effects of plant density and mepiquat chloride application on cotton boll setting in wheat–cotton double cropping system

Sowing cotton directly after harvesting wheat in the Yangtze River Valley of China requires early mature of cotton without yield reduction.Boll-setting period synchronisation and more yield bolls distributed at the upper and middle canopy layers are also required for harvesting.The objective of this study is to quantify the individual and interaction effects of plant density and plant growth regulator mepiquat chloride(MC)on temporal and spatial distributions of yield bolls,as well as yield and yield components.During the 2013–2016 cotton growing seasons,the experiments were conducted on a shortseason cotton cultivar CRRI50 at Yangzhou University,China.Various combinations of plant density(12.0,13.5 and 15.0 plants m^(–2))and MC dose(180,270 and 360 g ha^(–1))were applied on cotton plants.The combination of 13.5 plants m^(–2)and 270 g ha^(–1)MC resulted in the greatest boll number per unit area,the highest daily boll setting number and more than 90%of bolls positioned within 45–80 cm above the ground.In conclusion,appropriate MC dose in combination of high plant density could synchronize boll-setting period and retain more bolls at the upper and middle canopy layers without yield reduction in the system of direct-seeded cotton after wheat harvest,and thus overcome the labor-intensive problem in current transplanting cropping system.

Research on the allelopathic potential of wheat

Objective: This paper mainly discusses the Allelopathic potential of Wheat. Methods: This paper is prepared by reviewing the latest academic literatures. Result: The green revolution in the 1960s caused an increase in the demand for food. The agricultural sector and farmers tended to spend more time on the agricultural work but the crop yield was suppressed by the weeds. Hence, the usage of herbicide insecticides, fungicides and others chemicals had been increased. Although herbicides are efficient for weed controls, the continuous uses had gradually stimulated the weeds developing an effecttive resistance to the chemicals. Wheat (Triticum aestivum L.) is known as allelopathic against crops and weeds. Allelopathy of wheat (Triticum aestivum L.) has been extensively examined for its potentials in weeds management. The allelopathic activity of wheat has been attributed to hydroxamic acids, the related compounds and phenolic acids. Therefore, it could effectively reduce herbicide uses in order to maintain an eco-friendly environment and a cost-effective weed control.

Effects of Crop Stubble on Physicochemical Properties of Continuous Cropping Soil and Cucumber Yield and Quality

By a pot experiment, two kinds of crop stubble (wheat, soybean) were added into continuous cropping soil of cucumber according to different quantity (0.5%, 1% and 2%), the effects of different kinds of stubble and quantity on the continuous cropping soil and growth of cucumber were investigated. The results showed that two kinds of crop stubble significantly decreased soil bulk density, and increased total porosity of soil. Each of all treatments significantly decreased the accumulation of salinity in soil within the entire growth period of cucumber. 2% wheat stubble treatment had the biggest drop in soil EC in the later period of cucumber growth. Soybean stubble treatment had the lesser effect on soil EC. Wheat and soybean stubble promoted the growth of cucumber, increased the yield of cucumber, and improved the quality of cucumber. 2% of wheat stubble treatment had a biggest increase in cucumber yield, which increased the yield by 34.23% compared with the control.

抑制剂对稻茬小麦产量及氮素利用效率的影响

生化抑制剂是调控土壤氮素转化与提高氮肥利用率的有效途径之一。为明确生化抑制剂对沿淮稻茬小麦的效应,以淮麦38为供试品种,在安徽怀远县稻茬麦田设不施氮肥(CK)、尿素(U)、尿素+脲酶抑制剂NBPT(UN)、尿素+硝化抑制剂DMPP(UD)、尿素+硝化抑制剂NBPT+脲酶抑制剂DMPP(UND)共5个处理,研究了脲酶抑制剂NBPT(N-丁基硫代磷酰三胺)、硝化抑制剂DMPP(3、4-二甲基吡唑磷酸盐)及其两者组合对稻茬小麦产量及构成因子、氮素利用效率和土壤氮素的影响。结果表明,与U处理相比,UD和UND处理显著提高稻茬小麦产量、植株吸氮量和氮肥利用率;UD和UND处理分别增产8.9%和10.7%,穗数和穗粒数同步提高是其增产的主要原因,UN处理产量增加不显著;UD和UND处理氮肥农学利用率、氮肥吸收利用率、氮素吸收效率和氮肥偏生产力显著提高,氮收获指数无显著变化;UD和UND处理降低了小麦收获后耕层土壤无机氮的残留量,显著提高了微生物量氮的含量。综上,在沿淮地区稻茬小麦种植中,尿素配施DMPP或者配施DMPP+NBPT可以有效增加小麦产量,提高氮素利用效率。

不同类型肥料对稻茬弱筋小麦产量与品质的影响

为了选择适合稻茬弱筋小麦高产优质生产的合理施肥模式,以弱筋小麦宁麦13、皖西麦0638为供试品种,设置不施肥(CK)、常规施肥复合肥+尿素(T1)、缓释掺混肥料(T2)、控失肥(T3)、腐殖酸复合肥(T4)、小麦配方肥(T5),在养分供应量相同的条件下,分析对稻茬弱筋小麦干物质分配及转运、灌浆、产量及品质的影响。结果表明:缓释掺混肥料与小麦配方肥较常规施肥能显著提高干物质在籽粒中的分配量及比例、花后干物质转运量并且提高小麦籽粒灌浆速率、延长有效灌浆天数、增加粒质量。缓释掺混肥料、控失肥、腐殖酸肥料、小麦配方肥处理较常规施肥均能显著提高小麦籽粒产量,施用缓释掺混肥料和小麦配方肥增产效果显著,显著增加有效穗数及千粒质量,产量分别较常规施肥增产9.27%~24.30%,11.64%~22.98%。缓释掺混肥料2 a间两品种较常规施肥处理氮肥农学效率平均提高23.14%,36.88%,小麦配方肥2 a两品种较常规施肥平均提高36.31%,39.35%。小麦配方肥处理2个供试小麦品种籽粒品质均达到国家弱筋小麦标准。综上所述,小麦配方肥可作为试验地区稻茬弱筋小麦高产优质生产的施肥模式之一,或适当降低缓释掺混肥料的施用量作为稻茬弱筋小麦的高产优质生产施肥模式之一。

基于多效唑和微喷灌量的麦茬复播谷子品质及矮化效应研究

为有效提升麦茬复播谷子品质及防倒技术,2017—2019年在山西临汾采用裂区、随机区组方法分别开展了多效唑(PP333)不同叶龄期的不同喷施浓度、不同生育期微喷灌量对麦茬复播谷子品质及矮化的影响研究。结果表明,不同叶龄期喷施不同浓度PP333、不同生育期微喷灌量对麦茬复播谷子蛋白质及其3类氨基酸、脂肪、淀粉、纤维品质性状的影响均存在极显著差异(P<0.01)。其中PP333在8叶期以1.2%浓度喷施可显著提高蛋白质含量、8种必需氨基酸、4种半必需氨基酸、3种非必需氨基酸平均含量;除色氨酸性状外,蛋白质及其他14种氨基酸含量在0.8%~1.2%浓度范围喷施PP333均优于清水喷施(对照);4叶期以1.0%、0.8%浓度喷施PP333分别有利于脂肪、淀粉含量的提高。随微喷灌水量的增加蛋白质含量及其8种必需氨基酸、4种半必需氨基酸、3种非必需氨基酸平均含量基本呈现下降趋势,除半胱氨酸、色氨酸性状外,蛋白质、3类氨基酸平均含量及其13种氨基酸含量、脂肪含量均以生育期微喷灌量0.0 mm(拔节期0.0 mm+孕穗期0.0 mm)处理最高,且与其他3个微喷灌量处理(拔节期37.5 mm、孕穗期37.5 mm、拔节期37.5 mm+孕穗期37.5 mm)间存在极显著差异(P<0.01)。6叶期以1.0%~1.2%浓度喷施PP333、关键生育期减少微喷灌量均有较好的矮化效应。该项研究可为提升麦茬复播谷子品质及矮化防倒提供理论与技术支撑。

带旋和全旋耕作对稻茬小麦生长和土壤理化性质的影响

为明确带旋耕作在稻茬麦区的适用性,该研究于2018—2020年在水稻秸秆切碎匀铺还田条件下,以全旋(full rotary tillage,FRT)耕作为对照,研究了带旋(strip rotary tillage,SRT)耕作对稻茬麦田土壤理化性质、小麦生长和籽粒产量的影响。结果表明,与FRT相比,SRT在土壤偏干状况下大幅提升了0~10cm土层贮水量,提升幅度为15%~43%,而在土壤偏湿时提升幅度仅为3%~9%。带旋耕作下土壤温度日变化幅度平缓,且在低温条件下有助于提升5和15cm土层温度。2 a间5~15cm土层SRT土壤速效氮与速效钾含量较FRT分别增加12%、55%、41%和17%,差异显著(P<0.05),SRT促进了土壤养分在浅层富集。在2019—2020年,SRT较FRT显著增加了幼苗单株次生根数、单株地上部生物量、植株可溶性糖含量和叶片RuBPCase活性(P<0.05),明显提升了幼苗质量,同时2 a间均提高了开花期和乳熟期单茎叶面积、叶片RuBPCase活性以及开花期和成熟期单茎干物质量。2 a间均以SRT产量最高,比FRT分别增产11%和14%,穗粒数比FRT分别增加16%和5%,差异均达显著水平(P<0.05)。综上,带旋耕作下良好的土壤水、热、肥条件有助于幼苗健壮生长,提升了单茎光合生产能力,促进了幼穗发育和穗粒数形成,但带旋耕作出苗率较全旋耕作低了19.3%,未来还需结合其壮苗优势开展农机农艺配套技术研究。

六安市裕安区稻茬麦新品种比较试验

[目的]筛选适合裕安区乃至周边地区稻茬麦种植的高产、优质、多抗春性小麦新品种。[方法]于2021—2022年以11种小麦品种为试材,开展了小麦新品种对比试验,综合比较品种间产量、生育期、抗性等农艺性状。[结果]参试品种产量变幅为5105.0~6000.0 kg/hm^(2),有6个品种比对照增产,扬麦33增幅最大。参试品种生育期变幅202~206 d,扬麦33、扬麦29、皖农505、凯麦1138、乐麦0858生育期202~203 d,与对照品种扬麦20(203 d)相当。[结论]初步筛选出扬麦33、扬麦25、镇麦10号、宁麦24、镇麦168、皖农505适合在六安市裕安区乃至周边地区扩大示范种植。

小麦和大豆茬口对黄瓜土壤微生物生态特征的影响

采用常规稀释平板法和BIOLOG ECO微平板反应系统,研究了小麦和大豆茬口对黄瓜土壤微生物生态特征的影响.结果表明,两种茬口均显著提高了黄瓜土壤微生物真菌、细菌和放线菌的数量,显著降低了尖孢镰刀菌黄瓜专化型的数量(P<0.05);显著提高了土壤微生物群落的Shannon-Wiener指数、均匀度指数、Simpson指数和McIntosh指数(P<0.05)、以及土壤微生物生物量碳,降低了土壤基础呼吸和代谢商(P<0.05),改变了土壤微生物对单一碳源的利用能力.此外,两种茬口还显著提高了土壤中速效磷和速效钾含量,以及黄瓜产量.说明小麦和大豆茬口改善了土壤微生态环境.

免耕秸秆覆盖对旱作麦田土壤温度的影响

通过2001～2004年的大田试验研究了免耕秸秆覆盖对黄土高原西部旱地麦田土壤温度的影响。结果表明，土壤温度与气温关系密切；雨季土壤贮水多会导致土壤比热增大而来年早春地温回升慢；免耕秸秆覆盖与传统耕作的地温差不受天气状况的影响。与传统耕作相比，免耕秸秆覆盖可以稳定土壤温度，白天升温较慢，下午至夜间降温更慢。免耕秸秆覆盖降低春小麦全生育期的平均温度0．5℃～1．6℃，拔节至成熟期降低得更多，但对休闲期土壤温度影响不大。免耕秸秆覆盖春小麦经济产量可提高8．8％～28．8％，但产量与耕层平均地温无明显相关性。