Characteristics of Mulching Plastic Film Residue in Cotton Fields in the Yellow River Delta

In order to get a clear picture of distribution characteristics of mulching plastic film residue in cotton fields in the Yellow River Delta and make scientific pollution prevention and control strategies, an investigation was conducted in Dongying City. Five typical cotton fields were chosen, and then the number, distri- bution density and area of residual film were measured. The results showed that the residual film was 18. 84-53. 53 kg/hm^2 in cotton fields for more than 20 years, and the differences between fields were larger. The residual density was 225-340 thousand per hectare. There were great differences among residual pieces. The proportion of residual pieces over 25 cm^2 was 94. 1%, that between 100 cm^2 and 500 cm^2 was more than 50. 0%, and that bigger than 500 cm^2 was about 21. 0%. In the Yellow River Delta cotton region, large, thin and difficult to recovery were the main characteristics of mulching plastic film residue, and it had the possibility of mi- grating to deep soil. Thus, the ecological risk of mulching plastic film residue was higher. Key words The Yellow River Delta; Cotton field; Residue of mulching plastic film; Distribution characteristic

Effects of Tillage and Mulch Methods on Soil Moisture inWheat Fields of Loess Plateau, China

Effects of different methods of tillage and mulch on soil moisture at fallow stage were studied in rainy andrain-deficient years. Soil moisture content per 20 cm was measured vertically within 0-300 cm soil layers in anexperiment with five treatments: deep-loosening tillage (DLT), traditional tillage (TT), plastic mulch (PM),straw mulch (SM) and plastic plus straw mulch (PSM). All mulch treatments were under no tillage conditions.Total storage of precipitation in soil from 0 to 300 cm was determined before sowing. Results showed thatthe new methods of tillage and mulch were the basic ways to improve water condition in dryland wheat fields.In a rainy year, PM with no tillage played a significant role in storing and conserving precipitation, while ina rain-deficient year, the role was not significant. Due to evaporation, DLT did not promote the storage ofsoil moisture. SM was the best way to store and conserve soil moisture. In SM treatment the wheat yieldsincreased by more than 20%.

Effects of Different Gravel Mulched Years on Soil Microbial Flora and Physical and Chemical Properties in Gravelsand Mulched Fields

Soil microbial flora and influencing factors of soil microbes in soil and gravel-sand mixed layer（ SGSML）,roots denseness layer（ RDL）,eluviate layer（ EL） and calcium accumulation layer（ CAL） in gravel-sand mulched fields（ GSMFs） with different gravel mulched years（ 1,6,12,19 and 25 years） were studied. The results showed that in the composition of soil microbes in the GSMFs,the quantity of bacteria was the largest,followed by actinomycetes,while the number of fungi was the smallest. The total quantity of soil microorganisms in the GSMFs dropped rapidly with the increase of soil depth,which was related to the sudden decrease in the quantity of bacteria. The number of microbes in the RDL was larger than that in the SGSML with few roots due to the effects of root distribution. The number of bacteria and actinomycete in the growing season was larger than that in the non-growing season,while the quantity of fungi in the growing season was smaller than that in the non-growing season. The quantity of bacteria and fungi was the largest in the GSMFs which had been mulched with gravel for 6-12 years. With the increase of mulching time,the GSMFs aged gradually,so their quantity reduced gradually. The quantity of actinomycetes was the smallest in the GSMFs which had been mulched with gravel for 6-12 years and increased with the increase of mulching time. The number of soil microbes in the GSMFs had a good correlation with soil moisture content,p H and mulching time. Soil total carbon content was an important factor restricting the quantity of soil microbes in the GSMFs.

Information Technology Research on Productivity Evaluation of Gravel-mulched Field in Ningxia

The evaluation process of traditional land productivity is relatively complex,and the evaluation indices and results cannot display visually.With the development of geographic information system science,there are more and more studies on the GIS-based land productivity evaluation.GIS system can combine the evaluation model with information system software,realizing the visual display of all the evaluation factors.In this paper,with the development process of GIS-based management information system as references,the management information system for GIS-based gravel-mulched field productivity evaluation was designed and developed by combining with the SI model for gravel-mulched field productivity evaluation.The system was developed under VB environment,integrated with MapInfo,and the evaluation results could be shown visually in the system windows.

Performance Evaluation of Manually Operated Mulch Laying Machine on Different Soil Conditions

A machine with manual operation for mulch-laying machine with a punching arrangement was developed,and its performance was assessed at three different mulch paper thicknesses(15 m,20 m and 25 m),three different disc angles(35 degrees,40 degrees,and 45 degrees),three different punch spacings(250 mm,500 mm,and 1000 mm),and three different forward speeds(1.3 km/h,1.5 km/h,1.7 km/h)to investigate their effects on field capacity,effective field efficiency,and punching efficiency.Utilizing randomised block design and response surface methods,the experimental plan for optimization was created.All of the independent variables’combined effects on the dependent variables were found to be statistically significant.The influence of operating speed and mulch paper thickness was found to be the most significant on the dependent variable.The effective field capacity and field efficiency increased from 0.11 ha/h to 0.19 ha/h and 72.04 percent to 89.51 percent,respectively,by increasing mulch paper thickness from 15μm to 25μm and operating speed from 1.3 km/h to 1.7 km/h,whereas punching efficiency fell from 85.18 percent to 84.40 percent.Mulch paper of 15μm and a disc angle value of 40 degrees were optimised from the independent factors that were chosen for optimal soil covering over the laid plastic mulch sheet.Punching efficiency was maximised with performance optimised at 500 mm punch spacing.Additionally,the machine operated more efficiently at 1.5 km/h.

不同覆砂年限果园土壤水盐及矿质元素变化与砂田衰退关系研究

通过研究不同覆砂年限砂田土壤水分特征和矿质元素变化规律,探索砂田衰退的机理。对可用砂田和废弃砂田的砂土混合层变化、土壤含水量、矿质元素及盐分含量进行了长期定位的分析测定。结果表明,种植1、3、7、15 a砂田砂土比由9.16降低至1.60,而撂荒地为3.59。砂覆盖3 a后土壤平均水分含量较原生地高13.1 mg/g;砂覆盖15 a后土壤0~20、20~40、40~60、60~80、80~100 mm土层含水量比原生地分别高2.4、3.5、4.0、4.4、4.7 mg/g。不同覆砂年限果园0~60 cm土壤有机质、土壤全氮与碱解氮、全磷与速效磷、全钾与速效钾及全盐含量变化随覆砂年限增加均呈先增加后降低的趋势,这与砂田功效及衰退密切相关,也是中老砂田衰退的主要特征。

不同覆盖方式对桃园土壤性状及果实产量品质的影响

连续2年在上海市12年生蟠桃园将修剪枝条粉碎后翻埋还田,并将此措施与碎枝覆盖、果园生草或反光地布覆盖相结合,探索桃园碎枝利用及复合覆盖的适宜形式。结果表明,相对于对照(不做任何处理),翻埋粉碎树枝、翻埋粉碎树枝+覆盖粉碎树枝、翻埋粉碎树枝+人工生草、翻埋粉碎树枝+铺设反光地布4种措施能使蟠桃单果质量提升13.8%~35.0%,增产16.0%~36.9%,其中以碎枝覆盖结合翻埋的增产提质效果最佳。连续2年的碎枝覆盖结合翻埋,使得0~30 cm土层土壤有机质、全氮、有效磷和速效钾含量比对照显著高出82.1%、52.0%、48.5%和47.7%,0~10 cm土层土壤容重比对照显著降低12.0%,0~20 cm土层土壤平均含水量比对照显著高出10.0%,且在土壤含水量偏低时的保水作用更显著。蟠桃单果质量和产量与土壤含水量、孔隙度、有机质、全氮、有效磷、速效钾含量等土壤理化指标表现出极显著或显著正相关关系。碎枝翻埋和覆盖相结合是适宜华东地区的桃园废弃物就地利用的良好方式。

不同种植方式对高寒旱区地膜小麦耗水特征和产量的影响

于2019—2022年在陇中高寒旱区以裸地条播为对照(CK),设置全膜覆土穴播(FM)和膜侧沟播(FS)两种覆盖方式,研究不同覆盖种植方式对冬小麦耗水特性、生长发育及产量的影响。结果表明:与CK相比,FM和FS处理播种期~拔节期0~20 cm土层土壤温度分别平均提高3.1℃和2.1℃,灌浆期分别降低0.6℃和1.0℃。覆盖能不同程度提高冬小麦各生育期0~200 cm土层土壤含水量,其中出苗期、返青期、拔节期和灌浆期提高幅度均高于20%。与CK相比,FM处理返青后冬小麦耗水量平均显著提高29.2%,返青前显著降低42.4%;FS处理返青期~灌浆期耗水量提高12.6%,返青前降低25.7%。各处理冬小麦基本苗、分蘖数、公顷穗数、穗粒数、千粒重和产量均表现为FM>FS>CK,处理间差异显著,其中FM和FS处理产量分别较CK平均提高74.7%和45.4%;处理间耗水量差异不显著;FM处理水分利用效率最大,较CK平均提高67.3%,FS次之,较CK平均提高46.1%。综上,地膜覆盖可调节土壤水分状况,改善冬小麦生长发育和成穗情况,显著提高产量和水分利用效率,其中全膜覆土穴播调节效应优于膜侧沟播,是适宜在高寒旱区地膜小麦生产中推广应用的种植方式。

旱区连作砂田土壤质量和土地生产力演变与调控研究进展

砾石覆盖在改变旱区水文循环和物质转化方面有着至关重要的作用。然而,长期连作给砂田土壤质量及土地生产力带来危机和不确定性。以连作砂田为研究对象,归纳总结了连作年限对砂层质地结构、土壤物理结构、土壤水盐热效应、土壤养分状况、土壤酶活性、土壤微生物特性、作物生长发育以及产量品质的影响效应和可能机制,发现砂田土壤生态环境和土地生产力在人类活动及自然侵蚀的扰动和破坏下整体呈现退化态势,但对不同覆盖条件、施肥水平和种植结构等农田管理措施的响应过程表现出差异性。继而,基于土壤质量和土地生产力的协同和互作效应深入揭示了砂田性能逐年退化机理,并简述了生物、农业及工程调控措施在砂田退化阻控和修复方面的应用进展。在此基础上,提出了砂田退化进程中急需解决的关键科学问题和未来发展方向,主要包括土壤质量演变的基本过程及其发生机制、“砾石-土壤-微生物-植物”系统的叠加和互作效应及其分子机理、土壤改良与生物防治措施的定量化及其调控机制三个方面。在气候变化、植被演替和土地退化背景下,废弃风化砾石的劣化增肥机制及其环境效应将是今后研究的重点。

3种除草剂和除草膜及其组合对烟田杂草的防除效果

为了筛选高效安全的烟田除草方式,在广西烟区开展3种除草剂和除草膜及其组合对烟田杂草防除效果试验。结果表明,除草剂50%敌草胺可湿性粉剂对杂草株数总防效较好,施药后30 d和45 d防效分别为59.3%、89.94%;异丙甲草胺乳油对杂草鲜重总防效最好,施药后45 d,防效为89.47%;盖黑膜对杂草的鲜重和株数防效均显著高于白色膜与双色膜,白色膜与双色膜无显著差异,防效均不佳,仅为30%左右。盖黑膜的处理组烟叶长势差且出现明显的灼伤现象,黑膜不适用于广西烟区;除草剂结合地膜组合处理组中,50%敌草胺可湿性粉剂+双色地膜的防效最高,药后45 d杂草鲜重总防效为83%、株数总防效为83.26%。综合对烟田杂草防除效果和对烟草的生长影响情况,建议在广西烟区推广除草剂50%敌草胺可湿性粉剂和物理防控双色地膜结合使用。

宁夏中部不同年限退耕压砂地土壤质量评价

探讨宁夏压砂区域退出耕地对土壤性状和土壤质量的影响,对于促进黄河流域生态保护和高质量发展先行区建设具有重要的生态学意义。以宁夏中卫市环香山地区退耕压砂地为研究对象,采用空间序列代替时间序列的方法,选取地势平缓一致、土壤类型相同的不同退耕年限压砂地,研究压砂地退耕2、5、10、15、20、30和100 a的土壤理化性质及酶活性的变化,采用隶属函数结合因子分析的方法评价压砂地退耕不同年限下的土壤质量。结果表明:1)自退耕5 a后,土壤全钾含量整体随退耕年限增加呈下降趋势;土壤硝态氮含量在退耕2 a时最高,其余年限间无显著差异;土壤全磷、有效磷、速效钾含量随退耕年限增加呈波动变化趋势,分别在退耕15、2、15 a时最高。2)土壤孔隙度随退耕年限增加呈先减后增趋势;田间持水量和土壤含水量均于退耕2 a时最大,退耕5 a时急剧降低,之后随年限增加显著增加;土壤含水量在退耕20 a后趋于稳定。3)土壤脲酶、蔗糖酶活性随退耕年限增加呈先下降后升高趋势,两者均在退耕30 a时活性最大。4)不同退耕年限土壤质量综合得分为2 a>30 a>100 a>15 a>20 a>10 a>5 a,退耕恢复2 a时土壤质量评价得分最高,综上所述,压砂地退耕2 a土壤质量有一定恢复,退耕5 a时土壤质量衰退,并随退耕年限增加土壤质量呈正向演替的趋势。

中国西北旱区砂田表层土壤养分效应对连作响应的整合分析

为明确砂田表层土壤养分对连作的响应规律,深入揭示砂田性能逐年退化机理,文章基于国内外已发表的16篇相关文献的586组有效数据,借助Meta-analysis方法进行整合定量研究,定量分析覆砂1—3年农田与其他连作年限砂田(4—6年、7—9年、10—12年、13—15年、16—20年)在表层土壤水分状况(SWC)、养分特性(有机质SOM、全氮TN、全磷TP、全钾TK、碱解氮AN、速效磷AP、速效钾AK、全盐TSS)和酸碱环境(pH)方面的差异效应,系统阐释砂田表层土壤养分特性逐年变异的发生路径及驱动因素,进而综合评估其肥力水平。结果表明:伴随种植年限的增加,砂田表层土壤水分储量和养分强度整体呈现下降态势(P<0.05),4—20年的土壤SWC、SOM、TN、TP、TK、AN、AP、AK含量分别较1—3年减少39.06%、14.21%、14.96%、10.06%、8.20%、15.87%、37.01%、18.60%(P<0.05)。表层土壤SOM、TN、TP、TK、AN、AP、AK主要于10—12年开始大幅流失(P<0.05),而4—6年土壤SOM、TP、TK、AK含量的相对变化则不显著(P>0.05)。砂田在耕作12年内具有显著压盐效果,12年以后的表层土壤TSS含量则开始呈现逐年增加的发展趋向(P<0.05),其土壤pH整体增加1.29%(P<0.05)。连作年限是砂田表层土壤TN、TP和AK变异的关键因子;SWC则为土壤SOM、AP和TSS演化的主导要素。总体而言,砂田在连作10年左右即可出现明显的养分亏缺状态。因此,亟需提出科学合理的农田管理措施,以有效提升退化砂田的土壤肥力水平。

基于SHAW模型的北疆地区不同滴灌年限棉田冻融期土壤水热盐动态模拟研究

为探究SHAW(Simultaneous heat and water)模型在北疆地区长期膜下滴灌棉田冻融期土壤水热盐动态模拟的适用性,本研究选用滴灌起始年限为1998年(21 a)的棉田土壤水热盐实测数据对SHAW模型进行率定,以滴灌起始年限为2006年(13 a)、2008年(11 a)、2012年(7 a)和荒地(0 a)的水热盐实测数据进行验证。模型率定结果表明,随土壤深度增加土壤温度的模拟效果越好;土壤水盐的模拟效果先增强后减弱。模拟土壤温度Nash系数(NSE)、均方根误差(RMSE)和R2分别为0.713~0.993、0.209~2.498℃和0.911~0.994;模拟土壤水分NSE和RMSE分别为0.824~0.967和0.009%~0.032%;模拟土壤盐分NSE和RMSE分别为0.609~0.844和0.001~0.012 g/kg。模型验证结果表明,随滴灌年限增加模拟效果越好,模拟除荒地20~60 cm土层土壤温度NSE小于0.600,滴灌7、11和13 a地块各层土壤温度NSE均大于0.600,RMSE介于0.143~3.213℃;滴灌0、7、11和13 a地块模拟的各层土壤水分NSE均大于0.670,RMSE为0.009%~0.057%;滴灌0、7、11和13 a地块模拟的除120~140 cm土层土壤盐分NSE小于0.600,其他各层土壤盐分NSE均大于0.616,RMSE为0.000~0.016 g/kg。总体而言,SHAW模型适用于北疆地区冻融期长期膜下滴灌棉田的一维土壤水热盐模拟。

新疆地区棉田膜面杂质测定试验研究

现有残膜回收机回收的残膜普遍存在杂质含量较高、残膜易与秸秆及泥土混合以及膜杂分离困难等问题,为了指导残膜回收机具的设计,本文依据新疆地区棉田情况,开展棉田膜面杂质测定试验。采用五点取样法对7个区域进行膜面杂质测定。结果表明,膜面杂质主要成分为土壤约占71.38%,落地棉、棉壳、碎秸秆以及叶片等杂质占比为28.62%。该试验结果可为后续膜面杂质去除机构提供理论支持。

不同大果型西瓜品种砂田农艺性状及丰产性鉴定

为增强压砂西瓜产业活力,筛选出在砂田种植条件下具备发展潜力的大果型西瓜品种,在宁夏压砂西瓜核心产区对选取的8个大果型西瓜品种,从生长势、抗病性、果实性状和产量等方面综合分析了各品种的特征特性。结果表明,供试品种1912主蔓长、节间长优势较高,蔓粗最粗,枯萎病、霜霉病、白粉病和炭疽病发病率均为最低,抗病性表现最优,综合表现突出。该品种果实横径最大,为245.80 mm;果实纵径较大,为333.90 mm;果实中心糖度、边缘糖度均为最高,分别为12.80%、9.60%;单瓜质量最高,为9.04 kg,较对照品种金城红金五高0.53 kg;商品率较高,为91.33%;西瓜折合产量和商品瓜折合产量也最高,分别为31391.20、28669.58 kg/hm^(2),较对照品种金城红金五分别增产6.24%、5.47%。综合以上各项性状表现,认为1912种植优势突出,适宜在砂田种植模式进一步推广。

不同类型地膜覆盖和环境条件对蔬菜土壤温度的影响

本文以不覆盖地膜为对照,选用普通聚乙烯PE黑色地膜和黑色生物降解膜进行覆盖,研究其在露地、单体大棚、连栋大棚等不同环境条件下对蔬菜土壤温度的影响。结果表明:黑色生物降解膜和普通聚乙烯PE黑色地膜的增温效果接近,露地和单体大棚内二者的平均土壤温度比不使用地膜高1℃左右,连栋大棚内增温效果稍差。在露地条件下,普通聚乙烯PE黑色地膜覆盖下的土壤温度变化较大,白天增温快,夜晚则下降到与黑色生物降解膜相近的温度;而黑色生物降解膜覆盖下土壤温度变化幅度比较小,在昼夜温差大的天气,夜间最低温比普通聚乙烯PE黑色地膜覆盖高2℃左右。由此可见,在露地条件下,黑色生物降解膜夜间保温效果要好于普通聚乙烯PE黑色地膜,更适合在露地早春作物上应用,可有效抑制杂草生长。

南方湿润平原区露天菜地氮磷流失特征及其防控

为探究南方湿润平原区的露天菜地氮磷流失特征及其防控效果,设置了常规施肥(CK)、优化施肥(KF)以及优化施肥结合地膜覆盖(BMP)3个处理,在2015-2022年间开展了定位观测。结果表明:各处理径流中的氮均以硝态氮为主,占比85.22%~86.10%,其总氮含量随种植年限增加均呈现先升高再降低趋势,KF和BMP处理分别显著降低径流总氮含量14.29%和21.43%;可溶性磷是径流中磷的主要形态,占比76.87%~79.16%,径流总磷含量呈现逐年升高趋势,KF和BMP处理可使其显著降低26.78%和29.10%。即便优化施肥并覆盖地膜后,径流氮、磷含量仍超出地表水V类标准限值,其风险尚需重视。

甘肃砂田西瓜覆膜补灌效应研究

为证明集雨补灌对砂田西瓜是否有效,在甘肃省皋兰县进行了集雨补灌效应研究,结果表明:在西瓜全生育期,各处理的土壤水分呈波动性下降,0～120cm土层含水量下降幅度在2.59%～4.13%之间,补灌量愈大,土壤含水量的下降幅度愈小。砂田西瓜全生育期耗水较少,不同补灌量处理的耗水量在175.9～218.9mm之间,比小麦等大田作物低100mm以上。灌水量对结瓜期的耗水量影响很大,灌水量增加,结瓜期耗水量增大。不同补灌量处理的西瓜产量差异达显著水平,随灌水量的增加,产量、单瓜重和采收瓜数相应增加。补灌量对西瓜的含糖量也有影响,补灌量低于45mm,各处理之间含糖量的差异不大,补灌量为67.5mm,西瓜含糖量降低4.4%以上。适量补灌可以提高西瓜水分利用效率,其中滴灌67.5mm处理水分利用率最高,达到267.2kg·hm-2·mm-1,比不补灌处理提高17.0%。但随灌水量的增加,灌水效率降低,单方水产值减少。由于补灌对西瓜的产量、含糖量和水分利用率都有影响,只有适时适量补灌,才能即提高产量和水分利用率,又不降低品质。研究结果证明,砂田集雨补灌栽培西瓜是集雨水利用的一种较经济高效的方式,但最佳补灌量应控制在45mm左右为宜。

玉米秸秆覆盖麦田下的土壤温度和土壤水分动态规律

玉米秸秆覆盖冬小麦田后 ,冬季和早春季节对土壤温度有明显的增温作用 ,有利于保护小麦安全越冬 ,春季则有降温作用 ,影响春季小麦的分蘖和生长 ;覆盖处理能有效地抑制土壤无效蒸发 ,提高麦田的水分利用率 ;覆盖量为 30 0 0kg/hm2 时 ,有增产作用 ,覆盖量为 6 0 0 0kg/hm2 时 ,有一定的减产作用。

黄土高原西北部砂田西瓜集雨补灌效应研究

在黄土高原西北部地区对砂田西瓜的集雨补灌效应进行了研究。试验采用滴灌方式 ,设 0 mm (D0 )、2 2 .5mm(D1 )、45.0 mm(D2 )和 67.5mm(D3 ) 4个灌水量处理。区组内各处理随机排列 ,四次重复。试验结果表明 :在西瓜全生育期 ,每个处理 0～ 1 2 0 cm土层的土壤水分含量均呈下降趋势 ,下降的幅度随着补灌量的增加而减小。全生育期补灌 67.5mm的处理土壤含水量最高 ,比没有补灌的对照处理高 2 .2 %。土壤水分的变化在 0～ 40 cm土层比较活跃 ,其次是 40～ 80 cm土层 ,而 80～ 1 2 0 cm土层的含水量变化相对比较稳定。对砂田西瓜进行补灌可以提高产量和水分利用效率。补灌 45mm和 67.5mm的处理比对照分别增产36.3%和 45.7%。补灌 67.5mm处理的水分利用率最高 ,为 2 6.7kg/ m3 ,比对照增加 1 7.0 % ;该处理的净利润和每单位 (m3 )水的净利润也最高 ,分别达 43.677元 / hm2 和 1 8.48元 / m3 ,比不补灌的对照处理高2 9 .9%和 1 5.3%。补灌量对西瓜的含糖量也有影响 ,补灌量低于 45mm,各处理之间含糖量的差异不大 ,补灌量为 67.5mm,西瓜含糖量降低 0 .44%。补灌对西瓜的产量、含糖量和水分利用率均有影响 ,砂田西瓜只有补灌量控制在 45mm左右 ,才能既提高产量和水分利用率 。