番茄、玉米套种膜下滴灌条件下农田地温变化特征

土壤水热状况是影响作物生长的重要因素,以膜下滴灌及套种双重效应为背景,针对番茄、玉米套种农田设置了高(番茄:180 mm,玉米:270 mm)、中(番茄:132 mm,玉米:202.5 mm)、低(番茄:84 mm,135 mm)3种不同的灌溉定额,采用定位监测法测定番茄带膜间裸地(A)、覆膜番茄行间(B)、番茄带与玉米带膜间裸地(C)、覆膜玉米行间(D)共4个位置的不同深度主根区含水率和地温动态变化,研究了地膜覆盖、土壤水分以及作物遮阴对套种农田不同行间,不同深度土壤温度的影响特征。结果表明:全生育期内,4个水平位置的地温大小顺序与土壤深度有关,10 cm以上的地温大小顺序为CDAB,10 cm以下的地温大小顺序为DBAC;从土壤温度场的分布情况来看,地温的最大变幅出现在C处,为8.10℃;最小变幅出现在B处,为4.71℃;含水率与地温的关系表现为:5 cm以上地温与含水率呈反比关系,20 cm以下地温与含水率呈正比关系。可见,套种覆膜滴灌农田合适的土壤水分状况将有利于根区良好水热的形成,从而更有利于作物的生长。研究结果将对西北地区滴灌农田管理有一定的参考价值。     

东北雨养区黑色地膜和种植密度对玉米田间地温和产量的影响

在不同颜色地膜覆盖和种植密度条件下地温和作物产量将发生改变,为了研究其变化规律,2016年在沈阳农业大学水利学院试验场开展了玉米覆膜种植田间试验,设置了3种种植方式(裸地、透明地膜和黑色地膜覆盖)和3个种植密度(60000、75000和90000株·hm~(-2))的田间试验,对玉米田间地温和产量进行了对比研究。结果表明:不同处理下田间0~25 cm深度平均地温的日变化呈现正态分布规律,总体上,透明地膜地温高于黑色地膜和裸地,低密度处理地温高于高密度处理;裸地种植条件下,玉米产量随密度的提高先增加后减小,覆膜处理下产量随着种植密度的增加而增加;黑膜处理下的玉米产量高于透明地膜和裸地,黑膜覆盖处理、密度为90000株·hm~(-2)的组合产量达到最大,为14264.6kg·hm~(-2);产量与抽穗期的地温相关性最大,且表现为负相关关系。本文研究结果对提高东北雨养区玉米产量具有指导意义。     

不同耕作措施下冬小麦生长季农田二氧化碳排放通量及其与土壤温度的关系

利用长期定位试验研究了华北平原不同耕作措施下冬小麦生育期农田CO2排放通量,并对CO2排放通量和土壤温度进行了回归模拟.结果表明冬小麦生育期CO2排放速率表现为翻耕＞旋耕＞免耕,平均分别为343.69、337.54和190.47 mg·m-2·h-1.各处理冬小麦生育期CO2排放通量与土壤温度呈显著正相关;翻耕地CO2排放通量与10 cm地温相关性最高,旋耕地和免耕地则与10 cm和20 cm地温相关性较高.CO2排放通量和土壤温度呈指数函数关系(P＜0.01),利用10 cm地温对冬小麦生育期农田CO2排放通量进行估算表明,翻耕、旋耕和免耕地CO2排放分别为1.88、1.89和1.03 kg·m-2.     

耕作和覆盖对黄土高原果园土壤水分和温度的影响

研究了几种不同耕作方式（免耕、旋耕和翻耕）和覆盖措施（覆草、生草和覆膜）对黄土高原果园土壤水分和温度的影响.结果表明：5月不同耕作方式下0～1 m土层土壤水分差异极显著,表现为免耕（14.28%）>旋耕（14.13%）>翻耕（13.57%）,9月差异不明显;不同覆盖措施中,覆草处理的土壤水分最高,且与生草、覆膜、裸地处理间差异极显著;不同耕作方式和覆盖组合处理中以免耕覆草保水效果最好.不同覆盖处理白天土壤平均温度表现为覆膜>裸地>生草>覆草,土壤温度变幅表现为裸地>覆膜>生草>覆草.各覆盖处理的蓄水量与其土壤温度并不都呈负相关,而是由不同覆盖物的保水效果和保温性质共同决定.综上所述,黄土高原果园的保护性耕作体系应以免耕覆草为主.     

黄土旱塬裸地土壤呼吸特征及其影响因子

于中国科学院长武生态试验站(始于1984年),采用动态密闭气室法(Li-8100,USA)于2008年3月至2009年3月监测了裸地土壤呼吸日变化、季节变化以及0-60cm土层的温度和含水量,研究了裸地土壤呼吸的日变化、季节变化特征及其与土壤温度和含水量之间的关系。结果表明:裸地土壤呼吸四季的日变化和季节变化均呈单峰型曲线,与气温变化趋势一致;日变化峰值出现在14:00左右或16:00左右,最低值出现在0:00左右或者6:00左右;季节变化表现为夏季最高,冬季最低,春秋季无明显差异,年平均呼吸速率为0.94μmolCO₂·m^-2·s^-1。土壤呼吸与温度具有极显著(P<0.01)的正相关关系,且可以用R_s=ae^bx形式的指数函数很好地拟合,其中与5cm深度的土壤温度相关性最好。水分对土壤呼吸的影响复杂。裸地土壤呼吸的双变量模型关系显著(P<0.01),比相应的单变量模型更好地解释了土壤呼吸变异。     

内蒙古农牧交错区不同土地利用方式下土壤呼吸速率及其温度敏感性变化

2009年8-10月, 采用动态气室法观测了内蒙古农牧交错区多伦县农田、弃耕和围封3种土地利用方式下, 土壤呼吸速率从6:00到18:00的变化规律, 分析了不同深度的土壤温度与土壤含水量对土壤呼吸速率的控制作用。结果表明, 空间尺度上, 不同土地利用方式的土壤呼吸速率由高到低依次为: 农田>弃耕>围封; 时间尺度上, 土壤呼吸速率在6:00-18:00的变化趋势为单峰曲线, 在12:00-15:00达到峰值, 随后降低, 在18:00基本恢复到6:00左右的呼吸水平, 同时, 土壤呼吸速率在9、10月显著降低。利用Van’t Hoff指数模型研究不同深度土壤温度对土壤呼吸速率的影响发现, 10-15 cm深度的土壤温度对土壤呼吸速率的影响最为显著, 其中, 土壤呼吸温度敏感性由高到低分别为: 农田>围封>弃耕。相反, 由于8-10月土壤含水量变化较小, 故土壤含水量与土壤呼吸速率间的相关性不显著, 土壤含水量不能解释该时段土壤呼吸速率的变化。     

海南岛尖峰岭热带山地雨林区26年的热量因子变化特征

尖峰岭热带山地雨林作为中国典型的热带森林生态系统,其长期的气候动态状况对研究全球变化具有重要的意义。本文采用海南尖峰岭森林生态系统国家野外科学观测研究站天池气象站1980—2005年的地面常规气象观测资料,分析了尖峰岭热带山地雨林区热因子的变化趋势。结果表明：26年来,林区热因子（平均气温、平均地温、平均最高/最低气温、平均最高/最低地温、极端最高/最低气温、极端最高/最低地温、地气温差、年积温）均呈上升趋势,其中平均气温、平均地温、地气温差、平均最低气温和极端最高/最低地温升高趋势明显,每10年分别增加0.32 ℃、0.59 ℃、0.27 ℃、0.39 ℃、2.03 ℃、1.62 ℃,最低温度的升高趋势都大于最高温度的增长速率,说明尖峰岭热带山地雨林区气候变暖来自于最低温度升高的贡献。     

绿洲农业不同种植方式防止土壤风蚀和保持土壤水分的比较

2001年～2002年,在河西走廊中断黑河中游,研究了不同方式对春季就地起沙、风速梯度、水分保持等方面的效应．结果表明,冬灌免耕、粮草间作和早春覆膜措施都不同程度地遏制了就地起沙,减少了土壤风蚀．早春覆膜在减少土壤风蚀量的同时,提高了土壤蓄水量,比春耕裸露农田蓄水量增加了35．6％．目前．春耕播种裸地是形成沙尘暴和浮尘的粉尘含量的主要来源之一,黑河中、上游农田耕地每年产生的粉尘输移量达4．8×10^6～6．0×10^6t,高于同区域沙漠粉尘输移量．河西走廊粉尘输移量1hm^2农田相当于1．5hm^2沙漠．     

寒温针叶林土壤呼吸作用的时空特征

利用Li-6400便携式CO2分析系统对寒温针叶林土壤呼吸作用观测数据分析表明,土壤呼吸作用日、季动态均呈单峰型变化,日最大值出现在16:00左右,与5 cm土壤温度日动态相似,滞后于气温日动态变化;月最大值出现在8月份,2006年和2007年分别为8.19 和6.89 μmol CO2 m-2 s-1。日、季土壤呼吸作用与土壤温度的相关性均好于气温。土壤呼吸作用存在较大的空间变异性,一天内3:00 am、7:00 am和11:00 am的土壤呼吸作用变异系数分别为35.5%、27.6%和23.0%,根系和凋落物与土壤呼吸作用表现出相似的空间变异性,其中细根与土壤呼吸作用的相关性最好。     

土地利用方式对喀斯特地区环境小气候日动态的影响

2007年6月,通过典型样地观测,研究了广西凌云县典型喀斯特地区5种不同土地利用方式下光照强度、气温、空气相对湿度、土壤温度、表层（0～5 cm土层）土壤含水量的日动态.结果表明：不同土地利用方式改变了地上植被的组成、覆盖度和高度,进而改变了环境小气候,研究区不同土地利用方式的小气候质量依次为林地＞灌林＞草地＞农耕地＞石漠化裸地; 石漠化裸地光照强度较强、气温和土壤温度较高、空气相对湿度和土壤含水量较低,且各因子的变幅均较大,样地环境趋于干热化;与石漠化裸地相比,林地、灌林地、草地和农耕地内的光照强度分别下降96.4%、52.0%、17.0%和44.2%,气温分别下降30.1%、20.2%、12.7%和17.8%,空气相对湿度分别提高129.2%、57.2%、18.0%和41.2%,土壤温度分别下降11.5%、8%、2.5%和5.5%,表层土壤含水量分别提高42.6%、33.2%、15.7%和14.0%,林地与灌林地各因子的变幅相对趋缓,样地环境趋于凉湿化.各样地光照强度、气温和土壤温度之间呈正相关,三者均与空气相对湿度、土壤含水量呈负相关,空气相对湿度与表层土壤含水量呈正相关.     

Gravel-sand mulch thickness effects on soil temperature,evaporation, water use efficiency and yield of watermelon in semi-arid Loess Plateau,China

Mulch thickness is one of the important factors affecting soil moisture and temperature. Two field experiments were conducted at Gaolan, Gansu, China, to investigate the influence of gravel-sand mixture mulch thickness on soil temperature, evaporation, evapotranspiration, water use efficiency (WUE) and yield. There were 5 levels of gravel-sand mulch thickness in Experiment 1 (3, 5, 7, 9 and 11 cm; without crop) and 4 levels of gravel-sand mulch thickness plus 80% plastic film mulch in Experiment 2 (3, 5, 8 and 11 cm; cropped to watermelon). There was a close negative relationship between mulch thickness and soil evaporation, with exponential function. Mulch decreased soil evaporation up to a thickness of 7 cm. The soil temperature from 11:00 to 18:00 was slightly lower with mulching compared to no mulching and, as a result, mulch not only decreased the temperature difference between day and night, but also it had a lag. In addition, the peak soil temperature at 5 cm depth was reduced and the soil temperature at night was raised with increased mulch thickness. Mulch had no further effect on soil temperature when thickness is greater than 7 cm. With 80% plastic film mulch, a significant effect on watermelon yield and WUE was detected among the different treatments used in this study, with the highest yield and WUE obtained with the 8 cm mulch thickness treatment. Therefore, 7–8 cm of mulch thickness appears to be the most appropriate option for gravel-sand mulch to sustain high watermelon yield and WUE.     

不同耕作措施对黄土高原旱地土壤呼吸的影响

在甘肃省定西市李家堡镇设置不同耕作措施试验,对春小麦、豌豆双序列轮作下的土壤呼吸及其对应时间的冠层温度、土壤水分进行了测定.结果表明：春小麦和豌豆在整个生育期内的土壤呼吸都表现出不同的变化趋势,春小麦地土壤呼吸在拔节前期、灌浆期和收后分别达到高峰期;豌豆地土壤呼吸在五叶期、吐丝期、开花结荚期和收后分别达到高峰期.免耕秸秆覆盖处理和传统耕作处理下春小麦地土壤呼吸日变化明显,免耕秸秆覆盖处理明显低于传统耕作处理;而豌豆地土壤呼吸日变化不明显.春小麦和豌豆冠层温度均与土壤呼吸呈显著线性相关,春小麦孕穗期相关性最高,灌浆期次之;豌豆开花结荚期相关性最高,分枝期次之.土壤含水量与土壤呼吸间存在极显著的凸型抛物线型相关,保护性耕作下的相关性都高于传统耕作,其中免耕秸秆覆盖处理的春小麦地和豌豆地土壤含水量与土壤呼吸的相关性在各层次土壤中均为最高,10～30 cm土壤含水量对春小麦地土壤呼吸的影响最大,5～10 cm土壤含水量对豌豆地土壤呼吸的影响最大.与传统耕作相比,免耕秸秆覆盖、免耕、传统耕作秸秆还田、传统耕作结合地膜覆盖、免耕结合地膜覆盖5种保护性耕作措施都能不同程度地降低土壤呼吸,其中免耕秸秆覆盖优势最明显.     

宁南旱区耕作覆盖对马铃薯产量及土壤水热特征的影响

为探究耕作覆盖对土壤水热及旱作马铃薯产量的影响,连续2年在宁南旱区不同耕作深度结合覆盖模式下开展了研究工作。结果表明: 耕作深度、覆盖材料对马铃薯播种期0～100 cm土层土壤贮水量有极显著影响,而二者交互作用无显著影响;2019年土壤贮水量以深松30 cm覆盖地膜处理最高,2020年以深松40 cm覆盖秸秆处理较高,分别较翻耕15 cm不覆盖处理(对照)显著提高16.9%和33.4%;耕作深度、覆盖材料可显著影响马铃薯关键生育期土壤贮水量;同一耕作深度下土壤贮水量以秸秆、地膜覆盖处理效果较好,同一覆盖材料下以深松30～40 cm处理最佳。覆盖材料、耕作深度与覆盖材料二者交互作用对播种-现蕾期0～25 cm土层土壤有效积温影响显著;同一耕作深度下覆盖地膜处理土壤有效积温平均较不覆盖处理显著增加9.3%,而覆盖秸秆处理较不覆盖处理显著降低18.7%;2019和2020年各处理全生育期土壤有效积温分别以深松30 cm和深松40 cm覆盖地膜处理最高。2019年马铃薯总产量和经济效益以深松30 cm覆盖秸秆处理较高,分别较对照显著提高84.6%和107.9%;2020年以深松40 cm覆盖秸秆处理最佳,分别较对照显著提高81.7%和105.7%。耕作深度、覆盖材料对作物水热利用效率均有显著影响,水分利用效率以深松30～40 cm覆盖秸秆处理较高,而积温利用效率不同耕作深度结合秸秆覆盖各处理均较翻对照显著提高。相关分析表明,块茎形成期的土壤水分和有效积温对马铃薯总产量的形成至关重要,而全生育期土壤水分对总产量的影响高于土壤有效积温。可见,深松30～40 cm覆盖秸秆处理可改善土壤水热状况,实现马铃薯增产增收和水热资源的高效利用,在宁南半干旱区马铃薯生产中有一定的应用推广价值。     

Plastic pollution in croplands threatens long‐term food security

Plastic pollution is a global concern given its prevalence in aquatic and terrestrial ecosystems. Studies have been conducted on the distribution and impact of plastic pollution in marine ecosystems, but little is known on terrestrial ecosystems. Plastic mulch has been widely used to increase crop yields worldwide, yet the impact of plastic residues in cropland soils to soil health and crop production in the long term remained unclear. In this paper, using a global meta‐analysis, we found that the use of plastic mulch can indeed increase crop yields on average by 25%–42% in the immediate season due to the increase of soil temperature (+8%) and moisture (+17%). However, the unabated accumulation of film residues in the field negatively impacts its physicochemical properties linked to healthy soil and threatens food production in the long term. It has multiple negative impacts on plant growth including crop yield (at the mean rate of ?3% for every additional 100 kg/ha of film residue), plant height (?2%) and root weight (?5%), and soil properties including soil water evaporation capacity (?2%), soil water infiltration rate (?8%), soil organic matter (?0.8%) and soil available phosphorus (?5%) based on meta‐regression. Using a nationwide field survey of China, the largest user of plastic mulch worldwide, we found that plastic residue accumulation in cropland soils has reached 550,800 tonnes, with an estimated 6%–10% reduction in cotton yield in some polluted sites based on current level of plastic residue content. Immediate actions should be taken to ensure the recovery of plastic film mulch and limit further increase in film residue loading to maintain the sustainability of these croplands.     

农牧交错带不同耕作方式土壤水分动态变化特征

从耕作方式、覆盖和轮作3个因素系统地对莜麦整个生育期土壤含水量进行了动态的观测研究,结果表明,干旱地区单纯的免耕在提高土壤水分含量上作用不太明显,尤其是降低了表层土壤的含水量,免耕只有在覆盖下,才能真正起到增加土壤水分含量,提高水分利用效率的作用;而对于深松处理,无论是覆盖还是不覆盖,与传统翻耕处理相比,土壤水分均明显提高;同种耕作措施覆盖与无覆盖相比,覆盖处理下土壤含水量明显高于无覆盖处理;说明保护性耕作之所以能够提高土壤水分含量,关键因素在于残茬覆盖;同种耕作方式下轮作种植土壤水分含量与水分利用效率明显高于连作。可以看出,从理论上轮作深松覆盖处理是当地应采用的最佳耕作方式,然而,由于当地缺乏覆盖材料,因此,轮作深松是目前当地最适合的耕作方式。     

Effects of straw mulching on soil temperature, evaporation and yield of winter wheat: field experiments on the North China Plain

Straw mulching is an effective measure to conserve soil moisture. However, the existence of straw on the soil surface also affects soil temperature, which in turn influences crop growth, especially of winter crops. Five‐year field experiments (2000–2005) investigated the effects of straw mulching and straw mass on soil temperature, soil evaporation, crop growth and development, yield and water use efficiency (WUE) of winter wheat (Triticum aestivum L.) at Luancheng Station on the North China Plain. Soil is a moderately well‐drained loamy soil with a deep profile at the station. Two quantities of mulch were used: 3000 kg ha^?1 [less mulching (LM)] and 6000 kg ha^?1 [more mulching (MM)], representing half and all of the straw from the previous crop (maize). In the control (CK), the full quantity of mulch was ploughed into the top 20 cm of soil. The results showed that the existence of straw on the soil surface reduced the maximum, but increased the minimum diurnal soil temperature. When soil temperature was decreasing (from November to early February the next year), soil temperature (0–10 cm) under straw mulching was on average 0.3°C higher for LM and 0.58°C higher for MM than that without mulching (CK). During the period when soil temperature increased (from February to early April, the recovery and jointing stages of winter wheat), average daily soil temperature of 0–10 cm was 0.42°C lower for LM and 0.65°C lower for MM than that of CK. With the increase in leaf area index, the effect of mulching on soil temperature gradually disappeared. The lower soil temperature under mulch in spring delayed the development of winter wheat up to 7 days, which on average reduced the final grain yield by 5% for LM and 7% for MM compared with CK over the five seasons. Mulch reduced soil evaporation by 21% under LM and 40% under MM compared with CK, based on daily measuring of microlysimeters. However, because yield was reduced, the overall WUE was not improved by mulch.     

Soil Solarization and Gliocladium virens Reduce the Incidence of Southern Blight Sclerotium rolfsii in Bell Pepper in the Field

The timing of solarization with clear plastic mulch in relation to the planting of pepper and the timing of soil amendment with a bran prill formulation of Gliocladium virens were evaluated for the control of southern blight and the survival of sclerotia of the pathogen Sclerotium rolfsii in bell pepper in the field. Solarization during crop growth increased the incidence of southern blight, and G. virens was not effective under the mulch. In addition, pepper yields were low when the soil was solarized during crop growth. In contrast, the solarization of fallow soil in raised beds for 6 weeks prior to crop growth significantly reduced disease incidence in the pepper crop. In addition, in 2 years, G. virens alone reduced southern blight in non-solarized soils and reduced the survival of sclerotia of S. rolfsii to depths of 30 cm at all locations in soil in both years. These data demonstrate two effective biological control strategies for the management of southern blight in the southeastern US.     

不同水分下限对温室膜下滴灌甜瓜开花坐果期地温的影响

土壤水热状况是影响甜瓜生长及坐果的重要因素.本文以膜下滴灌为供水方式,在开花坐果期设计了重度亏缺（55%田间持水量,T₁）、中度亏缺（65%田间持水量,T₂）、轻度亏缺（75%田间持水量,T₃）和不亏缺（85%田间持水量,CK）4种水分控制下限处理,研究了不同水分控制下限对温室滴灌甜瓜耕层温度的影响,在此基础上探讨了耕层（0～20 cm）不同水热比值对甜瓜生长发育及坐果情况的影响.结果表明;甜瓜在开花坐果期间,耕层的平均地温为T₁＞T₂＞T₃＞CK,地温与土壤含水率呈反比.晴天、阴雨天及灌水后的地温日最大变幅均出现在膜内地表,最小变幅出现在膜外地表以下20 cm处;地温极值与土壤深度密切相关,地表极值与地下10和20 cm的极值差异显著.该阶段选择T₃作为灌水标准,即水热比值为1.62 mm·℃^-1时,植株的生长速率最快,坐果历时最短且坐果率最高.综合考虑温室膜下滴灌甜瓜在开花坐果期的土壤水分与地温的关系,认为T₃处理可使耕层土壤水热比值（水热比值为1.62 mm·℃^-1）达到最佳状态,更有利于甜瓜的生长发育和坐果.     

Growth Suppression of Canola Through Wheat Stubble I. Separating Physical and Biochemical Causes in the Field

A field experiment was conducted to investigate the causes of poor canola growth through surface-retained wheat stubble. The experiment was designed to separate the role of biochemical factors such as stubble phytotoxicity, nitrogen (N) immobilisation and disease incidence from the physical effects of the stubble including changes in the seedbed microclimate on crop growth and yield, as these had been previously identified as possible mechanisms for the poor growth. Treatments included: two stubble cultivars, three levels of decomposition, two levels of nitrogen and inert plastic mulch. A novel approach involving leachates collected from intact field cores with a rainfall simulator was also used to assess the phytotoxic impacts of the stubble. Surface-retained wheat stubble (5 t/ha) reduced the canola vegetative biomass by 46% and yield by 26%, consistent with previous field observations. There was no impact of stubble variety or level of stubble decomposition on canola growth and yield, and an inert plastic mulch designed to simulate the physical effects of the wheat stubble had a similar effect on growth and yield as wheat stubble. Leachates collected from intact field cores through surface stubble also had no impact on canola germination or radicle elongation in petri-dishes in the absence of soil, nor on emergence of canola in pots of soil. Together, these observations suggest phytotoxicity was not contributing to the poor growth. N-immobilisation was evident in stubble-retained treatments although tissue N concentrations were adequate in all treatments and the growth limitation could not be overcome with added N. The principal mechanism of growth reduction was associated with the physical impact of the stubble including a reduction in photosynthetically active radiation, the red:far red ratio of incident light under the stubble, and the temperature above the stubble layer. These effects led to elongated hypocotyls, reduced investment in early leaf and root growth, delayed emergence and slower leaf area development as well as an increase in seedling disease complex, effects apparent in both wheat stubble and inert plastic mulch treatments. The results suggest that physical, rather than biochemical factors are the main cause of poor growth of canola in surface-retained wheat stubble, and that much of the impact could be avoided if the stubble were moved away from directly above the emerging seedlings.     

半干旱雨养区不同覆膜方式对冬小麦土壤水分利用及产量的影响

在黄土高原半干旱雨养条件下,于2008—2009、2009—2010两个年度,以露地种植为对照(CK),研究了不同覆膜方式(全膜覆土穴播,全膜穴播,垄膜沟播)对旱地冬小麦产量和水分利用的影响。结果表明:两年度覆膜平均较CK产量分别显著提高49.4%和53.2%,水分利用效率提高11.8%和14.3%。覆膜的高产建立在高生长量、高耗水基础上,产量与生育期耗水量显著正相关(r=0.952*—0.958*),两年度覆膜分别平均较CK多耗水33.5%和34.1%。覆膜处理中以全膜穴播较CK的增产幅度和WUE提高幅度最大,耗水量也最大。由于覆膜耗水量大,覆膜各处理收获期0—200 cm土壤贮水量均显著低于CK,但通过全年连续覆膜和夏闲期降水补充,在下茬秋播时,覆膜各处理0—200 cm土壤贮水量均超过CK,夏闲期覆膜的水分休闲效率两年度分别平均高出CK 41.8和86.4个百分点,覆膜有利于土壤水分恢复和下茬作物的可持续生产。覆膜方式中,以全膜覆土穴播种植效益最高,两个年度纯收益平均达5531.6元/hm2,较CK增收2542.2元/hm2。综合考虑,全膜覆土穴播是一种高产高效兼顾、操作简单、适宜于半干旱雨养区推广应用的冬小麦覆膜种植方式。