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.

Effects of Ridge-Mulching with Plastic Sheets for Rainwater-Harvesting Cultivation on WUE and Yield of Winter Wheat

A field experiment was conducted in a manural loesial soil in middle of Shaanxi Province ofChina, a sub-humid area prone to drought, to study the effects of rainwater-harvestingcultivation on water use efficiency (WUE) and yield of winter wheat. Ridge-furrow tillage wasused, the ridge being mulched by plastic sheets for rainwater harvesting while seeding in thefurrows. Results showed that from sowing to reviving stage of winter wheat, water stored in 0-100 cm layer was significantly decreased whereas that in 100-200 cm layer did not change.Compared to the non-mulching, plastic mulch retained 6.5 mm more water as an average of the twoN rate treatments, having a certain effect on conservation of soil moisture. In contrast, atharvest, water was remarkably reduced in both the 0-100 cm and the 100-200 cm layers, andmulched plots consumed 34.8 mm more water as an average of the two treatments: low N rate (75kg N ha-1) with low plant density (2 300 000 plants ha-1) and high N rate (225 kg N ha-1)with highplant density (2 800 000 plants ha-1), in 0-200 cm layer than those without mulching, the formerbeing beneficial to plants in utilization of deep layer water. Mulching was significant inharvesting water and in increase of yield. Mulched with plastic sheets, biological and grainyields were 22.5 and 22.6% higher for the average of the high N rate than for the low N rate,and the high N rate with low plant density was 29.8 and 29.1% higher in both biological andgrain yields than that of the low N rate with low plant density. With high N rate and high plantdensity, the mulched biological and grain yields were 39.5 and 28.9% higher than the correspondingtreatments without mulching. Of the treatments, that with high N rate and low plant density wasthe highest in both biological and grain yields, and the water use efficiency reached 43.7 kgmm-1 ha-1 for biological yield and 22 kg mm-1 ha-1 for grain yield, being the highest WUE reportedin the world up to now.

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.

Effects of film mulching regime on soil water status and grain yield of rain-fed winter wheat on the Loess Plateau of China

Shortages and fluctuations in precipitation are influential limiting factors for the sustainable cultivation of rain-fed winter wheat on the Loess Plateau of China. Plastic film mulching is one of the most effective water management practices to improve soil moisture, and may be useful in the Loess Plateau for increasing soil water storage. A field experiment was conducted from July 2010 to June 2012 on the Loess Plateau to investigate the effects of mulching time and rates on soil water storage, evapotranspiration （ET）, water use efficiency （WUE）, and grain yield. Six treatments were conducted： （1） early mulching （starting 30 days after harvest） with whole mulching （EW）; （2） early mulching with half mulching （EH）; （3） early mulching with no mulching （EN）; （4） late mulching （starting 60 days after harvest） with whole mulching （LW）; （5） late mulching with half mulching （LH）; and （6） late mulching with no mulching （LN）. EW increased precipitation storage efficiency during the fallow periods of each season by 18.4 and 17.8%, respectively. EW improved soil water storage from 60 days after harvest to the booting stage and also outperformed LN by 13.8 and 20.9% in each growing season. EW also improved spike number per ha by 13.8 and 20.9% and grain yield by 11.7 and 17.4% during both years compared to LN. However, EW decreased WUE compared with LN. The overall results of this study demonstrated that EW could be a productive and efficient practice to improve wheat yield on the Loess Plateau of China.

Effect of different mulch materials on winter wheat production in desalinized soil in Heilonggang region of North China

Freshwater shortage is the main problem in Heilonggang lower-lying plain, while a considerable amount of underground saline water is available. We wanted to find an effective way to use the brackish water in winter wheat production. Surface mulch has significant effect in reducing evaporation and decreasing soil salinity level. This research was aimed at comparing the effect of different mulch materials on winter wheat production. The experiment was conducted during 2002-2003 and 2003-2004. Four treatments were setup： （1） no mulch, （2） mulch with plastic film, （3） mulch with corn straw, （4） mulch with concrete slab between the rows. The result indicated that concrete mulch and straw mulch was effective in conserving soil water compared to plastic film mulch which increased soil temperature. Concrete mulch decreases surface soil salinity better in comparison to other mulches used. Straw mulch conserved more soil water but decreased wheat grain yield probably due to low temperature. Concrete mulch had similar effect with plastic film mulch on promoting winter wheat development and growth.

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。

不同覆盖方式对旱地冬小麦土壤水热及光合特性的影响

为了探明不同覆盖方式对旱地冬小麦土壤水热、光合特性的影响,在陇中半干旱区,设置了露地无覆盖(CK)、秸秆带状覆盖(SM4、SM5)和地膜覆盖(PM),对不同处理下小麦田土壤水热状况、叶片光合指标和产量进行测定与分析。结果表明,与CK比较,SM4、SM5和PM处理均显著增加了冬小麦播种至收获期的土壤平均含水量,增幅分别为7.0%、9.0%和8.5%;SM4和SM5处理显著降低了冬小麦全生育期土壤平均温度,降幅分别为11.3%和13.7%,而PM处理显著增加了全生育期土壤平均温度,增幅为6.7%;SM4、SM5和PM处理使小麦净光合速率(P_(n))、蒸腾速率(T_(r))、气孔导度(G_(s))分别增加了16.3%、18.4%、2.6%,17.2%、19.2%、8.9%和26.0%、30.7%、8.9%,使胞间CO_(2)浓度(C_(i))分别降低7.2%、9.1%和3.1%,SM5处理较SM4处理的变幅更大。与CK相比,SM4、SM5、PM处理显著增加了冬小麦籽粒产量和生物产量,增幅分别为11.9%、18.0%、20.9%和16.7%、19.0%、25.5%。相关分析表明,冬小麦籽粒产量与旗叶P_(n)(r=0.539*)和T_(r)(r=0.633*)呈显著正相关;冬小麦开花期和灌浆前期旗叶光合生理特性对籽粒产量和千粒重的影响大于灌浆后期。可见,在旱地小麦种植中,秸秆带状覆盖能显著改善土壤水热情况,提高旗叶光合能力,使小麦产量显著增加。

不同覆盖栽培对旱作冬小麦土壤水分、产量和品质的影响

为探明不同栽培措施下全膜覆土穴播种植对不同基因型冬小麦生产的土壤水分状况、产量和品质的影响,为旱作冬小麦覆膜适水种植与农业绿色可持续高质量生产提供依据。采用普通聚乙烯地膜覆土穴播(PE)和生物降解地膜全膜覆土穴播(BM)2种覆盖材料种植方式,以传统露地穴播(LD)为对照,研究不同栽培措施对冬小麦土壤水分状况、产量、水分利用效率和主要品质的影响。结果表明,在干旱气候和作物耗水影响下,地膜覆盖处理较LD降低0—300 cm土层土壤平均含水量,BM较PE显著降低0—300 cm土层土壤水分。冬小麦全生育期耗水量BM较LD和PE分别增加22.0,23.0 mm,全生育期土壤水分消耗量BM>LD>PE。“陇鉴110”2个种植季地膜覆盖均较露地栽培显著增产;2018—2019年种植季,“陇鉴111”PE、BM较LD分别增产40.3%和29.7%,2019—2020年种植季,受严重倒伏影响PE、BM较LD分别减产2.5%,3.5%。与LD相比,地膜覆盖降低冬小麦籽粒品质,BM较PE极显著提升面团稳定时间和形成时间,“陇鉴110”籽粒平均蛋白质含量、湿面筋含量和弱化度分别较“陇鉴111”增加10.6%,11.1%,10.3%。因此,生物降解地膜覆盖可起到与聚乙烯地膜类似的蓄水保墒功能,但在旱作区冬小麦生产中,生物降解地膜覆盖要依据品种耗水特性及地膜栽培适应性,选择适宜的品种。

秸秆带状覆盖对旱地冬小麦土壤温度及产量的影响

为探明秸秆带状覆盖对西北半干旱雨养农业区冬小麦土壤温度和产量的影响,以露地不覆盖为对照(CK),设置秸秆带状覆盖4行(SM1)、秸秆带状覆盖5行(SM2)、黑膜覆盖(PM1)和白膜覆盖(PM2)共5个处理,利用大田试验研究了不同覆盖处理冬小麦土壤温度及产量相关指标的异同。结果表明,与CK相比,秸秆覆盖处理(SM1、SM2)显著降低了冬小麦全生育期0~25 cm土层温度,返青期和灌浆期降温幅度最大,平均降温2.0℃;越冬期降温幅度最小,平均降温0.1℃;上层土壤(0~10 cm)的降温幅度大于下层土壤(15~25 cm),SM1降温效应大于SM2。地膜覆盖在不同生育时期存在增温和降温的双重效应,成熟期增温幅度最大,较CK增加2.4℃;灌浆期5 cm土层降温幅度最大,降低1.8℃;无论增温还是降温,PM1效应均高于PM2。覆盖处理一天中,表层土壤温度以中午14:00变化最大,晚19:00次之,早7:00变化最小,且中午14:00均表现为降温效应;秸秆覆盖降温效应(4.9℃)大于地膜覆盖(0.8℃)。覆盖降低土壤有效积温,地膜覆盖有效积温显著高于秸秆覆盖。秸秆覆盖平均增产9.6%,SM2增产率高于SM1;地膜覆盖显著增产(20.8%),PM2增产率高于PM1。产量三要素中,穗粒数受温度影响最大,与各生育时期0~25 cm土层土壤温度、阶段土壤有效积温均呈显著或极显著正相关。综合考虑土壤温度、土壤有效积温、产量、千粒重和穗数等,SM2处理更有利于旱地冬小麦产量的形成。

不同覆盖方式对旱地春小麦土壤水热及生长的影响

为明确不同覆盖方式对旱地春小麦生长和产量的影响,在西北半干旱雨养条件下,以露地无覆盖为对照(CK),设置了秸秆带状覆盖(SM)、白膜全覆盖(BM)和黑膜全覆盖(HM)三种覆盖方式,分析覆盖对旱地春小麦土壤水热、干物质积累及产量的影响。结果表明,与CK相比,覆盖能明显提高春小麦各生育时期0~200 cm土壤水分0.8~0.9个百分点,且SM处理以开花期增幅最大,HM和BM处理均以灌浆期增幅最大;同时,SM、HM和BM处理能明显增加关键生育时期的土壤水分1.0、1.4和1.1个百分点。HM和BM处理下春小麦全生育期0~25 cm平均土壤温度较CK分别增加0.7和1.3℃,均以苗期增幅最大;而SM处理较CK下降2.5℃,降幅在孕穗期最大。覆盖能显著提高春小麦干物质积累量,SM、HM和BM处理相对于CK的增幅分别为19.4%、16.7%和31.6%。覆盖显著增加了春小麦产量,增幅表现为BM(18.5%)>HM(15.1%)>SM(12.1%)。由此可见,覆膜与秸秆覆盖均有利于旱地土壤保墒和增温以及春小麦的产量形成;从环保及可持续发展等方面综合考虑,秸秆带状覆盖栽培是一种更加高产高效的覆盖方式,更有利于西北旱地农业可持续生产。

有机肥部分替代化肥对旱地地膜冬小麦产量及水肥利用效率的影响

为探求旱地冬小麦全生物降解地膜绿色覆盖栽培条件下有机肥氮替代化肥氮的适宜比例,于2020—2021年在甘肃定西布设大田试验,比较分析了单施化肥(CK)、15%有机肥氮替代化肥氮(OR_(15))、30%有机肥氮替代化肥氮(OR_(30))、45%有机肥氮替代化肥氮(OR_(45))处理下旱地冬小麦干物质积累、籽粒产量、耗水量、水分利用效率、氮素效率等的差异。结果表明,与CK相比,适宜比例的有机肥替代化肥可有效调节冬小麦生长发育,优化干物质积累和耗水过程,提高籽粒产量和水肥利用效率。有机肥替代处理的花前群体干物质积累量均显著低于CK,而OR_(15)和OR_(30)处理的花后群体干物质积累量分别较CK增加了20.22%和5.39%,OR_(45)处理则降低21.84%;与CK相比,OR_(15)处理增产6.15%,OR_(30)和OR_(45)处理分别减产2.87%和10.43%;OR_(15)和OR_(30)处理的水分利用效率较CK提高了7.76%和3.78%,OR_(45)处理降低了1.89%;OR_(15)、OR_(30)和OR_(45)处理的生育期耗水量分别较CK低1.53%、6.43%和8.67%,而花后耗水量分别高7.46%、1.82%和0.80%;相比于CK,适宜比例的有机肥替代化肥主要通过增加小麦穗数和千粒重提高籽粒产量;有机肥替代处理均显著提高了冬小麦氮素利用效率、氮素收获指数和化肥氮偏生产力,且分别平均较CK提高了10.36%、4.46%和42.16%;OR_(15)处理的籽粒氮积累量较CK增加了7.81%,OR_(30)和OR_(45)处理分别降低了8.63%和20.35%。通过综合分析,有机肥氮15%替代化肥氮可作为陇中旱地冬小麦全生物降解地膜绿色覆盖栽培条件下实现小麦稳产增产及提质增效的氮素管理模式。

免耕一膜两年用及水氮减量对西北灌区小麦水氮利用效率的影响

【目的】针对长期连作作物生产力低、水氮减量作物稳产技术研究薄弱等突出问题,研究前茬地膜覆盖玉米收获后免耕留存地膜,在水氮减量投入下提高种植后茬小麦的水氮利用效率对于建立西北灌区小麦生产的节本增效技术具有实践指导意义。【方法】通过田间试验,设置了免耕一膜两年覆盖利用(NT)和传统耕作(CT)2个耕作方式,传统灌水(I_(2),2400 m^(3)/hm^(2))与减量20%灌水(I_(1),1920 m^(3)/hm^(2))2个灌水水平,传统施氮(N_(3),225 kg/hm^(2))、减量20%施氮(N_(2),180 kg/hm^(2))和减量40%施氮(N_(1),135 kg/hm^(2))3个施氮水平。【结果】免耕一膜两年覆盖利用较传统耕作提高小麦籽粒产量与水分利用效率分别为10.4%与12.4%,增加小麦籽粒与植株氮素累积量分别为17.7%与15.6%。减量20%灌水与减量20%施氮同步集成于免耕一膜两年覆盖利用措施进一步增强小麦增产与氮素积累能力而提高水氮利用效率,较传统耕作和传统水氮供应处理小麦增产15.2%、水分利用效率提高20.5%,小麦籽粒与植株氮素累积量分别增加27.6%与16.0%,氮素收获指数提高10.0%,氮素利用效率提高8.4%。【结论】前茬玉米免耕一膜两年覆盖利用配套减量20%灌水(1920 m^(3)/hm^(2))与减量20%施氮(180 kg/hm^(2))是提高西北绿洲灌区小麦水氮利用效率的节水节氮有效措施。

碎麦秸垫膜覆盖对民勤绿洲食葵产量及土壤酶活性的影响

为解决民勤绿洲灌区水资源短缺、土壤耕层状况恶化、食葵产量不佳等问题,在民勤灌区设置无覆盖(CK)、秸秆覆盖(S)(秸秆量为4500 kg/hm^(2))、地膜覆盖(F)、碎麦秸垫膜覆盖(SF_(1))(秸秆量为4000 kg/hm^(2))、碎麦秸垫膜覆盖(SF_(2))(秸秆量为4500 kg/hm^(2))5个处理,采用当地农户普遍的灌溉水平(750 m^(3)/hm^(2)),研究了食葵生长状况及土壤酶活性的变化。结果表明:碎麦秸垫膜覆盖(SF_(1))处理下土壤温度显著高于其他处理,并且有着更高的保水效果,保证了食葵的正常生长发育;碎麦秸垫膜覆盖(SF_(1))条件下平均出苗率较CK处理提高了12.1%(P<0.05),较S处理的出苗率提高了9.7%(P<0.05);碎麦秸垫膜覆盖(SF_(1))条件下食葵产量达到4780.95 kg/hm^(2),较SF_(2)、F、S、CK处理分别提高了2.8%(P>0.05)、7.3%(P>0.05)、34.1%(P<0.05)、44.7%(P<0.05),且在碎麦秸垫膜覆盖(SF_(1))处理下食葵的株高、茎粗、叶面积均为最优,与CK、S、F处理均呈显著性差异(P<0.05),该覆盖方式更有利于食葵干物质的积累;碎麦秸垫膜覆盖(SF_(1))条件下的土壤蔗糖酶和脲酶活性显著高于CK、S、F、SF_(2)处理,且全生育期表现基本一致。可见,碎麦秸垫膜覆盖可解决民勤绿洲秸秆覆盖引起的土壤温度低、保水率差、出苗率低和产量低等问题,也可改善长期单一地膜覆盖而引起的地力下降的情况。

秸秆带状覆盖对旱地冬小麦产量及土壤水分的影响

为探讨西北半干旱雨养条件下秸秆带状覆盖麦田水分利用特征和增产效果,通过田间试验,以露地条播为对照（CK）,研究了3种不同覆盖处理[秸秆带状覆盖常规条播（SM1）、秸秆带状覆盖宽幅条播（SM2）和全膜覆土穴播（PM）]对旱地冬小麦田土壤含水量、小麦产量和水分利用效率的影响。结果表明,秸秆带状覆盖和全膜覆土穴播均可显著改善小麦全生育期0-20cm以及开花前20-90cm土壤墒情,但开花后20-90cm以及全生育期90-200cm土壤墒情普遍不如CK。3种覆盖处理均能促进冬小麦对土壤贮水的利用,显著提高开花至成熟阶段的耗水量及其占总耗水量的比例。秸秆带状覆盖和全膜覆土穴播生育期耗水量分别比CK增加4.6%和7.6%。秸秆带状覆盖在孕穗前0-200cm土壤墒情与全膜覆土穴播无显著差异,孕穗期开始则好于全膜覆土穴播;全膜覆土穴播0-200cm土壤贮水消耗量显著高于秸秆带状覆盖,而开花至成熟阶段的耗水量及其占总耗水量的比例则略低于秸秆带状覆盖。3种覆盖处理均显著提高产量和水分利用效率,PM、SM1和SM2较CK分别增产36.8%、29.7%和27.5%,水分利用效率分别提高27.3%、23.9%和22.7%。产量与生育期耗水量呈显著正相关（r=0.97＊）。覆盖处理中,全膜覆土穴播产量虽最高,但从产量、水分利用效率和经济效益角度综合考虑,秸秆带状覆盖优于全膜覆土穴播。因此认为,秸秆带状覆盖是一种更加高产高效、适宜在西北半干旱雨养区推广的覆盖种植方式。

不同地膜周年覆盖对冬小麦土壤水分及利用效率的影响

为了探明不同地膜覆盖对旱地冬小麦土壤水分及其利用效率的影响,选用普通地膜、生物降解膜以及液体地膜在陕西渭北旱塬旱作农田进行周年覆盖集雨栽培定位试验,研究了不同地膜周年覆盖对冬小麦不同生育时期土壤水分总贮量和不同土壤深度水分动态变化及其利用效率的影响。结果表明,周年覆盖地膜可提高土壤含水量,有利于土壤水库的扩蓄增容,并且能显著提高冬小麦的产量和水分利用效率。普通地膜和生物降解膜覆盖处理在冬小麦不同生育期对0~200 cm的土壤贮水量有显著的提高作用,与液体地膜和不覆盖平播处理（CK）比较,差异显著（P〈0.05）;不同地膜周年覆盖处理的土壤水分空间变化规律相同,普通地膜和生物降解膜覆盖处理可有效提高土壤含水量,但液体地膜的集雨作用不明显;此外,普通地膜和生物降解膜两年的平均产量较对照（CK）分别提高了38.01%和36.28%,水分利用效率分别比对照提高19.85%、16.85%,且呈显著性差异（P〈0.05）。可见,周年覆盖生物降解膜与普通地膜具有良好的蓄水保墒效果,可以提高冬小麦产量。

氮肥管理与地膜覆盖对旱地冬小麦产量和氮素利用效率的影响

降雨偏少且季节分布不均,施肥偏多且方式不合理,缺少有效的保水栽培措施是西北旱地小麦生产面临的主要问题。2010年10月至2012年6月连续2个小麦生长季,在陕西渭北旱塬进行田间试验,比较了氮肥追施和总量减少、覆膜、增加种植密度措施较传统施肥和农民习惯施肥种植模式对冬小麦籽粒产量及氮素利用效率的影响。与农户习惯施肥相比,传统施肥不能持续增加产量和氮素利用效率;而减氮追肥、减氮垄覆和减氮垄覆增密处理的增产效果明显,同时提高了氮素利用效率,但减氮垄覆或增加种植密度却使籽粒含氮量降低,主要原因是进入开花期后土壤硝态氮累积量减少,氮素供应不足所致。综合分析,减氮垄覆增产增效更明显,小麦产量、氮肥偏生产力、氮肥生理利用率在第1年分别提高38.6%、49.6%和35.1%,在第2年分别提高7.6%、16.3%和25.7%,说明控氮与覆膜结合是实现旱地冬小麦增产的重要措施,但需注意生长后期土壤氮素供应,在增产的同时保证小麦品质。

不同覆膜方式对旱作冬小麦耗水特性及籽粒产量的影响

【目的】研究黄土高原雨养条件下,不同地膜覆盖方式对冬小麦耗水特性、产量和休闲期土壤水分补给的影响,为促进增产和提高水分利用效率提供理论依据。【方法】2008—2009和2009—2010年小麦生长季,设置全膜覆土穴播(A)、全膜覆盖穴播(B)、垄膜沟播(C)和露地条播(CK)4种不同栽培模式,测量不同处理的土壤贮水量、耗水量、产量和水分利用效率。【结果】全膜穴播可使冬小麦增产64.4%—79.1%,水分利用效率提高22.1%—24.0%,达到11.9—16.6 kg·hm-2·mm-1;全膜覆土穴播可增产43.4%—44.4%,水分利用效率提高8.8%—14.6%,达到11.0—14.8 kg·hm-2·mm-1;垄膜沟播可增产37.0%—39.3%,水分利用效率提高4.2%—4.4%,达到10.0—14.2 kg·hm-2·mm-1。主要原因是,地膜覆盖可增加冬小麦拔节前0—200 cm土层贮水量,提高拔节至成熟阶段的耗水量及其占总耗水量的比例,促进生育期对土壤贮水的利用,同时干旱年份可促进冬小麦利用深层土壤水分,最终提高冬小麦成熟期的生物量和籽粒产量;虽然生育期耗水增加,但水分利用效率也提高。冬小麦产量与生育期耗水量呈显著正相关(r=0.96*)。覆膜的高产建立在高耗水基础上,但通过休闲期水分补充,地膜茬0—200 cm土层水分在冬小麦秋播前可恢复到露地水平。覆膜处理间的耗水差异远小于覆膜与露地间的差异。综合考虑产量、经济效益和田间操作难易程度,全膜覆土穴播一次覆膜可多茬使用,节省地膜成本,田间操作简单,经济效益高,是本试验条件下的最优栽培方式。【结论】全膜覆土穴播是西北黄土高原旱地小麦兼顾高产高效的栽培模式。

施肥和覆膜垄沟种植对旱地小麦产量及水氮利用的影响

通过大田试验研究了施肥和覆膜垄沟种植对旱地冬小麦群体动态、产量构成及水氮利用的影响。结果表明,覆膜垄沟种植和追肥处理可显著提高旱地冬小麦穗数,追肥处理可减少后期无效分蘖;覆膜垄沟种植和追肥处理产量分别比农户模式提高了11.73%和13.91%,穗数和穗粒数是其产量提高的关键因素;覆膜垄沟种植方式可减少土壤水分损耗,水分利用率为11.60kg.hm-.2mm-1,显著高于其他处理;追肥处理能有效促进小麦生育中后期对氮素的吸收利用,在基施氮量165 kg/hm2上再追肥30 kg/hm2,地上部分吸氮总量增加15.45 kg/hm2,追肥氮的利用率显著高于底肥氮利用率,为51.5%。

旱地冬小麦不同栽培模式、施氮量和种植密度土壤水分利用状况

通过3年田间试验,研究不同栽培模式、不同施氮量及种植密度对冬小麦田土壤水分特征的影响,结果表明：无论何种栽培模式,冬小麦生长期间水分动态变化具有相似的规律,播前贮存在土壤中的水分经过一个生长季后都会有大量消耗,消耗深度延伸到2 m及其以下土壤深层。小麦收获后,各种处理土壤在40-80 cm和120-160 cm深度均出现两个低水层。覆盖栽培措施对水分利用的影响表现出较大的年度变异性,原因可能主要与生育期降水量和播前土壤贮水量有关系：与无覆盖相比,秸秆覆盖在降水较少的年份可显著提高水分生产效率;地膜覆盖具有稳定的促进水分有效利用的作用;垄沟种植没有表现出预期的增产增效的效果。施用氮肥显著促进土壤水分的消耗,这种作用随着种植年限的增加而增大,这种作用在0-200 cm整个土壤深度都有反映,而且深层比表层更显著,低水土层（40-80 cm和120-160 cm）比其它深度土层更显著。施氮显著提高水分生产效率。适当增加小麦种植密度有利于提高旱地水分生产效率。

地膜覆盖对土壤水温和春小麦产量形成的影响

通过大田试验研究了地膜覆盖对土壤水温状况及春小麦产量形成的影响 .结果表明 ,地膜覆盖对土壤的增温作用在春小麦生育期内呈“U”型变化 ,地膜覆盖可以通过防止蒸发和提升土壤深层水分至作物可利用层来增加土壤中有效水含量 ,利于作物利用 .地膜覆盖的增温保墒作用利于作物前期生长和水分利用 ,在生育后期覆膜 ,作物根系发育受到抑制 ,作物蒸散量和水分利用效率下降 ,影响产量的形成 .对照(CK)、播前灌水 (W )、全程覆膜 (M)、播前灌水 +覆膜 3 0d(WM3 0 )、播前灌水 +覆膜 60d(WM 60 )及播前灌水 +全程覆膜 (WMw) 6个处理的产量分别为 2 5 5 4、2 42 4、2 75 0、3 13 8、3 3 0 5、3 12 3kg·hm-2 ,最佳覆膜时间在 40～ 60d .