不同水分管理下全田土下微膜覆盖的冬小麦耗水特性

【目的】针对海河平原水资源匮乏与冬小麦生产水分高耗的现实矛盾,研究不同水分管理条件下全田土下微膜覆盖的冬小麦耗水特性,探索区域小麦节水生产新方法。【方法】采用大田试验,以小麦常规种植方法为对照,进行两地3年试验研究。【结果】全田土下微膜覆盖下,小麦生育期田间耗水量显著降低116.1—167.9 mm,土壤贮水消耗占总耗水的55.5%—77.9%。覆膜显著减少了小麦返青前的耗水量,生育后期耗水占总耗水量的比例提高。覆膜条件下,拔节前根系吸水深度较露地处理浅40 cm,生育期2 m土体可供水212.2—240.3 mm,春季灌水75 mm小麦对土壤贮水消耗集中在0—140 cm土层,比常规生产(CK,3次灌水共225 mm)深40 cm,灌水时间后移可显著减少2 m土体贮水消耗。土下微膜覆盖条件下,雨养耗水284.3 mm可获得不低于7 500 kg·hm-2的小麦产量,播前灌水≥60 mm或抽穗期灌水75 mm,可获得与CK相当的产量,水分利用效率比CK提高40%以上、净水分利用效率和灌溉水利用效率达到最高。【结论】全田土下微膜覆盖雨养或适时少量灌水是海河平原大幅降低小麦耗水,缓解水资源供需刚性矛盾的一种新型种植方法。

不同种植制度与土下微膜覆盖的小麦玉米水分利用效果

针对华北平原北部水资源极度稀缺与小麦-玉米一年两熟生产水资源高耗的矛盾,在河北省平原代表性区域采用大田试验方法,在常规露地(-PM)和土下微膜覆盖(+PM)条件下设置冬小麦-夏玉米一年两熟(W-M)、冬小麦-夏玉米-春玉米两年三熟(W-M-M)2种种植制度,分析了不同种植模式的产量、水资源利用效果与土壤水分的时空变化动态。结果表明:土下微膜覆盖的冬小麦平均产量较露地降低3.9%~4.8%,夏玉米产量提高5.1%~6.0%,覆盖与露地的周年产量无显著差异;春玉米较夏玉米产量提高16.9%~24.6%,但两年三熟较一年两熟产量在2年周期内平均降低了13.4%。常规一年两熟平均年耗水量859.9mm,两年三熟周年比一年两熟平均减少耗水15.5%,因产量降低水分利用效率(WUE)未能显著提高;土下微膜覆盖可减少周年耗水200mm,WUE提高28.4%~36.0%,覆盖的节水效果冬小麦季好于夏玉米季,两年三熟下减少非生育期(上年夏玉米收获至翌年春玉米播种)耗水是节水的关键所在。常规露地条件下一年两熟农田水分亏损两年累计616.6~799.0mm,两年三熟比一年两熟可减少农田水分亏损38.6%~55.8%,覆盖比露地减少56.8%~73.5%,在年均降水560mm条件下土下微膜覆盖结合两年三熟基本可实现地下水和农田水分的平衡。土下微膜覆盖和减少熟制可有效平衡土体水分垂直分布、减少土壤表层水分损失。实施周年农田土下微膜覆盖结合小麦玉米两年三熟种植,是有效缓解华北水资源危机与稳定粮食生产的新型实践方法。

土下微膜覆盖与灌水管理对冬小麦水分利用与物质生产效果的影响

针对华北平原小麦生产水资源高耗与存量极度稀缺的问题,通过河北省两地大田试验,研究了全田土下微膜覆盖与不同灌水管理对冬小麦水分利用和物质生产效果的作用。结果表明,土下微膜覆盖条件下,冬小麦雨养或少量灌水消耗了占常规生产（对照）2/3-3/4的耗水量,生产了不少于7500 kg hm^–2的籽粒产量；籽粒产量水分利用效率达到24.8-26.5 kg mm–1 hm^–2,较对照提高28.3%-41.0%。与对照相比,生物产量水分利用效率高峰由抽穗扬花期提前至拔节期,且提高1.3-2.7倍,雨养或少量灌水还可有效提高小麦收获指数。土下微膜覆盖下的土壤贮水消耗速度变缓,2 m土体贮水量播种时不小于600 mm就可满足小麦的全生育期耗水,壤质土壤供水量为212.2 mm,黏质土壤供水量为230.0 mm。土下微膜覆盖下,雨养或扬花前少量灌水能够显著促进花后20 d内的净光合速率,蒸腾速率减小同步显著提高光合水分利用效率,但在灌浆中期灌水则对提高净光合速率及光合水分利用效率无意义。在华北平原,全田土下微膜覆盖雨养或适时少量灌水是大幅降低小麦耗水和提高水分利用效率,保证小麦产量的有效方法。

土下覆膜与适宜灌水提高冬小麦水分利用率

为缓解河北平原区水资源匮乏与小麦生产水分高耗的特征性矛盾,该文采用大田试验方法,设置土下微膜覆盖结合拔节期灌水75 mm、抽穗期灌水75 mm、灌浆期灌水75 mm、雨养,露地条件下雨养和常规生产(CK)共6个处理,定位研究了连续3个生长季的土下微膜覆盖与不同时期灌水对冬小麦用水与产量形成的效果。结果表明,采用土下微膜覆盖种植小麦,基本苗数和有效穗数较CK分别降低了8.6%~12.0%和7.4%~11.7%,拔节至抽穗期75 mm灌水保证了覆盖下小麦生物产量形成及穗粒数、粒重的提高。土下微膜覆盖并适时灌水75 mm,开花后营养器官干物质向籽粒转运量比CK提高37.2%~57.3%,对籽粒贡献率提高4.7%~10.1%。土下微膜覆盖结合抽穗前一次灌水,全生育期田间耗水减少99.9~118.9 mm,用占CK 3/4的耗水量生产了与其相当的籽粒产量,水分利用效率提高26.1%~34.5%。回归分析表明,土下微膜覆盖下拔节-抽穗田间耗水118 mm可获得最高的生物产量,抽穗-灌浆耗水78 mm可获得15个以上的结实小穗数和灌浆期不小于5的叶面积指数,从而籽粒产量得以有效维持。2 m土体贮水随小麦生育进程和种植年限的推进而呈现亏损态势,而且趋近地表土壤水分亏损就越多。从第2季开始,持续干旱导致覆盖下灌浆期灌水对提高产量已不具有作用,反而增加耗水,灌溉时间前移可增加产量并提高水分利用效率。播种时土壤贮水较上季小麦收获时大幅增加,播种-拔节期间土壤贮水保蓄是小麦节水生产的关键,土下微膜覆盖则可实现麦田土壤贮水的秋冬保蓄、春季供应的跨季节调用。在河北省小麦产区,土下微膜覆盖结合春季适时少量灌水是有效降低小麦耗水、提高水分利用效率和维持小麦产量的新型种植方法。

Effects of Different Plastic films Mulching on Soil Temperature and Moisture, the Growth and Yield of Sugarcane

[Objective] The effects of different plastic films mulching on soil temperature and moisture, and growth and yield of sugarcane were discussed in order to provide references for using different plastic film in sugarcane pro-duction. [Method]Four kinds of plastic films viz., normal colorless transparent plastic film, milky photodegradation weeding plastic film, black plastic film and gray-black plastic film were used in sugarcane cultivation by using no film mulching as the control. Soil temperature and moisture were measured during plastic film mulching period, and sugarcane agronomic traits such as emergence rate, tillering rate, plant hight, stalk diameter and effective stalk number were investigated during growth period, the cane yield and economic benefits were calculated during harvest period. [Result] The results showed that plastic film mulching could significantly increase soil temperature and moisture. Com-pared with the control, soil temperature was increased by 0.3-0.8 ℃ in three plastic films mulching treatment except for gray-black plastic film mulching. The soil moisture of all mulching treatments was 10.1%-17.4% higher than the control. Furthermore, the seedling emergence rate, tillering rate, effective stalk number and cane yield also could be improved using plastic film mulching,which were increased by 0.8%-9.9%, 20.6%-34.9%, 5190-10980 stalks/hm^2and6.4%-14.9% as compared to the control,while plant height and stalk diameter were found to be no significant effect by plastic film mulching. The results of benefit analysis indicated that, milky photodegradation weeding film mulching had the highest economic benefit, the second were normal colorless transparent plastic film mulching and black plastic film mulching, which were 5 987.2, 1 876.5 and 1 813.5 Yuan/hm^2 higher than the control. The gray-black film mulching treatment had poor benefit.[Conclusion] The milky photodegradation weeding plastic film could be vigorously extended in sugarcane production. Normal colorless transparent plastic film and black plastic film could be ex-tended gradually as a new kind of plastic film. The grayblack film should not be used for its higher cost and more thickness.

Effects of Plastic Film Mulching on Physical Characters of Soil and Yield and Yield Components of Sweet Potato

Field experiments were carried out to study the effects of plastic film mulching on soil physical characters, including soil temperature, soil moisture content and soil bulk density, and yield and yield components of sweet potato. The results showed that plastic filming mulching increased soil temperature. Considering the soil temperature-increasing effect, the treatments ranked as black plastic film treatment 〉 white plastic film treatment 〉 control. However, with the deepening of soil layer, the warming effect of plastic film mulching was weakened. Black or white plastic film mulching was conducive to low T/R value, especially in the early growth stage of sweet potato. Plastic film mulching significantly improved the storage root yield of sweet potato. In terms of yield-improving effect, the treatments ranked as black plastic film treatment 〉 white plastic film treatment 〉 control. The storage root num- ber per plant showed a downward trend, but the weight of single storage root was increased.

Soil Air Regime of Corn Field Under Plastic Mnlching

The effects of plastic inulching on soil aeralion at the soil dcpth uf 0-100 cm were studied in a corn tield.The resnlts indicated that the CO_2 concentration of unmulched soil in the 0-100 cm layer layer ranged from 0.00 1to 0.016 m￣3/m￣3, and that of mulched soil 0.002 to 0.018m￣3/m￣3, about 32.39% higher than the forrner on theaverage. Such a CO_2 concentration in the soil air is still suitable for crop growth. The O_2 concentration wasinversely correlated with CO_2 concentrat ion in the soil air ( unmulching r=-0.92￣(**), mulching r=-0. 79￣*). O_2concentration ranged from 0. 1 1 to 0. 17 m￣3/m￣3 in the mulched soil and 0. 1 3 to 0. 18 m￣3 /m￣3 in the unmulchedsoil. By contrast, N_2 concentration in soil air remained relatively steady, with no difference between the twotreatments. The relationship between the soil respiratory intensity and the depth of a soil layer appeared tobe a power function. At the layer of 0-20 cm, the soil respiration intensity in the mulched soil was obviouslyhigher than that in the unmulched. Plastic mulching could also affect soil structure. In comparison withthe unmulched soil, the content of >0.25 mm aggregate and 0.05-0.001 mm microaggregate in the mulched soil was reduced by 82.1% and 35.8%, respectively; the soil total porosity, gaseous phase rate and aerationporosity in the depth of 10-20 cm were reduced by 2.85%, 19.89% and 26.54% respectively, but contrary at the depth of 0-10 cm.