| Drought is main limiting factor of sustainable development in drylandfarming region. To seek a method of raising rainfall use efficiency and wateruse efficiency of crops has become an important content of dry farmingagricultural study. As a new soil management method in the arid, semi-aridand semi-humid drought area, mulch tillage could improve soil environmentby reduced tillage, no tillage, subsoiling and mulching, and then achieve thegoal of sustainability of soil quality for high and stable yield. Both fieldexperiments and physical and chemical assessment was employed withLatin square design to study effects of maize stalk mulching, perforatedplastic film mulching, returning corn stalks into the soil and open-groundplanting on some soil environmental factors and growth and development,physiological properties and the yield of maize. The result showed:1. Effects of maize stalk mulching on decreasing soil water evaporationand increasing the depth of rainfall permeation were obvious, whichprovided more water consumption for transpiration of the crops. Because ofno permeating water, plastic film mulching has the significant waterretaining and worse water storing effects. Because of raising humidity, soilwater content with plastic film mulching was lower than that of maize stalkmulching in the middle and lower layer of soil profile and it couldn't beenrestored even though it obtained a large number of precipitation. Effects ofwater retaining and storing of returning corn stalks into the soil was betterthan that of open-ground planting, although they had the drawback of waterconsumption for evaporation. At the same time, the results showed thateffects of retaining and storing water with different mulch tillagemanagements was not distinct because soil water content was lower in theearlier stage of crop growth. But water storage from 0 to 120cm depth ofmaize stalk mulching, perforated plastic film mulching and returning cornstalks into the soil was 235.9mm, 223.5mm and 214.8mm respectively,which was 33.1mm, 20.7mm and 12mm higher than that of open-ground planting respectively. Water consumption of maize stalk mulching,perforated plastic film mulching and returning corn stalks into the soil was37.9mm, 31.8mm and 14.9mm lower than that of open-ground plantingrespectively.2. Plastic film mulching treatment had marked effects of increasing soiltemperature, which had important applying value for earlier spring crops invery clod area. Maize stalk mulching had clear effects of decreasing soiltemperature in high temperature season and day variation of soiltemperature of maize stalk mulching became alleviative, which alleviatedinjury for the crops because of distinct variation of air temperature.Generally, soil temperature of returning corn stalks into the soil was higherin midday and lower in the morning and night than that of open-groundplanting, even though soil temperature effects of returning corn stalks intothe soil was not clear. Soil temperature differences among differenttreatments in seedling stage were more distinct than that in the booting stage.Soil temperature with plastic film mulching was higher 1.7～4.0℃in theseedling stage and 0.4～2.0℃in the booting stage than that of open-groundplanting on 5cm soil layer. Soil temperature with maize straw mulching waslower 2.2～7.7℃in the seedling stage and 2.2～5.3℃in the booting stagethan that of open-ground planting on 5cm soil layer.3. Maize stalk mulching significantly improved soil fertility, which notonly increased soil organic matter, total nitrogen and available nutrientcontents but also decreased the leaching of nitrate nitrogen of soil. Thus itcaused more nitrate nitrogen of soil keeping at soil layer that was favorableto assimilating nutrient of crops. Plastic film mulching quickened thedecomposition of organic matter and transformation and release of availablenutrient, which especially increased the contents of available phosphate.Effects of improving soil fertility with returning corn stalks into the soilafter one year was lower than that of maize stalk mulching. On 0～20cm soillayer, compared with open-ground planting, Maize stalk mulching andreturning corn stalks into the soil could increase soil organic matter by 3.47g/kg, 1.07g/kg, respectively, but plastic film mulching could decreaseby 0.36g/kg.4. According to the effects of different mulch tillage treatments on thecrop growth progress, crop growth condition, leaf area index of crops, cropnet photosynthesis rate and so on, maize stalk mulching and perforatedplastic film mulching had the relatively higher improvement effects on cropgrowth and development, but the improvement effects of maize stalkmulching mainly appeared in the middle and later stage of crop growth, andthe improvement effect of plastic film mulching mainly showed in theearlier stage of crop growth. The improvement effects of returning cornstalks into the soil on crop growth and development were limited or notsignificant. Effects of increasing the corn yields with maize stalk mulchingwas significant in comparison with open-ground planting. And the cornbiological yields and economic yields of maize stalk mulching were11315.1kg.hm-2,4070.2kg.hm-2, which were 32.5%, 35.1% more than thatof open-ground planting respectively. In the period of heading stage of cornplastic film mulching was encountered serious drought, male ear can't drawentirely for a long time and time between the appearance of female and maleear was prolonged. It affected the pollination of corn seriously, whichresulted in the waste of corn biomass and the decrease of yield of corn, andeconomic yields were 73.6% lower than that of open-ground planting. Thecorn economic yields of returning corn stalks into the soil were 3.9% morethan that of open-ground planting, but they had not significant difference.The increases of corn yield with maize stalk mulching were due to theremarkable increase of grains per ear, but the decreases of corn yield withplastic film mulching were because of significant decrease of grains per earand 100-grain weight.Thus it can be seen that different mulch tillage treatments have differentenvironmental effects. Farmers can choose different treatments according tomajor problem to be solved by mulch tillage treatments and apply themrationally. At the same time, we can obtain the result that plastic film mulch should be carefully chosen and applied in semi-arid area. |
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