Effects Of Sand-Gravel Mulching On Soil Moisture Regime And Summer Maize Growth

Sand-gravel mulching technology is a very effective measure for conserving soil water and precipitation in arid and semi-arid areas.It can reduce ineffective water,coordinate the ratio between the soil evaporation and crop transpiration,improve water use efficiency and crop production.Field experiments were conducted to estimate the impact of sand-gravel mulching on soil water condition and summer maize growing and development in two seasons(2014 and 2015).The sand-gravel mulching treatments included five different levels(different covering depths of 0cm,1 cm,2 cm,3 cm and 4 cm,respectively).Two irrigation levels of 0 mm and 50 mm were applied.Therefore,a total of ten treatments(including five rainfed under mulching treatments named CK,S1,S2,S3,S4,and five irrigation-plus-rainfed under mulching treatments named WCK,WS1,WS2,WS3,WS4,respectively)with three replicates for each,following a randomized plot experiment design.Based on the two-year field experiment data,the influences of sand-gravel mulching on soil moisture change,evapotranspiration and summer maize growing and and development was analyzed systematically.The evapotranspiration under different sand-gravel mulching amounts/depths was estimated by single and dual crop coefficient models.Some main conclusions have been drawn as follows based on the above analysis:(1)The gravel-sand mulching mainly affected the soil water content of the shallow soil(0 ～ 40 cm).The deeper the sand-gravel mulching depth,the more obvious the water retention effect was.The sand-gravel mulching had obvious water storage and moisture conservation ability,which effectively improved the soil water storage in the 0～200 cm depth range.Under the condition of the same sand-gravel mulching depth,the increasing effect of soil water storage was better than that of rainfed-plus-irrigation because of the less the irrigation recharge,the more serious the water deficit and the more effective of sand-gravel mulching on storing and preserving soil moisture as well as reducing evaporation.(2)Ad the early stage of summer maize growth,the sand-gravel mulching had little effect on crop coefficients.The sand-gravel mulching accelerated the growth of summer maize from jointing stage,the growth of summer maize treated with sand-gravel mulching was faster than that of CK,and the transpiration of crops began to accelerate and gradually occupied the main component of evapotranspiration.Thus,the crop coefficient was increased.Compared with the single crop coefficient method,the dual crop coefficient method can accurately indicate the variations of summer maize crop coefficient with time under the sand-gravel mulching,especially the effects of rainfall and irrigation on summer maize crop coefficient.It provides an important reference basis for actual irrigation management.(3)The sand-gravel mulching promoted the growth process of summer maize,accelerated dry matter accumulation,increased the economic yield of summer corn,and increased yield obviously with the increase of sand-gravel mulching depths.The plant height,leaf area index,dry matter accumulation of aboveground part and grain yields for the sand-gravel mulching were all higher than that of control treatment.The sand-gravel mulching increased grain yield mainly by increasing the number of grains per panicle,and it increased with the increase of sand-gravel mulching depths.The dry matter accumulation and grain yield of summer maize for the treatment S4 increased by 49.79% and 22.29%,respectively,when compared with CK,which indicated that sand-gravel mulching techonology had obvious effects on increasing the yields of summer maize.