| The Loess Plateau is the main dry rain-fed agricultural regions in northern China.The annual rainfall is less but relatively concentrated.The main problem is the scarcity of water resources,uneven characteristic of rainfall,low temperature and cold damage during sowing time,which limited the growth potential of spring maize yield in this region.In order,to solve these problems,a 2-year field experiment was conducted from 2015 to 2017 at the Changwu Agro-ecological Experimental Station of the Chinese Academy of Sciences on the Loess Plateau,China.’Xianyu 335’was selected as tested cultivar,and the trial was arranged in the two-factor of film-covering periods and modes with randomized block.Five different treatments,namely traditional flat planting(CK),before sowing semi-film flat covering(SP-S),the autumn semi-film flat covering(SP-A),before sowing whole mulching of double ridges(WP-S)and the autumn whole mulching of double ridges(WP-A),were conducted in the experiment,respectively.The objective of this study was to explore the effects of interaction of film-covering periods and modes of soil moisture,temperature,nutrients,growth and yield of spring maize.The principal results of this research are as follows.(1)Film mulching could significantly increase the soil moisture content of 0~80 cm soil depth in the early growth period of spring maize,and the effect of autumn mulching was better than the mulching before sowing,and the whole mulching of double ridges was better than the semi-film flat covering.With the advance of the growth period and intensification of crop transpiration,the soil moisture content of the mulching treatment gradually becomes less than that of traditional flat planting.The mulching film increased the water consumption of the spring maize during its growth period,and the water consumption pattern changed to “low in early period-high in medium period-low in late period”,which promoted more water using dry matter accumulation.the autumn whole mulching of double ridges(WP-A)maximized the rainfall accumulation in the fallow period and reduced the evaporation of soil moisture,which supplements the high water consumption during the growth period of spring corn infilm-covering,and not only does it increase production,it does not worsen soil moisture in the next crop.The water storage during the fallow period of 2015~2016 and 2016~2017 increased by 16.13 mm and 86.35 mm respectively over CK.(2)Compared with the uncovered treatments,the mulching treatment significantly increased the soil temperature in the early growth stage and improved the germination and emergence of the corn seed.In different mulching treatments,the autumn whole mulching of double ridges(WP-A)could reduce soil temperature diurnal variation of 5 cm and 15 cm of soil layer.With the advance of the growth period,the warming effect was gradually weakened,and the soil temperature between different treatments was not significant.(3)Soil nutrient content in spring maize harvest decreased with the deepening of the soil layer.Nitrate nitrogen and ammonium nitrogen decreased significantly,total nitrogen and organic matter trend is not obvious.In the harvesting period,the average soil content of total nitrogen from 0 to 100 cm in mulching treatment was higher than that in flat land,but the difference was not significant.(4)Compared with the uncovered treatments,the height of the autumn whole mulching of double ridges(WP-A)was significantly increased during the whole growth period,and LAI was significantly higher than CK within 70 days after sowing.The dry matter accumulation at each growth stage and the SPAD value at the grain filling stage of the mulching film treatment were higher than that of CK,and the effect of autumn mulching was better than the mulching before sowing,and the whole mulching of double ridges was better than the semi-film flat covering.The ratio of plant parts occupying the whole plant dry matter was expressed as grain > stalk > leaf > cob axis,temporal leaf.(5)Film mulching could increase the number of effective panicles,grains per panicle and100-grain weight of spring maize,which increased the yield of the mulching treatment.Yield and water use efficiency of WP-A was significantly higher than that of CK and other treatments.And the water use efficiency of WP-A were higher than those of CK,SP-S,and SP-A.WP-S increased by 74.49%~102.20% 、 24.28%~42.29% 、 32.87%~45.29% and7.21%~7.50%.In conclusion,WP-A can become better the efficient cultivation pattern of the Loess Plateau Dryland rainfed agriculture areas. |
