Effects Of Gravel Mulching Degree On Farmland Moisture And Growth Of Crop Rotation Systerm

Gravel mulching as a major agricultural measures, compared with the Comparison,It can effectively maintain soil moisture,suppress soil water evaporation, improve the soil environment, and Coordination nutrient supply,improve agricultural water use efficiency and production. Gravel mulching was applied to arid and semi-arid areas under different conditions of climate, geography, soil and etc. Field plot experiment was carried out to investigate the effects of gravel mulching degree on soil moisture dynamics, water consumption characteristic, water use efficiency, growth and development and crop yields in the whole growth period of summer maize and winter wheat in the crops rotation. In this paper, the field experiment had five coverage levels: CK, no gravel mulching,0 kg m-2;S2, the gravel mulching degree is 2 kg m-2; S4, the gravel mulching degree is 4 kg m-2; S6, the gravel mulching degree is 6 kg m-2; S8, the gravel mulching degree is 8 kg m-2. Each treatment were randomly arranged in 3 replicates per treatment. Main results have been drawn as follows through research and analysis:(1) In the crops rotation of summer maize and winter wheat field plot experiment, The results showed that gravel mulching can hold soil water storage and suppress evaporation, the increase of gravel mulching degree could improve soil storage ability for precipitation and irrigation, compared with CK, and the water storage capacity is mainly reflected in the 0~40 cm soil layer, followed by the 40~100 cm soil layer water storage,100~200 cm soil water storage did not change obviously. The gravel mulching improving soil water storage ability was observed mainly in seedling stage of summer maize and jointing stage of winter wheat in the crops rotation system, and the gravel mulching degree of 8 kg m-2 increased the soil water storage by 12.77% and 6.63% compared with CK respectively, and the effects was weakened because of the increased canopy and rainfall. The total water consumption was decreased during growing period approximately,and the water consumption coefficient was decreased with gravel mulching degree in the crops rotation systems. The water consumption percentage in each stage was increased with the increase of gravel mulching degree besides the period before jointing. Gravel mulching treatments significantly improved the WUE and PUE of summer maize and winter wheat. In the growing period of summer maize, WUE and PUE increased by 33.05%, 26.65%,and the winter wheat increased by 12.68%, 20.00% respectively. 2 years(2013-2015) of winter wheat field experiment results showed that with the change of growth stage in winter wheat, effect degree of gravel on crop growth increases firstly and then decreases. When the amount of Gravel mulching is 8 kg·m-2(S8), soil(0~100 cm) water storage capacity at winter wheat seedling stage significantly increased 13.28 ~ 22.02% compared with control group(P < 0.05), at the grouting period, there was no significant difference among different treatments, However, soil water storage capacity rises greatly 23.67~12.45% at mature period(P < 0.05). Summer maize experiment also showed that gravel mulching could maintain water at the beginning of crop growth by 12.8%, reaching the maximum at the jointing stage, and then became decreased because of canopy.(2) Gravel mulching treatment can promote crop growth, increase the amount of crop dry matter, leaf area, plant height, and with the amount of degree increase the effects more obviously. Dry matter weight and leaf areas of winter wheat increases firstly and then decreases, they respectively reached the peak at filling period and growth period, Dry matter weight of S8 respectively increases by 35.03% and 18.17% at filling stage, and there respectively were 10.79% increase and 10.00% increase. With the increase of Gravel covering in soil, the growth period of winter wheat was gradually shorten compared with none Gravel covering, and S8 was 1~5 d shorter than other treatments. A linear relationship between gravel degree and crop coefficient was found. The larger the amount of coverage, the higher the increases of the corresponding crop coefficient at different growing stages. Leaf area and plant height had a good regression relationship with crop coefficient, and thus corn evapotranspiration can be forecast during growth period. Gravel mulching made the growing period shortened, reaching a the maximum of nineteen days.(3) gravel mulching treatments, compared with CK, could significantly increase economic yields and biomass yields. The effects become enhanced when the mulching coverage was increased extonsively within the extent of this research. In the growing period of summer maize, economic yields and biomass yields increased by 4.45%~26.66% and 5.81%~25.78%,the winter wheat increased by 2.06%~15.34% and 2.32%~26.49% respectively. Therefore, the purpose to obviously increase soil water content, the yield of winter wheat and improve the growth and development of winter wheat could be realized when the amount of Gravel covering was 8 kg?m-2.