Effects Of Straw Mulching And Tillage Measures On Soil Water And Temperature And Maize Yield Formation In Black Soil Region

In order to reveal the response mechanism of soil water and temperature characteristics,physiological indexes of maize growth,yield formation and water use efficiency to straw mulching and tillage measures in northeast black soil area,corn feild in heilongjiang province is used as research subject under rainfed conditions.Five treatments were established: conventional tillage with no mulching(CK),conventional tillage with full-quantity straw mulching(CM1),no tillage with half-quantity straw mulching(NM0.5),no tillage with full-quantity straw mulching(NM1)and no tillage with 1.5 times-quantity straw mulching(NM1.5).Determining soil water,soil temperature,physiological and ecological indexes of maize and yield components,studying the change trends of these indicators of maize under different straw mulching amounts and tillage measures,revealing the effects of soil water and heat on maize yield under different straw mulching amounts and tillage measures,and putting forward straw mulching and tillage models that suitable for northeast black soil area to provide theoretical basis and scientific guidance for the application of conservation tillage in black soil area.The main conclusions were as follows:(1)Except for the soil layer of 40-60 cm in the seedling stage,straw mulching treatment can improve the soil water content,which increases with the increase of straw mulching.The soil water content under no-tillage treatment is higher than that under traditional tillage except for the jointing stage of corn.The soil water content under no tillage with 1.5-times straw mulching treatment is the highest in different soil layers and growth periods.Straw mulching treatment can increase soil water storage in the whole growing period of corn,which increases with the increase of straw mulching,and the soil water retention effect is the best under 1.5-times straw mulching,and the change of tillage has little effect on soil water storage.The effects of straw mulching and tillage measures on soil water consumption showed different trends in different growth periods.(2)Straw mulching treatment can affect soil temperature,and the response of soil at different depths is different.With the increase of straw mulching,soil temperature at different depths showed different change trends with the growth period.No-till can improve the soil temperature at different depth than traditional tillage,and the effect of 1.5-times straw mulching treatment on raising soil temperature is the most significant.Straw mulching treatment can raise the intensity of soil heat conduction and soil effective accumulated temperature,and reduce soil temperature difference.With the amount of straw mulching increase,the change trend of soil temperature gradient and soil temperature difference is not obvious,and the soil effective accumulated temperature except the seedling stage and jointing stage was increased.The response of soil heat transfer intensity and soil temperature difference to tillage method was different in different growing period,and compared with traditional tillage,no-tillage treatment can increase soil effective accumulated temperature The response of soil temperature to atmospheric temperature and soil water was the most obvious under 1.5-times straw mulching treatment.(3)Except the jointing stage,the net photosynthetic rate and stomatal conductance of maize leaves under no tillage with 1.5 times-quantity straw mulching were higher than those in the other treatments at other growth stages.Photosynthesis at each growth stage is affected by nonstomatal factors,and straw mulching can reduce the limitation of photosynthesis of maize leaves by nonstomatal factors.The maximum net photosynthetic rate,light saturat ion point,apparent quantum efficiency and dark respiration rate increased with an increase in straw cover quantity,increasing straw mulching can improve the light response characteristics of leaves effectively,such that the effect of no-tillage with 1.5 times-quantity straw mulching on the light response characteristics of maize leaves is optimal.(4)Straw mulching treatment can improve the maize yield components and water use efficiency of yield than bare land treatment,water use efficiency,hundred gr ain weight and yield increases with the increased amount of straw mulching,no-till treatment can significantly improve the corn grain yield,panicle weight,hundred grain weight and yield water use efficiency than traditional tillage treatment,leaf water use efficiency under different processing reduce gradually with growth stage.The yield,water use efficiency and economic coefficient of corn under no-tillage with 1.5 times-quantity straw mulching were better than those under other treatments.(5)There was a positive correlation between net photosynthetic rate of maize leaves with yield,and there was an exponential relationship between soil water in different soil layers with net photosynthetic rate of maize leaves at different growth stages.The effect s of soil temperature on net photosynthetic rate of maize leaves were significantly increased by straw mulching treatment,which increased with the increase of straw mulching amount.The yield of maize could be improved by increasing the soil water content in the 0-40 cm soil layer and the soil temperature in the 0-25 cm soil layer.There was a significant positive correlation between the water use efficiency under different treatments and the surface soil water conten t,but the correlation between soil temperature was not significant.