Soil And Water Conservation Effect Of Different Tillage Measures On Sloping Farmland In The Loess Plateau

Loess Plateau is the main crux of the drought,soil erosion,soil fertility problems,resulting in the deterioration of agricultural environment,and adopt suitable soil tillage management measures is one of the ways to solve the problem.In this study,in a water-wind erosion region on the Loess Plateau,based on long-term experiments conducted in 2008-2016 using conventional tillage(CT),no-tillage(NT),straw mulching(SM),plastic mulching(PM),ridging and plastic mulching(RPM),and intercropped alfalfa(IN)methods without fertilization.Based on runoff and sediment erosion,soil nutrient status,soil water and heat condition,soil physical properties,factors of soybean yield in six different tillage measures,we explore soil and water conservation and nutrient maintenance effect of different conservation tillage measures,in order to select a new conservation tillage technology of area farming technology.It has important guiding significance for the soil erosion area of the Loess Plateau to sacrifice some of the grain yield,to obtain better effect of soil erosion control and prevention and control of non-point source pollution.The main results are as follows:(1)After runoff observation in 2015 and 2016 years,through the comparison of runoff and sediment size of each plot,plastic mulching,we can see that the ridging and plastic mulching,and intercropped alfalfa have good effect of soil and water conservation and runoff,the runoff is 61.05% ? 25.82% and 15.93% for conventional tillage,ediment erosion for conventional tillage is 55.03%?7.20% and 0.31%respectively.However,intercropping crop is more serious,although can produce a certain ecological benefit in water-wind erosion crisscross region,and in agricultural production should not be pushed.(2)From 2008 to 2015,the nutrient index of CK treatment was gradually decreased,and was lower than that of other treatments;the other tillage treatment available nutrient early rapid decline and later gradually stabilized,the available nutrient content was higher than that of CK;in addition to CK,the organic matter and total nitrogen content was not decreased,but showing a slow upward trend.In most years,organic matter,total nitrogen and available nitrogen,available phosphorus and available potassium content in ridge film mulching,straw mulching and other conservation tillage were significantly higher than that of traditionalfarming.In consecutive eight years of no tillage fertilization,soil nutrient showed the slope gradient distribution,soil nutrient index(0-30 cm)from the top to the bottom of the slope increased.(3)Conservation tillage has a great influence on the soil moisture of cultivated slope on the Loess Plateau.After the rain,IN and RPM significantly increased soil moisture in20-60 cm,infiltration and water holding capacity of IN and RPM treatment is good.In the whole growth period,0-100 cm soil moisture of straw mulching,film mulching and furrow ridge mulching was significantly higher than that of conventional tillage,showed significant advantages of water conservation,but the 0-60 cm water content in alfalfa intercropping was highest,but below 60 cm water content decreased sharply.For the soil temperature,at the seedling stage,mulching reduced soil and air exchange,so as to improve the soil temperature.At the crop growth process,mulching reduced water evaporation,thus soil temperature slowing down,thus we can increase soil water content to alleviate the harm of soil high temperature on the growth and development of plants.(4)Conservation tillage had no significant effect on soil physical properties,compared with conventional tillage,SM can reduce the surface 0-10 cm soil bulk density,and significantly improve total porosity of 0-10 cm surface soil,but had little effect on the deep soil,other tillage is not obvious.For the soil saturated hydraulic conductivity,alfalfa was the highest,followed by straw mulching.In the surface soil moisture saturation,water infiltration rate in alfalfa intercropping and straw mulching is faster.No tillage infiltration ability is the worst possible and long-term no tillage increased soil bulk density,caused soil compaction,is not conducive to the water seepage.(5)Combined with soil water and heat conditions,chemical properties and yield of soil physical properties,soil factors on the yield of soybean,soybean production in 2016 is RPM>SM>PM>CK>NT>IN.Study showed that conservation tillage could increase yield of soybean,furrow ridge mulching had the best effect,was 1.5 times higher than that of conventional tillage.When there is no manual input the fertilizer case,after 2008-2015 years of long-term tillage,compared to the 2008 yield,straw mulching,film mulching and other measures slowed down the decline of soybean.But alfalfa intercropping had severe cuts,some years even close to zero.In view of this,in the application of the ridge furrow planting cultivation measures in the basin to reduce soil erosion,reduce the loss of soil nutrients,has broad prospects for improving ecological environment.