Research On Combined Application Of PAM And SAP On Hydraulic Characteristics And Water And Fertilizer Loss For Sloping Farmland In Arid Area

As two types of soil chemical regulation materials with significant soil fixing and runoff interception capability and soil water retention capability respectively,PAM(Polyacrylamide)and SAP(Super Absorbent Polymers)are of great significance for soil and water conservation and ecological protection in sloping cultivated land widely distributed in dry areas of the Inner Mongolia Autonomous Region.At present,the studies of PAM and SAP are concentrated on a single material according to their respective characteristics and certain application conditions,but the study on the combined application of PAM and SAP in the sloping farmland in dry areas has not been reported.In this paper,the effects of PAM and SAP on water infiltration and water and fertilizer loss for sloping farmland in arid area are studied through the combination of indoor and field experiments.The effects of PAM and SAP on the characteristics of soil water characteristic curve,infiltration rate,soil erosion amount,total nitrogen leaching amount,surface evaporation,yield and so on are discussed in different ways and means of intersection and application of PAM and SAP,surface slope,soil depth and so on.The results of the study are as follows:(1)Combined application of PAM and SAP has significant effects on soil water characteristic curve and infiltration.Under the same suction,the greater the amount of PAM and SAP,the greater the soil water content.With the increase of the amount of PAM and SAP,the steady infiltration rate and the cumulative infiltration of soil decrease.And the influence degree of PAM is greater than SAP.The effects of the 5 ways of application are compared: PAM mixed with SAP mixed > PAM spraying with SAP mixed > PAM spreading with SAP mixed > PAM spraying with SAP layer > PAM spreading with SAP layer.(2)With the increase of PAM and SAP application amount,soil and water loss,surface runoff and soil erosion decrease significantly,with a maximum decrease of about 80%.When PAM and SAP are applied to 5kg/ mu,the best effect is achieved.And the effect of PAM mixed with SAP mixed is more significant than PAM spraying with SAP mixed.In contrast,soil solid current interception capability of PAM is better than that of SAP.(3)Soil moisture content increase with the increase of the amount of application of PAM and SAP.The bigger the application amount of soil water,the more moisture could keep in the root layer.When PAM and SAP are applied to 5kg/ Mu respectively,soil moisture content reaches the maximum.And the water holding capacity of SAP is better than that of PAM.(4)Combined application of PAM and SAP has a significant effect on total nitrogen leaching and total nitrogen loss.The application of PAM and SAP in sloping fields effectively inhibits soil nutrient loss and keeps nutrients in 0-15 cm soil depth.When the amount of SAP and PAM application is 4kg/ Mu and 5kg/ mu,the leaching resistance is the best.(5)Combined of PAM and SAP could significantly increase the emergence rate and yield of potato.When SAP was applied to 4kg/ Mu,the yield was the highest and the yield increased to 30.12%.When PAM was applied to 4kg/ Mu,the yield was the highest and the yield increased to 32.56%.Moreover,PAM mixed with SAP mixed application had higher yield than PAM spraying with SAP mixed.All in all,the best technical mode for PAM and SAP application in sloping fields in typical arid areas is PAM mixed with SAP mixed,the amount of application is 4kg/ Mu respectively.