Effects Of PAM Mixed With Urea On Soil And Apple Production In Weibei Rainfed Highland

With the purpose of promoting the practical application of PAM in agricultural field,understanding the effect of PAM in droughty orchard, and determining the technicalparameters of field application, this study researched the effects of PAM mixed with Ureaon soil infiltration, evaporation and nutrients leaching by soil column experiment, andstudied the influence of PAM mixed with Urea on soil and apple production in WeibeiRainfed Highland by orchard test. The main contributions are as follows:（1）The effect of PAM mixed with Urea on soil infiltration was investigated throughone-dimensional vertical infiltration in laboratory experiment. The results showed that bothPAM and Urea inhibited soil infiltration process. The inhibition effect of PAM on soilinfiltration was greater than that of Urea. The infiltration rate and cumulative infiltrationgradually decreased with the increase of PAM amount. The time attained to stableinfiltration state was significantly lasted with the increase of PAM amount. The infiltrationrate and cumulative infiltration were decreased with the increase of Urea amount. However,the difference caused by Urea was not significant when the ratio of PAM amount to soilwas more than0.1%. The Philip Infiltration Model provided the best description of therelationship between cumulative infiltration and elapsed time. Soil water content greaterwith the increasing of PAM amount, thus the effect of Urea soil water content was notsignificant. Therefore, PAM mixed with Urea in soil cores can reduce soil infiltrationprocess and deep water percolation, and increase soil moisture storage. PAM can easilykeep soil moisture and nutrients for the needs of crop growth. Thus, PAM as a reliablematerial increases water and fertilizer use efficiency and reduces the effect of fertilizerpollution on ground water. In the foregoing analysis, it would be better if PAM mixed withfertilizer were applied to the bottom of the arable soil layer in an agricultural field. The measurement can ensure water storage in arable soil layer, reduce deep water and nutrientpercolation, and inhibit soil evaporation.（2）The effect of PAM mixed with Urea on soil evaporation was investigated throughsoil column experiment. The results showed that when PAM and Urea were mixed usingwithin10cm in the soil column, under the level of P1, P2and P3, the effect of Urea onevaporation was not significant at the beginning, after12days, the evaporation decreasedwith the increase of Urea amount, besides, under the same level of Urea, the evaporationdecreased with the increase of PAM amount. When PAM and Urea were mixed using from10cm to20cm in the soil column, under the same level of PAM, the evaporation of N1wasthe biggest in the four levels of Urea, and under the same level of Urea, the evaporationdecreased with the increase of PAM amount. The total soil evaporation of deep applicationwas bigger than shallow application. Under the condition of shallow application, the dailyevaporation decreased rapidly in the first5days, then a slow decline in volatility from5to25days, and then tended to be stable. Under the condition of deep application, the dailyevaporation kept consistent grossly in the first10days, and then declined gradually, after25days, tended to be stable. In a word, both PAM and Urea inhibited soil evaporation. Theinhibition effect of PAM on soil evaporation was greater than that of Urea.（3）Through soil column experiment, and by spouted-spraying methods, this paperstudied the effect of PAM mixed with Urea on soil leaching. The results showed that theleaching amount of total nitrogen increased with the increase of Urea amount, besides, theleaching amount of the first time accounted for most of the total five leaching. In this study,only a few treatments showed the law that the leaching amount decreased with the increaseof PAM amount, most treatments showed the leaching amount increased at first and thendecreased with the increase of PAM amount.（4）Viewing the17-year-old fuji apple trees as test material, using completelyrandomized design with two factors and four levels to research the effects of PAM mixedwith Urea on soil and apple production in Weibei Rainfed Highland. The results showedthat: The shoot length, single fruit weight and the fruits’ transect diameter increased withthe increase of Urea amount. The weight of100leaves and the fruit yield increased at firstthen decreased with the increase of Urea amount. The shoot length, single fruit weight, thefruits’ transect diameter and the fruit yield increased at first then decreased with the increase of PAM amount, and the maximum was present to the level P3.The soluble solidscontent was higher in the treatment of P2N2and P4N4. The acid content was lower in thelevel P2. After leaching for one year, the nitrogen in the orchard soil had changed. Withinone meter, a part of treatments presented a law that the amount of nitrate nitrogen increasedwith the increase of Urea amount. The retention of PAM to Urea was the strongest in thetreatments of P2N1and P3N2. In this study, the best ratio of PAM and Urea is P3N2,namely the mass ratio of Urea to PAM is about6.