Effects Of Polyacrylamide Application On The Nitrogen's Move And Eluviation In Purple Sloping Field

Polyacrylamide(PAM),as an ameliorant of soil,can immobility surface soil and reduce the runoff,to preserving nitrogen in the soil at utmost.This study takes "source control" as fundamental point,adopt laboratory simulating and field experiments,research the effects of PAM application on the nitrogen's move and eluviation in the Three Gorges purple sloping field.Finally,we draw some conclusion as follows:(1)PAM had effect on the adsorption of NH₄⁺-N in evidence.The magnitude and direction is closely related to the dosage of PAM.Along with the dosage of PAM go larger,the effects of adsorption falls.When added the dosage for 0.1%(the percentage of soil)and 0.2%,the capacity of adsorption had increase 7.47%and 2.80%in average;but when overrun 0.2%,the adsorption of NH₄⁺-N reduced,compared with the control,the dispose added 0.4%had reduce by 4.71%.The equation of Langmuir,Freundlich and Temkin can reflect the reaction all-right(P＜0.01).Imitate by Langmuir can educe that,add PAM of 0.1%,the most adsorption compared with the control can increase to 1634.46μg/g.(2)PAM also had distinctly effect on moving and leaching of nitrogen,The impact is closely related to the dosage of PAM.Among the low dosage range(0.01～0.05%),restrain the uprightness-move of nitrogen,but when the PAM dosage was overrun 0.1%,had on effects or accelerated the leaching.Added PAM for 0.01%is strikingly,the cumulation of NH₄⁺-N and NO₃^--N in soluble liquid had reduce 12.43%and 18.08%compared with the control.The output of TN decreased by 16.97%compared with the control.The NH₄⁺ and NO₃^- in soil surface layer increased by 322%and 31.3%;in the substrate,The NH₄⁺ and NO₃^- decreased by 41.3%and 78.8%.PAM has good effects on keeping fertilizer and Anti-water-washing of nitrogen,but must notice its suitable dosage.(3)To the runoff loss of nitrogen,the use of PAM had good effects.Impact with the dosage of PAM,slope,rainfall intensity.Add calcareousness or plaster can strengthen the effects.When the slope is 15°,rainfall intensity is 33.7mm/h,vary dosage of PAM all can reduce the runoff loss of nitrogen effective.Compared with the CK(182.09mg),the loss of nitrogen which use PAM of 8g/m²,4g/m² and 16g/m² had decrease 53.28%,41.43%and 31.67%.Middling dosage had the best effect.NH₄⁺-N is the primary loss form,about 58.65%in total nitrogen.In the first rainfall, the dispose of 8g/m² had the least loss,compared with the CK decrease 73.04%,in the second rainfall,it's the dispose of 16g/m²,decrease58.44%.When the dosage of PAM is 8g/m²,rainfall intensity is 83.55mm/h,the loss of nitrogen in different slope disposal are:20°(275.21 mg)＞8°(235.01mg)＞15°(211.98 mg).The loss in 15°is reduce by 10.21%compared to the 8°,to the 15°sloping field,PAM has good effects.According to the nitrogen form,NH₄⁺-N and NO₃^--N has the same orderliness to the TN,NH₄⁺-N is the primary loss form,about 63.63%in TN According to the time of the rainfall,two rainfalls has no difference. In the drencher of 83.55mm/h,to the 15°sloping field,PAM has good control.When the dosage of PAM is 8g/m²,slope is 15°,the loss of nitrogen in different rainfall intensity are 83.55mm/h(217.76mg)＞17.10mm/h(140.88mg)＞33.7mm/h(85.08mg).To the moderate rain,PAM has good control in the loss of nitrogen,flurry and drencher go against. According to the nitrogen form,NO₃^--N is the primary loss form in flurry;NH₄⁺-N is the primary loss form in drencher;in the moderate rain,NH₄⁺-N and NO₃^--N are almost.To the moderate rain, the effect of PAM is incarnate in the first rainfall,the loss of nitrogen in the second rainfall is more than the first rainfall,but the flurry and drencher are reverse.The avail of PAM is being distinct influence.When the slope is 15°,rainfall intensity is 17.10mm/h,and the dosage of PAM is 8g/m²,added calcareousness can reduce the runoff loss of nitrogen,according to the PAM disposal(140.88mg) decrease 24.92%;Added plaster accelerate the loss,increase 55.95%.NO₃^--N is the primary loss form,about 63.28%in total nitrogen.The NH₄⁺-N and NO₃^--N in the calcareousness-added disposal are reduce 37.59%and 15.89%to the PAM disposal,the control effects for the NH₄⁺-N is better than NO₃^--N.The effect of calcareousness-added disposal is incarnate in the first rainfall,According to the PAM disposal(92.53mg)lessened 29.30%.In the second rainfall,the effects is tiny,the dosage of calcareousness maybe increase.PAM can influence the runoff production time,it delays as the dosage augment;when the slope increase,it ahead little.The two rainfall are same.According to the different slope,the use of PAM is very efficiency.The runoff production time which Added calcareousness and plaster also advance, add plaster is strikingly.(4)Use PAM and fortifier in the farm can decrease the runoff loss of nitrogen,and release permanence.The average concentration in runoff of PAM,PAM added calcareousness,PAM added plaster disposal,are reduce 13.58%,23.68%,30.84%Compared with the CK,added calcareousness is strikingly.Use PAM and fortifier also can decrease the leaching of farm nitrogen,The average concentration in soluble liquid of PAM,PAM added calcareousness,PAM added plaster disposal,are reduce 19.13%,21.29%,21.43%Compared with the CK,added calcareousness and plaster are unconspicuous.PAM can keep nitrogen in the farm field,added fortifier are better.After harvest crops,the concentration of nitrogen in the CK soil is debase 18.24%compared with plant crops.But the PAM,PAM added calcareousness,PAM added plaster disposal are increase 30.92%,40.19%,45.95%.PAM has the effects of increase production to wheat and potato,added calcareousness or plaster can strengthen the effects.The output of wheat in the PAM,PAM added calcareousness,PAM added plaster disposal can increase 8.95%,19.49%,34.72%compared with the CK;the output of potato also can increase 13.24%,29.68%,24.20%.