Effects On Different Treasures Controlling Runoff And Sediment Yield And Nitrogen&Phosphorus Transfer In The Sloping Land

In this paper, a dynamic monitoring on the characteristics of soil and water lossfrom2007to2011in a sloping farmland were conducted at a natural rainfall runoff plot inthe watershed of Jianshan river, Chengjiang, and combined with the indoor artificialrainfall simulated tests, aimed to study the effects of woil and water engineering and forestand grass treasures on controlling runoff\sediment yield, nitrogen/phosphorus transfer, andreduce rates by these different treasures compared with contrast, further analyzed thedynamic process of runoff/sediment yield, the rainfall-runoff process in sloping land,relationship between runoff/sediment yield and rainfall intensity, runoff time and fertilizerlevels; the characteristics of nitrogen and phosphate transfer, the relationship between thenitrogen/phosphorus transfer flux and rainfall intensity, fertilizer levels, which are ofimportant significance on soil erosion, non-point source pollution control and ecologicalconstruction guidance. The conclusions are as follows:(1) There was a significant difference between runoff/sediment yield and precipitations,rainfall intensity. The relationship is linear equation and power function equation.(2) The planting grass strip treasure made the initial runoff time lagged3′6″~18′28″, therunoff and soil erosion content increased with the increase of rainfall intensity, in thecondition of planting grass strip treasure, the runoff and soil control rate was3.3%~59.81%and39.66%~83.51%, the function was highest in the small rainfall.In the signal natural rain event, under the function of the accordant reverse-slopeterrace regulated treasure, it clearly reduced about1.10%than that without regulatedtreasure on the rainfall season precipitation, the runoff control rate61.90%, and the soilerosion control rate was77.40%, under the function of the wide grass strip regulatedtreasure, it clearly reduced about20.55%than that without regulated treasure on therainfall season precipitation, the runoff control rate72.70%, and the soil erosion controlrate was81.28%, under the function of the narrow grass strip regulated treasure, it clearlyreduced about58.14%than that without regulated treasure on the rainfall seasonprecipitation, the runoff control rate was86.65%, and the soil erosion control rate was93.08%. These soil and water conservation treasures had a significant function to controlsoil and water lose, it was better to control soil erosion lose, and the grass strip in the different position in the sloping land has different function, too.(3) The majority of nitrogen form in the runoff nitrogen erosion was NO-3-N, the averageof NO-3-N concentration in the total nitrogen concentration was21.28~88.36%, theNH+4-N concentration in the total nitrogen concentration was very lower, only3.39~22.28%, the max value of the sum of NO-3-N and NH+4-N was near1, and theNO-3-N concentration was1.3~16.9times of NH+4-N concentration; PO34-concentration inthe total phosphorus concentration was different in the different fertilizer levels, andincreased with the increase of fertilizer levels, the range variation was1.47%to87.41%.Though under the function of the different soil and water conservation treasures, thenitrogen/phosphorus transfer concentration in the runoff was higher or lower than that inthe contrast sloping land. Under the condition of accordant reverse-slope terrace, thecontrol rate in the runoff transfer flux of TN, NH+4-N and TP was51.04%,45.77%and57.40%, respectively, the control rate in the sediment transfer flux of TN, hydrolysis N, TPand available P was81.10%,90.93%,92.37%,88.00%, respectively. Under the conditionof wide and narrow grass strip, the control rate in the runoff transfer flux of TN, NH+4-Nand TP was81.23%,78.25%,71.36%and81.68%,59.50%,82.03%, respectively, and thecontrol rate of wide/narrow grass strip on the nitrogen/phosphorus transfer flux in thesediment was90.34%~98.43%and57.43%~94.30%, respectively.The planting grass stripcan control nitrogen and phosphorus transfer flux effective, the control rate was64.31%~91.10%and47.32%~96.64%.(4)The control function of accordant reverse-slope terrace in interflow nitrogen/phosphorustransfer concentration and nitrogen/phosphorus content in the soil was different, it simulateor suppress the transfer concentration, at the same time. Under the condition of differentrainfall intensity and different fertilizer levels, there was difference betweennitrogen/phosphorus transfer concentrations in the different soil layer, planting grass stripcan reduce or increase the transfer concentration.