2014•Unpublished venueRequires access
Soil Nutrient Differences and Effects of Nitrogen Fertilization on Residual Nitrate Nitrogen in Soil Under Maize/Soybean and Maize/Sweet Potato Relay Strip Intercropping Systems
Wang Xiao-chu
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Abstract
This four-year field experiment integrated maize/soybean and maize/sweet potato relay strip intercropping systems to assess soil nutrient differences and effects of nitrogen fertilization on nitrate accumulation in the profile under various application of N fertilizers.It demonstrated that nitrate nitrogen accumulated in soybean grown soil was significantly higher than that in sweet potato grown soil.Results were opposite for the accumulation of ammonium nitrogen.By field located experiment of maize/soybean and maize/sweet potato relay strip intercropping for successive 3years,there was a significantly higher inorganic nitrogen accumulation in maize/soybean intercropping system and a significant decreasing in maize/sweet potato intercropping system.Furthermore,N concentration,N use efficiency and N harvest index of maize intercropped with soybean were significantly higher than that intercropped with sweet potato.For maize/soybean relay strip intercropping system in Shehong and Ya'an,nitrate nitrogen that accumulated mainly in0-60cm soil layer were higher(9.97% and 13.32%,respectively)than that in maize/sweet potato relay strip intercropping system.However,nitrate nitrogen concentrated in 60-120cm soil layer under maize/soybean relay strip intercropping in Shehong and Ya'an were 2.79% and 9.22% lower than that under maize/sweet potato intercropping respectively.Nitrate nitrogen concentration in soil profile increased with the increase of N fertilizer application rate.Results showed a significant interactive effect between plantingpatterns and N application rate on nitrate nitrogen concentration in soil.Nitrate nitrogen concentration in soil profile under maize/soybean relay strip intercropping system was significantly higher than that under maize/sweet potato intercropping in low nitrogen application level but no significance in high nitrogen level.Nitrate nitrogen concentration in 80-100cm and 100-120cm layers under maize/soybean intercropping was lower than that under maize/sweet potato intercropping,indicating that leaching losses of maize/sweet potato intercropping was greater than that of maize/soybean intercropping.