Plateforme des connaissances sur l'agroécologie

Effects of nitrogen application and intercropping on spatio-temporal distribution of soil inorganic nitrogen in pea-maize intercropping field

The aim of this study was to determine nitrogen use efficiency and reduce environmental pollution caused by excessive use of nitrogen fertilizer in pea-maize intercropping fields in irrigated areas of Hexi Corridor, Gansu Province. To that end, a field experiment was conducted in 2011 to determine the spatial and temporal distributions of soil inorganic N (Nmin) in orthic anthrosol soils under pea-maize intercropping at different N application rates (no application, 75 kg·ha-2, 150 kg·ha-2, 300 kg·ha-2 and 450 kg·ha-2). Soil samples were collected at 0-20, 20-40, 40-60, 60-80, 80-100 and 100-120 cm soil layer. Nmin concentrations were measured by flow analysis of extracted CaCl2.

The results showed that NO3--N was the major form of Nmin in orthic anthrosol soils with a concentration 7.55 times that of NH4+-N. During maize growth season, NO3--N concentration increased by 29.7%, 67.5%, 88.2% and 134.3% respectively under N rates of 75, 150, 300 and 450 kg·ha-2 over no fertilization treatment. Compared with that after pea harvest, NO3--N concentration decreased by 44.2% after maize harvest. Soil NO3--N concentration in the 0-120 cm soil layer under intercropped pea-maize decreased respectively by 6.1%-5.1% over that of each corresponding monocultured crop. The highest soil Nmin accumulation occurred in the 0-20 cm soil layer at different nitrogen application rates and growth stages. After pea harvest, Nmin accumulation in the 0-60 cm soil layer under intercropped pea-maize respectively decreased by 4.9%-1.9%, and in the 60 -120 cm soil layer by 10.8%-9.2% compared with that of each corresponding monocultured crop. After maize harvest, soil Nmin accumulation in the 0-60 and 60-120 cm soil layers under intercropped pea-maize decreased respectively by 28.2%-9.4% and 23.5%-12.5% over each corresponding monocultured crop. Also soil Nmin residue in the 0-60 and 60-120 cm layers under intercropped pea decreased respectively by 4.9% and 10.9% over monocultured pea.

The study showed that nitrogen fertilizer application significantly increased soil inorganic nitrogen concentration and accumulation with higher effect on soil NO3--N. Also, excessive N application resulted in environmental pollution in the study area. Pea-maize intercropping significantly reduced soil inorganic nitrogen concentration and accumulation. It was obvious that intercropping reduced soil inorganic nitrogen accumulation especially in the later growth stages of the crops.

Title of publication: Chinese Journal of Eco-Agriculture
Volume: 22
Issue: 12
ISSN: 1671-3990
Nombre de pages: 1397-1404
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Année: 2014
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Pays: China
Couverture géographique: Asie et le Pacifique
Langue: Chinese (Traditional)
Author: WU Kesheng , SONG Shangyou, LI Long, SUN Jianhao, BAO Xingguo, LI Weiqi
Type: article de journal
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