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Northwest University of Science and Technology (2008)

Residual Nitrogen in Soil and Its Utilization in Dryland

Cheng Jie

Titre : Residual Nitrogen in Soil and Its Utilization in Dryland

Auteur : Cheng Jie

Grade : Master’s Theses 2008

Université : Northwest University of Science and Technology

Résumé
Nitrogen fertilizer in China continues to grow, the the increasingly serious residual nitrogen in the soil , especially dry farmland calcareous soil residual NO3 - N cumulative amount becomes more obvious . The study of different factors on soil residual nitrate nitrogen and its effective utilization , improve N fertilizer use efficiency , reduce production costs , and the protection of the ecological environment and promote the continued development of the agricultural and economic significance . In Binxian and Yangling , Shaanxi , two field positioning test , the experimental study crop cultivation mode , nitrogen application and planting density on soil NO3 - N residues and crop nitrogen uptake of wheat and alfalfa two kinds of different crops on soil residual nitrate utilization differences , in order to provide for the use and management of dryland soil nutrient scientific basis . The study made ??the following main results : 1 mulching and furrow planting could increase wheat grain yield and grain N uptake , straw mulch had no significant effect on wheat yield and N uptake . After four years of continuous cultivation of wheat , soil 0 200 cm residual nitrate 29.87 462.59 kg/hm2, mainly accumulated in the 80 140 cm soil layer , the cumulative depth compared to the previous three years was Down trend , the cumulative amount of increased significantly over the previous three years . Film mulching promote soil organic matter mineralization and significant increase of 0 200cm soil residual nitrate in the furrow planting and straw mulch mode can reduce the amount of residual soil nitrate . Residual nitrate nitrogen with increasing nitrogen rate increase : After four years of winter wheat planting , N0 process 0 200 cm soil residual nitrate in 57.69 kg/hm2 N120 processing an average of 97.04 kg/hm2, N240 processing an average of 355.43 kg/hm2, reached a very significant difference in the level of 120 kg/hm2 processing with no N fertilizer and nitrogen fertilizer . Planting density of soil residual nitrate accumulation in no significant impact . 3 years after planting alfalfa , 0-300cm soil residual nitrate reduced 75.5% , reduced nitrate from soil 100cm ; residual nitrate in the soil after planting three quarters of wheat decreased by 71.6% , reduced nitrate mainly from soil 200cm above the soil

Mots clés : Mulching Straw mulch Furrow mode Nitrogen rate Planting density Residual NO3 - N Winter Wheat Alfalfa

Présentation (Dissertation topics)

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