有机无机肥配施对江苏滨海盐碱土农田生产力和碳库的影响.

[Objectives]Combined application of organic with inorganic fertilizers technology is the main effective soil improvement way in mild saline-alkali land. The objective of this paper was to investigate the effects of different organic fertilizers partial substitution for chemical nitrogen(N)fertilizer on crop yield and soil carbon pool in maize cropping system, and find out the best ratio of organic fertilizer substitution to increase crop yield and improve carbon sequestration efficiency in farmland under smashing ridge tillage. [Methods]Field experiments on replacing nitrogen fertilizer with different proportions of organic fertilizer under the principle of equal nitrogen input in maize cultivation under the powder ridge cultivation mode were designed. Five treatments with local nitrogen fertilizer application as the control(CK), organic fertilizer substituted the whole chemical N fertilizer(CT100), 75% organic fertilizer substitution for chemical N fertilizer(CT75), 50% organic fertilizer substitution for chemical N fertilizer(CT50), 25% organic fertilizer substitution for chemical N fertilizer(CT25)were formed. The measurement of maize agricultural productivity and soil carbon pool were determined. [Results]Compared with the full application of nitrogen fertilizer, when the proportion of organic fertilizer replacing chemical fertilizer was 25%-50%, the maize grain yield increased by 8.74%-11.21%. Especially 25% organic fertilizer replaced nitrogen fertilizer, the photosynthetic rate(Pn), stomatal conductance(Gs), transpiration rate(Tr), and intercellular CO2 concentration(Ci)of maize significantly increased. The soil total nitrogen(TN), total phosphorus(TP), total potassium(TK), as well as contents of available N, P, K all significantly increased. When the organic substitution ratio increased to more than 50%, there was no significant change in maize yield and soil nutrients compared with pure nitrogen fertilizer. Compared with pure nitrogen fertilizer, soil carbon storage increased by 9.47%-14.61% when the replacement ratio of organic fertilizer was 25%-75%, which was mainly dependent on the significant increase of soil organic carbon content and bulk density. There was a significant correlation between soil organic carbon content and maize yield. [Conclusions]Partial substitution of 25%-50% nitrogen fertilizer with organic fertilizer under smashing ridge tillage could significantly improve soil physical and chemical properties, increase soil carbon storage, and increase maize yield, which could be used as a recommended fertilization technique for maize cultivation in coastal dryland areas of Jiangsu Province. [ABSTRACT FROM AUTHOR]