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Development of Regional Nitrogen Rate Guidelines for Intensive Cropping Systems in China.
- Source :
- Agronomy Journal; Sep/Oct2013, Vol. 105 Issue 5, p1411-1416, 6p
- Publication Year :
- 2013
-
Abstract
- The intensification of agricultural production has been accompanied by an overuse of N fertilization and has accelerated global N consumption in the last 20 yr. We undertook 269 on-farm demonstration trials to evaluate variations in the optimal N rate (ONR) and developed regional N rate guidelines for intensive wheat (Triticum aestivum L.)-maize (Zea mays L.) rotation systems in the North China Plain. Large variations in the ONR (coefficient of variation = 38~39%) were observed across the 269 fields, resulting from large variations in the initial soil NO<subscript>3</subscript>-N supply before sowing. A negative linear relationship between the ONR and initial soil NO<subscript>3</subscript>-N suggested that 1 kg soil NO<subscript>3</subscript>-N ha<superscript>-1</superscript> was equivalent to applications of 0.54 and 0.71 kg fertilizer N ha<superscript>-1</superscript> for wheat and maize, respectively. The current cropping system, with excessive N inputs and large variations in residual NO<subscript>3</subscript>-N in the top 90-cm soil depth (averaging 188 kg N ha<superscript>-1</superscript> season<superscript>-1</superscript> and ranging 20-987 kg N ha<superscript>-1</superscript> season<superscript>-1</superscript>), could be transformed with optimal N management to a steady state, in which the residual NO<subscript>3</subscript>-N content is maintained at about 90 to 100 kg N ha<superscript>-1</superscript>. Regional N rate guidelines should be 154 to 159 and 164 to 171 kg N ha<superscript>-1</superscript> for yields of 6 and 9 Mg ha<superscript>-1</superscript> for wheat and maize, respectively. This regional N rate guideline may not be completely accurate but is a robust and simple guideline acceptable to the 100 million smallholder farmers in China. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00021962
- Volume :
- 105
- Issue :
- 5
- Database :
- Supplemental Index
- Journal :
- Agronomy Journal
- Publication Type :
- Academic Journal
- Accession number :
- 108642824
- Full Text :
- https://doi.org/10.2134/agronj2012.0398