On‐Farm Evaluation of the Improved Soil N_min–based Nitrogen Management for Summer Maize in North China Plain

Abstract

A gronomy J our n al • Volume 10 0 , I s sue 3 • 2 0 0 8 517 ABSTRACT Th e improved soil N min -based N management is a promising approach to precision N management, which determines the optimum side-dress N rates based on N target values and measured soil nitrate N content in the root soil layer at diff erent growth stages. A total of 148 on-farm N-response experiments, in seven key summer maize (Zea mays L.) production regions of North China Plain (NCP) from 2003 to 2005, were conducted to evaluate the N min -based N management compared to traditional farmer's N practices. Th e recommended N rates based on the improved soil N min method were not signifi cantly diff erent ( ≤31 kg N ha -1 ) from those determined by yield response curves (n = 13). Th e average N rate determined with the soil N min method (157 kg N ha -1 ) was signifi cantly lower than farmer's practice (263 kg N ha -1 ), while maize grain yield was 0.4 Mg ha -1 higher than farmer's N practice (8.5 Mg ha -1 ) across all sites (n = 148). As a result, the improved soil N min -based N management signifi cantly increased net economic gains by $202 ha -1 , reduced residual nitrate N content and N losses by 44 kg N ha -1 and 65 kg N ha -1 , respectively, and improved recovery N effi ciency, agronomic N effi ciency and N partial factor productivity by 16%, 6 kg kg -1 and 36 kg kg -1 , respectively, compared with farmer's N practice. We conclude that the improved soil N min -based N management can be applied for summer maize production in NCP for improved N use effi ciency and reduced environmental contamination.

On-farm trials of optimal fertilizer recommendations for the maintenance of high seed yields in winter oilseed rape (Brassica napus L.) production

“…Besides the seed yield of the 0-N plot and the plant-available soil N supply, the use of real-time monitoring via plant analysis or soil mineral N testing might provide a more timely reflection of the crop N demand to guide the N fertilization in each specific condition. Li et al (2012) showed that the use of a soil plant analysis development (SPAD) meter was the most suitable method for rapidly diagnosing the N status in rapeseed; soil mineral N testing has been widely used for the specific N management of upland crops (Magdoff et al 1990;Cui et al 2008). Based on the differences between the results of soil mineral N tests before fertilization and the critical soil mineral N content during this period (Peng et al 2013), synthetic fertilizer is then applied to match crop N requirements in quantity and synchronize in time and space.…”

“…Nevertheless, no yield responses to the regional fertilizer recommendation usually occurred. This is easy to understand because the supposition of implementing the regional fertilizer recommendation is similar soil nutrient supply and crop yield responses to fertilization among different fields (Mulvaney et al 2006;Cui et al 2008). However, greater variability of soil nutrient content is a frequent occurrence, especially for small farmers.…”

Long-term experiments for sustainable nutrient management in China. A review

“…Based on results from over 100 on-farm experiments across [2003][2004][2005] in the North China Plain, mineral N application rates by farmers for winter wheat (Triticum aestivum L.) varied from 120-729 kg N ha −1 , with a mean of 325 kg N ha −1 (Cui et al, 2008a), and varied from 96 to 482 kg N ha −1 , with a mean of 263 kg N ha −1 for summer maize (Zea mays L.) (Cui et al, 2008b (Zhen et al, 2006). The average N application rate for rice (Oryza sativa L.) in China was 193 kg ha −1 in 2006, but rates from 150 to 250 kg ha −1 are common now, and can reach 300 kg ha −1 in some places (Roelcke et al, 2004;Peng et al, 2010).…”

Long-term reduction of nitrogen fertilizer use through knowledge training in rice production in China

“…In 2006, China consumed 31 million tons of chemical nitrogen (N) fertilizer, accounting for about 32 percent of global N consumption (Heffer, 2009). Several studies have shown that in China, N-fertilizer use has been excessively used in grain production (Cai et al, 2002;Chen et al, 2006;Cui et al, 2008;Fan et al, 2007;Ma et al, 2008;Peng et al, 2002;Yan et al, 2012) and vegetable farming (Chen et al, 2004;He et al, 2009).…”