Application of the end-of-season stalk nitrate test for a high-yield maize production system in Northwestern China

ABSTRACT

Excessive nitrogen application has caused serious environmental pollution under high-yield maize system in China. Our objective was to evaluate critical stalk nitrate (NO₃⁻) levels that support high yield (>13 Mgha⁻¹), but are not in excess. Optimal stalk NO₃⁻ concentration was determined by conducting seven nitrogen levels experiments in two high yield maize regions: Dongyang County (DY) and Wenshui County (WS). Optimal stalk NO₃⁻ concentration category range to obtain maximum yield in DY (sandy loam, higher accumulated temperature and solar radiation compared with WS) was 0.44–1.19, which similar to the criteria of US (0.70–2.0 g kg⁻¹). While for WS (loam soil, lower accumulated temperature and solar radiation compared with DY), optimal stalk NO₃⁻ concentration category range to obtain maximum yield was 1.95–4.15, greatly higher than the US criteria. These results suggested thatit is necessary to establish matching optimal stalk NO₃⁻ category ranges for different ecological regions in China.

KEYWORDS:

• critical nitrate concentration
• grain yield
• N translocation efficiency
• stalk nitrate test

Funding

We thank the China's International Science and Technology Cooperation Fund (2015DFA90990) and the Special Fund for Agro-Scientific Research in the Public Interest (201103003) for its financial support.