Optimizing nitrogen fertilization for forage maize production to maximize profit and minimize environmental costs in a rainfed region in China

ABSTRACT

Appropriate nitrogen (N) fertilizer application can improve crop yield, increase N-use efficiency and reduce environmental pollution. A two-year field experiment was performed to explore the influences of N fertilizer rates on dry matter yield, crop N removal, N-use efficiency and apparent N budget. Five N application rates, i.e. 0, 70, 140, 210 and 280 kg N ha⁻¹ (referred to as N0, N70, N140, N210 and N280) were tested. The application of fertilizer N markedly increased the dry matter yield of forage maize, which was highest for N210 with a two-year average of 22.6 t ha⁻¹. The N210 treatment increased crop N removal by 34.9% on average compared with N0. As the N rate increased, soil nitrate-N accumulation increased exponentially, apparent N loss increased linearly and agronomic efficiency clearly decreased. The apparent N loss and soil nitrate-N accumulation decreased by 19.4% and 19.0%, respectively, and partial-factor productivity increased by 24.5% under the N rate that maximizes profit (195.1 kg ha⁻¹) in comparison with those under the N rate that maximizes yield (244.4 kg ha⁻¹). The N rate (195.1 kg ha⁻¹) is recommended to maximize profit and minimize environmental costs in forage maize production in the semi-arid region in China.

KEYWORDS:

• Forage maize
• dry matter yield
• nitrate accumulation
• N-use efficiency
• N budget

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was financially supported by the National Key Research and Development Plan (2021YFD1100501), Natural Science Foundation of Gansu Province (21JR7RA488) and the Fundamental Research Funds for the Central Universities (lzujbky-2021-14)