Optimized nitrogen rate, plant density, and irrigation level reduced ammonia emission and nitrate leaching on maize farmland in the oasis area of China

Aziiba Emmanuel Asibi; Wen Yin; Falong Hu; Zhilong Fan; Zhiwen Gou; Hongwei Yang; Yao Guo; Qiang Chai

doi:10.7717/peerj.12762

Optimized nitrogen rate, plant density, and irrigation level reduced ammonia emission and nitrate leaching on maize farmland in the oasis area of China

PeerJ. 2022 Jan 19:10:e12762. doi: 10.7717/peerj.12762. eCollection 2022.

Authors

Aziiba Emmanuel Asibi^#^{1

2

3}, Wen Yin^#^{1

2}, Falong Hu^{1

2}, Zhilong Fan^{1

2}, Zhiwen Gou^{1

2}, Hongwei Yang^{1

2}, Yao Guo^{1

2}, Qiang Chai^{1

2}

Affiliations

¹ State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou, China.
² College of Agronomy, Gansu Agricultural University, Lanzhou, China.
³ Council for Scientific and Industrial Research-Savanna Agricultural Research Institute, Bawku, Ghana.

^# Contributed equally.

Abstract

Nitrogen fertilizers play a key role in crop production to meet global food demand. Inappropriate application of nitrogen fertilizer coupled with poor irrigation and other crop management practices threaten agriculture and environmental sustainability. Over application of nitrogen fertilizer increases nitrogen gas emission and nitrate leaching. A field experiment was conducted in China's oasis irrigation area in 2018 and 2019 to determine which nitrogen rate, plant density, and irrigation level in sole maize (Zea mays L.) cropping system reduce ammonia emission and nitrate leaching. Three nitrogen rates of urea (46-0-0 of N-P₂O₅-K₂O), at (N₀ = 0 kg N ha^-1, N₁ = 270 kg N ha^-1, and N₂ = 360 kg N ha^-1) were combined with three plant densities (D₁ = 75,000 plants/ha^-1, D₂ = 97,500 plants/ha^-1, and D₃ = 120,000 plants/ha^-1) with two irrigation levels (W₁ = 5,250 m₃/hm² and W₂ = 4,740 m³/hm²) using a randomized complete block design. The results showed that, both the main and interaction effects of nitrogen rate, plant density, and irrigation level reduced nitrate leaching (p < 0.05). In addition, irrigation level × nitrogen rate significantly (p < 0.05) reduced ammonia emission. Nitrate leaching and ammonia emission decreased with higher irrigation level and higher plant density. However, high nitrogen rates increased both nitrate leaching and ammonia emission. The study found lowest leaching (0.35 mg kg^-1) occurring at the interaction of 270 kg N ha^-1 × 120,000 plants/ha^-1 × 4,740 m³/hm², and higher plant density of 120,000 plants/ha^-1 combined with 0 kg N ha^-1 and irrigation level of 5,250 m³/hm² recorded the lowest ammonia emission (0.001 kg N)^-1. Overall, ammonia emission increased as days after planting increased while nitrate leaching decreased in deeper soil depths. These findings show that, though the contributory roles of days after planting, soil depth, amount of nitrogen fertilizer applied and year of cultivation cannot be undermined, it is possible to reduce nitrate leaching and ammonia emission through optimized nitrogen rate, plant density and regulated irrigation for agricultural and environmental sustainability.

Keywords: Environmental sustainability; greenhouse gas; nitrogen application; sustainable cropping.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Ammonia
China
Farms
Fertilizers / analysis
Nitrates* / analysis
Nitrogen / analysis
Soil
Zea mays*

Substances

Ammonia
Fertilizers
Nitrates
Nitrogen
Soil

Grants and funding

This research was funded by the National Key Research and Development Program of China, (2021YFD1700204), Joint funds for Regional Innovation and Development of the Natural Science Foundation of China (U21A20218), and the ‘Double First-Class’ Key Scientific Research Project of Education Department in Gansu Province (GSSYLXM-02). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.