Reducing Nitrogen Leaching from Agriculture: An Essential Step toward Protecting the Environment in High Rainfall Areas of Taiwan
2013
Adhikari, Keshav Raj | Chen, Zueng-Sang
Reducing nitrogen (N) leaching from croplands is important to protect environmental quality and improve recovery of applied N. To contribute to this broader goal of nutrient management, a simple pot experiment evaluated the potential differences among urea (250 kg N ha ⁻¹), urea+compost (125 kg N ha ⁻¹ from urea + 125 kg N from 8 Mg ha ⁻¹ of compost), compost (250 kg N from 16 Mg ha ⁻¹ of compost) and a zero control (Ctrl), in terms of their effects on apparent N recovery (ANR), mineral N (N ₘᵢₙ) leaching and soil retention of applied N. Cabbage (Brassica oleraceae L.) and corn (Zea mays L.) were grown in rotation where compost application was not repeated in the 2nd year. N ₘᵢₙ leaching was monitored by adding 83 mm and 62 mm of water fortnightly to cabbage and corn crops, respectively for a total of 28 times in a two-year period. Combined (urea+compost) and independent (compost) treatment application retained 1.5 to 2 times higher N, and lowered 2.1 to 4.6 times N ₘᵢₙ leaching, relative to independent (urea) application. We conclude that farmers’ practice of fertilization that has an inherent problem of N leaching for high rainfall areas in Taiwan could be improved by proper compost and urea combinations within agronomically recommended rates of N application.
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