The course of fertilizer nitrogen uptake by rainfed sugarcane in Mauritius

• Published in: The Journal of agricultural science 1994-06, Vol.122 (3), p.385-391
• Main Authors: Kwong, K. F. Ng Kee, Deville, J.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Crops and Soils; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Nitrogen fertilization; Nitrogen, phosphorus, potassium fertilizations; Soil-plant relationships. Soil fertility. Fertilization. Amendments
• ISSN: 0021-8596; 1469-5146
• DOI: 10.1017/S0021859600067319

The patterns of N uptake and dry matter synthesis by sugarcane (Saccharum hybrid spp.) were studied at four locations in Mauritius with 15N–labelled ammonium sulphate (100 kg N/ha) applied either in a single dressing in September or in two split applications in September and the following February. More than 80% of the total N recovered at harvest (100–120 kgN/ha) was absorbed by the sugarcane during an active uptake period from October to January. Split application prolonged this active N uptake until April only and had no effect on dry matter accumulation. While total Nabsorbed by above-ground sugarcane showed no decline over time, 10–20 kg N/ha of the 15N–labelled N was lost from the green tops even when the N was applied on two occasions. The fertilizer N losses from above-ground sugarcane were, however, not evident when fertilizer N recovery with time was studied by the difference method. In view of the observed losses of fertilizer N from the aerial parts of sugarcane, measurement of fertilizer N recovery at harvest by the N isotope dilution technique underestimates fertilizer N uptake by sugarcane and attributes too large a fraction of N loss to denitrification/volatilization of NH3.