Dynamics of Fertilizer Nitrogen Applied to Sweet Sorghum (<i>Sorghum bicolor</i> (L.) Moench) in the Semi-Arid Tropics

Abstract

Although sweet sorghum is in focus as a promising multi-purpose crop in semi-arid tropical regions, information on optimum nitrogen (N) management remains rather limited. To determine and understand the N dynamics in sweet sorghum-soil ecosystem, we evaluated the N recovery of applied fertilizer in the Alfisol field during the 2009 and 2010 rainy seasons. Sweet sorghum was grown under six N rates (0, 30, 60, 90, 120 and 150 kg N ha -1 ) with split application (at 0, 30 and 60 days after sowing) and N concentration and N recovery efficiency (NRE) were measured. In addition, to determine the fate of basal and topdressed N, . There was no significant difference in NRE calculated by the difference method between six N rates and N uptake rose with increasing N rate. The total dry weight and sugar yield increased at rates up to 90 kg N ha -1 and higher N rates did not significantly affect sorghum productivity. As a total of basal and topdressing applications, 33% of the applied 15 N-labeled urea was absorbed by the sorghum plant, while 36 and 30% remained in the soil and unaccounted for, respectively. The NRE calculated by the isotopic method was about 39 and 37% for topdressings at 30 and 60 days after sowing, respectively. The distribution ratio of absorbed N in leaves was higher for basal applications and topdressing at 30 days after sowing, while that in grains was higher for topdressing at 60 days after sowing, compared to the other application timings. In contrast to topdressings, the NRE was very low (13%) for basal N application: about 70% of the basal applied N remained in the soil at the physiological maturity. The results imply that the NRE might be increased by improving the ways in which basal N is applied. Discipline: Biofuel/Soils fertilizers and plant nutrition Additional key words:15 N-labeled urea, fertilizer application timing, nitrogen recovery efficiencyThis study was part of a research project titled "Development of sustainable soil fertility management for sorghum and sweet sorghum through effective use of biological nitrification inhibition (BNI)" and was funded by a grant from Japan's Ministry of Agriculture, Forestry and Fisheries (MAFF).

İkinci ürün olarak yetiştirilen bazı tatlı sorgum [Sorghum bicolor var. saccharatum (L.) Mohlenbr.] genotiplerinin verim ve verim ögelerinin belirlenmesi

“…Bu durum; Gülşeker, M81-E ve USDA Tayvan genotiplerinde oldukça belirgin bir şekilde kendini göstermektedir. Tatlı darı çeşitleri ile farklı ekolojilerde yapılan çalışmalarda KM verimlerinin 763.0-8456.3 kg/da arasında değişim gösterdiği rapor edilmiştir (Girgin, 2012;Khaled, 2013;Hiroshi et al, 2015;Avcıoğlu, 2018;Geren vd., 2019;Adıyaman vd., 2020;Kaplan, 2021;Öktem vd., 2021b). Çalışmada elde edilen KM verimlerinin literatürde belirtilen bu değişim aralığı içerisinde olduğu görülmüştür.…”

Agriculture in the Semi-Arid Tropics with Sustainable Use of Scarce Resources: Contribution of Japanese Scientists through Collaboration with ICRISAT

“…They collaborated with ICRISAT scientists of the Resilient Dryland Systems Research Program under the project title, "Development of sustainable soil fertility management for sorghum and sweet sorghum through effective use of BNI," for five years. These researchers elucidated that the N fertilizer use efficiency of sweet sorghum was as low as 13% to 40% (Uchino et al 2015) and the optimum N application rate was 90 kg ha -1 by examining agronomic N use efficiency and growth analysis parameters (Kurai et al 2015). These findings could aid development of a new N fertilization management guideline.…”