Decision-making on the optimum timing for nitrogen fertilization on sugarcane ratoon

Abstract

Low efficiency of nitrogen from fertilizers is a major concern worldwide, threatening the sustainability of sugarcane production. The N use efficiency (NUE) by sugarcane can be improved by adopting better fertilizing management practices, reducing environmental impacts.This work evaluated the effects of varying N rates and time of application on stalks and sugar yield in ratoon harvested early in the crop season. The experimental design was a randomized block in a 2 × 4 factorial design and a control (no N) with five replications, including two application times (45 or 90 DAH -days after harvest) and four N rates (50, 100, 150, or 200 kg N ha -1 ).The time of N fertilizer application promoted differences in stalk yield, as the cumulative yield of two harvests was increased by 8 % (15 Mg ha -1 ) at 45 DAH when compared to the application at 90 DAH. The application performed at 45 DAH augmented sugar yield by 10 % (2.8 Mg ha -1 of sugar) in relation to 90 DAH. The N rates that promoted the highest sugarcane yield were, respectively, 122 and 144 kg N ha -1 in the first and second crop cycles. The average economical rates obtained for the first and second agricultural cycles were, respectively, 104 and 127 kg N ha -1 , demonstrating that the gains by applying high amounts of fertilizers (rates above 150 kg N ha -1 ) may not cover the investment.

Multisite response of sugarcane to nitrogen rates and split application under Brazilian field conditions

“…Castro et al. (2019) also found that N application in the winter period was of little value in increasing sugarcane yield. The authors attributed this lack of yield gain from N fertilization in the dry period to the lack of soil moisture for fertilizer uptake.…”

“…In green sugarcane fields, a large amount of straw (range, 7–20 Mg ha −1 ) is maintained over the soil surface (Menandro et al., 2017), and this residue presents a C/N ratio as high as 128 (Almeida et al., 2016; Lisboa et al., 2018) and thus a high potential for N immobilization. However, several studies have failed to identify an improved response of green sugarcane to N compared with the past practice of burning sugarcane fields before harvest (i.e., no trash retention) (Castro et al., 2019; Mariano et al., 2017; Otto et al., 2013, 2016). Consistent with previous findings, an erratic response of sugarcane to N was observed in the current study (Figures 3 and 4; Supplemental Table S1).…”

“…Therefore, there is a lack of synchrony between N application and crop nutritional demand because N application occurs a couple of months before high N demand. Castro et al (2019) evaluated two periods of ratoon fertilization and found that N application under adequate soil moisture conditions favored N uptake and sugarcane yield compared with application in the dry period. However, they evaluated only the timing of fertilizer application, with no further investigation of split N application.…”

“…The principles of 4R nutrient management (right source, right rate, right time, and right place) for sugarcane have been studied extensively in recent years (Borges, Bordonal, Silveira, & Coutinho, 2019; Castro, Rossi Neto, Kölln, Borges, & Franco, 2019), but the lack of synchrony between plant N demand and N fertilization, which can also influence sugarcane NUE, has not been properly addressed. The sugarcane harvesting season usually extends from March to November under Brazilian conditions, and N application is often performed days or weeks after harvest for operational reasons.…”

Harnessing perennial and indeterminant growth habits for ratoon cotton ( Gossypium spp.) cropping

“…Ratoon cropping is the production of an indeterminate crop without sowing, and it is common in crops such as rice (He et al 2019), sugarcane (Castro et al 2019), pigeon pea (Grabowski et al 2019) and sorghum (Snapp et al 2019), as well as cotton (Komala, Kumar, and Ganesan 2019). Ratoon cotton is advantageous for sustainable development, and has been cultivated in many cotton-growing countries, such as Australia, Brazil, China, Guyana, Kenya, India, Israel, Pakistan, Peru, South Africa and the USA (Plucknett, Evenson, and Sanford 1970;Khan and Shabbir 1974;Bullen, Granger, and Persaud 1982;Macharia 2013;Khader and Prakash 2014;Zhang et al 2015a).…”