Critical nitrogen dilution curves and productivity assessments for plant cane

Abstract

Nitrogen is the most limiting nutrient for the development of sugarcane and particularly the use of more productive and demanding varieties, for which the doses of nitrogen fertilization necessary during the plant cane cycle may be underestimated and the critical levels of nitrogen in the leaf may be modified. The objective of this study was to determine the critical nitrogen dilution curve (CNDC) for leaves, evaluate the aboveground dry mass production (DM) and productivity of two varieties fertilized with N in the plant cane cycle. The study was conducted under field conditions, evaluating two sugarcane varieties RB92579 and RB867515, fertilized with seven doses of N (0, 30, 60, 90, 120, 150 and 200 kg ha-1). The varieties and doses were arranged in randomized blocks and analyzed in the 2 × 7 factorial scheme. It was found that the nitrogen concentration in the leaf decreased with four repetitions increase in DM yield and adjusted an exponential model, which enabled to estimate the critical levels of 13.03 and 12.46 g N kg-1 dry matter in the varieties RB92579 and RB867515, respectively. The plant cane cycle were observed to respond positively to nitrogen fertilization, with increase of 18.66% in tons of stalk per hectare (TSH) in response to the application addition of up to 129.45 kg N ha-1. The variety RB92579 showed the lowest dilution of the critical nitrogen concentration, the highest production of DM and higher stalk yield, and accordingly is considered to be the more efficient of the two varieties with respect to nitrogen fertilizer utilization.

Critical dilution curves for calcium, magnesium, and sulfur in potato (Solanum tuberosum L. Group Andigenum) cultivars Diacol Capiro and Pastusa Suprema

“…On the other hand, S is mainly found in amino acids, proteins, and as part of glutathione, whose need and synthesis rate may be lower than the growth rate (Moussa et al, 2018). The greater slope of Sc for Capiro may indicate that this variety is more efficient in the use of S than Suprema (Santana et al, 2020). The dilution in the Sc curve was similar to that previously established for N (Gómez et al, 2019b), confirming the interaction between the assimilation of S and N in relation to their function in protein formation (Kopriva & Rennenberg, 2004).…”

Dry Matter Accumulation and Sugar and Alcohol Yield of Sugarcane Submitted to Nitrogen Sources and Doses

“…These results corroborate those found by Rhein and Silva (2017), who observed linear increments of stalk yield up to a Nitrogen dose of 200 kg ha -1 in the form of urea. Santana et al (2020) concluded that the cane plant responded positively to nitrogen fertilization and increased the ton of stalks per hectare (TSH) by 18.66%, adding up to 129.45 kg ha -1 of N in the form of urea. In Figures 5A and 5B, it can be seen that the behavior of the gross sugar and alcohol yields were similar to that presented by the stalk yield, which shows that at higher N doses (180 kg ha -1 ), no difference between the use of ammonium nitrate or urea was found.…”

Estimation of leaf nitrogen levels in sugarcane using hyperspectral models

“…The results obtained using our models may be related to the variable response of the crop to nitrogen fertilization and the fact that canopy spectral data are influenced by factors other than nitrogen; therefore, nitrogen concentration is estimated indirectly (MIPHOKASAP et al, 2012). INOUE et High nitrogen levels in the soil due to mineralization of organic matter from the previous season can affect the relationship between the leaf nitrogen and biomass and;consequently, the spectral readings (SANTANA et al, 2020). Critical nitrogen concentration in dry biomass is the minimum amount of nitrogen required for maximum crop growth.…”