Abstract
The experiment evaluated the morphogenesis and structure of Tifton 85 (Cynodon spp.) cultivated in subtropical climate and fertilized with nitrogen (N). The experiment was a completely randomized design with four levels of N (Zero; 75; 150 or 225 kg ha-1) in nine replicates per area. The experimental animals were Suffolk female lambs. The grazing method was continuous to maintain the sward height at 15 cm ± 10%. The stem expansion increased by 0.000027 cm degree-days-1 to each kg N applied (linear model). According to nonlinear model, the highest stem expansion (0.0226 cm degree-days-1) was observed with the use 220.1 kg ha-1 N. The leaf lifespan fitted a linear regression model, with increase of 50 degree-days leaf -1, comparing the levels zero and 225 kg ha-1 of N. According to nonlinear regression model, the longest leaf lifespan (407.1 degree-days) was observed with the use 208.8 kg ha-1 N. With the maintenance of sward height at approximately 15 cm, we recommended to use 200 kg ha-1 N in Tifton 85 cultivated in subtropical climate.
Highlights
Low production rates in pasture areas are one of the causes of low profitability and competitiveness of animal production systems compared to other agricultural production systems (Moreira et al, 2015)
This study aimed to evaluate the effect of nitrogen levels on morphogenesis and structure of Tifton 85 cultivated in subtropical climate
The sward height was maintained at 14.3 ± 1.1 cm and similar in all paddocks used to evaluate N levels (p > 0.05) and was in agreement with the experimental protocol
Summary
Low production rates in pasture areas are one of the causes of low profitability and competitiveness of animal production systems compared to other agricultural production systems (Moreira et al, 2015). The use of nitrogen fertilization in grass pastures is an alternative to intensify production systems by increasing the production of biomass. Forage accumulation process can be better understood through the effect of nitrogen fertilization on the morphogenesis of plants. Animal Sciences plant growth to reduce costs of fertilizers and the environmental contamination risk (Primavesi, Primavesi, Corrêa, Silva, & Cantarella, 2006). The effect of using N can be measured by herbage accumulation rate and the consequent total production of dry matter (Salvador et al, 2016). The magnitude of this response, can be better understood when the measurements are performed on individual tillers
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