Optimum nitrogen fertilization rate and nitrogen use efficiency forBrachiariahybrid andMegathyrsus maximusvaries with stage of regrowth

Abstract

Background Traditionally, recommended nitrogen (N) fertilization rates that maximize biomass yield and nutritive value in tropical grass forages tend to be fixed and do not consider possible stage of maturity‐induced variations. Therefore, this study investigated biomass yield and nutritive value of Brachiaria hybrid and Megathyrus maximus at different stages of maturity in response to incremental levels of N fertilizer. Both grasses were fertilized with urea at rates equivalent to 0, 25, 50, and 75 kg N ha−1 and harvested after 4‐, 8‐, and 12‐week regrowth. Results Crude protein (CP) had a linear response to increasing N fertilization at all stages of regrowth. Herbage yield of M. maximus was optimized with 57.1–63.0 kg N ha−1, while herbage yield in 4‐weeks regrowth Brachiaria hybrid was optimized with 59.1 kg N ha−1. The combination of herbage yield, 24 h in‐vitro organic matter digestibility, and CP were optimized with 59.1 and 68.2 kg N ha−1 in 4‐weeks regrowth Brachiaria hybrid and 8‐week regrowth M. maximus, respectively. The efficiency of N fertilizer use for herbage and CP yield was highest with 25 and 75 kg N ha−1, respectively except for 8‐weeks regrowth Brachiaria hybrid. Conclusion It was concluded that the herbage yield and nutritive value of 4‐week regrowth Brachiaria hybrid and 8‐week regrowth M. maximus are optimized with 59.1 and 68.2 kg N ha−1, respectively, while all other stages of regrowth were optimized with 75 kg N ha−1.

Brachiaria Hybrid and Pennisetum purpureum Supplemented with Pueraria phaseoloides Increased the Concentration of Rumen-Undegradable Protein in Forages for Ruminants

“…The CP contents of Brachiaria hybrid in the present study were significantly lower than those of similar maturity and appended with 25-75 kg N/fertilizer/ha −1 [8], suggesting Brachiaria hybrid is highly responsive to N fertilization. The CP contents of EG.8 and EG.12 were low but are typical of the species for the stage of maturity [28].…”

“…However, a much higher proportion was observed in the present study, possibly because of the spatial distribution of N [38] and high cell wall contents in Kudzu herbage tissues. Additionally, fiber-bound N is associated with the rapid growth of tropical forages causing a reduction in the leaf:stem ratio and an incremental increase in fiber and lignin content [8]. Therefore, management approaches like nitrogen fertilizer application and harvesting forages at an earlier stage of maturity can reduce the accumulation of N in the cell wall.…”

“…Other important limitations are seasonal fluctuations in herbage availability and nutritive value [5] and their inability to supply the required amounts of rumen-undegradable protein (RUP) needed to support high-productivity ruminants [6]. It was previously demonstrated that properly managed grasses in the Caribbean can supply adequate quantities of crude protein (CP) [7,8]. However, most of the CP supplied by these grasses is rapidly degraded in the rumen to facilitate the synthesis of microbial protein [9] and contribute to N loss in urine.…”

Effect of using hydrogel polymers on morphometric, forage production, and nutritional characteristics of cactus pear

“…The plants will express greater nutritional value with the maximum potential for nutrient utilization. In agricultural scenarios, cultivating plants with forage potential, when there is no compromise in the supply of N, higher values of crude protein will be measured (Leite et al, 2021;Hughes et al, 2022). Leite et al (2018) verified that the increasing offer of N does not influence the morphology of cactus pear plants, however, when the supply occurs without the interference of abiotic factors, it generates positive effects on the concentration of crude protein in the cladode.…”

Comparison of Nutritive Values of Tropical Pasture Species Grown in Different Environments, and Implications for Livestock Methane Production: A Meta-Analysis

“…Even though the nutritive value changes due to these phenological and physiological changes were not disentangled in our meta-analysis, the relationships reported in Table 3 explain the typical changes in nutritive value of tropical pasture species during maturity. It is widely known that CP and DMD decrease as harvesting intervals increase [ 46 , 47 , 48 , 49 , 50 , 51 ], and that NDF, ADF, and ADL increase with increasing harvesting intervals [ 14 , 47 , 48 , 49 ]. This data set is also consistent with the previous literature.…”