Morphogenetic and structural traits of Ipyporã grass subjected to nitrogen fertilization rates under intermittent grazing

Abstract

This study examined the effects of annual nitrogen (N) rates of 100 and 200 kg ha-1 on the morphogenetic and structural traits of Ipyporã grass (Brachiaria brizantha × Brachiaria ruziziensis) under intermittent grazing during the seasons of the year. The experiment was laid out in a randomized-block design with two treatments and three area replicates. Ipyporã grass pastures were grazed by beef cattle. Morphogenetic and structural traits of the forage canopy were evaluated using the marked-tiller technique. Forage accumulation and tiller density (TD) were also evaluated. Significant interaction effects (P < 0.05) between N rates and seasons were observed for the rest period, leaf lifespan (LLS), phyllochron, stem elongation rate (SER) and final leaf length (FLL). During winter, the rest period was shorter (40 vs. 50 days) in the pastures fertilized with 200 kg ha-1 N. Conversely, in winter, the pastures fertilized with 100 kg ha-1 N showed higher LLS, SER and phyllochron values, but lower FLL values. There was no isolated effect of N rates (P > 0.05) on forage accumulation rate; leaf appearance, elongation or senescence rates; leaf:stem ratio; or TD. However, the effect of seasons was significant for these variables, with the highest values occurring during spring and summer. The use of 200 kg ha-1 N in Ipyporã grass pastures reduces the seasonality of forage production.

Investigating the effects of Brachiaria (Syn. Urochloa) varieties on soil properties and microbiome

“…However, most BI variety studies focused on plant productivity and their potential for animal nutrition (Valle et al, 2017;(Camargo et al 2022). Our results indicated that the BI variety also presented a higher association with the fungi community, highlighting its potential to recruit the soil microbiome to help its nutrition.…”

“…In addition, we also found an increase in soil porosity and a decrease in soil bulk density. Forage grasses, in general, have a high potential to accumulate leaf nutrients and produce high plant biomass (below-and aboveground), but some varieties require soils with high fertility and N amendments to maintain their growth (Valle et al, 2017;(Camargo et al 2022). In addition, the BI variety had more microbial N-xers than the Control but less than the BR variety, as well as, had a smaller in uence on the accumulation of SOC compared to other treatments.…”