Could forage peanut in low proportion replace N fertilizer in livestock systems?

Abstract

Palisadegrass [Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster cv. Marandu] is widely used in Brazil and is typically managed with little or no N fertilizer, which often leads to pasture decline in the long-term. The current relationship between beef price and fertilizer cost in Brazil does not favor fertilizer use in pastures. Legume inclusion is an alternative to adding fertilizer N, but often legumes do not reach a significant proportion (> 30%) in pasture botanical composition. This study evaluated herbage responses to N inputs and pasture species composition, under intermittent stocking. Treatments included palisadegrass-forage peanut (Arachis pintoi Krapov. & W.C. Greg. cv. Amarillo) mixture (mixed), unfertilized palisadegrass (control), and palisadegrass fertilized with 150 kg N ha-1 yr-1 (fertilized). Treatments were applied over two rainy seasons with five growth cycle (GC) evaluations each season. Response variables included herbage biomass, herbage accumulation, morphological components, total aboveground N of forage peanut (TAGNFP), and contribution of biological N2 fixation (BNF). Herbage biomass was greater for fertilized palisadegrass [5850 kg dry matter (DM) ha-1] than for the palisadegrass-forage peanut mixture (3940 kg DM ha-1), while the unfertilized palisadegrass (4400 kg DM ha-1) did not differ from the mixed pasture. Nitrogen fertilizer increased leaf mass of palisadegrass (2490 kg DM ha-1) compared with the control and mixed treatments (1700 and 1310 kg DM ha-1, respectively). The contribution of BNF to the forage peanut ranged from 79 to 85% and 0.5 to 5.5 kg N ha-1 cycle-1. Overall, benefits from forage peanut were minimal because legume percentage was less than 10%, while N input in the system by N-fertilizer increased palisadegrass herbage biomass.

Intensive Production and Management of Marandu Palisadegrass (Urochloa brizantha ‘Marandu’) Accelerates Leaf Turnover but Does Not Change Herbage Mass

“…Thus, in pastoral production systems, soil N immobilization is predominant, explaining the decrease in the percentages of dead material with the intensification of the system in which N fertilizer was applied. In fact, a previous study observed that marandu palisadegrass pastures fertilized with N produced higher concentrations of N in the litter (7.9 ± 0.4 g kg −1 organic matter, OM), resulting in a lower C:N ratio (34.0 ± 2.8) than in unfertilized pas-tures (44.1 ± 2.8; [41]), which might have favored the decomposition of dead material by microorganisms.…”

Arachis species: High‐quality forage crops—nutritional properties and breeding strategies to expand their utilization and feeding value

“…ex A. Rich) R. D. Webster] (Longhini et al, 2021). However, forage peanuts provide limited nitrogen fertilization to palisade grass, and the mixed fodder does not reduce enteric methane emissions from crossbred dairy heifers (Berça et al, 2019; Longhini et al, 2021).…”

Sward characteristics, herbage accumulation and nutritional value of elephantgrass based mixed with or without pinto peanut

“…Thus, it is possible to reduce the use of nitrogen fertilizers, reducing nitrous oxide emissions (Macedo et al 2014). Several studies evaluating intercropping with this legume have shown promising results (Homem et al 2021, Longhini et al 2021, Pereira et al 2020), but there are few studies evaluating pinto peanut under grazing conditions. Despite the potential of intercropped pastures, the use of forage legumes has been decreasing on farms (Emater 2021).…”