Produtividade e qualidade da brachiaria irrigada no outono/inverno

Abstract

RESUMO:Um dos fatores que determinam os baixos índices zootécnicos na pecuária brasileira é a estacionalidade da produção das plantas forrageiras tropicais. A irrigação pode proporcionar aumento e estabilização da produtividade durante o outono e o inverno. Objetivou-se pelo presente estudo avaliar: a) a produtividade de massa seca e qualidade de forragem de Brachiaria brizantha, em função de lâminas de irrigação, no período do outono e do inverno; b) a umidade do solo e a temperatura do ar a fim de determinar seus efeitos na produtividade de forragem. O experimento foi conduzido na Fazenda Experimental da FCAV-Unesp, em Jaboticabal-SP. Utilizou-se de um sistema de aspersão em linha para estabelecer tratamentos com cinco lâminas de irrigação correspondentes a frações da evapotranspiração de referência (L 1 = 0,18; L 2 = 0,52; L 3 = 1,00; L 4 = 1,45 e L 5 = 1,67), em duas estações do ano: outono e inverno. A produtividade de forragem foi mais elevada no outono, e a resposta de produtividade à lâmina de água foi ajustada por uma função quadrática, atingindo produtividades máximas com lâminas de 267 e 269 mm para o outono e o inverno, respectivamente. Alto valor nutritivo da forragem fo i obtido em ambas as estações do ano, com incrementos nos teores de proteína bruta com acréscimo da lâmina de irrigação somente no outono. As lâminas de água não afetaram os teores de fibra detergente neutro da forragem. PALAVRAS-CHAVE: Brachiaria brizantha, forragem, irrigação. HERBAGE YIELD AND QUALITY OF IRRIGATED BRACHIARIA IN AUTUMN AND WINTER ABSTRACT:One of the reasons of low performance of the Brazilian livestock industry include the seasonal growth of tropical pasture grasses. Irrigated grasslands may have higher and most stable rates of yield during autumn and winter seasons. Therefore, we aimed at evaluating: a) Brachiaria brizantha dry matter yield and forage quality as a function of different water depths during the autumn and winter, and b) soil moisture and air temperature effects on forage yield. The experiment was carried out at the Experimental Farm of the University of São Paulo State (FCAV -UNESP), campus in Jaboticabal -SP, Brazil. We used a line-source sprinkler system to provide five levels of irrigation (L 1 = 0.18, L 2 = 0.52, L 3 = 1.00, L 4 = 1.45, and L 5 = 1.67). These water depths corresponded to fractions of reference evapotranspiration in both autumn and winter. Forage yield was higher in autumn and water depth responses were fitted by a quadratic function, reaching maximum values at 267 and 269 mm during autumn and winter, respectively. During the autumn, we observed a highly nutritive forage with crude protein increment by increasing water depths. However, water application had no effect on neutral detergent fiber content.

<b>Forage yield and quality of marandugrass fertigated with treated sewage wastewater and mineral fertilizer

“…Furthermore, we observed a gradual increase in herbage quality in 2014, which occurred due to the increased TSW rates applied. Similar results were obtained by Dantas et al (2016). Foliar analysis showed that the reference treatment (E3) had an ideal CP content, albeit below average, for every season except fall-winter.…”

“…Fertigation control was in accordance with plant nutritional demand, according Dantas et al (2016), and consisted of 15 kg ha -1 nitrogen (N), 3.5 kg ha -1 phosphorus (P) and 18 kg ha -1 potassium (K) per dry biomass megagram (Mg). However, water demand followed the FAO 56 method in the reference treatment (E3), which was considered the criterion of greatest value within a 28-day interval.…”

“…It is worth mentioning that in warmer periods with high solar radiation, as in 2014, increased yields occurred. Dupas et al (2010), Matos et al (2013) and Dantas et al (2016).…”

Application of swine wastewater for irrigation of Tifton 85 grass: Part I-productivity and nutritional quality

“…The climate change have been causing direct effects on grasses in the last decades (Raz-yaseef et al, 2015;Barbosa, 2016;Kalaugher et al, 2017), including changes in rainfall patterns that may lead to a considerable decline in agricultural production (Mall, Gupta and Sonkar, 2017), causing the seasonality of the production of tropical plants (Dantas et al, 2016), common in various regions of Brazil (Gomes et al, 2015a).…”

Effect of Irrigation Schemes on Forage Yield, Water Use Efficiency, and Nutrients in Artificial Grassland under Arid Conditions

“…Studies have shown that irrigated grasslands may have higher and more stable rates of yield [6][7][8]. However, achieving high output yields with less irrigation in an efficient and sustainable manner is one of the key challenges in artificial grasslands in arid areas.…”