Efluente de estação de tratamento de esgoto aplicado em solo com Brachiaria colhida com duas alturas
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Data
2019-03-19
Autores
Dantas, Geffson de Figueiredo [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Em manejo de pastejo intensivo de forragens tropicas dispendem-se níveis de trabalho e recursos elevados para se aumentar a produtividade por área e ou por animal. Dentre as estratégias de manejo, destaca-se a frequência de corte por altura do dossel, que estimula maior produção de folhas do que colmo e material morto para obtenção de maior produtividade e valor nutritivo da forragem. Outra estratégia é a adubação nitrogenada, que possibilita o crescimento vegetal mais rápido, além de forragem de melhor qualidade. As águas residuárias são promissoras para uso em pastagens, na forma de fertirrigação, pois pode suprir as necessidades hídrica e nutricional do cultivo em parte ou na sua totalidade. Devido às limitações climáticas ao longo do ano, a efetividade dessas estratégias pode ser comprometida, o que resulta a sazonalidade de produção. Há carência de estudos sobre a interação das estratégias de manejo de fertirrigação com água residuária e de colheita da forragem com diferentes alturas de corte para as forrageiras tropicais. Os objetivos deste trabalho foi determinar a produtividade e o valor nutritivo da forragem, e as características morfogênicas e estruturais de Urochloa brizantha, em função da fertirrigação com efluente de estação de tratamento de esgoto (EETE), complementada com ureia (U), associada à colheita com duas alturas de plantas, durante os períodos seco (PS) e chuvoso (PC). O experimento foi conduzido em Jaboticabal, SP (Latitude 21º15'S, Longitude 48º18'W), de fevereiro de 2015 a fevereiro de 2017. As estratégias de manejo por alturas de corte da forragem foram 30 cm (A1) e 40 cm (A2), e as doses de adubação nitrogenada foram 9,1 (D1), 12,1 (D2), 22,5 (D3), 26,6 (D4) e 34,0 (D5) kg de N por Mg-1 de matéria seca (MS) produzida, aplicadas por EETE via aspersão, mais 7,5 kg de N por Mg-1 de MS produzida, aplicada na forma de ureia por cobertura em todos os tratamentos. A Urochloa brizantha mostrou-se baixa eficiência produtiva em função da adição da adubação nitrogenada no PS, em relação ao PC. No PC a produtividade foi maior na estratégia D5A2, enquanto que no PS as estratégias D5A1 e D5A2 não diferenciaram e foram superiores à demais. Maiores teores de proteína bruta (PB) e menor de fibra em detergente neutro (FDN) foram observados nas estratégias D5A1, enquanto a estratégia D1A2, proporcionou maior valor de FDN e menor PB. As análises de fatores para os períodos seco e chuvoso identificaram dois processos que correspondem ao crescimento de massa da forragem (taxas de alongamento foliar e de pseudocolmo, e de senescência foliar, comprimentos foliar e de pseudocolmo, e número de folhas mortas) e o desenvolvimento foliar (taxa de aparecimento foliar, número de folhas vivas, filocrono e duração de vida foliar). A análise de variância mostrou que as estratégias D5A2 e D5A1 apresentaram respostas superiores às demais estratégias de manejo, tanto nos períodos seco quanto chuvoso. A estratégia de manejo D5A2 destacou-se no processo de crescimento de massa da forragem, enquanto o D5A1 no desenvolvimento foliar.
In tropical forages under intensive grazing management, high labor and resources are used to increase productivity per area and / or animal units. Among the management strategies, the frequency of harvesting by canopy height is advantageous because it stimulates more leaf production than stalk and dead material to obtain high productivity and forage nutritive value. Another strategy is nitrogen fertilization, which enables faster plant growth, in addition to better forage quality. Wastewater is promising for use in pasture in the form of fertigation, since it can meet the water and nutritional needs of the crop in part or in its entirety. Due to climatic limitations throughout the year, the effectiveness of these strategies can be compromised, resulting in seasonality of production. There is a lack of studies on the interaction of fertigation management strategies with wastewater and forage harvesting with different cutting heights for tropical forages. The objectives of this work were to determine the productivity and nutritive value of forage, and the morphogenic and structural characteristics of Urochloa brizantha, as a function of fertigation with treated sewage (TSW), complemented with urea (U), associated with harvest at two plant heights during the dry (DP) and rainy (RP) periods. The experiment was conducted in Jaboticabal, SP, Brazil (Latitude 21º15'S, Longitude 48º18'W), from february, 2015 to february, 2017. The management strategies for forage harvesting heights were 30 cm (A1) and 40 cm (A2), and N fertilization doses were 9.1 (D1), 12.1 (D2), 22.5 (D3), 26.6 (D4) and 34.0 (D5) kg of N per Mg-1 of dry matter, applied by TSW via sprinkler, plus 7.5 kg of N per Mg-1 of DM produced, applied as urea by cover in all treatments. Urochloa brizantha showed low productive efficiency due to the addition of nitrogen fertilization in DP, in relation to RP. In RP the productivity was higher in the D5A2 strategy, whereas in the DP the strategies D5A1 and D5A2 were not different and were superior to the others. Higher crude protein (CP) and lower neutral detergent fiber (NDF) levels were observed in the D5A1 strategies, while the D1A2 strategy provided higher NDF and lower CP values. The analyzes of factors for both periods identified two processes that correspond to forage mass growth (leaf, pseudostem elongation and leaf senescence rates, leaf and pseudocolus length, and number of dead leaves) and leaf development (number of life leaves, phyllochron and leaf life span). The analysis of variance showed that the strategies D5A2 and D5A1 presented superior responses to the other management strategies, both in the dry and rainy periods. The D5A2 management strategy was highlighted in the forage mass growth process, while the D5A1 in leaf development.
In tropical forages under intensive grazing management, high labor and resources are used to increase productivity per area and / or animal units. Among the management strategies, the frequency of harvesting by canopy height is advantageous because it stimulates more leaf production than stalk and dead material to obtain high productivity and forage nutritive value. Another strategy is nitrogen fertilization, which enables faster plant growth, in addition to better forage quality. Wastewater is promising for use in pasture in the form of fertigation, since it can meet the water and nutritional needs of the crop in part or in its entirety. Due to climatic limitations throughout the year, the effectiveness of these strategies can be compromised, resulting in seasonality of production. There is a lack of studies on the interaction of fertigation management strategies with wastewater and forage harvesting with different cutting heights for tropical forages. The objectives of this work were to determine the productivity and nutritive value of forage, and the morphogenic and structural characteristics of Urochloa brizantha, as a function of fertigation with treated sewage (TSW), complemented with urea (U), associated with harvest at two plant heights during the dry (DP) and rainy (RP) periods. The experiment was conducted in Jaboticabal, SP, Brazil (Latitude 21º15'S, Longitude 48º18'W), from february, 2015 to february, 2017. The management strategies for forage harvesting heights were 30 cm (A1) and 40 cm (A2), and N fertilization doses were 9.1 (D1), 12.1 (D2), 22.5 (D3), 26.6 (D4) and 34.0 (D5) kg of N per Mg-1 of dry matter, applied by TSW via sprinkler, plus 7.5 kg of N per Mg-1 of DM produced, applied as urea by cover in all treatments. Urochloa brizantha showed low productive efficiency due to the addition of nitrogen fertilization in DP, in relation to RP. In RP the productivity was higher in the D5A2 strategy, whereas in the DP the strategies D5A1 and D5A2 were not different and were superior to the others. Higher crude protein (CP) and lower neutral detergent fiber (NDF) levels were observed in the D5A1 strategies, while the D1A2 strategy provided higher NDF and lower CP values. The analyzes of factors for both periods identified two processes that correspond to forage mass growth (leaf, pseudostem elongation and leaf senescence rates, leaf and pseudocolus length, and number of dead leaves) and leaf development (number of life leaves, phyllochron and leaf life span). The analysis of variance showed that the strategies D5A2 and D5A1 presented superior responses to the other management strategies, both in the dry and rainy periods. The D5A2 management strategy was highlighted in the forage mass growth process, while the D5A1 in leaf development.
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Palavras-chave
Frequência de pastejo, Morfogênica, Reúso de água, Frequency of grazing, Morphogenics, Water reuse