ABSTRACT The response of biomass flow components of forage from the interaction between fertigation with wastewater and cutting height during the year is little known. The objective of this work was to verify the responses of morphogenic and structural characteristics of Urochloa brizantha as a function of fertigation application strategies with sewage treatment plant effluent (TSE), complemented with urea (U), associated with harvest with two plant heights during the dry and rainy periods. The forage cutting heights were 30 cm (H1) and 40 cm (H2), and nitrogen 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 (DM) produced, applied by TSE via fertigation, plus 7.5 kg N per Mg−1 of DM produced, applied in the form of urea by cover in all treatments. Factor analyses for the dry and rainy periods identified two processes that correspond to forage mass growth and leaf development. Analysis of variance showed that treatments D5H2 and D5H1 presented superior responses over the other treatments, in the dry, and rainy periods. The treatment D5H2 stood out in the process of forage mass growth, and D5H1 in leaf development.

RESUMO Objetivou-se, neste trabalho, avaliar o desempenho de três modelos de gotejadores de fluxo normal utilizando não apenas o efluente de esgoto tratado puro e diluído mas também dois tipos de filtro, tela e disco. O efluente de esgoto tratado utilizado no experimento foi proveniente da estação de tratamento da cidade. Esta unidade experimental foi composta por 12 linhas laterais com três modelos de gotejadores, dois modelos de filtro e se utilizou, como água de irrigação, o efluente de esgoto tratado puro (100%) e diluído em água (50%). Para cada modelo de gotejador foram definidos os tratamentos, sendo: T1 (efluente diluído em 50% com água subterrânea e uso de filtro de tela); T2 (efluente diluído em 50% com água subterrânea e uso de filtro de disco); T3 (efluente 100% e uso de filtro de tela); T4 (efluente 100% e uso de filtro de disco). Os resultados permitem afirmar que há modelos de gotejadores menos susceptíveis ao entupimento, sendo o gotejador de pastilha menos sensível ao entupimento. O filtro de disco é o mais indicado para prevenir o entupimento. O uso de efluente de esgoto puro ou diluído aumenta o coeficiente de variação de vazão dos gotejadores.

ABSTRACT The objective of this study was to evaluate the performance of three models of drippers using treated sewage effluent, pure and diluted, and two types of filters, screen and disc. The treated sewage effluent used in the experiment was collected from the city’s treatment plant. The experiment included 12 lateral lines with three types of emitters to apply pure (100%) and diluted (50%) effluent filtered by screen and disc filters. The combination of those factors set the treatments: T1 (50% effluent diluted in fresh water filtered by a screen filter); T2 (50% effluent diluted in fresh water filtered by a disc filter); T3 (pure effluent filtered by a screen filter); T4 (pure effluent filtered by a disc filter). The results showed that the flat type emitter is less sensitive to clogging, the disc filter is the most suitable to prevent clogging and the use of pure or diluted sewage effluent increases the drippers’ flow rate coefficient of variation.

ABSTRACT: Simulation models of crop growth enable estimating crop yield and water balance components with low cost and high precision. This study aimed to calibrate and evaluate the performance of the CS-CROPGRO model for common beans under the conditions of Jaboticabal city (SP), Brazil. The model was calibrated and tested with data previously collected from two experiments conducted in 2002 and 2003. In these experiments, treatments corresponded to two irrigation scheduling methods (tensiometers and class A pan evaporation) and two cropping systems (conventional and no-till). For calibration, data from the experiment carried out in 2002 were used. For testing, we used data from the experiment conducted in 2003. By using the genetic coefficients calibrated for cultivar IAC-Carioca, the model could correctly simulate phenology, leaf area, dry matter and grain yield during both, calibration and testing, under no-till and conventional systems, combined with tensiometer and class A pan irrigation scheduling methods. Conversely, the model did not show the same performance for soil moisture simulations.

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 (L1= 0,18; L2= 0,52; L3= 1,00; L4= 1,45 e L5= 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 foi 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.

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 (L1= 0.18, L2= 0.52, L3= 1.00, L4= 1.45, and L5= 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.