Irrigação deficitária na cultura do amendoim – avaliando nutrição e produção agronômica na segunda safra
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Data
2021-12-20
Autores
Bertino, Antonio Michael Pereira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O estresse hídrico é considerado o fator ambiental mais crítico para a cultura do amendoim no estado de São Paulo, principalmente na segunda safra, de fevereiro a junho. Em condições de limitação hídrica, os agricultores reduzem a área cultivada ou o aporte de água para os cultivos, o que resulta em decréscimos de produção ou de produtividade. Nessas condições, deve-se aplicar as normas de manejo de irrigação deficitária, dentre as quais a produtividade da cultura é reduzida em determinado grau pela redução da lâmina de irrigação aplicada, porém é mantida a renda líquida positiva. O objetivo deste trabalho foi avaliar a marcha de absorção e o efeito do estresse hídrico nos componentes de produção e produtividade do amendoim na segunda safra em Jaboticabal, SP. Os experimentos foram conduzidos de março a agosto de 2019 e de março a agosto de 2020 na Universidade Estatual Paulista (UNESP), em Jaboticabal, SP. O delineamento experimental foi em blocos casualizados com cinco tratamentos e quatro repetições. Os tratamentos consistiram em cinco níveis de irrigação deficitária, L1, L2, L3, L4 e L5, correspondentes às reposições de 100%, 89%, 56%, 29% e 10% do consumo hídrico da cultura (evapotranspiração menos precipitação). As produtividades máximas dos experimentos variaram de 3.5 a 3.9 t ha-1, sendo superior à média da região na entressafra, demostrando que o manejo da irrigação é uma opção para os agricultores produzirem de forma satisfatória. Temperaturas sub-ótimas alongaram o ciclo de cultivo e reduziram a produtividade da cultura em cerca 33%, em decorrência do menor crescimento da planta. As produtividades máximas foram obtidas sob lâminas totais de 250 a 330 mm, resultando em produtividade da água entre 1 e 2 kg m-3. Maiores demandas nutricionais do amendoim ocorreram dos 63 aos 105 dias após a semeadura. Os maiores acúmulos totais estimados ocorreram dos 118 aos 147 dias após a semeadura (DAS), com 234,8; 173,5; 79; 45,8; 23,4; 18,8 para N, K, Ca, Mg, P e S, respectivamente.
Water stress is considered the most critical environmental factor for peanut farming in the state of São Paulo, especially in the second harvest, from February to June. Under water-limited conditions, farmers reduce the cultivated area or the supply of water for crops, which results in a decrease in production or productivity. Under these conditions, the rules for managing deficit irrigation must be applied, among which the crop productivity is reduced to a certain degree by the reduction of the applied irrigation depth, but the positive net income is maintained. The objective of this work was to evaluate the absorption rate and the effect of water stress on the production and yield components of peanut crop in off season in the northeast region of the State of São Paulo, Brazil. The experiments were carried out from March to August 2019 and from March to August 2020 at UNESP, in Jaboticabal, SP. The experimental design was in randomized blocks with five treatments and four replications. The treatments consisted of five levels of deficit irrigation, L1, L2, L3, L4 and L5, corresponding to replacements of 100%, 89%, 56%, 29% and 10% of the crop water consumption (evapotranspiration less precipitation). The maximum yields of the experiments ranged from 3,5 to 3,9 kg ha-1, being higher than the region average in the off-season, demonstrating that irrigation management is an option for farmers to produce satisfactorily. Suboptimal temperatures lengthened the growing cycle and reduced crop yield in about 33%, due to the lower plant growth. The maximum yields were obtained under total depths of 250 to 330 mm, resulting in water productivity between 1 and 2 kg m3. Greater nutritional demands of the peanut tree occurred from 63 to 105 days after sowing. The highest total nutrient accumulations occurred from 118 to 147 days after sowing (DAS), with 234.8; 173.5; 79; 45.8; 23.4; 18.8 for N, K, Ca, Mg, P and S, respectively.
Water stress is considered the most critical environmental factor for peanut farming in the state of São Paulo, especially in the second harvest, from February to June. Under water-limited conditions, farmers reduce the cultivated area or the supply of water for crops, which results in a decrease in production or productivity. Under these conditions, the rules for managing deficit irrigation must be applied, among which the crop productivity is reduced to a certain degree by the reduction of the applied irrigation depth, but the positive net income is maintained. The objective of this work was to evaluate the absorption rate and the effect of water stress on the production and yield components of peanut crop in off season in the northeast region of the State of São Paulo, Brazil. The experiments were carried out from March to August 2019 and from March to August 2020 at UNESP, in Jaboticabal, SP. The experimental design was in randomized blocks with five treatments and four replications. The treatments consisted of five levels of deficit irrigation, L1, L2, L3, L4 and L5, corresponding to replacements of 100%, 89%, 56%, 29% and 10% of the crop water consumption (evapotranspiration less precipitation). The maximum yields of the experiments ranged from 3,5 to 3,9 kg ha-1, being higher than the region average in the off-season, demonstrating that irrigation management is an option for farmers to produce satisfactorily. Suboptimal temperatures lengthened the growing cycle and reduced crop yield in about 33%, due to the lower plant growth. The maximum yields were obtained under total depths of 250 to 330 mm, resulting in water productivity between 1 and 2 kg m3. Greater nutritional demands of the peanut tree occurred from 63 to 105 days after sowing. The highest total nutrient accumulations occurred from 118 to 147 days after sowing (DAS), with 234.8; 173.5; 79; 45.8; 23.4; 18.8 for N, K, Ca, Mg, P and S, respectively.
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Palavras-chave
Conservação, Ecossistemas, Estresse hídrico, Amendoim