Wellington Alves de Freitas

Viabilidade técnica e econômica da produção de ervilha (Pisum sativum L.) cultivada sob diferentes lâminas de irrigação

This work had the aim to verify the technical and economic feasibility of pea (Pisum satiums L.) yield under different irrigation depth levels, cultivated in greenhouse. It was used a completely randomized design (CRD), with five levels of replacement of water irrigation (50%, 75%, 100%, 125% and 150% of field capacity) with four replications. The crop was drip irrigated when the average soil water tension obtained from the tensiometers installed in the treatment of 100% was equivalent to 15 kPa. The results were affected by drought and water excess for total production of the plant and for number of beans for plant. The maximum productivity obtained was equal to 4,197 kg ha-1 for a water depth of 188.4 mm and the economic great irrigation depth was 187.4 mm; the greatest water use efficiency was 27.23 kg ha1 mm-1 for a water depth of 86.25 mm.

Análise produtiva e econômica do pimentão-vermelho irrigado com diferentes lâminas, cultivado em ambiente protegido

The irrigation management is not only an important factor to supply plants water needs, but also to minimize problems with diseases, nutrient leaching as well as unnecessary expenses with water and energy. This study had the aim to verify the economic feasibility of red bell pepper (Capsicum annuum, L.) yield under different irrigation depths, cultivated in greenhouse. A completely randomized design (CRD) was used, with five levels of replacement of irrigation water (50, 75, 100, 125 and 150%) with four replications. Significant differences were found for number of fruits per plant and total production of the plant. The maximum productivity obtained was equal to 35,300 kg ha-1 for a water depth of 443.9 mm and the optimum economic irrigation water depth was 443.5 mm; higher economic returns are obtained by keeping the crop with a water content near field capacity, restoring the full amount of water consumed. The highest water use efficiency was 74.76 kg ha 1 mm-1 for a water depth of 334.1 mm.

Produção da ervilha cultivada em ambiente protegido sob diferentes tensões de água no solo

Os efeitos de diferentes tensoes de agua no solo aplicadas em dois estadios fenologicos da cultura da ervilha (Pisum sativum L.) foram avaliados por meio de dois experimentos, ambos conduzidos em delineamento experimental inteiramente casualizado com quatro tratamentos e quatro repeticoes. Os tratamentos se constituiram de quatro diferentes tensoes de agua no solo: 15, 30, 60 e 120 kPa. Os resultados permitiram concluir que diferencas significativas foram encontradas para producao total da planta, numero de vagens por planta e para peso medio da vagem, independentemente da fase fenologica em que foi aplicado o tratamento de tensao de agua no solo; maiores quedas de producao foram observadas na fase reprodutiva, demonstrando que esta fase e mais sensivel a escassez de agua no solo, prejudicando o desenvolvimento da cultura; obtiveram-se maiores producoes com irrigacao realizada sob a tensao de 15 kPa.

Potential of calcium silicate to mitigate water deficiency in maize

The aim of this study was to evaluate the potential of calcium silicate to mitigate the effects of water deficiency in maize plants yield. A completely randomized factorial design, consisting of five combinations of calcium silicate (0, 25, 50, 75, and 100%) and five different soil moisture levels (30, 70, 100, 130, and 160%), was adopted. The following parameters were evaluated: soil matric potential, xylem water potential, silicon concentration, leaf dry weight, and dry mass production. Matric potential monitoring confirmed that the irrigation depths employed resulted in different environments for maize plant development during the experiment. Confirming the hypothesis of the study, at the lower irrigation depths, the maize production has accompanied the increase in calcium silicate used as corrective up to the proportion of 50%. These results indicate that silicon mitigated the impact of water deficiency in maize plants and increased the xylem water potential.

Manejo da irrigação utilizando sensor da umidade do solo alternativo

Um sensor alternativo utilizando a medida da capacitância para determinacao da umidade do solo foi desenvolvido e calibrado em laboratorio, e avaliado por meio da comparacao com tensiometros, no manejo da irrigacao da cultura do feijoeiro. Utilizou-se um delineamento inteiramente casualizado com 5 repeticoes e esquema fatorial com dois metodos de manejo (alternativo e tensiometria) alem tensoes de agua no solo (20, 40 e 60 kPa). Observou-se que, independente do metodo empregado, a producao do feijoeiro foi maior quando submetido a tensao de 39 kPa; entretanto, o manejo da irrigacao utilizando-se o metodo alternativo levou a um numero maior de irrigacoes e tambem do volume de agua aplicado, com consequente reducao da eficiencia do uso da agua em comparacao com o uso de tensiometros.