Resumo A irrigação do cafeeiro já é realidade na maior parte das regiões produtoras do Brasil, já atingindo 300.000 ha. Na região do cerrado mineiro, grande parte das lavouras de café é irrigada. Porém, nos últimos anos, com alterações climáticas, têm sido observados anos com déficits superiores a 150 mm, afetando o desenvolvimento vegetativo e produtivo da cultura e também o reabastecimento dos mananciais superficiais e subterrâneos. Uma prática que permite aumentar a capacidade de retenção de água no solo é a adubação orgânica. Dentro deste contexto, propôs-se o presente trabalho que teve como objetivo avaliar diferentes combinações de irrigação e adubação orgânica na produtividade e qualidade do café produzido no cerrado mineiro. Os tratamentos foram: T1: Irrigação total; T2: Sem irrigação; T3: Irrigação Total + Adubação Orgânica (esterco de galinha, 10 ton. Ha-1); T4: Sem irrigação + adubação orgânica (esterco de galinha, 10 ton. ha-1); T5: Irrigação 50% + adubação orgânica (esterco de galinha, 10 ton. ha-1). Após 7 safras, concluiu-se que o tratamento que combinou a adubação orgânica a aplicação de metade da irrigação necessária apresentou o melhor resultado em produtividade, superior ao tratamento com irrigação total e nutrição exclusivamente mineral.

Abstract Coffee irrigation has increased in the main Brazilian coffee regions. However, in recent years, with climate change, years with water deficits greater than 150 mm have been observed, affecting the vegetative and productive development of the crop and also the replenishment of surface and underground springs. One practice that increases soil water retention capacity is organic fertilization. This work evaluated different combinations of irrigation and organic fertilization on the yield and quality of coffee produced in the Minas Gerais cerrado region. The treatments were: T1: total irrigation; T2: no irrigation; T3: total irrigation + organic fertilization (chicken manure, 10 ton ha-1); T4: no irrigation + organic fertilization (chicken manure, 10 ton ha-1); T5: 50% irrigation + organic fertilization (chicken manure, 10 ton ha-1). After 7 harvests, it was concluded that the treatment that combined organic fertilization with application of half of the necessary irrigation presented the best yield, superior to the treatment with total irrigation and exclusively mineral nutrition.

The wetted area fraction is a factor critical to the success of drip irrigation. This study aimed to evaluate the effect of partial soil wetting on transpiration, vegetative growth and root system of young orange trees. The experiment was carried out in a greenhouse where plants were grown in 0.5 m3boxes internally divided into compartments. The wetting of 12 % of soil area was tested on two types of soil cultivated with ‘Valencia’ orange trees grafted onto Rangpur lime and ‘Swingle’ citrumelo rootstocks. Transpiration was determined in 40 plants. Water extraction and root density were evaluated in the compartments. Transpiration is reduced by restriction in wetted soil area, and such reduction is influenced by the number of days after the beginning of partial irrigation, atmospheric evaporative demand and plant phenological stage. Mean transpiration of plants with partial irrigation was equivalent to 84 % of the mean transpiration of plants with 100 % of wetted soil area in the period studied. However, after 156 days of imposing partial irrigation there was no difference in transpiration between treatments. Plant acclimation was caused by an increase in root concentration in the irrigated area. After a period of acclimation, if the entire root system is wetted, soil water extraction becomes proportional to the percentage of wetted area after a short period of time. Despite the reduction in transpiration, there was no difference between treatments with 12 % and 100 % of wetted soil area in terms of vegetative growth.