ABSTRACT-This study aimed to evaluate, under field conditions, different combinations between 'Pera' sweet orange and eight rootstocks: 'Rangpur' lime (RL), 'Volkamer' lemon (VL), 'Cleopatra' mandarin (CM), 'Sunki Maravilha' mandarin (SMM), 'Indio' and 'Riverside' citrandarins, and VL x RL ('Rangpur' lime)-010 and TH-051 hybrids. The soil water matric potential (Ѱm) was characterized for all scion-rootstock combinations at distance of 1.0m from the trunk at the plant row direction and depths of 0.25 m, 0.50 m 0.90 m in the dry and wet seasons. For two years, fruit production parameters and fruit quality were assessed. Differences of Ym among scion-rootstock combinations were observed during the dry season (p≤0.05). The lowest Ym values for RL and the highest for TH-051 indicate the existence of different intrinsic mechanisms affecting the water extraction of each scion-rootstock combination. Rootstocks have influenced fruit yield and quality (p≤0.05). The best combinations for fruit quality and production were sweet orange grafted on 'Riverside', 'Indio' and TH-051 rootstocks. Index terms: Citrus, matric potential, drought tolerance, rootstock. PRODUÇÃO E QUALIDADE DE FRUTOS DA LARANJEIRA-'PERA' EM COMBINAÇÃO COM DIFERENTES PORTA-ENXERTOS EM CONDIÇÕES DE SEQUEIRORESUMO-este trabalho objetivou avaliar, em condição de campo, combinações entre a copa laranjeira 'Pera' e oito diferentes porta-enxertos: limoeiro 'Cravo' (LCR), limoeiro 'Volkameriano' (LVK), tangerineira 'Cleópatra' (CLEO), tangerineira 'Sunki Maravilha' (TSKMA), citrandarins 'Indio' e 'Riverside', híbridos LVK x LCR (limoeiro 'Cravo')-010 e HTR (híbrido trifoliado)-051. Foi estimado o potencial matricial do solo (Ѱm) para todas as combinações copa-porta-enxerto na posição a 1,0 m do tronco, na linha de plantas, nas profundidades de 0,25 m, 0,50 m e 0,90 m, nos períodos secos e úmidos. Durante dois anos, foram avaliadas a produção e a qualidade dos frutos. Foram observadas diferenças entre as combinações copa-porta-enxertos em relação ao Ѱm (p≤0,05) apenas para o período seco. O menor valor de Ѱm para limoeiro 'Cravo' e o maior para o HTR (híbrido trifoliado)-051 indicaram a existência de diferentes mecanismos intrínsecos de cada combinação estudada que influenciaram na extração de água do solo, na posição avaliada. Em relação à produção e à qualidade de frutos, os porta-enxertos 'Riverside', 'Indio' e HTR (híbrido trifoliado)-051 destacaram-se como as melhores combinações com a laranjeira 'Pera'. Termos para indexação: Citros, potencial mátrico, tolerância à seca, porta-enxertos.

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Pasture degradation is an evolutionary process of losing vigor, productivity and capacity of natural recovery of pastures. It can economically cripple the production and the forage quality required by the animals. This process can have a physical and/or chemical and/or biological origin. The aim of this study was to evaluate the effects of tillage, liming and fertilization on a yellow distrofic oxisol from a oastal land zone and its consequences on Brachiaria decumbens root system. The experiment was located at UFRB experimental area, Cruz das Almas – BA, Brazil. The experimental design was arranged in a split plot, with two tillage treatments: heavy disc harrowing (Gp) and heavy disc harrowing + subsoiling (Gp + Subs) in three blocks and five fertilizers combinations: control (Test.); liming (Cal); NPK; NPK + Cal; and Cal + Agricultural Gypsum + NPK (CalGA + NPK). Were evaluated: density, porosity and the mechanical resistance of soil to penetration, pH, Al3+ and V% values and also root density. It was observed that the effect of subsoiling on soil physical attributes lasted for two years, increasing soil porosity and decreasing soil density and resistance to root penetration. Subsoiling interacted with lime leading to a depth correction.