Soil application of fungicides affects nutrient dynamics in ‘Blood Red’ sweet orange

Abstract

Infected and damaged root system of sweet oranges (Citrus sinensis Osbeck L.) budded on rough lemon (Citrus jambheri Lush.) in Punjab-Pakistan has been suspected to affect nutrient uptake due to rootstock susceptibility to soil born fungal diseases. The experiment was performed on 12-15 years old ‘Blood Red’ sweet orange ‘Blood Red’) trees of uniform size and vigour at the Fruit Garden Sq. 9, Institute of Horticultural Sciences, University of Agriculture, Faisalabad, Punjab, Pakistan. This study was conducted for consecutive two years. The objective of the research was to introduce sweet oranges in the main streamline of the citrus industry by improving their root health through fungicides treatments ultimately enhancing mineral nutrient uptake from the soil. The experiment was laid out according to Randomized Complete Block Design (RCBD) replicated thrice, taking a single tree as a treatment unit. The fungicides used in the experiment were Metalaxyl Mencozeb (Ridomil Gold), Fosetyl-Al (Alliette) and copper sulphate (CuSO4), in different combinations. Nutritional status of tree leaf macronutrients (N, P and K) and micronutrients (Mg, Fe, Mn, Cu and Zn) during flowering and final fruit set was evaluated at fortnight intervals with respect to different treatments. The different treatments enhanced nutrient uptake through roots and improved health and vigour of trees. It was more evident from the improvement of fruit quality and yield of treated trees compared with control. Although fungal analysis could not be performed, the improvement in general health and vigour of trees lead to the conclusion that root health was improved substantially. It might be concluded from this study that best orchard management emphasizing improvement in the root health could enhance the yield and quality of sweet oranges.