INFLUENCE OF WEED COVER ON MANGO NUTRITION, PRODUCTIVITY AND FRUIT QUALITY

ISHS Acta Horticulturae 820: VIII International Mango Symposium

INFLUENCE OF WEED COVER ON MANGO NUTRITION, PRODUCTIVITY AND FRUIT QUALITY

Authors:	M.D. Torres, E. Guirado, J.M. Farré, J.M. Hermoso
Keywords:	mango, nutrition, weeds, productivity, quality
Abstract: Sensation avocado trees grafted on unnamed local seedling stocks were 17 years old at the beginning of the experiment. They had been part of a N and Ca nutrition experiment (Torres et al., 2004) and had therefore different N and Ca contents. The natural weed cover was allowed to grow in the interrows and cut when its height reached 15-20 cm in the rainy period (December-May). The plot was drip irrigated whenever tensiometers at 50 and 100 cm depth reached a mean reading of - 40 kPa. The 3 drippers were within the 2 m wide herbicide strip. At the start of this experiment in half the trees weeds were allowed to grow in the herbicide strip. Their aerial parts were cut and exported twice per year. Each single plot had 4 trees. No fertilisers were applied during the three years of this experiment. The resulting treatments were: Previously high N – low Ca without weed cover (8 replicates) Previously low N – low Ca with (4 replicates) or without (4 replicates) weed cover Previously low N – high Ca with (4 replicates) or without (4 replicates) weed cover. The design was completely randomized. Nitrogen contents of the weed tops were higher in spring than in autumn. Two years after weed establishment mango leaf blade N levels were slightly lower on trees with weeds. Consistent differences of 0.5 to 2.4 g.kg^-1 were registered by the end of the 3^rd season. By then Ca contents were slightly higher and the relation N/Ca much lower with weeds. Mineral contents in the fruit mesocarp showed a parallel behaviour. In spite of these differences fruit internal breakdown (jelly seed and stem end cavity) was similar with or without weed cover. This was probably caused by the moderate (12.9 g.kg^-1) mean leaf blade N content in the trees without weed cover. For the second and third year of the experiment mean yields decreased over 20% with weed cover.
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