Root pruning and fertilization for growth of coffee plants cultivated in soil columns

The effects of soil fertility levels, root pruning and localized fertilization on root and shoot growth in 'Catuai' coffee plants were studied in a greenhouse experiment. Sub-superficial (30-70 cm) samples of a Red-Yellow Latosol (Oxisol) were packed in PVC columns consisting of three 15 cm high rings of 20 cm diameter. Four treatments with three fertility levels [low (FB), medium (FM) and high (FA), and medium without root pruning with only two rings (FM2)] were installed before planting by adding three levels of liming and three doses of poultry manure. The P and K doses at planting were applied in inverse amounts of the soil fertility levels. After eight months of cultivation, the lowest ring was removed, and roots were pruned. This ring was replaced by another one filled with soil with four fertilization rates [low (AB), medium (AM), medium plus poultry manure (AM2) and high (AA)], representing localized fertilization. After 17 months of cultivation the shoot and root system were evaluated. Plant height and number of branches decreased with the level of soil fertility, due to the lower P and K doses applied along the increasing fertility level. The same trend was observed for shoot dry matter production, but root system growth was not affected. Growth and dry matter production of shoots and roots was not affected by root pruning, except when poultry manure was applied in localized fertilization at medium fertility level, at which a negative effect was observed. The localized fertilization had no affect on shoot and root growth in the FB pots, but caused positive and quadratic effects in the FM pots and a linear increase in the growth of 'Catuai' coffee plants for the FA treatment. The results showed that planting fertilization as a function of the fertility level was sufficient for FB, balanced for FM and insufficient for FA.