Flowering an leaf water potential in coffee under diferent water regimes and planting densities

Abstract

The study of water relations in coffee is of utmost importance at all stages of crop development. The aim of this study was to evaluate “pre-dawn” leaf water potential and the total average production of flowers in non-irrigated and irrigated coffee plants under different water regimes in four planting densities over a two-year period. The cultivar Rubi MG-1192 was used, planted in January 2001 in a randomized block experimental design in split-plots with three replications. Treatments consisted of three water regimes: (i) irrigation when soil water tension reached values around 20 kPa and suspension of irrigation during July and August; (ii) irrigation when soil water tension reached values around 60 kPa and suspension of irrigation during July and August and (iii) a non-irrigated control. Four planting densities were used: (i) 2500 (4.0 x 1.0 m),
(ii) 3333 (3.0 x 1.0 m), (iii) 5000 (2.0 x 1.0 m) and (iv) 10000 plants ha-1 (2.0 x 0.5 m). The “pre-dawn” leaf water potential (Yf) was determined using a pressure chamber. In 2009, the lowest values observed were -1.6 MPa in non-irrigated and irrigated coffee at 60 kPa at a density of 2500 plants ha-1. These values were observed during September, October and November. In the second year, the value of -1.5 MPa was reached at the end of the period of suspension of irrigation (August) and occurred in less dense plantings. In both years, in dense coffee plantings, the water regime did not affect total average production of flowers. The values of leaf water potential did not correlate with the total average production of flowers.