SPAD index in the leaves of potato under splitting and doses of nitrogen and potassium

Abstract

With the purpose of assessing the leaf greenness of potato under application times and doses of nitrogen and potassium, this experiment was carried out in the municipality of Mucugê-BA.Three doses of N and K were used (75% of the recommended dose; the recommended dose according to soil analysis; 125% of the recommended dose). Five application times (100% upon planting; 1/3 upon planting and 2/3 upon tuberization; 50% upon planting and 50% upon tuberization; 1/3 upon planting, 1/3 upon tuberization and 1/3 25 days after tuberization; 1/4 upon planting, 1/4 upon tuberization, 1/4 25 days after tuberization and 1/4 50 days after tuberization were utilized. The experimental design was factorial (5 x 3), with plots arranged in randomized blocks with four replications. Tubercles from Ágata, Monalisa and Vivaldi cultivars, uniformly budded, were planted with spacing of 0.8 x 0.3m on a prepared soil as recommended for the culture. Was measured, throughout the cycle, the leaf greenness of potato, 30, 55 and 80 days after planting, using the indirect chlorophyll meter SPAD. The doses of N and K did not influence SPAD index, in potato cultivars over the cycle. The SPAD index can be used as a tool to indicate the most correct time for tubercule potato harvest.