Excesso hídrico e seu efeito no crescimento e na produtividade da mandioca

Abstract

Cassava is characterized as sensitive to excess of water. Flooding periods directly interfer with the availability of oxygen in the soil, affecting the aerobic processes of the plants. The objectives of this study were: (i) to characterize the effects of excess water on the soil on cassava growth and development; (ii) to identify management practices that reduce the impact of excess water on cassava productivity, and (iii) to estimate the yield potential (PP) and quantify the yield gap (LP). The effects of excess water were evaluated through experiments in vases and in the field and to obtain the PP, the Simanihot model used was. The LP calculated was through the difference between the PP and the yield of the field experiment. Cultivation in vases indicated greater damage to cassava after exposure of 96 and 120 hours of excess water. After 24 hours of excess water about 20% of the plants did not emerge and after 96 hours of excess the emergence of plants was null. In the field, the use of raised beds guaranteed about 60% of the emergency. At the beginning of plant development, 96 and 120 hours of excess water resulted in premature senescence of the leaves. The use of raised beds is a management practice that reduces the impact of excess water. The PP was 11.95 Mg ha-1 for leaves, 61.5 Mg ha-1 for stems and 60.4 Mg ha-1 for roots, and plantings in the months of August and September expressed the maximum PP of up to 27 Mg ha-1.