Distribuição de raízes e armazenamento de água da chuva em cinco variedades de palma (Opuntia e Nopalea) cultivadas no semiárido baiano

Abstract

The objective of this study was to evaluate the root distribution and rainwater storage capacity of five varieties of palm. The five varieties of palm cultivated were: (i) Orelha de Elefante Mexicana (Opuntia stricta (Haw.) Haw); (ii) IPA-Sertânia (N. cochenillifera Salm Dyck); (iii) Doce (N. cochenillifera Salm Dyck); (iv) Gigante (O. Ficus-indica Mill) e (v) orelha de onça (O. Ficus-indica Mill). Each palm-variety was subjected to two forms of cultivation: (i) dryland for two consecutive cycles; (ii) irrigated in the first cycle, kept dry in the second. A 5 x 2 factorial scheme was followed, with a randomized block design composed by four replications and experimental plots consisting of 12 plants. For each palm-variety, the Number of Cladodes (NC), Fresh Plant Mass (FPM), Fresh Cladode Mass (FCM), Volume of Water Stored in the Plant (VWSP) were evaluated. Root distribution was determined at the end of the second cultivation cycle. Regarding the distribution of roots, it was found that in general, more than 90% of the roots of the palm- varieties studied are concentrated in the first 0.2m of soil depth. The “Orelha de Elefante Mexicana (OEM)” variety is the varieties with the greatest capacity to store rainwater. It can be considered that it will be possible to obtain at the end of each production cycle around 260,000 liters of water stored per hectare of OEM cultivated in rainfed conditions. This volume is equivalent to the storage volume of 5 production cisterns (51,000 liters) - commonly adopted as an alternative for storing rainwater in the semi-arid region. It was noticed that the Orelha de Onça, IPA and Gigante varieties, when irrigated in the first cycle and kept dry in the second, produced around five times more than plants kept dry in both cycles.