Fenologia e produção do cacaueiro no semiárido

Abstract

The cultivation of irrigated cocoa in the semiarid region, in full sun, can be a viable alternative for agricultural production, allowing the growth of plants, good productive indexes, besides contributing to improve the chemical characteristics of the soil, due to the high supply of nutrients by the residues of the culture. Therefore, the objective was to evaluate growth, production, fruit quality, nutritional demand as well as the chemical characteristics of the soil under cultivation of cocoa clones under two conditions of water availability in the soil. The study was outlined in randomized blocks, with three replications, in a split plot scheme, with eight treatments related to the cacao clones in the plots and in the subplots two water conditions available in the soil. The cacao clones used were: SJ 02, CEPEC 2002, CEPEC 2005, CEPEC 2006, PS 1319, Ipiranga 1, PH 16, CCN 51. The two conditions of water available in the soil in the subplots: strip with full irrigation (row of plants with nearby micro sprinklers, providing 100% of the water made available to the soil) and strip that received 25% less water compared to the first (row with micro sprinklers) away, so as to make 75% of the water available in the soil, verified by periodic monitoring of soil moisture). Plant and fruit growth, production, post-harvest quality, nutritional demand and soil chemical attributes were evaluated. The cocoa clones cultivated in full sun in the semiarid region start flowering and fruiting at 540 days after planting (DAP), with flowering peaks and leaf launches in February (810 DAP) in the second year of cultivation. The cacao clones cultivated in full sun in the semiarid region present a peak of bilation in June (930 DAP). The season of greatest fruit sinning for all clones tested in the semiarid occurs in September (1020 DAP). The cacao fruits produced in full sun and in a semiarid climate have sigmoidal growth behavior with a tendency to stabilize with the accumulation of 954 degrees-day (92 days after anthesis). All cacao clones evaluated, in the condition of full sun in a semiarid environment, have agronomic cultivation viability. The CEPEC 2005 clone shows better agronomic performance in the semi-arid conditions with superior results for productivity and production of dried almonds per plant in the second year of cultivation. The availability of water in the soil of 100 and 75% does not affect the production of cocoa grown under full sun in a semiarid climate in the second year of cultivation. The cultivation of cacao can be implemented within bananas already implanted, thus reducing the production costs of the crop. The productivity of dried almonds and average production per plant among the tested clones increased by 21% compared to the first harvest. The accumulated production of the CEPEC 2005 clone is higher when the availability of water in the soil has been reduced to 75%. The organic carbon content of the soil increases during the pruning seasons of the banana plantation and the cacao tree in the superficial layer. The change in the shading system with banana trees to full sun reduces C stocks in the soil under semi-arid climate conditions. The cultivation of cacao increases the NT content and stock in the layers of 0-0.2 and 0.2-0.4 m of soil depth over time. The C/N ratio presents higher values in the 0-0.2 m flow at 700 DAP (dry season). The use of irrigation in a semi-arid climate intensifies the decomposition of soil organic matter. The leaf nutrient content in all clones, at two times of the year, has the following decreasing order: N> Ca> K> Mg> S> P. The SPAD chlorophyll index in cacao leaves does not correlate with the N content in plants grown in the semiarid region. The treatment with less water availability in the soil reduces the availability of K and increases that of Ca in cacao leaves at the end of the rainy season. The cocoa clones CEPEC 2002 and CCN 51, in the dry season, and PS 1319 and SJ 02, in the rainy season, presented the highest leaf contents of sulfur, nitrogen and potassium, in full sun and in semiarid climate.