Resumo

PUENTES-PARAMO, Yina; MENJIVAR-FLORES, Juan  e  ARANZAZU-HERNANDEZ, Fabio. Nitrogen, phosphorus and potassium use efficiency in cocoa (Theobroma cacao L.). Bioagro [online]. 2014, vol.26, n.2, pp.99-106. ISSN 1316-3361.

The fertilizer management is an important aspect for the crop growth, and an excessive nutrient input may exceed the absorptive capacity of the plant and generate an environmental risk, as well as economic loss to the farmer. Therefore, this study aimed to determine the nutrient use efficiency (NUE) of nitrogen, phosphorus and potassium in four cocoa clones (TSH-565, ICS-39, ICS-95 and CCN-51), and its influence on yield. A randomized complete block design with five treatments and four replications were used. The treatments were NPK increases by 25 % (T1), 50 % (T2), 75 % (T3) and 100 % (T4) on the natural level of the soil fertility (TR: control). Differences in agronomic efficiency (AE) for N, P and K were detected (P≤0.01); the highest AE was for clone CCN-51 in T1, while for the rest of clones the highest AE took place in T2. With the treatment T4, the four clones had the lowest values​​. The highest recovery efficiency (RE) of nitrogen and phosphorus was shown by CCN-51 in T1, and by the other clones in T2; however, the highest RE of potassium occurred in T2 for all the clones. The highest yield was for CCN-51 in T1, and in T2 for clones ICS-39, ICS-95 and TSH 565. In general, lower yields were for TR and T4, suggesting that cocoa crop has an appropriate nutrient extraction resulting in good yields, but when the limit is exceeded a nutritional imbalance might occurred.

Palavras-chave : Nutrient use efficiency; fertilization; mineral nutrition.

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