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Critical phosphorus concentrations in potato plant parts at two growth stages

1997; Taylor & Francis; Volume: 20; Issue: 4-5 Linguagem: Inglês

10.1080/01904169709365275

1532-4087

F. A. T. Rocha, Paulo Cézar Rezende Fontes, Renildes Lúcio Ferreira Fontes, Fernando Pinheiro Reis,

Potato Plant Research

Abstract Adequately evaluating the phosphorus (P) nutritional status of a potato crop is dependent upon sampling the appropriate plant part at a defined growth stage. To establish P critical concentration levels in various potato plant parts (leaves, stems, tubers, leaflets, and petioles) at two growth stages [20 and 50 days after plant emergence (DAE)], an experiment under Brazilian climatic and soil conditions was conducted using seven P treatment levels (0, 40, 80, 160, 320, 640, and 1,280 kg P2O5 ha‐1) applied in a randomized complete block design with four replications. ‘Baraka’ potato tubers were seeded at a spacing of 0.80 x 0.30 m following agronomic cultural practices recommended for this crop. Phosphorus concentrations in all the potato plant parts were significantly affected by the P fertilizer rates applied. The highest correlation between the P concentration in the various plant parts and marketable yield and optimum profit yield was obtained for the petiole taken 20 days DAE. Critical P levels associated with optimum profit yield were lower than those for maximum marketable tuber yield, and they were, 0.41, 0.39,0.39,0.57, and 0.57 g P 100 mg‐1 DM in the leaf, stem, tuber, petiole, and leaflet, respectively. Notes Graduate Student. CNPq Fellow.