Estimation of the minimum leaf area for surveys of weeds in irrigated fruit crops.
Kiill L. H. P., Lima P. C. F.
Author Affiliation: Embrapa Semi-Árido, Caixa Postal 23, 56300-000 - Petrolina, PE, Brazil.
Científica (Jaboticabal) 29 : 95-102
Abstract : A study was carried out to estimate the minimum area of plots for weed survey in the main fruit crop growing area of Petrolina, Pernambuco, Brazil. Eleven plot sizes were evaluated: 0.5 × 0.5 m (0.25 m2), 0.5 × 1.0 m (0.5 m2), 1.0 × 1.0 m (1.0 m2), 1.0 × 2.0 m (2.0 m2), 2.0 × 2.0 m (4.0 m2), 4.0 × 2.0 m (8.0 m2), 4.0 × 4.0 m (16.0 m2), 8.0 × 4.0 m (32.0 m2), 8.0 × 8.0 m (64.0 m2), 8.0 × 16.0 m (128.0 m2) and 16.0 × 16.0 m (256.0 m2) in areas of grapes, mangoes and guavas, where the frequency of weeds was recorded. The minimum plot size was determined by species per area curve and maximum curvature of the coefficient of variation methods. Variations in the ideal size of plots were found between the 2 methods. In the first method, the minimum area of plot was estimated to be 35 m2 and in the second, 25 m2.