Garlic productivity and profitability as affected by seed clove size, planting density and planting method

Depending on clove size and plant stand, planting represents a considerable proportion of the total production costs in garlic cultivation. The objectives of this study were to analyze the influence of seed clove size, planting density and planting method on yield, bulb size and on the profitability of garlic for the fresh market, planted under fertigation. Two experiments were established to evaluate planting densities ranging from 300,000 to 500,000 plants/ha in the 1998-99 season, and 300,000 to 600,000 plants/ha during the 1999-2000 season. Two additional experiments were established to evaluate the effect of seed size in the range of 1.9 to 10 g/clove in 1998-99, and 1.9 to 17 g/clove in 1999-2000. Seed of Taiwan-type 'Tacatzcuaro' garlic was used in all the experiments. A fifth experiment was established to compare mechanical vs. hand planting. The experimental design in all cases was a randomized complete block with four replicates. For the plant density study, yields varied from 23.5 to 29.9 t.ha(-1) for the first year and from 32.1 to 39.7 t.ha(-1) for the second season. For the seed clove size study, yields varied from 18.7 to 27.3 t.ha(-1) for the first year and from 16.3 to 32.2 t.ha(-1) for the second season. Yields and leaf area index (LAI) were directly related to planting density and clove size. Highest yields were attained with maximum studied densities in both seasons. However highest profitability was attained with planting densities of 420,000 plants/ha for the first year, as calculated from the regression equation and 300,000 plants/ha for the second year as there was no statistical difference (P > 0.05) with the two subsequent population treatments and the former has lower costs than the others. The biggest diameters of bulb were always attained with the lowest population densities. In regard to seed size, the highest yield was achieved with 7.5 g/clove for the first season and 13 g/clove for the second season, which also resulted in biggest bulb diameters and therefore in more valuable commercial classes. In accordance with the regression analysis, highest profits were obtained with clove sizes 3.6 to 6.5 g/clove, which yielded from 24 to 27 t.ha(-1) for the first season and from 7 to 10 g/clove for the second season, for yields from 29 to 31 t.ha(-1). In general, the largest-sized seeds produced lower profits than medium-sized seeds, even though yields were significantly higher. The best planting method for garlic, as evaluated in terms of yield, quality and profitability, was associated with good plant distribution in the field and planting the seed with the apex upwards, characteristics obtained in the hand-planted treatment.