Influence of intra-row spacing and mulching on weed growth and bulb yield of garlic ( Allium sativum l.) in Sokoto, Nigeria

Two field experiments were conducted during 2000/2001 and 2001/2002 dry seasons under irrigation at Kwalkwalawa Research Fadama Farm of Usmanu Danfodiyo University, Sokoto to investigate the response of weed growth and bulb yield of garlic to intra-row spacing and mulching. The treatments consisted of three intra-row spacings (10, 15, and 20 cm) and four mulching rate (0, 5, 7 and 9 t/ha). These were laid out in split plot design and replicated three times. Intra-row spacing was assigned to main plots and mulching was allotted to sub plots. Gross and net plot sizes were 3 x 1.5 m and 2.5 x 1 m, respectively. Results indicated that the number of leaves/plant, weed growth and cured bulb yield responded significantly to intra-row spacing and mulching, except in 2000/2001 trial, when the effect of mulching on cured bulb yield was not significant. Based on the results obtained, it could be concluded that for optimum bulb yield in garlic, the intra-row spacing of 10 cm and 9 t/ha mulching rate should be adopted. field experiments were conducted during 2000/2001 and 2001/2002 dry seasons under irrigation at Kwalkwalawa Research Fadama (13°01' N, E and 300 m above sea level) to ascertain the effect of intra-row spacing and mulching on weed growth and yield of garlic. The treatments consisted of three intra-row spacings (10, 15 and 20 cm), and four mulching rates (0, 5, 7 and 9 t/ha) using rice straw. These were laid out in split plot design with three replications. Intra-row spacing was assigned to main plots while mulching was allotted to sub-plots. The intra-row spacing used was 20 cm. Gross and net plot sizes were 3 x 1.5 m and 2.5 x 1 m, respectively. In each trial, a local garlic variety named “Dagin-Kura” was used. Planting was done manually, using one clove per hole. In 2000/2001 season, planting was done on 2 nd December, 2000 while in 2001/2002 season cloves were sown on 16 th December, 2001. Immediately after planting, irrigation followed. For the first four weeks after planting, irrigation was carried out at three days interval. Thereafter, the irrigation frequency was extended to weekly basis throughout the remaining period of the plants’ growth. Irrigation was stopped two weeks before harvest. In both trials, farm yard manure at the rate of 20 t/ha was incorporated into the soil during land preparation and at four weeks after crop emergence, NPK 20:10:10 at the rate of 20 kg/ha was applied in a single dose. At two weeks after planting, all the experimental plots were hand weeded and then rice straw mulch at the rate of 5, 7 and 9 t/ha were applied to the appropriate plots. While control plots were further hand weeded at 4, 6 and 8 weeks after crop emergence, the mulched plots were left un-weeded. Bulbs were harvested at maturity, as indicated by slight yellowing and partial drying of the leaves and plant falling over. In both trials, observations were taken on stand count, number of leaves/plant, plant height, days to 50% bulb maturity, fresh bulb yield, cured bulb yield, bulb size, number of cloves/bulb, weed frequency, weed cover score and weed dry weight. The data obtained were subjected to analysis of variance and treatment effects were compared using least significant difference as described by Gomez and Gomez (1984).