EFFECTS OF MANURE, TILLAGE AND MULCH ON THE GROWTH, YIELD AND QUALITY OF GARLIC (Allium sativum L.)

Abstract

Nine experiments were conducted in the field laboratory, USDA-Alliums’ project, Bangladesh Agricultural University, Mymensingh during rabi seasons of 2006-2009 with the main objective of determining the effect of manure, tillage and mulch on the growth, yield and quality of garlic. The manure experiment revealed that the plant height; number of leaves per plant; length and breadth of the longest leaf; fresh and dry weights of leaves, bulb & roots; breadth of bulb, total number of cloves and yield per plot were markedly influenced by the treatments. Among the different levels of organic manure, the highest dose of mustard oil cake (5 t/ha) was the best to influence the yield and yield contributing traits followed by the highest dose of cowdung (25 t/ha). The experiment under zero tillage condition further demonstrated that organic manure had remarkable influence on almost all the parameters observed. The tallest plant, maximum number of leaves, highest breadth and length of the longest leaves were recorded from the treatment of mustard oil cake. But on the basis of economic analysis, maximum net return and BCR (2.59) were recorded with cowdung. Plants grown with mulch showed better performance in most of the yield contributing attributes, and ultimately produced higher yield than the nonmulched plants. Again, plants grown with 10 cm thickness of water hyacinth mulch gave better results in most of the cases. The treatment combination of zero tillage with 10 cm thick mulch produced the highest yield (9.92 t/ha). Moreover, zero tillage showed the highest storage quality because it resulted in the lowest weight loss (8.45%), insect infested bulbs (6.67%) as well as rotten bulbs (2.44%) even after 150 days of storage. In contrast, conventional tillage with no mulch and 6 cm thick mulch were found to have lower storage quality compared to the other treatment combinations. Two experiments were also conducted to study the effects of green manuring and organic sources of nutrients on the growth and yield of garlic. One experiment consisted of three green manuring (GM) species, namely Seshania rostrata, S. aculeata and Phaseolus mungo, and 6 organic manures viz. cowdung, compost, mustard oil cake, rotten water hyacinth and bone meal. The growth of the garlic was higher when it was cultivated with the residual effect of S. rostrata compared to seasonal fallow land (control). On the other hand, in another experiment P. mungo was found to have superior effect in terms of yield and yield contributing characters of garlic when this GM was incorporated with organic manure. Garlic grown under zero tillage showed remarkable variation in terms of percent emergence. However. differences were not significant between rice straw and water hyacinth mulch. It was also noticed that both the tillage conditions as well as mulches exerted profound effects on the yield and yield contributing parameters. Puddling and zero tillage practices resulted in higher yield compared to the conventional tillage. The treatment having organic and inorganic fertilizers (50% of the recommended dose of inorganic fertilizers + 2 ton of mustard oil cake/ha) produced the highest yield (11.5 t/ha) followed by 50% of the recommended dose of inorganic fertilizers + 15 ton cowdung/ha and the treatment control showed poor performance (6.2 t/ha). Integrated approach of organic farming (Green manure + organic manure + mulch) had the most pronounced effect compared to the control or inorganic fertilizers.