Differential Responses of <i>Allium</i><i> </i><i>sativum.</i><i> </i><i>(L)</i> (Alliaceae) to Compost Application and Mycorrhizal Inoculation Under Field Conditions

Although the dependency of garlic to arbuscular mycorrhiza fungi (AMF) has been proven in pot experiment with an appropriate 2/3 compost/soil ratio, whether this performance can also be successful under field conditions is yet to be investigated on growth and yield attributes of the crop. The experimental design was a randomized complete block comprising six treatments replicated four times each, where the main treatment 2/3 (compost/soil) ratio +30 g AMF was compared to 1/3 (compost/soil) ratio +30 g AMF, with or without NPK-fertilizer. How different fertilizer receipts affected the Allium sativum growth and yield parameters, as well as the post-harvest soil physico-chemical properties was assessed and compared. The growth and productivity of garlic positively responded and in repeated cropping campaigns to the integrated application of 2/3 ratio (compost/soil) inoculated with 30g mycorrhiza. Additional application of 5g NPK-fertilizer to compost-soil-mycorrhiza mix was detrimental to garlic growth, because of excess nutrients that hampered the garlic-plant mycorrhization frequency and intensity. Whereas organic treatment increased the soil pH from 6.07 prior to cultivation to 6.8 at post-harvest, the soil Mg, Ca and phosphate contents were instead reduced in post-harvest soil following assimilation by the host plant, while the organic matter content was significantly enhanced due to improved soil fertility by compost. For a sustainable production of garlic in the field, application of 2/3 ratio (compost/soil) inoculated with 30g mycorrhiza within the host-plant rhizosphere, and without NPK-fertilizer is highly suggested to enrich the soil in nutrients and organic matters.