RESPONSES OF ONION TO ARBUSCULAR MYCORRHIZAL FUNGI AND TO WATER STRESS IN TROPICAL PEAT SOIL OF WEST KALIMANTAN, INDONESIA

摘要

Peat soil is one of the soil types in West Kalimantan that is potentially used for onion cultivation. The main concern for onion cultivation in peat soil are its physical characteristics which is easy to store and release water. Onion planted during dry-season will grow well when supplied with enough irrigation. Therefore, the use of arbuscular mycorrhizal fungi (AMF) in onions cultivation during water stress is a potential alternative approach to be studied. This research is designed to study the response of onions to AMF application and to water stress treatments in peat soil of West Kalimantan. The main aim is to find out a specific recommendation for onion cultivation in peat soil with limited water supply. The experiment was conducted in polybags within a plastic-roof building at the Field Experimental Land of Faculty of Agriculture, Tanjungpura University. The research used Split Plot Experimental Design with three replications.. AMF treatments functioned as main-plot consisting of 2 levels. Water stress treatments functioned as sub-plot consisting of 4 levels. There were in total 8 treatment combinations and 32 experimental units. AMF used consisted of the mixture of 3 types of AMF, namely: Gigaspora margaritha, Glomus manihotis, and Acaulospora sp. Parameters observed for this paper consist of plant height, leaves per clump, tillers per polybag, and total plant dry weight. The results showed that water stress over a period of more than 4 weeks will be a major obstruction in onion cultivation in peat soil. Onion grown in peat soil with limited level water stress condition responded significantly to AMF application. During limited water supply, onion will grow well either at 3 or 5 days watering interval when combined with AMF application.