Response of shallots growth and yield to phosphate fertilizer and Trichoderma application on peat soil

Cultivating shallots on peat soils is quite challenging since it is considered less fertile regarding its high organic acid content and low nutrient availability. Trichoderma, as one of the plant-growth-promoting fungi (PGPF), is beneficial to promote shallots growth. However, there is still lack of information concerning its effectiveness and interaction effect with inorganic P fertilizer in peat soils. This study aimed to investigate the effect of Trichoderma application and P fertilization on the growth and yield of shallots on peat soils. A pot experiment arranged in a completely randomized design was conducted with two treatment factors. The first factor was P fertilizer comprised four application rates: 0, 100, 200, and 300 kg ha(-1). Meanwhile, as the second factor, Trichoderma treatment consisted of four application rates: 0, 2, 4, and 6 g plant(-1). The results showed an interaction effect of P treatment and Trichoderma on shallots growth and yield. A treatment combination of 2 g plant(-1) Trichoderma without P fertilizer addition increased yield by 34% compared to control. This yield was relatively similar to 100 kg ha(-1) P fertilizer without Trichoderma addition. It is proved that the Trichoderma application could reduce inorganic P fertilizer input.