Alternative of organic management of weeds in blueberry production in a volcanic soil of Chile

Production of organic blueberries (Vaccinium corymbosum L.) in Chile has increased in recent years and its main problem in vegetative and productive development is good organic weed control. The present study was carried out during the 2018-2019 season at Chillán (36°34’S, 72°06’W; 144 m a.s.l.), Chile, in a soil of volcanic origin. Two experiments were carried out to evaluate the effect of two soil conditioners that accelerate the decomposition of organic matter of vegetable origin, one of them as a mixture of vegetable oils (trade name as Fitosoil) and the other as plant extracts (trade name as Q-Tral active). The first experiment was under greenhouse conditions, Italian ryegrass (Lolium multiflorum L.) and white clover (Trifolium repens L.) were sown in separate pots with 100 seeds per species per pot with three replicates per treatment. The second experiment was in a 17-year-old plantation of organic blueberries, in 5-m plots with four replicates per treatment. The treatments were Fitosoil only in two doses and Fitosoil supplemented with Q-Tral active in one and two applications with two doses. Results indicate that Fitosoil alone has a short time to affect weeds and must be complemented with at least one application of Q-Tral active or another system to reduce interference. The recommended dose of 0.30 L m^‑2 of Fitosoil and Q-Tral active each, had a slow effect and does not decrease beyond 50% biomass of perennial weeds if it is applied only once. Increasing the dose of each one by 50% for complementary applications produces a greater and faster effect in perennial weeds but did not eradicate them, which would allow a rapid regrowth.