Weed seed inhibition under solarization treatment with different mulch color in tropical highland organic farming system

Abstract

Weeds are the major problem in organic crop production. Soil solarization is a method using clear plastic films to increase soil temperature to control pest organisms such as fungi, bacteria, and weed seeds. The study aimed to evaluate the effect of different plastic mulch color on weed seed inhibition. The experiment was carried out in CAPS Research Station located in Air Duku Village, Bengkulu, Indonesia at 1054 m above sea level, arranged in Randomized Completely Block Design with 3 replications. Treatments comprised 4 different colors of plastic films, i.e silver-black, black, clear, and red as well as control (without mulch). Plastic mulch was laid on 1 m wide x 2 m long raised soil bed for four weeks from April 20-May 23, 2016. Soil temperature underneath plastic mulch at depth of 5, 10, 15, 20 cm from the surface were measured daily at noon. After incubation, soil sample was collected from 0-5; 5-10; 10-15; 15-20 cm depths. Weed seed germination of each soil sample was tested in the greenhouse. A number of weeds were observed after four weeks. The experiment indicated that a month of soil solarization using clear plastic mulch resulted in greatest soil temperature, increasing by 0.54-1.84% as compared to control. Treatment of plastic mulches was effective to suppress seed inhibition at the soil depth of 0-15 cm, as indicated by numbers of germinated weed and its dry matter. Longer soil solarization is necessary to obtain the highest reduction of weed growth in the tropical highland organic farming system.