Document Type : Weed Science
Authors
Abstract
Adding fresh manure to cropland results in an increased weed population ensued from seeds present in the manure. Composting process can reduce weed seed viability. In an experiment seed viability of sixteen important weed species in forage fields were studied during composting process. Seeds enclosed within nylon mesh bags were buried into the two compost piles, at 0.5, 1 and 1.5 meters depths for 4 months in early summer in 2004. Two compost piles made from cow manure and one of them was covered by plastic sheets. Seed packets were removed monthly for 4 months to test seed viability.The results showed a dependence between weed seed viability lost in compost and composting high temperature. Compost piles tended to have higher temperatures at 0.5 meter (60-70°C) than 1 and 1.5m at first and second months, then the temperature decreased. This is probably because the pile was better aerated at the depth of 0.5m. Seed viability loss was different for each species. Some of species showed about 100% viability loss after one month. Weed seeds lost their viability at the 0.5m depth having higher temperature compared to deeper layers. In the covered compost pile, seed viability loss and temperature were lower than in uncovered compost pile. Almost all weed species were killed after being placed for 2 months at 0.5m depth of uncovered compost piles in summer. However, only viability of Cuscuta monogyna, Goldbachia laevigata, Chenopodium album and Amaranthus retroflexus were decreased after 3 months. Chemical test showed that water content reduced after one month composting at three different depths. pH values varied between 7 to 8. Carbon to nitrogen ratio was between 15-20 after three months of composting at three above-mentioned depths.
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