Norman Q. Arancon

The influence of humic acids derived from earthworm-processed organic wastes on plant growth

Some effects of humic acids, formed during the breakdown of organic wastes by earthworms (vermicomposting), on plant growth were evaluated. In the first experiment, humic acids were extracted from pig manure vermicompost using the classic alkali/acid fractionation procedure and mixed with a soilless container medium (Metro-Mix 360), to provide a range of 0, 50, 100, 150, 200, 250, 500, 1,000, 2,000, and 4,000 mg of humate per kg of dry weight of container medium, and tomato seedlings were grown in the mixtures. In the second experiment, humates extracted from pig manure and food wastes vermicomposts were mixed with vermiculite to provide a range of 0, 50, 125, 250, 500, 1,000, and 4,000 mg of humate per kg of dry weight of the container medium, and cucumber seedlings were grown in the mixtures. Both tomato and cucumber seedlings were watered daily with a solution containing all nutrients required to ensure that any differences in growth responses were not nutrient-mediated. The incorporation of both types of vermicompost-derived humic acids, into either type of soilless plant growth media, increased the growth of tomato and cucumber plants significantly, in terms of plant heights, leaf areas, shoot and root dry weights. Plant growth increased with increasing concentrations of humic acids incorporated into the medium up to a certain proportion, but this differed according to the plant species, the source of the vermicompost, and the nature of the container medium. Plant growth tended to be increased by treatments of the plants with 50-500 mg/kg humic acids, but often decreased significantly when the concentrations of humic acids derived in the container medium exceeded 500-1,000 mg/kg. These growth responses were most probably due to hormone-like activity of humic acids from the vermicomposts or could have been due to plant growth hormones adsorbed onto the humates.

Influence of earthworm-processed pig manure on the growth and yield of greenhouse tomatoes

The eAects of earthworm-processed pig manure (vermicompost) on germination, growth, and yields of tomato (Lycopersicon esculentum Mill.) plants were evaluated under glasshouse conditions. Tomatoes were germinated and grown in a standard commercial greenhouse container medium (Metro-Mix 360), substituted with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% (by volume) pig manure vermicompost. The control consisted of Metro-Mix 360 alone without vermicompost. Plants were grown for 158 days and were frequently supplied with a complete mineral nutrient solution. The germination rates of tomato seeds increased significantly upon substitution of Metro-Mix 360 with 20%, 30%, and 40% vermicompost. Seedlings grown in 100% pig manure vermicompost were significantly shorter, had fewer leaves, and weighed less than those in Metro-Mix 360 controls. Incorporation of 10% or 50% vermicompost into Metro-Mix 360 increased the dry weights of tomato seedlings significantly compared to those grown in the Metro-Mix 360 controls. The largest marketable yield was in the substitution of Metro-Mix 360 with 20% vermicompost (5.1 kg/plant). The average weight of a tomato fruit in substitution of Metro-Mix 360 with 20% vermicompost was 12.4% greater than that in the Metro-Mix 360 control. Substitution of Metro-Mix 360 with 10%, 20%, and 40% vermicompost reduced the proportions of fruits that were non-marketable, and produced more large size (diameter > 6:4 cm) than small size (diameter < 5:8 cm) tomato fruits. There was no significant diAerence in overall tomato yields between Metro-Mix 360 and 100% pig manure vermicompost. Some of the growth and yield enhancement resulting from substitution of Metro-Mix 360 with pig manure vermicompost could be attributed to the high mineral N concentration of the pig manure vermicompost. However, other factors might have also been involved since all plants were frequently supplied with all required nutrients. These factors need to be investigated in future studies. ” 2000 Elsevier Science Ltd. All rights reserved.

THE INFLUENCE OF EARTHWORM-PROCESSED PIG MANURE ON THE GROWTH AND PRODUCTIVITY OF MARIGOLDS

The effects of additions of earthworm-processed pig manure (vermicompost) on the growth and productivity of French marigold (Tagetes patula) plants were evaluated under glasshouse conditions. Marigolds were germinated and grown in a standard commercial greenhouse container medium (Metro-Mix 360), substituted with 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% (by volume) pig manure vermicompost. The control consisted of Metro-Mix 360 alone without vermicompost. Plants were supplied regularly with a complete mineral nutrient solution for 121 days. The greatest vegetative growth resulted from substitution of Metro-Mix 360 with 30% and 40% pig manure vermicompost, and the lowest growth was in the potting mixtures containing 90% and 100% vermicompost. Most flower buds occurred in the potting mixtures containing 40% pig manure vermicompost (19.4 buds), and fewest in the potting mixtures containing 100% vermicompost. Marigolds grown in Metro-Mix 360 substituted with 90% and 100% pig manure vermicompost had the fewest and smallest flowers. After substitution of Metro-Mix 360 with 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% vermicompost, the marigold roots were larger than those of plants grown in the Metro-Mix 360 controls. Substitution of Metro-Mix 360 with any concentration of pig manure vermicompost, with all needed nutrients provided, increased the overall nitrate-nitrogen concentrations of the marigold leaf tissues at flowering stage. Some of the marigold growth and productivity enhancement, resulting from substitution of Metro-Mix 360 with pig manure vermicompost, may be explained by nutritional factors; However, other, factors, such as plant-growth regulators and humates, might have also been involved since all plants were supplied regularly with all required nutrients.

Effects of vermicomposts on growth and marketable fruits of field-grown tomatoes, peppers and strawberries

Summary Vermicomposts, produced commercially from cattle manure, market food waste and recycled paper waste, were applied to small replicated field plots planted with tomatoes (Lycopersicon esculentum) and bell peppers (Capsicum anuum grossum) at rates of 10 t ha-1 or 20 t ha-1 in 1999 and at rates of 5 t ha-1 or 10 t ha-1 in 2000. Food waste and recycled paper vermicomposts were applied at the rates of 5 t ha-1 or 10 t ha-1 in 2000 to replicated plots planted with strawberries (Fragaria spp.). Inorganic control plots were treated with recommended rates of fertilizers only and all of the vermicompost-treated plots were supplemented with amounts of inorganic fertilizers to equalize the initial N levels available to plants in all plots at transplanting. The marketable tomato yields in all vermicompost-treated plots were consistently greater than yields from the inorganic fertilizer-treated plots. There were significant increases in shoot weights, leaf areas and total and marketable fruit yields of pepper plants from plots treated with vermicomposts compared to those from plots treated with inorganic fertilizer only. Leaf areas, numbers of strawberry suckers, numbers of flowers, shoot weights, and total marketable strawberry yields increased significantly in plots treated with vermicompost compared to those that received inorganic fertilizers only. The improvements in plant growth and increases in fruit yields could be due partially to large increases in soil microbial biomass after vermicompost applications, leading to production of hormones or humates in the vermicomposts acting as plant-growth regulators independent of nutrient supply.

Effects of humic acids derived from cattle, food and paper-waste vermicomposts on growth of greenhouse plants

Humic acids were extracted from cattle, food and paper-waste vermicomposts using an alkali/acid fractionation procedure which produced 1 g dry wt humates from 400 g vermicompost. They were applied to a soilless growth medium, Metro-Mix 360 (MM360), at rates of 0, 250 or 500 mg humates kg - 1 dry wt of container medium, to young marigold, pepper, and strawberry plants grown in pots in the greenhouse. A range of 0, 20, 100, 150, 200, 250, 500, 1000, 2000, 4000 mg of humates kg - 1 of container medium was used for tomatoes. Effects of the humic acids on the plant heights, leaf areas, shoot dry weights, root dry weights of peppers, tomatoes and marigolds and numbers of fruits of strawberries were assessed. Substitution of humates ranging from 250-1000 mg kg - 1 MM360 increased root growth of marigolds and peppers, and increased root growth and numbers of fruits of strawberries significantly (P ≤ 0.05). Leaf areas, plant heights and above-ground dry matter weights increased considerably in plants grown in pots containing humic acids but they were not significantly different from those grown in MM360 only (P ≤ 0.05).

The trophic diversity of nematode communities in soils treated with vermicompost

The effects of vermicomposts on plant parasitic, fungivorous and baterivorous nematode populations were investigated in grape (Vitis vinifera) and strawberry (Fragaria ananasa) field crops. Commercially-produced vermicomposts derived from recycled paper, and supermarket food waste were applied to replicated plots at the rates of 2.5 t ha - 1 or 5.0 t ha - 1 for the grape crop and 5.0 t ha - 1 or 10 t ha - 1 for the strawberry crops. All vermicompost treatments were supplemented with inorganic fertilizer to balance the initial availability of macronutrients especially N, to the crop in all plots. After extraction from soil samples in Baermann funnels, nematodes were identified to trophic levels under a stereomicroscope. Soils from all of the vermicompost-treated plots contained smaller populations of plant parasitic nematodes than soil from inorganic fertilizer-treated plots. Conversely, populations of fungivorous nematodes and to lesser extent bacterivorous nematodes increased in the vermicompost-treated plots in comparison with those in plots treated with inorganic fertilizers.