Vermicomposts have high porosity, aeration, drainage, water-holding capacity (nine times more than any other composts) and enhanced microbial activity, which make them excellent soil amendments or conditioners

One factor contributing to low crop productivity in Zimbabwe is the agricultural ecological imbalance that current farming and social systems have brought about.

What is produced on farms ends up in urban areas landfills, sewage ponds or water reservoirs as only chemical fertilisers are returned to farms.

The trees and tall grass in the forest (before fires) have maintained nature’s cyclic processes as no chemical fertilisers are applied to the many beautiful large trees and tall grass.

Dead leaves etc from the tree or grass are decomposed by soil microbes and nutrients are made available to the mother plant, a true personification of sustainable waste management.

We have often broken this circle with our continuous application of chemical fertilisers without returning organic waste back to farms.

When chemical fertilisers were first introduced in Zimbabwe, there was a lot of organic matter in our soils hence crops responded very well to chemical fertilisers.

The soils are getting tired and lack life as we continue to pump chemical fertilisers without the complementary organic matter and this has resulted in diminishing yields.

Zimbabwe produces about one million biodegradable organic waste (excluding sewage) in urban areas, most of which ends at landfills, it was established.

The use of organic matter such as animal manures, human waste, food wastes, yard wastes, sewage sludges and composts has long been recognised in agriculture as beneficial for plant growth, yield and the maintenance of soil fertility.

The new approaches to the use of organic amendments in farming have proven to be effective means of improving soil structure, enhancing soil fertility and increasing crop yields.

Organic matter is an excellent source of plant-available nutrients and its addition to soil maintains high microbial populations and an improved moisture-holding capacity of the soil.

Recently, there is increasing interest worldwide in the use of vermicomposts /earthworm excreta/vermicasts (also referred to as organic gold), which are products of a non-thermophilic bio degradation of organic materials through interactions between earthworms and micro organisms, as plant growth media and soil amendments.

Earthworms excreta (vermicast) is a nutritive organic fertiliser rich in humus, NPK, micronutrients, beneficial soil microbes; nitrogen-fixing, phosphate solubilising bacteria, actinomycets and growth hormones auxins, gibberlins and cytokinins.

Both vermicompost and its body liquid (vermiwash) are proven as both growth promoters and protectors for crop plants.

The vermicomposts have high porosity, aeration, drainage, water-holding capacity (nine times more than any other composts) and enhanced microbial activity, which make them excellent soil amendments or conditioners.

Imagine what would happen to our agriculture productivity if 50 percent of the one million biodegradable organic waste produced in Zimbabwe urban areas was returned to farms as an integral part of a sustainable society we are striving to achieve.

In response to the call to restore soil productivity as embodied in the Philippine Organic Agriculture Act of 2010, the Bureau of Soils and Water Management (BSWM) distributed a facility assistance to farmers and government sector partners for small-scale organic fertiliser (vermicompost) production.

Research work in Philippines with tobacco demonstrated that 15 bags (450 kg) of vermicompost could replace 50 percent of the chemical fertiliser requirements of traditional Virginia tobacco without reducing its yield and quality.

Similarly with corn – 10 bags (300kg) of vermicompost could replace 50 percent of the chemical fertiliser recommendation without reducing the grain yield of a white glutinous open pollinated corn variety.

Recent research at the Soil Ecology laboratory at Ohio State University demonstrated significant suppression of plant parasitic nematodes, above-ground foliar arthropod pests and both foliar and root plant diseases by soil drenches of aqueous extracts, produced from vermicomposts (worm tea).

In Zimbabwe, AGRITEX in association with Zim Earthworm Farms (The commercial producer of vermicompost in Harare) demonstrated at Domboshava that one 50kg bag of Compound D fertiliser mixed with two bags of vermicompost ( each 44kg ) increased maize yield by more than four times compared to compound D alone.

Written by Dr E. Whingwiri, a specialist in earthworm technology. For more information contact Tobacco Industry and Marketing Board on 263 4 613263/70/88/95; 613310/17/18/19; 613532; 613425; 613431; 613108; 613911; 613604; 613925. Switchboard Cell 0772 145 166-9 or email [email protected] . Visit our website on www.timb.co.zw