Friendly foes

Eupatorium being shredded i (Credit: Azam Zaidi) found in abundance in central Himalaya, two species of weeds -- Eupatorium adenophorum and Eupatorium adoratum -- have infested vast areas of forest, agricultural land and wastelands. While Eupatorium adenophorum is found between 4,000 ft and 6,500 ft, Eupatorium adoratum is found below 4,000 ft. The silviculture division of the forest department of West Bengal has developed a technique to convert this weed into a resource which involves the aerobic conversion of the weed into compost. By this technique, compost can be prepared in 25 days in summer and 40 days in winter.

In this process, the weeds are first collected, then chopped into small bits and finally dumped into specially designed compost rooms. The rooms have fibre glass roofs to trap heat. The chopped weeds are tightly packed in the compost rooms and sufficiently moistened with water. Micro-organisms begin to decompose the weeds into amino acids which act as nutrients for the plants. After the compost is ready, it is taken into the drying pit for drying and then stored in godowns.

According to Azam Zaidi of the silviculture division, West Bengal, "The Eupatorium compost is very light and is excellent for raising plants in a nursery as it takes less time -- only a year -- to raise seedlings by using this compost, compared to other composts which take nearly two years." Zaidi uses a mixture of Eupatorium compost, moss and coarse sand in the ratio of 2:1:1 for the nurseries. About 1,000 kg of Eupatorium is finally converted into 230 kg of compost. Eupatorium compost is also being used for growing vegetables. While the green matter of Eupatorium provides magnesium, the woody matter of the weeds provides potash and potassium.