Arun Kumar
In view of the fast changing agricultural scenario, a drift has resulted from sustenance to commercial farming. To maximize the yield, farmers are using high yielding varieties and hybrids with higher inputs of chemical fertilizers and pesticides to a large extent. The newly release hybrids, indiscriminate and injudicious use of fertilizers and pesticides have resulted in susceptibility to various diseases. Besides this, a number of other problems such as soil, water and air pollution, residual toxicity in fruit and vegetables, resistance to insects and pathogens, mortality of parasites, predators and pollinators, and resurgence with outbreaks of secondary pests have also cropped up.
With increasing environmental awareness, the focus has now shifted towards search for viable alternatives of disease control methods. Traditional farming systems are one of the sources of ‘non-chemical’ disease management strategies. The simple cultural practices such as increasing the seed rate to compensate for pest damage, adjusting the time of sowing to avoid pest damage, intercropping, trap cropping and crop rotation have been found to provide adequate protection from pest damage with no additional cost and without harmful effects on the environment.
Traditional farming practices developed by agrarian societies in particular ecological setting. Sustainability in these systems has been derived after a long tenure through trial and error with crops and practices. Most of the practices of traditional farmers for disease management in developing countries consist of cultural control. Some of the traditional practices of practical importance adopted by the farmers of semi-arid and arid Rajasthan which include districts of Barmer, Jodhpur, Pali and Jaipur are discussed in this paper.
Traditional Fungicides
Ash (farmers call it ‘lichhmi’) is frequently used by farmers in desert areas as a fungicide. Ash of the kitchen fire is saved, to be used later to dust on crops to prevent fungal infections. Ash as a fungicide is used in the following ways.
- Ten-day old pearl millet flour and ash are mixed in the ratio of 1:4 and dusted on the cumin crop before flowering to prevent infection of powdery mildew. This practice is being followed in Pali and Barmer districts.
- Jaipur farmers dust the ash (50-60 kg ha-1) on the growing crop of Lucerne (Medicago sativa) to check the growth of dodder (Cuscuta). Nowadays, farmers use a mixture of ash with some common salt for getting better control.
- Ash (2-3 kg) is mixed with castor oil (0.7-0.8 kg). This mixture is spread on the seedbed of cotton (0.01 ha) to control ‘damping-off’ disease.
- Farmers dust the ash at the rate of 50-60 kg ha-1 on mustard crop to prevent various diseases like white rust, downy mildew and powdery mildew.
- A spoonful of ‘hing’ (Asafoetida) powder is placed on the lower rotted portion of bottle gourd vine with a fine cloth bandage around it to prevent rotting.
Biological Control
Farmers use the following biological methods.
- Some farmers of Jodhpur district add copious amount of organic matter (Farm Yard Manure @ 10-25 t ha-1) in chilli fields to encourage the activities of microbial antagonists.
- In Pali district, extract of bark of Indian mesquite (Prosopis juliflora) and Aanwal (Cassia auriculata) is sprayed on chilli crop. This provides protection against diseases like leaf-curl, powdery mildew and leaf spots.
Organic Soil Amendments
Farmers of Jaipur district collect the leaves of ‘Besharam’ (Ipomoea biloba) and ‘Aak’ (Calotropis sp.) and stems of ‘Kheemp’ (Leptadaenia pyrotechnica) in a pit after cutting and chaffing. They add ash, common salt, animal dung, livestock urine and excreta of bats and birds in it. This matter is allowed to rot for 2-3 months. Completely rotted manure thus obtained, is mixed with irrigation water and applied to onion, garlic and chilli crops at the time of vegetative growth. This enhances the crop vigour and protects from diseases and pests.
Cultural Practices
- Multiple cropping: In arid area, traditional ‘mixture’ sowing is practiced. Seeds of pearl millet are sown with rainy season legumes (mung bean, moth bean and cluster bean) and sesame in the ratio of 7:1. Besides this, some farmers also grow cucurbits (melon, Citrullus spp. etc.) in addition to legumes. This practice is used to minimize the crop losses due to onset of drought or pests and diseases along with the problem of ‘rode’ (soil crusting).
- Fallowing: It is an old traditional practice in desert areas where crops are not planted in a field for 2-4 years. Besides agronomic benefits, this practice also helps in reducing losses from plant diseases. However, the practice of fallowing is gradually becoming less popular among young farmers because of shrinking land resources.
- Crop rotation: Growing economic plants in recurring succession and in defined sequence on the same land is a common practice in this part of the State. There are double-cropped areas with sprinkler irrigation facilities in some pockets of Barmer district. In these areas the farmers cultivate cash crops like ‘Zeera’ or cumin (Cuminum cyminum) and ‘Isabgol’ (Plantago ovata) in the Rabi season. In cumin crop there is a serious problem of wilt disease caused by Fusarium oxysporum f. sp. cumini. Farmers are rotating the crops with mustard and wheat in Rabi and with pearl millet during the rainy season to reduce the incidence of wilt.
- Flooding: Flooding has been used for insect and weed management. It has been noted that fungi, bacteria and actinomycete populations decline in flooded soil. The anaerobic or near anaerobic conditions produced by flooding are known to reduce the population of many fungal, nematode and soil pathogens
- In Pali district, the cotton crop was severely affected by sooty mould caused by Leptoxyphium fumago and Vermiculariopsiella sp. growing on leaf secretions of some insects. An innovative farmer practiced flooding the field with water, even in the rainy days, to suppress the fungal attack on the crop. He claimed to have successfully eliminated the disease from the cotton field using this practice.
Sustainability of Traditional Practices
These practices were assessed with regard to their sustainability. It was observed that all the practices discussed in this paper are de facto sustainable, as they have supported a large human population on the same land for hundreds of years without environmental degradation and serious reduction of crop productivity with low external inputs, however a few of the practices were labour intensive. Most of the practices help in bringing back a considerable amount of organic matter to the land, ensuring high levels of microbial diversity in the soil.
Arun Kumar
Central Arid Zone Research Institute, Jodhpur 342 003, Rajasthan, E-Mail: arpurster@gmail.com
