The term forage means the plants used for feeding domestic animals, this includes both fodder plants and pasture plants. Forage crops have served as an important source of feed of domestic animals for a long period, although the history of their use is shorter than that of the use of native forages. Nearly 200 plant species have been known as forage crops. The most commonly used forage plant species are bluegrass, timothy, brome grass, fescues, red clover, white clover and alfalfa. Alfalfa continues to grow in popularity because of its high quality, but its production is limited to only the better soil types. Corn grown for silage is increasing in popularity as forage on many dairy farms.
Agriculture and animal husbandry in India are interwoven with the intricate fabric of the society in cultural, religious and economical ways as mixed farming and livestock rearing forms an integral part of rural living. The benefit of forage crops to humans, however, is not limited only to livestock production. They also contribute to food crop production and many other aspects of human life through the following: (a) soil conservation and amelioration; (b) landscape and wildlife conservation; (c) improvement and protection of the environment from pollution; (d) reclamation, revegetation and ecological repair of degraded land; (e) outdoor recreation and pleasure; (f) potential conversion of biomass to energy; (g) sources of fiber for the manufacture of paper and building materials; (h) sources of extracts for high-quality proteins and medical and pharmaceutical products.
The history of forage crops can be traced back to about 1300 BC when alfalfa was cultivated in Turkey. Relatively widespread use of forage crops, however, appeared much later, around the beginning of the Christian era, when several species were cultivated in several areas of the world, mainly in the Mediterranean region of Europe. Little happened between the fifth and twelfth centuries, but the thirteenth to nineteenth centuries saw great advances in forage crops. They contributed to the development of mixed farming in the European agricultural revolution, and spread globally with the expansion of Europeans into other continents. The use of forage crops developed also with the rise of industrialized agriculture, which involved the use of new techniques and industrial inputs, the application of science and the rise of a forage seed industry. Since the first domestication of grazing animals in ancient times, forage has been a major concern of humans in the husbandry of animals. The early recognition of the importance of forage is also demonstrated by the early development of forage conservation. Forage is conserved as hay through drying or as silage through fermentation. The main objective of the conservation of forage is to preserve it at the optimum stage of growth for use during those seasons when the forage is unavailable.
Forage needs to be seeded in a fine, firm seedbed often achieved by cultivating the soil. The soil has to be analysed, and the proper amounts of nutrients added for the forage to grow. It can then be grazed by farm animals or it can be harvested and stored for winter feeding. Harvested forage is stored as dry hay, haylage or silage. In recent years there has been a dramatic shift towards the utilization of silage. Silage is forage with a higher moisture content that is stored in a structure called silo where oxygen is eliminated and the forage ferments.
Soil fertility management for forage crops is a continuous process that begins well before the forage crop is established. In the pre-establishment phase the soil conditions are adjusted to provide optimum soil fertility when the crop is established. At establishment the fertility program should deal with any last-minute small adjustments in soil fertility and any requirements for getting the plants established, such as a starter fertilizer. Finally, once the crop is established the fertility program focuses on maintaining good soil fertility levels for the life of the forage stand.
A great scope exists to increase forage availability through strengthening research and development activities in grasslands/grazing lands/rangelands. The future strategies should focus on developing dual type grain-cum-fodder crop varieties, stay green QPM maize varieties, application of biotechnology to evolve genetically engineered improved varieties tolerant to abiotic and biotic stresses and enhancing forage productivity in berseem (Egyptian clover), lucerne, oat, forage sorghum, range grasses and legumes as well as fodder trees, processing and nutrient enrichment of low quality roughage and designing economic feeding systems for different categories of livestock under different rearing systems.
Forage crop improvement requires a long-term and multidisciplinary approach involving several disciplines, viz. plant breeding, genetics, agronomy, pathology, nematology, entomology, physiology, biotechnology and animal nutrition, etc. A thorough understanding of species relationships, chromosomal constitution, genome structure, putative parentage and extent of possible gene exchange/recombination and nature of polyploidy is also required for the breeding programme. The strategy for various crops varies as per the problems encountered in particular species. Forage crop improvement has its own limitations. Many aspects related to forage breeding, plant genetic resources, plant-protection measures, forage quality, palatability and seed production need to be appropriately addressed adopting an integrated approach.
Some of the general constraints/limitations in forage crop improvement and production are as follows:
- Non-availability of sufficient quantity of quality fodder seeds as the crop for fodder is harvested before seed set and also the non-availability of dual-purpose varieties,
- Non-synchronous flowering /anthesis and spikelet
- Maturity, abscission of spikelet’s after maturity in grasses and the presence of large
- Number of sterile glumes in grasses,
- Overlapping of vegetative and reproductive
- Growth phases, uneven pod setting, non-synchronous maturity and seed shattering in
- Forage legumes and
- Apodictic nature of most of the tropical forage grasses that
- Limits their genetic improvement
The improvement of forage crops through biotechnological approach has started in late eighties has made remarkable headway at the global level. The various biotechnological tools include molecular techniques for understanding the genetic structure of the plants, inserting foreign genes directly into the plant genome, in-vitro regeneration of plants from any plant part. A number of techniques such as embryo rescue, micro-propagation, androgenic haploid plant production and creation of novel variations help at one or more steps involved in conventional breeding methods. These techniques save time and energy required for conventional methods. Genetic mapping and gene tagging in forage species have not been attempted much.
Systematic forage crop breeding programmes at the research institutions under the Indian Council of Agricultural Research (ICAR) and the State Agricultural Universities (SAUs) have led to the development and release of a large number of improved varieties in different forage crops suitable for different agro-ecological zones.
Forage crops occupy an important position across the world. For developing varieties resistant to various pests and diseases and to improve forage quality and quantity, there is a continuous need of diverse genetic resources. Acquisition of diverse and superior forage germplasm plays an important role in the development of varieties. Keeping this in mind, the Germplasm Exchange Division played the pivotal role and introduced a total of 13,181 accessions of forage crops into India mainly from Australia, Italy, USA, UK, Brazil, Germany, Egypt, Ethiopia, Bulgaria, Philippines, Singapore, Costa Rica, Zimbabwe, Japan, Russia and New Zealand. Most of the introduced germplasm was supplied to Indian Grassland and Fodder Research Institute and All India Coordinated Research Project on Forage Crops located at Jhansi, Uttar Pradesh. Some promising varieties introduced into India were directly used for cultivation. Forage species of Sesbania rostrata, Sesbania aculeata, Pennisetum squalatum and Pennisetum pedicellatum from different Institutes were registered for various traits and their seeds have been deposited for long-term storage in National Gene Bank. Details of trait specific germplasm, wild germplasm introduced and conserved in forage crops in India are highlighted.
The forage production is a consequence of the interactions between genotypes and environment. A crop environment may be regarded as having two components, the gross environment, which takes into account the environmental factors affecting crop growth, and the current environment, which takes into account the general soil and atmospheric conditions outside the crop and also the changes caused by the plant community. However, the phenomenal increase in productivity is possible mainly through better varieties, seeds, fertilizers and agronomic technology.