Structure of Strata of the System

Based upon the structure of stratification the systems are further subdivided using two criteria:

a) Vertical Stratification: On this basis the systems can be grouped as follows:

i. Single layered: System consisting of single stories: Tree garden e.g. Silvi-horticultural system;

ii. Double layered: System consisting of double stories: Tree gardens e.g. Wheat and Paddy cultivations under popular in Uttarakhand is a common practice under Silvi-agricultural system;

iii. Multilayered: System consisting of multiple stories e.g. Horti-silvi-agricultural system or random assemblage of trees of variable heights with shrubs and herb in a home garden.

b) Horizontal stratification (Spacing): On this basis the systems can be grouped as follows:

i. Dense: System consisting of close spacing plantations e.g. Fuel wood plantations with shade loving crops under Silvi-agricultural system;

ii. Scattered: System consisting of sparse plantations in pastures: Tree gardens of Shade trees with tea/coffee e.g. Silvi-pastoral system;

iii. Mixed intercropping: System consisting of mixture of several components having variable spacing e.g. Horti-silvi-agricultural system or random assemblage of trees of variable heights with shrubs and herb in a home garden.

Functional Basis

This criterionfocuses the functional role of the system, usually furnished by the woody components. Besides yielding tangible usufructs- a direct source of income for the farmers, the trees also afford important series of intangible services which not only protect the sites rather also accord effective restoration of the lost vitality- an indirect source of profit optimization for the farmers. Based upon this criterion the following types of Agroforestry systems are recognized.

a) Productive agroforestry systems: These systems are primarily designed with basic objective of production of goods like timber and non timber forest produce (flower, fiber, floss, fuel, gum, resin, honey, silk, lac, fruits, food, natural, dyes, medicines, condiments etc.) for optimization of returns per unit area and per unit time on sustainable basis. Trees yielding the valuable products are planted on farm bunds with the crops or in alley or on wastelands in combination of other agricultural or horticultural or pastoral crops under these systems in a scientific manner with special care to minimize the tree crop interactions.

b) Protective agroforestry systems: These systems are primarily designed with basic objective of protection and amelioration of the adversities of a site. Trees are combined with crops to cope up with the soil fertility problems, reduce erosion hazards and boost climate resilience for optimization of returns per unit area and per unit time on sustainable basis, by restoring the healthy site conditions. These systems primarily include Silvipastoral systems raised on deficient sites. The Wind brakes, Shelter belts, soil conservation plantations with some pastoral crops and cover/ nurse crops etc., also represent the protective agroforestry systems.

c) Multipurpose agroforestry systems: If the Agroforestry systems aim at addressing both the benefits- protection and production, this becomes Multipurpose Agroforestry System.

Practically all the agroforestry systems can be said to be Multipurpose systems, since whenever there is a tree plantation, both protection and production objects are met with the tangible and intangible benefits of trees.

Spatial and Temporal Basis

a) Spatial agroforestry systems: The Spatial (also named as simultaneous) agroforestry systems the tree and crop components occupy the same land unitat the same time. There is significant overlap in the growth cycles of tree/crop components. As a result there is a direct interaction between the two componentsi.e. the trees and the crops.

The spatial agroforestry systems may have any of the following variants:

Mixed dense plantations: Components (Trees and Crops) are closely planted to form a high density agroforestry plantation, e.g. Home gardens;

Mixed sparse plantations: Components (trees and crops) are planted at wide spacing to form a low density agroforestry plantation, e.g. Trees in pastures, Scattered trees on agricultural lands.

Strip plantations: The components are aligned in fixed rows or strips. Tree may be used in single rows on farm bunds as boundary plantations of in strips as in case of Alley Cropping.

Simultaneous agroforestry systems include following practices:

- Alley cropping - Parklands

- Fodder/protein banks

- Live fences

- Line/ boundary plantings and - Home gardens.

b) Temporal agroforestry systems: The Temporal (also named as Sequential) agroforestry systems are those in which trees and crops occupy the same land unit at different timesand interaction between them is indirect. The growth of the crop and the tree components occur at different times even when both components may have been planted at the same time. One component species may grow rapidly, while the other grows slowly. Nutrient uptake peaks of the component species may also occur in a sequence, which makes the species complementary in the use of soil resources. Interactions between tree and crop components are reduced with time in this agroforestry practice.

In simultaneous agroforestry systems, management should aim at limiting inter-specific competition while in sequential practice, the farmer utilizes the residual effects of the trees. Thus, in shifting cultivation the farmers pile the cut trees into smaller area, burn them and then plant a new crop, which depends on the accumulated ash. In improved fallows, nitrogen fixing trees are deliberately planted to improve soil physical conditions and soil fertility in general, which benefits subsequent crops grown after harvesting the trees.

The Temporal or Sequential agroforestry systems may have any of the following variants:

Coincident: The components under this variant of AFS occupy the land together e.g. Tea/

Coffee under trees or pastures under trees.

Concomitant: The components under this variant of AFS the components stay together for certain period of time, e.g.Taungya

Intermittent: The components under this variant of AFS the annual/ seasonal crops are grown with perennial trees e.g. Paddy under Coconut or other MPTs or seasonal grazing under trees.

Interpolated: The crop components (the annual/ seasonal crops) under this variant of AFS may vary with same space and time, e.g. Home garden

Separate: The components under this variant of AFS the annual/ seasonal occupy the space during separate phases of time e.g. Shifting Cultivation.

Temporal or Sequential agroforestry systems are implanted through following practices:

- Improved Fallows - Rotational Wood lots - Taungya

Physiognomical Basis

Systems recognized with the Physiognomical characters are grouped under this classification system like:

Xero-morphic systems (under deserts’ conditions with acute water shortage and extreme climatic conditions);

Meso-morphic systems (common land conditions with moderate water availability and moderate climate) and

Hydro-morphic systems (in aqueous conditions, like paddy & fish etc.).

Floristical Basis

This criterion classifies the AFS on the basis of floristic compositions depicting the species contributing in the agroforestry e.g. Systems like: Wheat-Poplar; Sugar cane-Eucalyptus/

Poplar; Babool-Wheat-Vegetables; Teak-Moringa-grass-Palas-Bamboo; Rice-Tobacco-Chillies-Albizia, etc.

Ecological Basis

This criterion classifies the AFS on the basis of specific ecological (Climatic and edaphic) condition which support the AFS. Based upon this criterion the systems are classified into:

Tropical;

Subtropical Temperate

Subalpine Alpine

Further based upon the moisture conditions each of the aforesaid groups can further be distinguished into following types:

Wet Moist &

Dry systems

For a country like India which has a very wide variation in climatic, edaphic and physiographic conditions and with a large biodiversity of flora and fauna, it is really a difficult task to segregate systems into distinct forms upon this ecological criterion.

Socio-Economical Basis

Socio-economic criterion such as the scale of production and objective of production The AFSs are classified into following types:

Commercial AFS: This covers the large scale production AFS with basic objective of trade.

Normally farmers with high economic profile having large farms practice this AFS. Under this system the land may be of Government or corporate sector and the system is managed by corporate sectors or companies for production of industrial raw materials e.g. Eucalyptus with Sugarcane or Popular with sugarcane.

Subsistence AFS: This covers the scale production AFS with basic objective of subsistence to satisfy the livelihoods requirements. Normally farmers with moderate to low economic profile having medium area of farm sizes practice this AFS. Under this system the land is of farmer and the products are need based consisting of food, fodder, fruits and variety of non wood forest products useful for livelihood support.

Intermediate AFS: As he name itself indicates, these systems are having both subsistence and some commercial objectives. The surplus products of these systems are sold for economic gains which exceed the subsistence needs. The best example of these systems is Casuarina plantations with agricultural crops, or gum Arabic with paddy.

Shifting Cultivation

The term shifting cultivation refers to farming or agricultural systems in which land under natural vegetation is cleared, cropped with agricultural crops for a few years, and then left untended while the natural vegetation regenerates. The cultivation phase is usually short (2-3 years), but the regeneration phase, known as the fallow or bush fallow phase, is much longer (traditionally 10-20 years). The clearing is usually accomplished by the slash-and-burn method (hence the name slash-and-burn agriculture), employing simple hand tools. Useful trees and shrubs are left standing, and are sometimes lightly pruned; other trees and shrubs are pruned down to stumps of varying height to facilitate fast regeneration and support for climbing species that require staking. The lengths of the cropping and fallow phases vary considerably, the former being more variable; usually the fallow phase is several times longer than the cropping phase. The length of the fallow phase is considered critical to the success and sustainability of the practice. During

this period the soil, having been depleted of its fertility during the cropping period, regains its fertility through the regenerative action of the woody vegetation.

System Overview

Shifting cultivation is still the mainstay of traditional farming systems over vast areas of the tropics and subtropics. Estimates of area under shifting cultivation vary. One estimate still used repeatedly is that it extends over approximately 360 million hectares or 30 % of the exploitable soils of the world, and supports over 250 million people. Crutzen and Andreae (1990) estimated that shifting cultivation is practiced by 200 million people over 300 million-500 million hectares in the tropics. Although the system is dominant mainly in sparsely populated and lesser developed areas, where technological inputs for advanced agriculture such as fertilizers and farm machinery are not available, it is found in most parts of the tropics, especially in the humid and subhumid tropics of Africa and Latin America. Even in densely populated Southeast Asia, it is a major land-use in some parts

Taungya System

The word Taungya is a Burmese word which literarily means Hill cultivation (“Taung = Hill & ya = cultivation). Originally it was the local term in Burma for shifting cultivation. The Taungya system essentially consists of cultivation of annual agricultural crops along with forest trees during the early years of establishment of the forest plantation. In order words, taungya system is a forest plantation establishment system in which forest trees are raised in “combination with temporary cultivation of field or agricultural crops”. The Taungya system can be considered as a step forward in the process of transformation from shifting cultivation to agroforestry.

Shifting cultivation is a sequential practice of growing woody species and agricultural crops, whereas Taungya consists of simultaneous combinations of the two components during the early stages of forest plantation establishment. Although wood production is the ultimate objective in the Taungya system, the immediate motivation for practicing it, as in shifting cultivation and other smallholder systems, is food production.

In 1862 the Taungya system was used in Burma for the first time and it was introduced to Nigeria in 1928 in a silvicultural experiment at Sapoba (Edo State). It is now a widely used agroforestry practice in the rainforest and derived zones of Nigeria. The system which has been modified in various parts of the tropics in general and India in particular is essentially a variation of the traditional shifting cultivation whereby the farmers raise food crops for at least one year in a forest land, usually a part of a forest reserve. The successive areas are then converted into plantations as the farmers shift their farming activities progressively to new reforestation areas.

Teak (Tectona grandis) and Gamhaar Gmelina arborea are the most popular trees used in taungya, planted as stumps or seedlings. Apart from the growth of tree crops for the production of timber and other traditional wood products, the taungya system may be used to raise each crop such as cashew (Anacardiun occidentale). This species has been successfully introduced on poor sites in the savannas of southern Guinea, sown at a spacing of 2 × 4 m with maize, or sometimes cotton, between the rows of trees. The cashew begins fruit production around the fifth year; which provides good returns to the farmers. The tree crops are planted with agricultural crops at a wider spacing to avoid early shade impacts over the intercrops to ensure longer production duration from the agricultural crops. The choice of agricultural crops is based upon need and feeding habits of the farmers. The most commonly cultivated agricultural crops are bajara, barley, beans, bhajee (Amaranthus spp.), brinjal (Solanum melangena), cabbage (Brassica spp.), castor (Ricinus communis), chilli peppers (Capsicum spp.), coco yam (Colocasia antiquarum), cotton (Gossypum spp.), cucumber (Cucumis sativus), dasheen (Colocasia esculenta), dhal (Cajanus spp), ginger (Zingibar officinale), groundnut (Arachis hypogaea), linseed

(Linum usitatissimum), melon (Citrullus vulgaris - Cucumis melo), millet (Pennisetum spp, Panicum spp.), mustard (Brassica spp.), oats (Avena sativa), ochra (Hibiscus esculentus), papaya (Carica papaya), pineapple (Ananas comosus), potato (Solanum tuberosum), pumpkin (Cucurbita maxima), rye (Secale cereale), sesame (Sesamum indicum), sorrel (Hibiscus sabdariffa), soyabean (Glycine soja), sweet potato (Ipomoea batatas), tomato (Lycopersicum esculentum), tumeric (Curcuma longa spp.), wheat (Triticum spp.).

There are several agricultural species which are controversial and are excluded in plantations in some countries, such as bananas and plantains (Musa spp.), cassava (Manihot utilissima), maize (Zea mays), rice (Oryza sativa), sugar cane (Saccharum officinarium), tobacco (Nicotina tabacum) and yam (Dioscorea spp.). Limitation or exclusion of bananas and plantains is due to various reasons, among which are: to avoid human interference in the plantations (since the farmers are reluctant to cut or abandon a plant which continues to produce foodstuff), to conserve soil fertility, and to prevent young trees from being deformed. However, at Mayumbe, Congo Brazzaville, bananas combined with Terminalia superba seedlings are exploited during four or five years in state sylvo-bananiers, the spacing of the trees being 12 × 4 m with bananas in two or three intervening rows. Cassava is excluded in Dahomey and Uganda because it exhausts the soil, it has a long life and it attains a height of 2-3 m rapidly, thereby retarding the development of the tree crop. The same reason, fast growth, is given for the exclusion of maize in Malawi, Mauritius and Senegal. However, maize has had no significant effect on the mortality of teak (from stumps and seedlings) in plantations made in Gambari in Nigeria, but may have an effect on height growth according to the type of planting stock used. Tobacco may be excluded because it has a deleterious effect on soil nutrients and because of its inability to provide adequate soil cover and therefore the liability of the land on which it is planted to erode.

Hill rice is grown with tree crops particularly in Malaysia, Senegal and India (Assam and Kerala). The growth of trees gets enhanced because the rice suppresses the weeds. However, in Sri Lanka it is felt that the returns from rice are so high that farmers are likely to exert their influence to convert the land to single use agriculture. Sugar cane is generally excluded because it is a long-growing crop, because of fear of soil depletion and because it casts a heavy shade. Nevertheless, where it has been cultivated with considerable success in Assam, India and in Burma, the presence of the cane led to increased height growth of the tree seedlings. Intercropping is not only regarded as a tending operation to replace weeding but also a multiple land-use practice for joint production of wood with food. Depending on soil quality, crops may be sweet potatoes, soyabeans, peanuts, watermelons, or maize. In general, intercropping with legumes is preferred as it enriches the soil, provides green manure and also feed for animals. Depending on crops and, on the management skill, intercropping may yield 1.4-4.0 tons of food per hectare. In some places, it may yield 20 tons/ha of green leaves which are used as feed for animals (pigs) or as manure. The effect on tree growth has been observed as very favourable. Survival rate of Cunning hamiana is 5 percent higher than that of non-intercropped plantations and plant height is 33 percent greater. A further example of mixed cropping can be taken from the southern Pacific coast of Colombia where Cordia alliodora and Cedrela odorata are planted on small landholdings concurrently with the traditional crops of plantain, maize and cocoa (Theobroma cacao).

Although mixed cropping may be contrary to the thought of many foresters, accustomed to the tidy and regular appearance of their plantations, this system is practiced not only for traditional reasons, but because it suite the environment, maintains soil fertility and combats erosion and leaching. There is also an economic justification, since more production may be achieved from mixtures of crops, thus making full use of the space available. Good management is an important factor in intercropping with strict enforcement of any rules that may be laid down. In cultivating and in harvesting the agricultural crops, and particularly tubers, great care must be

exercised in order not to damage the roots of the tree crop. If creeping species are used, against the general rule, the farmers should provide bean-stakes or poles (in the case of yams) to prevent strangulation of the tree seedlings. It is important to emphasize that growth and yield of the agricultural crops are directly influenced by the spacing and density of the tree crop. Concomitant with these two factors are the rate of growth and relative crown size of the tree species.

The taungya system is a way to reduce the costs of forest plantations, and at the same time to contribute to solving social problems. In Campeche, Mexico where Cedrela mexicana, Swietenia macrophylla and Cordia ciricote were main species planted, the cost per hectare for planting and tending during 5 years, were reduced to as much as 27 percent of the normal cost because the revenues from the maize harvest. If mechanization is used the costs would further drop to 18 percent. The taungya system is practiced under following four variants:

a) Traditional Taungya: Also known as called ‘own your crop’ type. In this type, each farmer is allocated one or more plots and a plot area is about 0.5ha. Under this system, the farmers are responsible for site preparation for the tree planting, and in return for their labour, they are allowed to grow some food crops. e. g. maize, yams, cassava, etc.; till the forest trees such as Gmelina arborea, Tectona grandis, and Shorea robusta etc., inter-planted by the Forestry Department close their canopy. Planting of the food crops can continue up to 3-4 years depending, among other things, on the species raised after which the common agricultural crops are replaced by shade bearing crops like ginger, turmeric, black pepper etc., when the shade effect becomes a limiting factor for the agricultural crops.

b) Departmental taungya: This second type of taungya is also called as farming for pay. This has been extensively practiced in the high sal forest areas of Gorakhpur in Uttar Pradesh.

Under this system, farming is practiced by selected families under control of the Forestry

Under this system, farming is practiced by selected families under control of the Forestry