Alternate land use systems – agroforestry systems
16.1 Introduction
Land use planning is a scientific evaluation of land area in question, study of
existing land use and their capabilities, suggesting alternative uses and predict the
possible impact to arrive at sound decisions for sustained land use. Land use is the
application of human control of natural ecosystems in a relatively systematic manner
in order to derive benefits from it.
Soils of the SAT regions are poor in fertility, structurally degraded, undulating
in topography and mostly shallow in depth. Since land resources vary spatially, all
drylands are not suitable for arable farming. Soils belonging to land capability classes
IV and above are not very suitable to arable farming due to certain inherent
limitations. Sustainable dryland agriculture demands land capability based alternate
land use technologies and management strategies.
16.2 Alternate land use systems
A pattern of land use that is different from the existing or the conventional can
be described as an alternative land use system. The term alternate land use is
applicable to all classes of land to generate assured income with minimum risk
through efficient use of available resources. The advantages of alternative land use
systems are
• Optimising resource use by enhancing biological productivity and
profitability,
• Conserving and enhancing the quality of resource base,
• Integrating crops (arable and pastoral) and livestock,
• Making agriculture less dependent on off-farm inputs,
• Generating employment potential, and
• Improving overall quality of farm life.
Commonly known alternate land use systems are agroforestry
(agrisilviculture, silvipasture, agrihorticulture and alley cropping), tree farming and
ley farming. The possible alternate land uses as per land capability classification and
rainfall is furnished in Fig.16.1
Fig. 16.1 Possible alternate land uses as influenced by resource
(LCC and mean annual rainfall) capability (Katyal et al., 1994).
16.3 Agroforestry
Agroforestry may be defined as an integrated self sustained land management
system, which involves deliberate introduction/retention of woody components with
agricultural crops including pasture/livestock, simultaneously or sequentially on the
same unit of land, meeting the ecological and socio-economic needs of people. It is
also defined as a collective name of land use systems and technologies where woody
perennials are deliberately used from the same land management units as
agricultural crops and/or animals in some form of special arrangement of temporal
sequence.
In agroforestry systems, there is both ecological and economic interaction
between different components. An agroforestry system is more acceptable than tree
farming alone, since the intercropped annuals regulate income when the trees are
too young to yield beneficial produce.
The different agroforestry systems are:
16.3.1 Agri-silviculture
This alternate land use system combines perennial arboreals with annual
arable crops. It integrate crops and trees. Tree component gives fodder, fuel or
timber, including green leaf manure. It is ideal for class IV soils of drylands with
annual rainfall around 750 mm.
Eg: Leucaena leucocephala + Sorghum
Sesbania aegyptica + Pulses
16.3.2 Silvi-pastoral system
This system is primarily meant for augmenting the scarce fodder supply. This
system integrate pasture and/or animals with trees (Fig.16.2).
Eg: Acacia + Cenchrus + Stylosanthus
Sissoo + Cenchrus + Stylosanthus
Fig. 16.2 Silvipasture system
16.3.3 Agri-silvi-pastoral system
This system integrate crop, pasture and/or animals with trees. Woody
perennials, preferably of fodder value, are introduced deliberately. Such systems can
be used for food production and soil conservation besides providing fodder and fuel.
16.3.4 Agri – horticultural system
It is one form of agroforestry in which the tree component is fruit tree. It is
also called as food-cum-fruit system in which short duration arable crops are raised
in the interspaces of fruit trees. Some of the fruit trees that can be considered are
guava, pomogranate, custard apple, sapota and mango. Pulses are the important
arable crops for this system (Fig.16.3). However, depending on the requirements,
crops like sorghum and pearl millet can be grown in the interspaces of fruit trees.
Fig. 16. 3 Mango + groundnut
16.3.5 Horti – pastoral system
Horti-pastoral system is an agroforestry system involving integration of fruit
trees with pasture. Guava, custard apple and ber suits well in an horti pastural
system with grasses like Cenchrus ciliaris (anjan), Panicum antidotale (blue panic),
Dicanthicum annulatum (marvel) and Chloris gayana (rhodes) and legumes like
Stylosanthus hamata (stylo) Stylosanthus scarba (stylo) and Macroptilum
atropurpureum (siratro) ( Fig.16.4).
Fig 16.4 Guava + Cenchrus ciliaris
16.3.6 Alley cropping
Food crops are grown in alleys formed by hedge rows of trees or shrubs in
arable lands. It is also known as hedgerow intercropping or avenue cropping.
Hedgerows are cut back at about one meter height at planting and kept pruned
during cropping to prevent shading and to reduce competition with food crops. It is
recommended for humid tropics, primarily as an alternative to shifting cultivation. In
semiarid regions of India, alley cropping provide fodder during dry period since
mulching the crop with hedgerow prunings usually does not contribute to increased
crop production. Advantages of alley cropping are:
• Provision of green fodder during lean period of the year
• Higher total biomass production per unit area than arable crops alone
• Efficient use of off-season precipitation in the absence of a crop
• Additional employment during off-season
• It serves as a barrier to surface runoff leading to soil and water
conservation.
Based on the objectives, three types of alley systems are recognised.
• Forage-alley cropping,
• Forage-cum-mulch system, and
• Forage-cum-pole system.
a) Forage alley cropping system: In this system, both yield of crop and forage
assume importance. The tree species suitable for hedge rows are Leucaena
leucocephala, Colliendra and Sesbania. .Pigeon pea or castor crops are suitable for
growing in the alleys of Leucaena.
b) Forage-cum-mulch system: In this system, hedgerows are used for both forage
and mulch. Loppings are used for mulching during the crop season and used as
fodder during off season. Substantial increase in crop yields of sorghum, groundnut,
greengram and blackgram have been observed at several places.
c) Forage-cum-pole system: Leucaena alleys are established at 5 m intervals along
the contours. Hedgerows are established by direct seeding and topped every two
months at 1.0 m height during crop season and every four months during the off
season. A Leucaena plant for every 2 m along hedgerows is allowed to grow into a
pole.
16.3.7 Tree farming
Trees can flourish and yield abundantly where arable crops are not profitable.
Farmers of drylands are inclined to tree farming because of labour cost, scarcity at
peak periods of farm operations and frequent crop failure due to drought. A number
of multipurpose tree systems (MPTS) have been tested for their suitability and
profitability under different situations.
Trees for areas where annual rainfall less than 500 mm: Acacia nilotica,
Acacia aneura, Acacia tortilis, Acacia albida, Prosopis cineraria, Prosopis juliflora,
Pithecallobium dulce, Leucaena leucocephala,. Tamarindus indica etc.,
Trees for areas where annual rainfall less than 500 mm: Acacia nilotica,
Acacia ferruginea, Albizzia lebbek, Azadirachta indica, Casuarina equisetifolia, Cassia
sturti, Dalbergia sissoo etc.,
16.3.8 Timber-cum-fibre system (TIMFIB)
It involves growing trees and perennial fibre crops together on the same piece
of land.Subabul intercropping with agave appears to be more remunerative at
Bijapur area of Karnataka..
16.4 Ley farming
This system involves rotation of legume forages with cereals. A rotation
system which includes pasture (ley) for grazing and conservation is called alternate
husbandry or mixed farming. It is a low risk system for drylands. Inclusion of
Stylosanthes hamata (legume fodder) in rotation improved soil fertility besides
increasing sorghum yield.