Concept of Agro-forestry; westland and means to reclaim them

 JPSC CS Paper-VI - Group C - Agricultural Science

Concept of Agro-forestry; westland and means to reclaim them.

Agroforestry

Agroforestry is a collective name for land-use systems involving trees combined with crops and/or animals on the same unit of land. It combines - 

• Production of multiple outputs with protection of the resource base;
• Places emphasis on the use of multiple indigenous trees and shrubs;
• Particularly suitable for low-input conditions and fragile environments;
• It involves the interplay of socio-cultural values more than in most other land-use systems; and
• It is structurally and functionally more complex than monoculture.

Benefits of Agroforestry      

• Environment Benefits: Combining trees with food crops on cropland farms yield certain important environment benefits, both general ecological benefits and specific on-site benefits. The general ecological benefits include:
• Reduction of pressure on forest.
• More efficient recycling of nutrients by deep-rooted trees on the site.
• Better protection of ecological systems.
• Reduction of surface run-off, nutrient leaching and soil erosion through impending effect of tree roots and stems of these processes.
• Improvement of microclimate, such as lowering of soil surface temperature and reduction of evaporation of soil moisture through a combination of mulching and shading.
• Increment in soil nutrients through addition and decomposition of litter-fall.
• Improvement of soil structure through the constant addition of organic matter from decomposed litter.
• Economic Benefits: Agroforestry systems on croplands/farmlands bring significant economic benefits to the farmer, the community, the region or the nation. Such benefits may include:
• Increment in an maintenance of outputs of food, fuelwood, fodder, fertilizer and timber;
• Reduction in total crop failure, and
• Increase in levels of farm incomes due to improved and sustained productivity.
• Social Benefits: Besides the economics benefits, social benefits occur from increase in crop and tree product yields and in the sustainability of these products. These benefits include:
• Improvement in rural living standards from sustained employment and higher incomes;
• Improvement in nutrition and health due to increased quality and diversity of food outputs; and
• Stabilization and improvement of upland communities through elimination of the need to shift sites of farm activities.

Types of Agro forestry in non-forest areas

1.      Farm Forestry: Farm forestry is the name given to programmes which promote commercial tree growing by farmers on their own land. It is defined as the practice of forestry in all its aspects in and the around the farms or village lands integrated with other farm operations.

2.      Extension  Forestry: It is the practice of forestry in areas devoid of tree growth and other vegetation situated in places away from the conventional forest areas with the object of increasing the area under tree growth. It includes the following.

o    Mixed forestry : It is the practice of forestry for raising fodder grass with scattered fodder trees, fruit trees and fuel wood trees on suitable wastelands, panchayat lands and village commons.

o    Shelter belts : Shelter belt is defined as a belt of trees and or shrubs maintained for the purpose of shelter from wind, sun, snow drift, etc.

o    Linear Strip plantations : These are the plantations of fast growing species on linear strips of land.

3.      Rehabilitation of Degraded forests: The degraded area under forests needs immediate attention for ecological restoration and for meeting the socio economic needs of the communities living in and around such areas.

4.      Recreation Forestry: It is the practice of forestry with the object of raising flowering trees and shrubs mainly to serve as recreation forests for the urban and rural population. This type of forestry is also known as Aesthetic forestry which is defined as the practice of forestry with the object of developing or maintaining a forest of high scenic value.

Types of agroforestry systems

Generally, there are three main types of agroforestry systems:

1. Agrisilvicultural systems

In agrisilvicultural systems, crops are combined with trees (silviculture). This could be your local forest garden in which fruit trees are grown next to shrubs carrying berries and herbs on the ground. They are common on smaller scales, very diverse, and produce loads of edible products on multiple layers. This way, they make great use of the available space.

2. Silvopastoral systems

The term ‘silvopastoral systems’ simply describes systems that integrate trees with either pastures or animals. This combination is often done for yielding additional tree products (e.g. fruits, nuts or biomass), storing CO2, creating better living conditions for animals, or building habitat for other animals (supporting biodiversity). For example,  an orchard growing on the pasture lands of chicken, sheep or geese.

3. Agrosilvipastoral systems

The third possible system is a combination of all three components: trees, crops, and animals. The aim is to reap the benefits of this integration. Bees, for instance, can be held for honey production, while pollinating trees and crops.

 

Wasteland and means to reclaim them

• Economically unproductive lands suffering from environmental degradation are known as wastelands.
• Wastelands include salt affected land, sandy areas, undulating lands, snow covered areas, glacial areas and areas that become barren after Jhum cultivation.
• More than our country's geographical area (around 175 million hectare) is estimated to be wasteland.

The main causes of wasteland formation are:

1. Soil erosion due to high speed wind and water
2. Salinization, alkalization, inundation of land areas
3. Natural factors like tsunami, floods and tidal actions
4. Anthropogenic activities like improper agricultural practices in terms of excessive usage fertilizers, pesticides, mono cropping, improper disposal of industrial waste, illegal and indiscriminate mining of minerals, Jhumming cultivation etc.
5. Climate change and Environmental conditions like changing rainfall pattern (arid, semiarid conditions)
6. Management constraints

Wasteland Reclamation

• It is the process of turning barren, sterile land into fertile land suitable for agriculture or vegetation and cultivation. Reclamation means recovering physical structure of land to rebuild the ecosystem. These lands can be reclaimed by three methods:

i) Soil Management: - The soil management can be done with following:

• Filling of Gullies and Leveling: This can be done by filling stones in gullies, followed by compacting after placing soil over it. The leveling of land should be done to reduce water erosion. Further changing course of water or small check dams are also useful for the purpose. Planting grasses and bushes along the water course also help to stop soil erosion.
• Terracing: In this the earth is shaped in the form of small leveled terraces to hold soil and water. The terraces are given inward slope to increase infiltration of water. The banks of terraces are made firm and compact by placing stones and planting grasses over the sides.
•  Scraping: This technique is used for soils covered with 2-3 cm thick layer of salts over it. This layer can be removed by scraping using spade. This is possible only at small scale and may not be possible at large scale.
•  Flushing: The method is used for lands where water soluble salts accumulate over land surface due to evaporation of water. To remove these salts, the area is first filled with water and allowed to remain there for few days. The water is checked for its conductivity so as to find that how much salts have dissolved. The water is then flushed off. Water should not be made to stand for long as salts can leach down to the sub soil.
•  Deep Ploughing: Fallow lands i.e. land that is normally used for farming but that is left with no crops for long time become hard due to trampling by animals, settling of soil particles and lack of vegetation. To recover such lands, ploughing should be done deep so that soil is opened to absorb moisture from rain. This also removes weeds, stones and pebbles etc.
• Drainage: Waterlogged soils are improved by this method. There are 2 types of drainage systems, Sub-surface drainage and Underground drainage.
• Addition of Green Manure and Soil Amendments: The method is used to reclaim the soils low in organic matter, nutrients and alkaline or acidic in nature. In this method legume crops or nitrogen fixing plants are cropped on the land and ploughed down in the soil when they are soft and without flowers. They fix atmospheric nitrogen and add organic matter to soil. The chemicals like calcium carbonate, gypsum, fly ash and farm yard manure are added to the soil to increase the nutrient level and lime is added to reduce the soil acidity.
• Wind Breaks: The method is used in areas having loose dry sandy soil and high intensity of speedy winds leading to movement of soil with wind. To reduce soil erosion due to high speed wind, row of fast growing trees are plated on boundaries of wastelands and banks of water courses. The trees species commonly used as wind breaks are Poplar, Neem, Shesham Bamboo and some fruit trees like, Ber, Jamun Mango etc.
• Silt Trapping Dams: When the water flowing from uplands cause soil erosion and siltation, to check the movement od eroded soil, big or small dams of reasonable height can be constructed against the course of water flow. Water is made to stand near these traps for a while and silt particles settle down thus reducing soil erosion.
• Contour Furrowing and Bunding: The method is adopted for sloppy wasteland. The contours or furrows are made to allow water to remain in contour or to move at a slow speed and hence reduce soil erosion by water. This increases Infiltration of water leading to water conservation.
• Mulching: The method is used to conserve soil moisture during droughts and when there are no rains. Mulches of dry grass, polythene, chemical mulch etc. are used to cover the soil surface. Mulching also check soil erosion and suppresses emergence of weeds.

ii) Water Management: Consists of three options:

Ø  Addition of water-Irrigation

Ø  Conservation of water- Protection

Ø  Removal of excess of water- Drainage

Addition of water-Irrigation: The addition of water to agriculture of vegetation is called irrigation. Irrigation or soil moisture is most important to provide water to the plants and maintain land productivity. Various methods are used for irrigation depending on the soil type, crop/vegetation type, water availability etc. Mainly following techniques are used for irrigation.

 Furrow or channel- Used where land is levelled and water is in plenty.

• Flooding – Water is allowed to flow over the field. It is used where water is in plenty.
• Sprinkler – Used where less but frequent water is required. It is very useful as no soil erosion, no loss of nutrients and water saving.
• Ring or basin method – Used for irrigating fruit and other trees, individual tree is given water at a time. No loss of nutrients, no soil erosion but time consuming and laborious method.
• Drip irrigation/Trickle irrigation method – This is relatively modern irrigation technology. In this, water is made to trickle down near root zone. Trickling of water drops is slow, underground and continues. There is no run-off of water, evaporation loss, no leaching down of water.
• Conservation of soil Moisture: It includes all the policies, strategies and activities to sustainably manage and conserve the soil moisture. It can be conserved by already discussed methods of terracing, mulching, wind barriers, silt trapping dams etc. Some other methods used for the purpose are:
•  Graded bunds– These are simple earthen embankments constructed across the slope/ contour of the area are called contour bunds. When these are constructed at pre-determined longitudinal grade, they are known as graded bunds. These are constructed where rainfall is more than 600 mm per year. The run-off from upper bund is retained in the lower bund and again the surplus water passed on to the next bund and in this way water is conserved in the soil.
• Water Storage in Ditch – During rainy season, water is collected in ditches made at regular intervals depending upon soil type and amount of water to be handled. The water stored in ditches and can be used during water scarcity. Evaporation losses are overcome by covering the top of ditches.
• Drainage: This is the method of removal of excess of water from soil/sub soil. The most common method used is pumping out the water with mechanical methods. On sloppy lands channels are laid down and water flows down by gravity.
• Crop Management: Growing suitable crops and their management is another approach to reclaim wasteland. Those crops selected for wastelands should have characteristics like drought tolerant, minimum rate of transpiration, less nutrient requirement etc. Growing leguminous crops and ploughing them young in the soil. Multiple cropping, mixed cropping and crop rotation is done.
• Aonla and Jatropha Plantations: The Aonla commonly called Amla is a minor sub-tropical deciduous tree. It can withstand drought conditions and can grow in neglected regions owing to its hardy nature. The fruit of the tree is in high demand due to its nutritional values. Similarly, another plant preferred to reclaim waste lands is Jatropha. It can grow on degraded soil and can resist drought conditions. The Seeds have high oil content which can be used for bio diesel production.
• Fuel Wood Plantations on Wastelands: The land which cannot use for agricultural purposes can be planted with fast growing species of trees having rotation cycle of 4-7 years .It can provide fuel wood and fodder for cattle. Hence, it reduces excessive pressure on pasture lands.