Mechanism or trend for soil productivity improvement in AF

Mechanism or trend for soil productivity improvement in AF

Trend in soil productivity improvement in agroforestry can been achieved planting compatible and desirable species. This helps to reduce soil erosion and to improve physical condition of soil. It also influences hydrological cycle by reducing surface run off and by increasing infiltration of rain water.

The soil productivity improvement trend in agroforestry is as follows:

1. Plantation of compatible and desirable species

Plantation of compatible and desirable trees species i) add organic matter through leaf litter, twigs, fruits, and roots into the soil ii) nutrient recycling more efficiently iii) biological nitrogen fixation iv) enhance nutrient use and nutrient economy planting shallow and deep rooting trees and crops v) better sharing of nutrients between trees and crops and vi) enhance nutrient release pattern adding more organic matter into the soil, vii) enhance microbial activities adding more organic matter.

2. Improve physical condition of soil with proper inclusion of trees, grasses and legumes

3. Reduce upstream soil erosion and downstream siltation problems through planting desirable trees and grass species in upstream

4. Planting trees and grasses for micro-climate improvement and for influencing hydrological cycle by reducing surface run off and increasing infiltration of rain water

5. Planting nitrogen fixing trees and crops like coffee, tea, cardamom to get more benefits from nitrogen rich leaf litter and soil nitrogen

How agroforestry helps to conserve biodiversity?

How agroforestry helps to conserve biodiversity?

Biodiversity is the variety and variability of plants, animals and microorganisms. Our planet’s essential goods and services depend on the variety and variability of genes, species, populations and ecosystems. The loss of world’s biological diversity is mainly from habitat destruction, over harvesting, pollution, environment change and inappropriate introduction of exotic species.

To overcome the problems of resource depletion and biodiversity loss, efforts are needed to conserve and maintain gene, species and ecosystem with a view to sustainable management and use of biological resources. In situ protection and exsitu conservation of biological and genetic resources can help in sustaining biological and genetic resources.

Agroforestry can play an important role in the conservation of biodiversity within deforested, fragmented landscapes by providing habitats and resources for plant and animal species, maintaining landscape connectivity, making the landscape less harsh for forest-dwelling species by reducing the frequency and intensity of fires, potentially decreasing edge effects on remaining forest fragments and providing buffer zones to protected areas (Schroth et al., In press).

Agroforestry systems cannot provide the same niches and habitats as the original forests and should never be promoted as a conservation tool at the expense of natural forest conservation. However they do offer an important complementary tool for conservation and should be considered in landscape-wide conservation efforts that both protect remaining forest fragments and promote the maintenance of on-farm tree cover in areas surrounding the protected areas.

The degree to which agroforestry systems can serve conservation efforts depends on a variety of factors, including the design and origin of the agroforestry systems, its permanency in the landscape, its location relative to remaining natural habitat and the degree of connectivity within the habitat, as well as its management and use, particularly pollarding, use of herbicides or pesticides, harvesting of timber and non-timber products and incorporation of cattle, goats, etc.

Home gardens provide a variety of niches and resources that support a high diversity of plant and animals, though usually less than that of intact forest (Perfecto et al., 1996; Rice and Greenberg, 2000). However, even agroforestry systems with low tree densities and low species diversity may help in maintaining biotic connectivity.

Agroforestry system with reference to plantation crop practice in Nepal

Agroforestry system with reference to plantation crop practice of tea, cardamom, coffee and medicinal plants in Nepal

Many farmers view shade as a challenging situation for growing plants. While some plants do not grow well in low light, numerous others thrive under these conditions. Just as moisture, temperature, and soil conditions may limit plant growth, the amount of shade present may determine which plants will grow successfully. Tea, cardamom, coffee etc are shade loving plants.

Tree shade can be divided into three categories that are light, medium and full shade, which are described below:

Light shade may be described as an area that is partially shaded. It may be shaded for only few hours each day. The sun's rays may be blocked by tree canopy for several hours at midday or early in the morning etc, but the area is sunny the rest of the day.

Light shade may also be found in areas that receive filtered or dappled sunlight for longer periods. Edges of shady areas under the canopy of solitary, lightly branched trees are typical of filtered sunlight. During the heat of summer, light shade at midday will provide a beneficial cooling effect. Flower and foliage color may be more brilliant when plants are shielded from intense midday sunlight.

Partial or medium shade is present when direct sun rays are blocked from an area for most of the day. Many established landscapes have large areas of partial shade, where sections of the yard are shaded by mature trees for much of the day but receive some direct sun early or late in the day. Bright, north-facing exposures may also be classified as medium shade.

Tea, coffee and cardamom are light to medium shade tolerant crops. In eastern Nepal, cardamom is planted as an under storey with Uttis (Alnus nepalensis) trees. Similarly, Siris (Albezia spp) and Sissoo (Dalbergia sisssoo) trees are planted for providing shade to tea, and Ipil Ipil (Leucaena leucocephala) is the best trees for providing shade to coffee plants. Medicinal plants such as Chiraito (Swertia chirayita) can also be grown successfully under light to medium tree shades.

Full shade lasts all day. Little or no direct sunlight reaches the ground at any time of the day. There may be reflected light from sunnier areas of the yard or off light-colored walls. Dense shade refers to full shade under thick tree canopies or in dense groves of trees. Some forage (Desmodium- Desmodium intortum and forage peanut - Arachis pinotoi and horticulture crops such as ginger (Zingiber officinale), turmeric (curcuma longa), yam (Dioscorea spp) etc can be grown well under full to medium shade. Plants growing in the shade must compete with shading trees for nutrients and water, and tolerate poor air circulation.

Agri-horti-silviculture

Agri-horti-silviculture

This system is defined as growing of agriculture crops, trees and fruit trees or ornamental trees or vegetables/flower together in same lands at the same time. This system is common in home gardens of mid-hills, Terai and Inner Terai of Nepal, where fodder trees such as Badahar, Tanki, Ipil Ipil etc and timber and fire wood species such as Sissoo, Eucalyptus, Baikaino, etc are grown around fruit orchard that act as shelter belt, and agriculture crops such as ginger, turmeric, yam, colocassia and vegetables are grown under fruit trees.

The main advantages of this system are as follows:

 Produce multiple products such as food, fruits, fodder and forage needed for livestock, fuel wood, timber, and leaf litter needed for organic manure production.

 Improve and sustain the livelihoods of farmers by increasing the level of income through the sale of fruit/vegetables.

 Trees grown around fruit gardens also provide extra-income.

 This is also the best practice for soil nutrient recycling, which also helps to reduce chemical fertilizer purchase.

 Improve the farm site ecology by reducing soil erosion and nutrient loss.

 Improve the local micro-climate and enhance the productive capacity of the farm.

 This practices helps for the beautification of the surrounding areas.

Agri-silvi-pastoral system

Agri-silvi-pastoral system

Growing of trees, agriculture crops and grasses together in same lands at the same time is known as agri-silvi-pastoral system. This is typical hill farming system of Nepal, in which agriculture crops are grown in terrace flat, trees in terrace bunds, border and slopes and grasses in terrace slopes, and some farmers have been growing improved legume and non-legume grasses such as Mott napier (Pennisetum purpureum), Setaria (Seteria splendida), Mulato (Brachiaria brizantha x B. ruziziensis) and Forage peanut (Arachis pinotoi) along terrace bunds and borders.

The main advantages of this system are as follows:
1. Produce multiple products such as food/vegetables/fruits, fodder and forage/grasses needed for livestock, fuel wood, timber, and leaf litter needed for organic manure production.
2. Improve and sustain the crop productivity which increases the level of income of the farmers.
3.  Improve the nutritive value of animal feed due to the supply of green fodder.
4. This is also the best practice for soil conservation and soil nutrient recycling, which also helps to reduce chemical fertilizer purchase.
5.  Improve the farm site ecology by reducing surface run off, soil erosion and nutrient loss, gully formation and landslides.
6.  Improve the local micro-climate and enhance the productive capacity of the farm.
7.  Reduce pressure of community forests and other natural forests for fodder, forage/grasses, fuel wood and timber.
8. This practices helps for the beautification of the surrounding areas.

Silvi-pastoral system

Silvi-pastoral system

This system can be defined as growing of trees and grasses or forage species together in same lands at the same time. This system is common in all agro-ecological zones of Nepal, where land is marginal for crop production. In mid-hilly region, land having grasses is known as kharbari. Trees grown in Kharbari in different regions are Terai (Sissoo, Eucalyptus, Ipil Ipil etc) hill (Mainly fodder trees such as Badahar, Tanki, Koiralo, Ipil-Ipil etc and timber species like Chilaune) and mountain (fodder trees such as Gogan, Dudhilo, Khasru etc.

The main advantages of this system are as follows:
 Produce multiple products such as fodder and forage needed for livestock, fuel wood, timber, and leaf litter needed for organic manure production.
 Improve and sustain the livestock productivity which increases the level of income of the farmers.
 Improve the nutritive value of animal feed due to the regular supply of green fodder.
 This is also the best practice for soil nutrient recycling, which also helps to reduce chemical fertilizer purchase.
  Improve the farm site ecology by reducing surface run off, soil erosion and nutrient loss, gully formation and landslides.
 Improve the local micro-climate and enhance the productive capacity of the farm.
 Reduce pressure of community forests and other natural forests for fodder, fuel wood and timber.
 This practices helps for the beautification of the surrounding areas.

Agri-silviculture system

Agri-silviculture system

It is defined as growing of trees and agriculture crops together in same lands at the same time. This system is common in all agro-ecological zones of Nepal, where agriculture crops are grown in terrace flat and trees are grown in terrace bunds, borders and slopes. Trees grown in different regions are Terai (Sissoo, Eucalyptus, Baikaino, Ipil IPil etc) hill (Mainly fodder trees such as Badahar, Tanki, Koiralo, Ipil-Ipil, Mulberry etc) and mountain (fodder trees such as Gogan, Dudhilo etc.

The main advantages of this system are as follows:

 Produce multiple products such as food/vegetables/fruits, fodder and forage needed for livestock, fuel wood, timber, and leaf litter needed for organic manure production.

 Improve and sustain the crop productivity which increases the level of income of the farmers.

 Improve the nutritive value of animal feed due to the supply of green fodder..

 This is also the best practice for soil nutrient recycling, which also helps to reduce chemical fertilizer purchase.

 Improve the farm site ecology by reducing surface run off, soil erosion and nutrient loss, gully formation and landslides.

 Improve the local micro-climate and enhance the productive capacity of the farm.

 Reduce pressure of community forests and other natural forests for fodder, fuel wood and timber.

 This practices helps for the beautification of the surrounding areas.

Inter cropping practices can also adopt in this system in plain areas where trees should be grown maintaining rows to rows distance (5 meters) and plant to plant distance (2-3 meters). Management operations such singling, pruning and thinning in timber species and lopping, coppicing and pollarding in fodder species should be applied to reduce shading effects of trees on agriculture crops.