Ecological basis

1. Multistory agro-forestry

It means multi-tier crop cover, in which tallest species like Coconut, Eucalyptus and other tree species are grown that is followed by Banana, Papaya, Pineapple, Coffee etc. Ginger, Turmeric, Pepper, Yam, Colocasia are the ground or lower tier crops.

While designing this 3 tier system, level of organic matter and mineral content into the soils should be considered.

This system improves the productivity and conserves the environment. It also controls soil erosion, moderates surface soil temperature, suppresses weeds, recycles nutrients and preserves moisture.

2.Alley cropping

It is also known as hedge row intercropping, and involves managing rows of closely planted woody trees with annual crops grown in alley in between hedge rows. Woody plants are cut regularly, and leaves and twigs are used as mulching materials on the alley cropping areas for reducing evaporation from soil, control weeds and add nutrients and organic matter into the soil. Increase crop yield due to the addition of organic matter into the soil.

Legume plants (Ipil-Ipil etc) are grown on the hedge rows which fix nitrogen into the soil. Hedge rows give products like fruit, fodder, leaf litter, fuel wood and poles.

This system is generally practice in sloppy lands which helps in reducing soil erosion. The position and spacing of hedge rows and crops plants in alley cropping system depend on plant species, climate, slope, soil condition and space required for the movement of people and tillage equipment.

Hedge row distance should be maintained 4-8 meters and plant to plant distance from 25 cms – 2 meters. Hedge rows should be developed across the slope of the land.

Criteria for species selection in hedge rows

• Easy to propagate.
• Easy to plantation establishment, care and management.
• Legume tree species to improve soil fertility through nitrogen fixation and to improve feeding value of fodder because legume species contain high protein.
• Tree should have light crown cover to permit sunlight.
• It should re-sprout rapidly after pruning, coppicing, pollarding and lopping operations.
• It should have deep root system with few lateral roots near the surface so as not to compete with crop roots.
• It should have shallow lateral roots that are easily pruned by ploughing along the hedge rows without serious damage to plants.
• It should have leaf litter which could be easily decomposed to add nutrients into the soil.
• It should be multipurpose species which should give fruits/food, fuel wood, fodder/leaf litter, timber and medicines.
• It should grow well under specific limitation sites such as acidic soil, alkaline soil, drought, degraded soil, floods and heavy windy areas.
• It should suitable in local environment.
• It should resistant to insects, pests and diseases.
• It should be fast growing.
• It should have high demand with high market value.

Suitable species

• Leucaena species (Ipil-Ipil)
• Gliricidia sepium
• Calliandra
• Sebania sesban
• Artocarpus lakoocha
• Morus alba

Limitation

Alley cropping requires fairly close tree rows which reduces the amount of lands left for growing agriculture crops.

3. Mix intercropping

This is field crop based agroforestry system, in which two or more crops are grown together as under storey crops. Trees species are selected based on farmers need as well as market demands.