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close this bookSoil and Water Conservation (SWC) Technologies and Agroforestry Systems (IIRR, 1992, 171 p.)
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View the documentWorkshop to revise
View the documentList of participants
View the documentCurrent program thrusts in Upland development
View the documentDegradation of the uplands
View the documentNutrient cycles in upland farms
View the documentEstablishing an swcsystem
View the documentFarm management practices that reinforce SWC
View the documentTraditional soil and water conservation (SWC) technologies
Open this folder and view contentsOptions for contour farming:
View the documentLand management practices for improved water conservation
View the documentIn-row tillage
View the documentMaking an A-frame
View the documentControlling Cogon and Talahib
View the documentUse of derris as botanical pesticide
View the documentFire control in the uplands
View the documentCultural management of pest infestation
Open this folder and view contentsOrganic fertilizer sources:
View the documentBiofertilizers
View the documentSelection of cover crops
View the documentBatao in the upland. Cropping system
View the documentIncreasing the woody contents in leaf litter
Open this folder and view contentsExamples of indigenous agroforestry systems:

Selection of cover crops

Cover crops are plants which are grown to cover and protect the soil. They help add fertility, improve soil structure and water retention and have a lot of practical benefits such as animal fodder, food and added farm income.

Cover crops can be used in a variety of ways in agricultural systems:


1. Interplanted or relay-planted with maize or other grain crops


2. Planted alone in the cropping cycle


3. Planted under trees in orchards or plantations


4. Planted as a fallow crop when the land is being rested

Note: For suggested species suitable to the above systems (1-4), please refer to accompanying table under systems applicable.

Cover crops offer farmers the following benefits:

1. Improved soil fertility through the addition of significant amounts of nutrients (more than 200 kg N/ha)

2. Suppressed weed growth

3. Reduced labor demands in soil preparation and in weeding

4. Reduced cost of inputs such as fertilizers, herbicides and hired labor

5. Improved soil structure: cover crops can provide up to 30 tons of organic matter per hectare. Improved soil structure means a better medium for plant growth; in addition, it improves the soil's ability to retain moisture during dry periods.

6. Soil and water conservation: cover crops help reduce erosion by protecting the soil surface for extended periods of time.

7. Rehabilitation of degraded marginal lands

8. Additional benefits: human food, animal forage, fuelwood and an added source of income

There are many plants which can be used for cover crops, depending on local conditions (rainfall, soils, local farming practices) and the objectives of farmers. However, most of the cover crops belong to the family of plants known as Leguminosae (beans).

The following general characteristics are considered important in selecting plants for use as effective cover crops:

1. Rapid, prolific growth habit

2. Ability to fix significant amounts of nitrogen

3. Tolerance to a wide range of soil conditions (poor fertility, texture or structural qualities, extremes in pH, etc.)

4. Good drought tolerance. This is an especially important factor since most of the green manures are grown during the dry season.

5. Seed availability or the ability of the plant to produce its own seed locally

6. Shade resistance, since cover crops are frequently interplanted grown in relay with taller grain crops or trees

7. Proven pest resistance

8. Easy to control. Cover crops must be readily removed from the farm when the time comes for land clearing.

Potential problems with cover crops:

1. Cover crops can be difficult to establish and farmers often perceive them to require extra work. Some farmers have been concerned that cover crops might compete with their staple crops.

2. Some cover crop species can be very aggressive and may be difficult to eliminate from the farm

3. Cover crops can become an alternate host to pests which attack food crops.

4. Rats and snakes may hide in the dense foliage of cover crops.

In general, the most popular cover crops are indeterminate (continuously produce flowers and pods), single-season legume species. However, perennial species can be of great value under certain circumstances; determinate bean species and even tuber crops such as camote can be used as effective cover crops. Some of the cover crops which have been used successfully by farmers are shown in Table 9.

There are many other species of plants which have been used traditionally by farmers to serve the same purpose as the above-mentioned cover crops. Many of them are as yet undocumented. Additionally, there are other plants which could also be used. Cover crops are gaining attention from farmers and agricultural scientists and they deserve much more field trials and research.

TABLE 9. SELECTED COVER CROPS.

SCIENTIFIC NAME

COMMON NAME

REMARKS

SYSTEM APPLICABLE

Mucuna pruners

Kokoa Velvet bean

Very vigorous growth - excellent fallow species; drought tolerant; pods

1,2,3,4

Dolichos lablab

Batao Lablab bean

Drought-tolerant, pods edible

1,2,3

Canavalia ensiformis

Jack bean

Drought-tolerant

1,2,4

Canavalia gladiata

Sword bean

Drought-tolerant

1,2,4

Cajanus cajan

Kadios Pigeon pea

Excellent drought- tolerant provides food and fuelwood

2,4

Crotolaria sp.

Sun hemp

Determinant growth habit

1,2.4

Vigna umbelata

Tahori rice bean

Food and green manure


Vigna unquiculata

Paayap black bean

Food and green manure

1,3

Psophocarpos tetragonolobus

Sigarillas manure

Food and green

1,3,4

Psophocarpus palustns

Winged bean

Non-edible species

3,4

Pueraria phaseoloides

Tropical kudzucrops or as extended fallow

Good under tree

3,4

Desmodium heterophylla


Excellent under plantation crops

3,4

Tephrosia candidaplantation crops


Used under

3,4

Dioscorea alata


Excellent for food or income

3,4

Ipomoea batatas

Camote

Good food and extended cover

3


Sayote


3


Squash


2,3,4


Yam bean


2,4