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ProTerra Methodology |
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Your online resource for soil protection in Mediterranean olives and vines |
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Current practice and its problems: (pictures of bad erosion and off site impacts) |
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| The Mediterranean landscape is dominated by the production of perennial crops such as vines, olives, nuts and top fruit. Many of the plantations occupy steep slopes and the soil is kept bare by cultivation to reduce competition for water and temporarily improve infiltration. This soil is extremely fragile. Left unprotected, it is highly vulnerable to erosion by rain splash and runoff and it can be difficult to access with machinery. | ||
| Frequent cultivation has a high energy and labour cost and the loss of soil leads to reduced fertility and land available for production. Off site, the sedimentation of surface waters and blockage of roads carries high environmental, economic and social costs. This method of soil management is therefore unsustainable. Farmers need to be given a practical alternative which is compatible with the cropping systems in place. | ||
A possible solution: |
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| If care is given to species selection and management, it is believed that permanent vegetation cover would provide a good solution. | ||
| To ensure good cover establishment, a variety of perennial species with differing growth habits would be required. The species selected would need to be relatively slow growing, low growing, suited to growth in the local conditions and available commercially. Grasses should be used in preference to broadleaved species because they will be easier to manage and their reticulated rooting habit will have a greater impact on soil structure and stability. Timing of installation will be dependent on field conditions and the availability of labour. | ||
| The use of slow growing and low growing species should mean that the level of maintenance and risk of pest harbourage and frost damage are kept to a minimum. If the primary crop is sensitive to water stress, potential competition for water can be avoided by using species which are dormant during the sensitive period, or by artificially inducing dormancy using a herbicide. | ||
The need for testing and demonstration: |
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| For this permanent vegetation method to be accepted by farmers and regulators, its successful implementation and soil conservation performance need to be demonstrated under field conditions. This demonstration work should be carried out under a variety of soil types, crops and slopes throughout the Mediterranean region, where erosion of the soil is known to be a problem. Confined plot studies, which can be used to directly compare the performance of conventional soil management with that of a managed cover, are thought to be the most appropriate way of achieving this. Some monitoring will also be necessary to show treatment effects on water availability to the crop. | ||
Site selection criteria: |
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| • The cultivation system must be orientated up-slope down-slope and soil erosion by water must be an obvious problem. There is little point in carrying out a soil conservation trial on land which is not actively eroding. | ||
| • Enough land must be available to demonstrate each soil management practice. | ||
| • The slope angle, slope length, age of crop and soil type under each management practice must be as homogeneous as possible. For management practices to be accurately compared, the initial field conditions need to be the same. | ||
| • The site must have good vehicular access. This is important for monitoring and sampling purposes but also for bringing visitors to the site. | ||
| • The farmer must be willing to allow the work to take place and form part of the project team; contributing local knowledge and helping to implement the different soil management practices. | ||
| • There must be a means of hydraulically isolating the different management treatments and room for the installation of a runoff and sediment collection system so that losses can be quantified and compared. | ||
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© Syngenta 2005
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