The work I conducted was to analyse the condition of the soil, at a physical-chemincal level, and study the population of nematodes in different towns of the region of "Tierra Estella". Different crop systems were studied-- in ecological agriculture as well as in conversion systems. The analysis was done in Madrid, in the Consejo Superior de Investigaciones Cientificas (CSIC), Department of Ciencias Mediombientales directed by Profesor Bello and his team. They took samples according to CSIC protocol of olive groves, vineyards, greenhouses and orchards. The samples were taken to Madrid within a period of 24 hours and were studied by Professor Bello and his team. Nematodes were found in the different samples, giving data like those shown in this work. They also analyzed the same samples in the labs of Agrolab de Pamplona (Navarra) in order to determine the physical-chemical characteristics of the soil, whose results are also shown (graphs, table 1, table 2). All this information was explained to all the farmers in succesive meetings and particularly in each of their fields, so that they could know the situation of their crops, and thus the correct management that they must do for the soil in order to maintain an healthy balanced state. In conclusion, we can say that the gardens on the shore of Ebro with the management of orchards over many generations, posess a good empirical knowledge of soil management. Since the way they practice natural biofumigation obtains two objectives, the control of soil microorganisms and fertilization. Dry land farming, like in the olive groves and vineyards, demonstrate the expected results for the form of traditional farming in the zone, with the exception of the vineyards due to the value reached in the last harvests, in which a higher level of inputs led to a higher level of organic matter. The cultivation of greenhouse vegetables results in an especially high level of organic material, as an intensive cultivation done with the correct rotation.

Crop rotation is especially important in order to maintian a balanced level of nutrients, organic material, and biodiversity. The planting of legumes is fundamental in order to maintain an adequate level of usable nitrogen for the crops. Plant species that have a positive allelopathic effect on crops. Incorporate the remains of the harvest with compost in order to establish a good level of microorganisms in the soil. Close the nutrient cycle, whenever possible, by means of integration of animals into the sub-ecosystem.

Use Renewable Resources

Incorporation of the remains of the harvest.

Conserve Resources

Close the nutrient cycle by incorporating compost prepared with manure from the cattle farms of the region.

Manage Ecological Relationships

Recover knowledge about good soil management that was practiced before the entrance of chemicals into the system.

Diversify

The main agriculture of the region is done in small parcels that faciliates a great diversity of crops and species.

Manage Whole Systems

The cultivation of irrigated land is a treatment maintained during centuries, like those of dry land farming.

Maximize Long-Term Benefits

The reality of ecological agriculture during the time of study demonstrates that it can give more benefits in the future.