This long term research is being carried out in degraded lands of low fertility conditions in the humid tropics of the Peruvian Amazon. The objective is to recover degraded lands for sustainable agriculture that was affected by shifting agriculture and overgrazed pastures. The recovering trials in three farms are fertilized cover crops with the legume Centrosema (Centrosema macrocarpum), and the establishment of th prototype agroforestry systems are based on a) woody trees with Swietenia macrophylla, Guazuma crinita (GC), Calycophylum spruceanum (CS) and Simarouba amara (SA), b) woody-fruit trees with Cedrelinga cateniformis, GC, SA, Inga edulis and Bactris gasipaes, and a c) silvopastoral system with Centrosema and woody trees with GC, SA and CS. Initial degraded compacted soils were covered with degraded grass (Brachiaria brizantha) and weeds, and the soil were very acid (80% of Al saturation) with 4 ppm of P and low soil organic matter and cation exchange capacity. Soil was weeded and fertilized with a combined fertilizer based on rock phosphate (40 kg/ha), and then Centrosema was planted followed by the plantation of trees with localized fertilization application. In three months we had 100% cover and weeds were controlled. Average Centrosema biomass in 8 months was 8.12 T/ha, and while the different trees were growing with 55 to 89 percentage of survival due to water stress, Centrosema recovered the soil compaction up to 20 cm depth. Biomass can be used as forage for small animals and to enrich soil. Mean total nitrogen accumulation in biomass was 232 kg/ha.

Sacha inchi (Plukenetia volubilis) is an oilseed crop that has gained importance due to the high contents of proteins and unsaturated fatty acids in its seeds. This study aimed at evaluating the growth characteristics of five leguminous species (Crotalaria juncea,Centrosema macrocarpum,Arachis pintoi,Cannavalia ensiformis and Phaseolus vulgaris) used as cover crops, as well as determining their influence on the sacha inchi yield. A complete randomized block design, with three blocks, was used. C. macrocarpum and C. ensiformis were the most appropriate cover crop species for the local edaphoclimatic conditions because they reached 100 % of soil coverage at six months, in addition to controlling the weeds growth and protecting the soil from erosion. Furthermore, the total leaf biomass at six months was significantly higher in C. macrocarpum, what allowed improving the soil fertility through nitrogen cycling. The use of leguminous cover crops, mainly C. macrocarpum, positively influenced the sacha inchi yield.

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