Submitted to: Ecologia Aplicada
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/17/2008
Publication Date: 6/27/2008
Citation: Puertas, F., Arevalo, E., Zuniga, L., Alegre, J., Loli, O., Soplin, H., Baligar, V.C. 2008. Establishment of five cover crops and total soil nutrient extraction in a humid tropical soil in the Peruvian Amazon. Ecologia Aplicada. 7:23-28. Interpretive Summary: Soils of the tropical region have been degraded due to soil loss by erosion and leaching losses of nutrients. Quick growing cover crops before or during early stages of plantation crops establishment could increase the soil vegetative cover thereby reducing the impact of raindrops that leads to soil erosion and nutrient losses as well as suppressing of weeds. Cover crops can improve soil fertility by fixing atmospheric nitrogen, adding organic matter and cycling of nutrients. An experiment was undertaken at the upper Amazon region of Peru to evaluate the effectiveness of five legume cover crops in improving soil vegetative cover and cycling of essential nutrients. Canavalia cover crop was a very effective management tool to reduce weed growth and to protect soil from erosion. Centrocema cover crop was very effective in improving soil fertility through enhanced nutrient cycling capacity. Findings of this study will help resource poor farmers of the region to use cover crops as an effective management tool to reduce soil degradation and improve soil fertility.
Technical Abstract: In order to evaluate the establishment of five cover crops and their potential to increase soil fertility through nutrient extraction, an experiment was installed in the Research Station of Choclino, San Martin, Peru. Five cover crops were planted: Arachis pintoi Krapov. & W.C. Greg, Calopogonium mucunoides (L.), Callisia repens (Jacq.) L., Canavalia ensiformis (L.) (Canavalia) and Centrosema macrocarpum Benth (Centrosema). The percentage of cover of Canavalia, was significatively higher than the others, reaching total cover at 90 days after planting. The above and below ground dry biomass was greater for Centrosema (9.61 t ha-1 and 2.76 t ha-1, respectively). The rates of Nitrogen (311 kg ha-1), Phosphorous (24.97 kg ha-1) and Potassium (155.61 kg ha-1) extracted by Centrosema were significantly higher than the other cover crops. Therefore the most appropriate cover crop under the study conditions to reduce spontaneous vegetation growth and to protect the soil from erosion by covering it in a shorter period of time was Canavalia. To improve soil fertility through nutrient cycling it is recommended to use Centrosema because of its higher nutrient extraction capacity and dry biomass production.