Beyond Yield: Assessing the Effects of Intercropping and Fertilizer Rotations On Soil and Crop Quality in Cassava (M. esculenta) Based Systems in the Kolli Hills, South India.

Continuous cropping of cassava over the past 20 to 30 years in the Kolli Hills of south India has led to yield reductions and decreased soil quality. While yield is a very important aspect of any agronomic study; environmental and economic considerations are also important. The purpose of this study was to examine whether intercropping cassava with beans, millet or a bean millet mixture would impact not only yield but also soil and crop quality. This study also examined whether various fertilization prescriptions - manure, manure and synthetic fertilizer, synthetic fertilizer and mulching - had an impact on yield, crop quality and soil quality. The experiment was set up in a split plot design and was conducted over two growing seasons in the Kolli Hills, south India under rain fed conditions. First season results demonstrated that synthetic and manure fertilizer combination treatments had the greatest impact on increasing cassava yields under all intercropping rotations.  The application of synthetic fertilizer alone also had positive effects under all intercropping rotations with respect to cassava yield.  Intercropping with leguminous plants had the greatest effect on yield when no fertilizer was added (manure or synthetic). Intercropping with a leguminous plant and a combination of millet and a leguminous plant increased the cassava yields in non-fertilized plots and those fertilized with synthetic fertilizer and a combination of organic and synthetic fertilizer. Soil and crop data, as well as second season data will be assessed to see if the trends observed in the first season continue. Increases yields from various fertilizer and intercropping rotations indicate that agricultural intensification of the cassava based system in the Kolli Hills could lead to improved yields and soil quality in these communities.