Importance of the organic matter application for soil health Kanako Suzuki, Mihoko Moriizumi, Kensuke Okada
Kanako Suzuki, Faculty of Agriculture, Shinshu University
Mihoko Moriizumi, Faculty of Agriculture, Ryukoku University
Kensuke Okada, Graduate School of Agricultural and Life Sciences, University of Tokyo
Abstract
Agricultural technologies have been improving and are very helpful to enhance agricultural productivity. These effects can be more useful with good soil health conditions. Soil is a very important foundation for agricultural activities.
In Japan, agricultural activities were conducted without focusing on soil conservation, e.g., intensive cultivation, continuous monoculture, high amount of chemical fertilizer application alone, and intensive use of germicide and insecticide. As a result, soil biodiversity was lost and it led to severe infections by soil borne diseases, e.g., clubroot and root rot in many parts of Japan.
In West Africa, the semi-arid region (called the Sahel) has been threatened by low food security due to low soil fertility. The Sahelian soil has been weathered during long period and became extremely sandy and acidic. For restoring the amount of soil nutrients, chemical fertilizer use can be very helpful, but it is very difficult for the smallholder farmers to apply enough amount due to its high price. These two regions have very different situations, but they have serious problems of soil health. We do not have a silver bullet to improve soil health quickly. However, organic matters such as green manure, livestock manure and crop residue are very useful to improve soil health gradually.
In the high-cool region of Nagano prefecture in Japan, the field experiment was conducted to elucidate the effect of green manures on clubroot infection. Tested green manures were hairy vetch (Vicia villosa) and sorghum (Sorghum bicolor) and they led to a decrease in clubroot infection in cabbage. After incorporating them into a clubroot-infected soil, the number of resting spores was gradually decreased. In the Sahel region of West Africa, the field experiment was conducted to elucidate the effect of co-application of organic matters and micro-dose of chemical fertilizer on pearl millet growth status and grain yield. The application of indigenous organic matters, e.g., crop residue and livestock manure, helped to improve soil fertility, growth status and grain yield of pearl millet.
These results demonstrated that organic matters could lead to good soil health without chemical substances use. And this showed the high possibility to provide safe and sufficient food for human being. Consequently, organic matter is an important connector between soil health and human health.
