Influence of certain soil amendments on the yield of cotton affected by the Fusarium-Heterodera complex

A study has been made of the effect of several organic soil amendments on the yield of cotton grown on Mississippi soils with F. vasinfectum and H. marioni. Eight years continuous cotton culture on Ruston sandy loam fertilized variously with stable manure and commercial 6-8-4 mixtures were compared. Four or more tons of stable manure per acre outyielded all of the commercial fertilizer plots up to and including the 1,200-pound application of 6-8-4. All materials were placed in the drill row. Spoiled alfalfa hay drilled, stable manure drilled and broadcast, cyanamid, sagrain, and cotton stalks drilled in the rows before planting were used on Sarpy fine sandy loam for 3 years. The alfalfa hay and stable manure, if drilled, outyielded all other material used. Use of diseased cotton stalks failed to increase wilt. Neither total amount of infection nor the distribution of Fusarium vasinfectum and Heterodera marioni on the Ruston and Sarpy soil series was influenced by any of the treatments. The average annual yield of seed cotton, however, was markedly influenced by certain treatments, except by low amounts of fertilizers and by cotton stalks. Although a high proportion of plants on all plots were invaded by F. vasinfectum and H. marioni little damage appeared among plants growing on the plots receiving high rates of organic manures. The writers suggest that unfavorable conditions for cotton root development in the field predisposes the plants to destruction by F. vasinfectum and that the commonly observed highly variable nature of the disease can be explained only by an understanding of those factors which influence root development. The writers also suggest that improving the culture of winter legumes and plowing down the vines, throwing the bulk of the vegetation under the future cotton rows, may prove effective in reducing wilt.