Use of Cottonseed Meal With or Without Soapstock or Canola Meal Without Soapstock as an Organic Fertilizer

Abstract

The objectives of this study were to determine whether cottonseed meal or canola meal could be used as organic fertilizers that add nitrogen (N) and other nutrients to the soil for plant use. Field experiments determined the affect of cottonseed meal with or without soapstock or canola meal on the growth and visual quality of marigold (Tagetes erecta L. `Inca II Gold' or `Inca II Yellow') and redbud (Cercis Canadensis L.) plants and nutrient partitioning in redbud trees at various seasonal stages. Rate of N mineralization from cottonseed meal with or without soapstock or canola meal was also determined.Cottonseed meal and canola meal did not affect growth of marigolds or redbuds growing outdoors in native soil and can provide adequate nutrients for healthy plant growth. Nitrogen mineralized from cottonseed meal and canola meal at rates sufficient for plant growth. Under controlled conditions, increases in inorganic N occurred as quickly as 3 days. Results suggested that the best time to fertilize is during rapid plant growth and this occurred for redbud trees in spring during budbreak as new leaves were formed. Cottonseed meal with and without soapstock and canola meal are reasonable organic fertilizers that can provide N and other essential nutrients for plant uptake.