The Effects of Citrus Fruits As Fertilizers

Environmental Pollution

• The residues from citrus processing are full of soluble and insoluble carbohydrates (ref. 3/intro). Nutritious, citrus waste is perfect for animal feed, but with water content from 80 to 92 percent, spoilage is a real dilemma. The price to dry the waste and preserve for fodder is preventatively high, causing some high citrus industry countries to allow peel and pulp waste to accumulate in the soil creating serious ecological troubles. Cost effective fertilizer conversion methods go a long way to solving citrus induced environmental pollution.

Composting and Fermentation

• Citrus fruit raw material consists of membranes, juice vesicles, seeds and peel after the juice is extracted commercially. Citrus waste can be composted alone because it naturally has the correct carbon to nitrogen ratios for optimal breakdown that results in rich, dark product. Solid state fermentation produces microbial enzymes such as amylase, pectinase and cellulose and metabolites. These citrus waste fertilizing conversion methods improve moisture retention, soil composition and act as biological controls, while solving an environmental hazard.

Plant Growth and Seed Germination

• A University of Michigan test found orange extract to contain the highest amounts of protein. According to the Egyptian Journal of Biology, fermented orange waste fertilizer stimulated water cultured wheat plant growth. All organic matter inhibits seed germination in varying degrees, which is why sterile conditions are often advised. Citrus fertilizers will hamper seedlings to either a greater or lesser degree than commercial composts depending on the plant species. Tests continue to determine all the effects of citrus fruit fertilizers on plant growth.

Root Rot Disease Resistance

• Diseases that cause root rot can devastate valuable, commercial crops. Root rot organisms, Phytophthora nicotianae and Phytophthora cinnamomi are a particular problem for South African avocado production. According to a study by the University of Pretoria, citrus waste compost contains aggressive microbes that suppress disease organisms. In the greenhouse controlled study, unsterilized citrus waste compost radically decreased plant mortality in phytophthora inoculated soil.