Effect of Organic Fertilizer and Mulch Sources on Growth and CO2 Assimilation in MM.106 Apple Trees
The study was conducted to investigate the effects of organic fertilizers and mulches on the growth and CO₂ assimilation in MM.106 apple trees. Growth and CO₂ assimilation of MM.106 apple trees grown in a greenhouse were affected by the nutrient concentrations and carbon (C) and nitrogen (N) ratio in the raw materials of organic fertilizers and mulches. The optimum C:N ratios, which makes microorganism convert the organic N into the inorganic N, were obtained in the organic fertilizer, poultry litter, green compost, and grass clippings, resulting in increasing single shoot height, SPAD, and CO₂ assimilation. The SPAD and CO₂ assimilation were affected by the treatments 5 weeks after the treatments, and then the tree growth was affected by the treatments 6 weeks later. The most efficient tree growth and development were observed in the 10 to 15 ㎎ㆍ㎏⁻¹ of the inorganic N in a soil, and the N was strongly related to the tree growth and development.