Effects of Organic Substrates Used Successively on Physical and Chemical Characteristics of Substrate and Growth and Yield of Strawberries in Soilless Culture

Abstract

An experiment was conducted to clarify the changes of the physical and chemical properties of organic substrates with different mixing ratios of coir and peat mixture (3:7, 5:5, 7:3 and 10:0) at different times of cultivation, and the relationship between physical and chemical properties of the substrates and growth and yield of strawberries grown in soilless culture. As for the chemical properties, nutrient fixation and leaching of new substrates changed greatly in the first cultivation, although there was little change afterwards. The water holding capacity of substrate at higher coir ratios increased with increasing times of cultivation. However, there was no change in the water holding capacity with increasing times of cultivation in the substrates at higher peat mixture ratios. The C/N ratio of substrates at higher coir ratios decreased with increasing times of cultivation, although there was no change in the substrate at higher peat mixture ratios. Therefore, it was considered that the increasing water holding capacity of substrate at higher coir ratios was caused by the decomposition of substrate. The yield of strawberries during the February-March period only decreased with increasing coir ratios regardless of times of cultivation. There was no difference in the yield of strawberries grown in substrate at higher peat mixture ratios irrespective of times of cultivation. However, the yield of strawberries grown in substrate at higher coir ratio increased with increasing times of cultivation. There was highly correlation between the yield of strawberries and water content of substrate during the February-March period (r=0.74) regardless of coir ratios or times of cultivation.