Edible quality of lettuce (Lactuca sativa L.) grown in different soil series under organic soil amendment

Abstract

Properties of planting soil have an influence on the amounts and uptake of the available plant nutrients. Physical properties of coarse and fine textured soils, especially, do not promote plant growth which affect the plant quality. Improving the physical property of soils by amending with organic material before planting is required. The objective of this research was to investigate the effect of amending soil types with organic materials on the edible quality of lettuce. The experimental design was completely randomized with six treatments. Green oak lettuce was grown in Ban Thon Soil Series, Ao Luek Soil Series and Ranod Soil Series, and each was amended with cow manure and chicken manure. The results revealed that the contents of phosphorus and iron in the edible part of lettuce were significantly affected by both soil types and organic amendments. There was no significant difference for potassium, calcium, magnesium, zinc and nitrate contents in the edible part of lettuce in any of the treatments. High content of phosphorus in lettuce was found in Ban Thon Soil Series and Ranod Soil Series amended with chicken manure treatment. Low content of iron was found in Ranod Soil Series amended with chicken manure treatment. Lettuce grown in all treatments had high content of potassium, except for a treatment of Ban Thon Soil Series amended with chicken manure and had low nitrate content. Vitamin C contents in the edible part of lettuce of all treatments were not significantly different. But type of organic soil amendment significantly affected vitamin C content in the lettuce. Therefore, the quality of lettuce grown in different soil types under organic soil amendments was affected by planted soil properties as controlling the availability and balance of soil nutrient. Also, manure application can improve the quality of lettuce.