Effect of organic materials and no-tillage system on soil chemical properties changed in paddy field

Thailand is a country located on the tropical agriculture. Natural soil fertility is low. Low organic matter content. Due to the rapid degradation of the heat and humidity. Therefore,the concept adding of organic material and reduced tillage to improve soil properties for the better. The study on the effects of tillage systems on changes in soil chemical properties of rice. The experimental design was Randomize Complete Block Design (RCBD) 5 treatments. 1) tillage (control) 2) tillage with sunnhemp incorporation 3) tillage with rice straw incorporation 4) no tillage with sunn hemp mulching 5) no tillage with rice straw mulching. Soil samples were collected during the period, before transplant and 2 weeks after harvest. The soil reaction, electrical conductivity, organic matter, total nitrogen, phosphorus and exchangeable potassium were measured. The results found that after harvesting, the soil reaction was reduced in all treatments, ranging from moderately acid to very acid. Electrical conductivity is likely to be lower in every treatment, and stay in normal soil (< 2 dS m-1). Organic matter contents were increased in every treatment. Total N were increased with increasing organic materials adding. Available phosphorus were increased in every treatment. They are very low concentration when compare to standard value. And exchangeable potassium was decrease in every treatment