Itthiphon khong phosphoros to kan charoen toepto phonphalit lae ongprakop thang khemi khong khao Ko Kho 7 nai din khem.

The influence of phosphorus on growth, yield and chemical composition of rice variety R.D. 7 in saline soil was investigated. The results of this experiment revealed that the tillers number and height of salt treated rice were markedly reduced. Although 0.15% NaCl treatment suppressed the vegetative growth of rice particularly at the first stage of growth, rice parts tended to recover before reaching the maximum tillering stage. Addition of 50-100 ppm. P. sequentially increased tiller number and plant height. The highest rate of phosphate fertilizer of 200 ppm. P. tended to decrease the growth of rice. Increasing salinity levels of the soil resulted in the reduction of plant dry weight obtained at maximum tillering stage, flowering stage, and final harvest. Significant decrease in dry weight of root, shoot and grain yield were observed in salt treatments. On the other hand, increasing salt levels resulted in increasing shoot/root ratio at maximum tillering stage and maturity. However, shoot/root ratio of rice at flowering was reduced the level of salinity was increased. NaCl treatments also depressed the leaf area at maximum tillering and flowering stages. It was clearly observed that rice grown in NaCl treated soil had less tiller number and lower grain yield when compared to those grown in normal soil condition. The addition of phosphate fertilizer significantly increased the dry matter of plants, shoot/root ration, number of panicles and grain yield per hill. The concentration of sodium and chloride ions in stem with leaf sheath and leaf blades of rice significantly increased with increasing NaCl levels in the soils. The sodium and chloride concentration of stem with leaf sheath is markedly higher tan leaf blades. Salinity also influenced the concentration of nitrogen, phosphorus, potassium, calcium and magensium in rice shooots. The concentration of these ions in plant tissue could not be considered as deficient or toxic levels for rice. Increasing the phosphate concentration in the soil caused the increase of phosphorus and magnesium but decreased sodium and chloride concentration in rice shoot.