2007 Volume 51 Issue 4 Pages 169-176
Sandy soils are generally unfertile, but limited information is available on the soil-plant nutrient dynamics. To examine the relationship between the nutrient contents in soil and growth, yield and nutrient uptake by plant and to propose rational practices for sustainable agricultural system, maize was cultivated in 2004 on a sandy soil in Khon Kaen, northeast Thailand. Six treatments were applied: NPK (100kg ha-1), PK, NK, NP, control and NPK+manure treatments. Soil samples were collected and available and total contents of NPK determined. Plants were harvested and the dry weight, yield and NPK contents determined. The amounts of available N, P and K within lm of soil were 47, 261 and 256 kg ha-1, or 2.2, 7.3 and 1.8% of the total, respectively. About 37% of available N and 50% of available P were stored within the surface 20cm, where more than 80% of the roots distributed. Aboveground biomass in the PK, NK, NP and NPK treatments were 4, 25, 79 and 98% higher than the control (3.71 t ha-1), respectively, indicating that N was the dominant limiting factor, followed by P and K. In conclusion, adequate N and P fertilization and erosion control would be essential for sustainable agricultural system for maize.
