| Paddy soil in Sing Buri province can be classified into 4 levels as high suitability (soil group 3, 4, 7 and 15), moderately suitability (soil group 21), low suitability (soil group 33) and unsuitability (soil group 38). Moreover, yield production potential of those paddy soils can also be divided into 4 levels as more than 850 kg/rai (R1), 701 - 850 kg/rai (R2), 551 - 700 kg/rai (R3) and less than or equal to 550 kg/rai (R4). Field survey of 547 farmers plantation in Sing Buri province during 2007 - 2009 found that at least five rice varieties, which are PTT1, SPR1, RD31, CNT1 and PSL2 were grown. The common varieties which were PTT1 (90.31%), SPR1 (6.22%) and RD31 (0.91%), respectively were planted by direct seeding method with 25-35 kg/rai seed rate,... |
