Acid sulfate soil is found in rather plain or plain area in Thailand. From the survay conducted by Land Development Department, acid sulfate soil is found in the Center of Thailand covering Nakhon Nayok, Ayutthaya, Pathum Thani, Saraburi, Chachoengsao, Chon Buri, Prachin Buri, Samut Prakan, Nakhon Pathom, Suphan Buri, Nonthaburi, Bangkok and Ratchaburi. Its total area is 6 million rai.
 
 
Adding marl to solve acid sulfate soil problem
Marl is Calciumcarbonate which is loamy. It is found in Lop Buri, Saraburi and Nakhon Sawan.
 
               Prepare marl in the ratio suitable for soil acidity. Pile it up as a small heap distributed in the area and scatter it throughout the area before soil preparatio. Then, incorporate the soil and leave it 2 weeks for reaction of soil to acidity before planting. Such method is effective and safe because adding marl only one time will solve acidity problem at least 5 years.
               Although adding marl can solve soil acidity problem, there are other factors for plant growth and crop yield. Such fzctors are varieties of plant, fertillzer and pesticide application, maintenance and irrigation. Farmers should select suitable techniques for their area.