Effect of soil improvent techniques on soil fertility and yield of sen pidao rice grown on prateahlang soil,(ប្រសិទ្ធភាពនៃបច្ចេកទេសកែលម្អ ទៅលើជីជាតិដី​ និងទិន្នផលស្រូវសែនពិដោរ នៅលើក្រុមដីប្រទះឡាង) LEANG SEREIKOL AGR LEA 2011 B048 Or.1 phnom penh RUA 2011 2011 Text xii, 48p. https://drive.google.com/file/d/1COoUxIeAYlc5mIGphGiAesnpuj4BnIh7/view?usp=sharing