Effect of gradually increased fertilizer rates and different fertilization methods on the changes of potassium fixation by soils

abonos agricultural chemicals alkali metals amendement du sol ammonium compounds ammonium nitrate analisis analyse analyse de sol analyse statistique analysis calcium fertilizers carence du sol chemistry chimie chimie du sol chlorure de potassium compuestos de amonio deficiencias del suelo elements engrais engrais calcique engrais organique engrais potassique enmiendas del suelo ensayo environment environnement evaluation farmyard manure fertilidad del suelo fertilizantes de oligoelementos fertilizantes fosfatados fertilizantes nitrogenados fertilizers fosfatos inorganic compounds leaching medio ambiente metal metales metales alcalinos metals methode methods micronutrient fertilizers nitrate d'ammonium nitrato de amonio nitrogen fertilizers organic compounds organic nitrogen compounds phosphate phosphate fertilizers phosphates potash fertilizers potasio potassium potassium chloride produit agrochimique sales salts sel site factors soil amendments soil chemistry soil deficiencies soil fertility soil testing statistical analysis statistical methods statistics superfosfato superphosphate testage testing