Estimation of the phosphate forms fractioned by method of Chang and Jackson affected by fertilization factors in long-term fertilization experiment (Pt. 2)

abonos inorgánicos abonos orgánicos analytical methods aplicación de abonos azote chaulage encalado engrais minéral engrais organique estiércol experimentación en campo expérimentation au champ farmyard manure fertilidad del suelo fertilisation fertilité du sol fertilizer application field experimentation fosfatos fumier fósforo inorganic fertilizers liming nitrogen nitrógeno organic fertilizers phosphate phosphates phosphore phosphorus poland pologne polonia potasio potassium sampling sandy soils soil soil fertility sol sol sableux suelo suelo arenoso technique analytique técnicas analíticas échantillonnage