Nitrogen losses from farmyard manure and nitrogenous fertilizers on a red latosol [urea, ammonium sulphate, Sri Lanka]

abonos agricultural chemicals amendement du sol ammonium compounds ammonium sulphate asia asie azote carence du sol compuestos de amonio deficiencias del suelo elements engrais engrais organique enmiendas del suelo farmyard manure fertilidad del suelo fertilizantes nitrogenados fertilizers gases gaz leaching nitrogen nitrogen fertilizers no metales nonmetals organic compounds organic nitrogen compounds physical states produit agrochimique soil amendments soil deficiencies soil fertility sri lanka sulfato de amonio urea uree