1. Utilization of organic wastws and its environmental implications;Amberger,1987
2. Response of corn to nitrogen in preplant and sidedress aplications of liquid dairy cattle manure;Beauchamp;Canadian Journal of Soil Science,1983
3. Determination and isotope-Ratio analysis of different forms of nitrogen in soil. 3. Exchangeable ammonium, nitrate and nitrite by extraction-distillation methods;Bremner,1966
4. Ammonia volatilization from liquid manure after application in the field;Döhler,1987
5. Carte mondiale des sols;Fao-Unesco,1989