1. Impact of animal manures and chemical fertilizers on yield components of saffron (Crocus sativus L.);Amiri;Am. Eur. J. Agric. Environ. Sci.,2008
2. The influence of source and timing of nitrogen fertilizers on yield and nitrogen use efficiency of four sweet potato cultivars;Ankumah;Agric. Ecosyst. Environ.,2003
3. Official Methods of Analysis;AOAC,2000
4. Phosphorus use efficiency as related to sources of P fertilizers, rainfall, soil, crop management, and genotypes in the West African semi-arid tropics;Bationo,2002
5. Dynamics of light and nitrogen distribution during grain filling within wheat canopy;Bertheloot;Plant Physiol.,2008