Grasses in agriculture - Part 1, agronomy of grasses

abonos agricultura agriculture agronomia agronomie agronomy aliment pour animaux climatic zones conduite des herbages crop rotation economia economic distribution economics economie engrais experimentation farming systems farmyard manure feed crops feeds fertilidad del suelo fertilizers fumier gestion graine gramineas graminee grasses grassland management grasslands herbage management manejo de praderas methods nutritive value orina pastizal sembrado pastizales pastures piensos planification planning plant introduction plantas forrajeras praderas prairie artificielle production de semences projet de recherche research projects seed production seeds semilla soil fertility sown pastures testing tropical zones urine valeur nutritive valor nutritivo zona tropical zone climatique zone tropicale