Effets des engrais N, P et K sur le rendement et la qualite de l'ensilage ue mais

Abstract

Thirteen fertility trials were made throughout Quebec''s [Canada] corn [Zea mays] growing region during 1972-74. These included 11 fertilizer combinations with corn silage as the test crop and were carried out on 9 soils. Total dry matter and digestible nutrients (TDN) varied greatly from year to year, though, mean yields increased by 23 and 30%, respectively, with the 50 kg N/ha treatment, compared to control receiving no N fertilization. However, 150 kg N/ha was required to attain a maximum yield of 1250 kg/ha crude protein. Despite a 0.2% nitrate content found in the silage grown on the most northerly site, a 120 kg P/ha combined with 100 kg N and K gave the highest mean TDN production (9580 kg/ha). K fertilization affected plant K content of corn grown at the most northerly site only, where a 0.5% was found with the control on a soil containing low K levels. Striking increases in Ca and Mg concentrations were observed with corn grown on that soil. However, Mg concentration ranging 0.11-0.14% were found with 9 field trials out of 12. Low K:(Ca + Mg)ratios were found on 3 trials which were increased with K fertilization levels of 150 kg K/ha. Uptakes of 200, 48, 200, 30 and 30 kg/ha of N, P, K, Ca and Mg are probably required for good corn silage crops.