Effects of different fertilization schemes on alfalfa performance and nutritional quality

In this experiment, Medicago sativa ‘Dongnong No.1,’ which was planted in the second year was treated with a newly developed special compound fertilizer (patent number: 201810193040.0). The experiment was conducted in a two-factor random block design using 18 fertilization schemes using different amounts of fertilizer (225, 300, 375, 450, 525, 600 kg·ha^–1) and varying periods of fertilization (regreening stage, after the first harvest, and after the second harvest) to determine the effects of the amount and time of fertilization on the yield and quality of alfalfa. No fertilizer was used for the control experiment . We found that fertilizing at various stages and at all the tests concentrations improved both the yield and quality of alfalfa. The highest annual hay yield was 12.15 t·ha^–1 following fertilization at 525 kg·ha^–1 once during the regreening period, which 38.54% higher than that of the control and 12.50% and 18.42% higher than fertilization with the same concentration after the first and second harvest, respectively. Lower or higher levels of fertilizer used once during the same period affected the hay yield of alfalfa. The highest hay yield was obtained following fertilization with 525 kg·ha^–1 once during the regreening period. This was 25.65% and 5.29% higher than fertilization at 225 and 600 kg·ha^–1, respectively. The highest crude protein content for the annual average was 23.54% when 450 kg·ha^–1 fertilizer was applied during regreening period, which was 14.83% higher than that of the control.