Variations in Timothy Dry Matter Yield and Nutritional Value as Affected by Harvest Date, Nitrogen Fertilization, Year and Location in Northern Sweden

Timothy was fertilized with three different levels of N (60+30, 120+60, 180+90) and harvested at different times in first and second crop. The experiments were conducted on six geographically different sites in altogether 36 experiment years. Dry matter yield increased by on average 120 kg/day and ha in the first growth period and by 50 in the second. The daily rates of decline in crude protein content and digestibility were 0.28% units and 0.49% units in the first growth period, and 0.17 and 0.17 in the second one, respectively. The differences in daily change of these variables between years and sites were analysed. Increased N application gave impaired digestibility. In the first crop, only the lowest level of N gave full apparent recovery of applied N. For N2, 30 kg/ha of N could not be accounted for, and for N3 the corresponding figure was 80 kg/ha.