The kale crop was harvested by hand in mid winter after which the plots were compacted by leading a dairy cow up and down each plot for a period of 15–20 min until the level of soil treading damages was deemed to be visually similar to that observed under typical winter forage grazing conditions. Excreta deposition
on the plots was prevented during this exercise. Following soil treading compaction, 3 urine patches (0.3 m2 each) were laid out randomly to cover 25% of each plot, using metal frames inserted 50–100 mm into the soil. Artificial urine (urea 11.5 g, glycine 2.87 g, potassium bicarbonate 13.8 g, potassium sulphate 1.36 g and potassium
chloride 5 g L−1) was applied at a rate of 2 L per patch to simulate deposition by cattle. The amount of urinary N applied to each plot was determined assuming that each cow would urinate 10 times per day and be offered a feed break of 10 m2 per day to provide an appropriate amount of forage for a grazing cow. In 2007 and 2008 the N content of the urine was increased from 6 to 8 g N L−1 to more closely reflect concentrations observed in fresh urine that had been recently analysed as part of another trial. The artificial urine applied resulted in urine patches with equivalent N application rates of 399 (2006) or 528 kg N ha−1
(2007–2008), respectively (Table 1)
The kale crop was harvested by hand in mid winter after which the plots were compacted by leading a dairy cow up and down each plot for a period of 15–20 min until the level of soil treading damages was deemed to be visually similar to that observed under typical winter forage grazing conditions. Excreta deposition
on the plots was prevented during this exercise. Following soil treading compaction, 3 urine patches (0.3 m2 each) were laid out randomly to cover 25% of each plot, using metal frames inserted 50–100 mm into the soil. Artificial urine (urea 11.5 g, glycine 2.87 g, potassium bicarbonate 13.8 g, potassium sulphate 1.36 g and potassium
chloride 5 g L−1) was applied at a rate of 2 L per patch to simulate deposition by cattle. The amount of urinary N applied to each plot was determined assuming that each cow would urinate 10 times per day and be offered a feed break of 10 m2 per day to provide an appropriate amount of forage for a grazing cow. In 2007 and 2008 the N content of the urine was increased from 6 to 8 g N L−1 to more closely reflect concentrations observed in fresh urine that had been recently analysed as part of another trial. The artificial urine applied resulted in urine patches with equivalent N application rates of 399 (2006) or 528 kg N ha−1
(2007–2008), respectively (Table 1)
การแปล กรุณารอสักครู่..