Trial-2In the 2nd trial at Ashburto

Trial-2
In the 2nd trial at Ashburton, fertiliser applied at low rate (25 kg N /ha) in FPA form exhibited higher N response improvements compared to their corresponding high rate (50 kg N /ha) (Data not shown due to space shortage). Agrotain treated urea applied at 25 kg N/ha in FPA form exhibited 52% improvement in N response over its urea treatments applied in granular form; while such improvements were only 15% for high rate. The lower pasture yield improvements at 50 kg N /ha rate compared to 25 kg N /ha highlight that the plants had perhaps reached their maximum uptake potential through the leaves therefore decreased the N efficiency. The response efficiencies of urea with Agrotain applied in FPA forms were 19 and 21 kg of pasture dry matter per kg of applied N for low and high rates respectively. These values of N response efficiencies by FPA treatments were lower than those we observed in experiment-1 and 3. Such lower N responses by FPA treatments were probably related to the extremely dry soil conditions and high soil temperature (25oC) and air temperature (32oC) on the day of fertiliser application which also caused moderate to severe pasture burning. Hot dry conditions are likely to inhibit N uptake through the leaves due to lack of sufficient solute to transport it. However such pasture burning was temporary and pastures came back to their normal growth after 1 week of fertiliser application. In trial-3, dry soil conditions and high soil temperature on the day of fertiliser application also affected N responses from urea with Agrotain applied in FPA form in the Lincoln trial (data not shown). Applying FPA to higher pasture covers and then applying light irrigation significantly improved N response and response efficiency in these conditions. FPA treatments applied to pasture cover of 5 cm, 10 cm and 10 cm with 10 mm leaf irrigation produced 27, 29 and 46 kg of pasture dry matter per kg of applied N respectively. This indicates that light irrigation is a critical after applying fertilisers in FPA form on a hot day to avoid N losses via NH3 volatilisation and leaf burning. These results suggest that applying chemical fertiliser in FPA form has the potential to improve fertiliser N response efficiency; while leaf irrigation pushes the applied N from surface soil and enable them to make good contact with plant roots.

Kết quả (Việt) 1:

Thử nghiệm-2In the 2nd trial at Ashburton, fertiliser applied at low rate (25 kg N /ha) in FPA form exhibited higher N response improvements compared to their corresponding high rate (50 kg N /ha) (Data not shown due to space shortage). Agrotain treated urea applied at 25 kg N/ha in FPA form exhibited 52% improvement in N response over its urea treatments applied in granular form; while such improvements were only 15% for high rate. The lower pasture yield improvements at 50 kg N /ha rate compared to 25 kg N /ha highlight that the plants had perhaps reached their maximum uptake potential through the leaves therefore decreased the N efficiency. The response efficiencies of urea with Agrotain applied in FPA forms were 19 and 21 kg of pasture dry matter per kg of applied N for low and high rates respectively. These values of N response efficiencies by FPA treatments were lower than those we observed in experiment-1 and 3. Such lower N responses by FPA treatments were probably related to the extremely dry soil conditions and high soil temperature (25oC) and air temperature (32oC) on the day of fertiliser application which also caused moderate to severe pasture burning. Hot dry conditions are likely to inhibit N uptake through the leaves due to lack of sufficient solute to transport it. However such pasture burning was temporary and pastures came back to their normal growth after 1 week of fertiliser application. In trial-3, dry soil conditions and high soil temperature on the day of fertiliser application also affected N responses from urea with Agrotain applied in FPA form in the Lincoln trial (data not shown). Applying FPA to higher pasture covers and then applying light irrigation significantly improved N response and response efficiency in these conditions. FPA treatments applied to pasture cover of 5 cm, 10 cm and 10 cm with 10 mm leaf irrigation produced 27, 29 and 46 kg of pasture dry matter per kg of applied N respectively. This indicates that light irrigation is a critical after applying fertilisers in FPA form on a hot day to avoid N losses via NH3 volatilisation and leaf burning. These results suggest that applying chemical fertiliser in FPA form has the potential to improve fertiliser N response efficiency; while leaf irrigation pushes the applied N from surface soil and enable them to make good contact with plant roots.