예취빈도가 다른 조건에서 무기태 질소와 액상구비의 시용이 Reed canarygrass의 건물수량과 질소이용효율에 미치는 영향

Effects of application rates of mineral N and cattle slurry on the dry matter yield and efficiency of N utilization of Reed canarygrass grown in different cutting frequency

예취빈도가 다른 조건에서 무기태 질소와 액상구비의 시용수준이 Reed canargrass 의 건물수량에 미치는 영향을 액상구비의 질소이용효율을 중심으로 검토하였다. 무기태 질소의 시용에 대한 액상구비의 상대건물수량은 연간 3회 예취구에서 84.3%, 4회 예취구에서 77.9%, 그리고 5회 예취구에서 81.2%를 나타내어 액상구비의 시용효과가 높았다. 무기태 질소의 건물생산효율(kgDM/kgN)은 모든 예취구에서 30kg/ha/cut 수준에서 가장 높았으며, 예취빈도에서는 3회 예취구가 질소 1kg당 23.9kg의 건물수량을 나타내어 다른 예취구보다 높았다. 그러나 전질소량(kgTN/kgN) 의 증가에서는 예취빈도에 따른 차이가 인정되지 않았다. 액상구비의 건물생산효율(kgDM/kgN) 은 3회와 4회 예취구에서는 30kg/ha/cut 수준, 5회 예취구에서는 60kg/ha/cut 수준에서 가장 높았으며, 전질소량(kgTN/kgN) 에서는 3회 예취구에서 0.11kg이었으나, 4회와 5회 예취구에서는 20kg 이상이었다. 무기태 질소에 대한 액상구비의 상대건물생산효율은 3회 예취구에서 33.1%, 4회 예취구에서 52.1%, 5회 예취구에서 50.0%였으며, 상대전질소량은 3회 예취구에서 28.9%, 4회 예취구에서 51.3%, 그리고 5회 예취구에서 55.3%를 나타내었다.

In order to investigate the effects of application rates of mineral N and cattle slurry on the dry matter yield of Reed canarygrass grown in different cutting frequency, was was cernpared for the efficiency of N utilization. Annual rates of mineral N and cattle slurry N of 0 (control), 90kg, 180kg, 270kg and 360kg/ha in 3 cuttings, 0, 120kg, 240kg, 360kg and 480kg/ha in 4 cuttings, and 0, 150kg, 300kg, 450kg and 600kg/ha were applied as urea and cattle slurry in 5 cuttings, respectively. The results were summarized as follows: 1. The annual dry matter yields were increased with application rates of mineral N and cattle slurry. The annual dry matter yields of mineral N obtained were 14.4 ton/ha(ranged from 10.46 ton to 16.91 ton/ha) in 3 cuttings, 13.88 ton/ha(ranged from 9.91 ton to 16.53 ton/ha) in 4 cuttings and 15.98 ton/ha(ranged from 12.0 ton to 18.25 ton/ha) in 5 cuttings. The annual dry matter yields of cattle slurry obtained were 12.14ton/ha(ranged from 8.92 ton to 11.79ton/ha) in 3 cuttings, 10.81ton/ha(ranged from 8.92 to 11.79 ton/ha) in 4 cuttings and 12.98ton/ha(ranged from 10.68 ton to 14.85ton/ha) in 5 cuttings. 2. Relative dry matter yield of cattle slurry as compared to mineral N were 84.3%, 77.9% and 81.2% in 3, 4 and 5 cuttings. 3. Average increase in dry matter production(kgDM/kgN) tended to decrease with application rates of mineral N and cattle slurry, and higher cutting frequencies. Average increase in dry matter production obtained were higher values at rates of 30kg/ha/cut in both of mineral N and cattle slurry. Average increase in dry matter production to mineral N were 23.9kg, 18.8kg and 15.2kgin 3, 4 and 5 cuttings, respectively. 4. Average increase in total nitrogen yield(kgTN/kgN) to mineral N obtained were 0.46kg at rates of 60kg/ha/cut in 3 cuttings, and 0.45kg and 0.40kg at rates of 30kg/ha/cut in 4 and 5 cuttings. 5. Average increase in dry matter production(kgDM/kgN) to cattle slurry obtained were 13.7kg and 19.5kg at rates of 30kg/ha/cut in 3 and 4 cuttings, and 9.7kg at rates of 60kg/ha/cut in 5 cuttings. 6. Average increase in total nitrogen yield(kgTN/kgN) to cattle slurry was not concern to the rates of application. Average increase in total nitrogen yield to cattle slurry obtained were 0.11kg, 0.20kg and 0.21kg in 3, 4 and 5 cuttings. 7. Relative average increase in dry matter production of cattle slurry as compared to mineral N were 33.1%, 52.1% and 50.0% in 3, 4 and 5 cuttings. Relative average increase in total nitrogen yield of cattle slurry as compared to mineral N were 28.9%, 51.3% and 55.3% in 3, 4 and 5 cuttings.