Park Sang Hyun, Lee Bok Rye, Jung Kwang Hwa, Kim Tae Hwan
Department of Animal Science, Institute of Agricultural Science and Technology, College of Agriculture & Life Science, Chonnam National University, Gwangju 61186, Korea.
Biotechnology Research Institute, Chonnam National University, Gwangju 61186, Korea.
Asian-Australas J Anim Sci. 2018 Mar;31(3):457-466. doi: 10.5713/ajas.17.0556. Epub 2017 Dec 19.
The present study aimed to assess the nitrogen (N) use efficiency of acidified pig slurry for regrowth yield and its environmental impacts on perennial ryegrass swards.
The pH of digested pig slurry was adjusted to 5.0 or 7.0 by the addition of sulfuric acid and untreated as a control. The pig slurry urea of each treatment was labeled with N urea and applied at a rate of 200 kg N/ha immediately after cutting. Soil and herbage samples were collected at 7, 14, and 56 d of regrowth. The flux of pig slurry-N to regrowth yield and soil N mineralization were analyzed, and N losses via NH, NO emission and NO leaching were also estimated.
The pH level of the applied slurry did not have a significant effect on herbage yield or N content of herbage at the end of regrowth, whereas the amount of N derived from pig slurry urea (NdfSU) was higher in both herbage and soils in pH-controlled plots. The NH-N content and the amount of N derived from slurry urea into soil NH fraction (NdfSU-NH) was significantly higher in in the pH 5 plot, whereas NO and NdfSU-NO were lower than in control plots over the entire regrowth period. Nitrification of NH-N was delayed in soil amended with acidified slurry. Compared to non-pH-controlled pig slurry (i.e. control plots), application of acidified slurry reduced NH emissions by 78.1%, NO emissions by 78.9% and NO leaching by 17.81% over the course of the experiment.
Our results suggest that pig slurry acidification may represent an effective means of minimizing hazardous environmental impacts without depressing regrowth yield.
本研究旨在评估酸化猪粪对多年生黑麦草再生产量的氮（N）利用效率及其环境影响。
通过添加硫酸将消化后的猪粪pH值调节至5.0或7.0，并将未处理的作为对照。各处理的猪粪尿素用N尿素标记，刈割后立即以200 kg N/ha的施用量施用。在再生7、14和56天时采集土壤和牧草样本。分析了猪粪氮向再生产量的通量和土壤氮矿化情况，并估算了通过NH、NO排放和NO淋溶造成的氮损失。
施用猪粪的pH水平对再生末期的牧草产量或牧草氮含量没有显著影响，而在pH控制的地块中，牧草和土壤中来自猪粪尿素的氮量（NdfSU）较高。pH 5地块中NH-N含量以及从猪粪尿素进入土壤NH组分的氮量（NdfSU-NH）显著更高，而在整个再生期内，NO和NdfSU-NO低于对照地块。酸化猪粪改良的土壤中NH-N的硝化作用延迟。与未控制pH的猪粪（即对照地块）相比，在实验过程中，施用酸化猪粪使NH排放减少了78.1%，NO排放减少了78.9%，NO淋溶减少了17.81%。
我们的结果表明，猪粪酸化可能是一种在不降低再生产量的情况下将有害环境影响降至最低的有效手段。
