Soil properties and poplar growth with pig manure biogas slurry

As scale and intensity increase with development of the animal husbandry industry, use of manure biogas slurry from livestock biogas slurry projects also increases. To counter any possibility of water eutrophication and environmental pollution from direct emissions of pig manure biogas which is rich in N, P, K, and other nutrients, the effects of pig manure biogas slurry applied on soil properties and growth of a poplar （Populus） plantation were studied. The biogas plant of COFCO carnivorous （Jiangsu） Co. Ltd produced the slurry. Results showed that 1 125 m3hm－2 biogas slurry fertilization （C5） increased soil organic matter （28%）, total N （35.5%）, available P （62.3%）, and available K 33.5%. Also, biogas slurry fertilization below 450 m3hm－2 was detrimental to poplar growth. ［Ch, 2 fig. 1 tab. 13 ref.］