The Sanjiang Plain, the largest inland freshwater marshland in China, was extensive reclaimed into agricultural land. To assess the effects of marshland reclamation on Collembola, we investigated collembolan communities in a chronosequence of soybean plantations (2, 15, and 25 years) in Sanjiang marshland, Northeastern China. We found that: 1) the densities and species richness of Collembola were promoted after short-term (2 years) cultivation of soybean, but significantly decreased after medium-term cultivation (15 years); 2) the densities of epi-edaphic Collembola increased while the densities of hemi-edaphic Collembola decreased as the elongation of soybean cultivation; 3) compared with S0, two species of Collembola appeared while five species disappeared in S25. The changes of plant communities and the soil traits were supposed to be the key factors affecting the composition of soil Collembola. We thus suggest that original marshland should be saved for preserving high diversity and densities of Collembola in the Sanjiang Plain.
There are approximately 2.5 million dairy cows in California. Emission inventories list dairy cows and their manure as the major source of regional air pollutants, but data on their actual emissions remain sparse, particularly for smog-forming volatile organic compounds (VOCs) and greenhouse gases (GHGs). We report measurements of alcohols, volatile fatty acids, phenols, and methane (CH4) emitted from nonlactating (dry) and lactating dairy cows and their manure under controlled conditions. The experiment was conducted in an environmental chamber that simulates commercial concrete-floored freestall cow housing conditions. The fluxes of methanol, ethanol, and CH4 were measured from cows and/or their fresh manure. The average estimated methanol and ethanol emissions were 0.33 and 0.51 g cow(-1) h(-1) from dry cows and manure and 0.7 and 1.27 g cow(-1) h(-1) from lactating cows and manure, respectively. Both alcohols increased over time, coinciding with increasing accumulation of manure on the chamber floor. Volatile fatty acids and phenols were emitted at concentrations close to their detection limit. Average estimated CH4 emissions were predominantly associated with enteric fermentation from cows rather than manure and were 12.35 and 18.23 g cow(-1) h(-1) for dry and lactating cows, respectively. Lactating cows produced considerably more gaseous VOCs and GHGs emissions than dry cows (P < 0.001). Dairy cows and fresh manure have the potential to emit considerable amounts of alcohols and CH4 and research is needed to determine effective mitigation. 相似文献
Sodium bisulfate (SBS) is extensively used in the poultry industry to reduce ammonia and bacterial levels in litter. It is also used in the dairy industry to reduce bacterial counts in bedding and ammonia emissions, preventing environmental mastitis and calf respiratory stress. The present study measured the effect of SBS on the air emission of ammonia, amine, and alcohol from a dairy slurry mix. Amine flux was undetectable (<5 ng L(-1)) across treatments. Application of SBS decreased ammonia, methanol, and ethanol emissions from fresh dairy slurry. Ammonia emissions decreased with increasing levels of SBS treatment. The 3-d average ammonia flux from the control (no SBS applied) and the three different SBS surface application levels of 0.125, 0.250, and 0.375 kg m(-2) were 513.4, 407.2, 294.8, and 204.5 mg h(-1) m(-2), respectively. The ammonia emission reduction potentials were 0, 21, 43, and 60%, respectively. Methanol and ethanol emissions decreased with an increase in the amount of SBS applied. The 3-d average methanol emissions were 223.7, 178.0, 131.6, and 87.0 mg h(-1) m(-2) for SBS surface application level of 0, 0.125, 0.250, and 0.375 kg m(-2), with corresponding reduction potentials of 0, 20, 41, and 61, respectively. Similar emission reduction potentials of 0, 18, 35, and 58% were obtained for ethanol. Sodium bisulfate was shown to be effective in the mitigation of ammonia and alcohol emissions from fresh dairy slurry. 相似文献
The formation potential of four trihalomethanes (THMFP) and seven haloacetic acids (HAA7FP) in 13 source waters taken from
four major water basin areas in China was evaluated using the simulated distribution system (SDS) chlorination method. The specific
ultraviolet absorbance (SUVA254: the ratio of UV254 to dissolved organic carbon (DOC)), which ranged between 0.9 and 5.0 L/(mg m),
showed that the organic compounds in di erent source waters exhibited di erent reactivities with chlorine. The HAA7FP of source
waters ranged from 20 to 448 g/L and the THMFP ranged from 29 to 259 g/L. The HAA7FP concentrations were higher than the
THMFP concentrations in all but one of the samples. Therefore, the risks of haloacetic acids (HAAs) should be of concern in some
source waters. TCM (chloroform) and BDCM (bromodichloromethane) were the major THM constituents, while TCAA (trichloroacetic
acid) and DCAA (dichloroacetic acid) were the major HAA species. Br-THM (brominated THM species) were much higher than Br-
HAA (brominated HAA species), and the formation of Br-DBP (Br-THM and Br-HAA) should be of concern when the bromide
concentration is over 100 g/L. 相似文献