Q2. What is the role of sulphuric acid in the extraction of organic acids?
The presence of sulphuric acid can increase the extraction of cations and form soluble sulphates from K and Na and Mg. Sulphuric acid can also catalyse the conversion of organic acids by esterification and promote decomposition reactions involving hydration and decarbonylation.
Q3. How much phosphorus is extracted in water?
Following thermal hydrolysis at 170°C, the extraction of phosphorus in water alone reduces to 13% while extraction of phosphorus using formic acid and acetic acid reduces to 21% and 22% respectively.
Q4. What is the process for determining total phosphorus?
The analysis for total phosphorus requires a pre-digestion step using the persulphate digestion method before the colorimetric analysis.
Q5. At what temperature did the hydrochar contain more nitrogen than the aqueous phase?
At 120oC, more phosphorus remained in the hydrochar (63 - 84%) than the aqueous phase for all additives (11 - 30%) except the H2SO4.
Q6. What is the main reason why farmers are concerned about storing excess manure?
Storing excess manure is a huge challenge to farmers due to odour issues, the high solubility of phosphorus and high degradation rate releasing ammonia (Vadas and Powell, 2013).
Q7. What is the effect of adding acid on the extraction of phosphorus?
The extraction of phosphorus increases by adding mineral and organic acids and the type of acid was shown to influence phosphorus extraction.
Q8. What are the strategies for reducing ammonia in livestock?
For instance, strategies for ammonia reduction includes renovation of barns, change in animal nutrition, regular cleaning of exhaust air from farm structures and proper manure treatment (Ndegwa et al., 2008).
Q9. What is the main reason for the lack of manure management?
Despite the keen interest in manure management over the past decades, development of sustainable management/treatment technologies on farm or nearby is still necessary to reduce these environmental concerns, improve agricultural benefits and reduce greenhouse gas emissions (Karakashev et al., 2008).
Q10. What is the main reason why livestock producers are concerned about the environmental standards?
Therefore livestock producers are concerned about developing new methods and technologies to meet regulatory requirements and maintain good environmental standards.
Q11. What is the effect of the hydrochar on the nitrogen content?
Analysis of the metal content in the hydrochars (not shown) indicates that treatment in H2SO4 reduces the levels of Ca, Mg and Fe in the hydrochar compared with the other reagents.
Q12. What is the average nitrogen content in swine manure?
The nitrogen levels in manure are typically high, reflecting the high levels of crude protein and range from 3-5 % (Heilmann et al., 2014).