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Strategies to Reduce Losses and Improve Utilisation of Nitrogen from Solid Cattle Manure

出版	Wageningen University, 2013
ISBN	94617351899789461735188
URL	http://books.google.com.hk/books?id=cQQlmwEACAAJ&hl=&source=gbs_api

註釋Results of the pot experiment showed that net N mineralisation and herbage ANR varied as function of manure storage method and soil type. Irrespective of the manure types, net N mineralisation and herbage ANR were highest in peat soil, which was characterised by the greatest N delivering capacity. Between the clay and sandy soils, both having similar N delivering capacity, net N mineralisation and herbage ANR were lower in the clay soil than in the sandy soil, likely because of immobilisation and fixation of ammonium-N by its inherited higher clay content. On each soil type,ANR was lower from SCM than cattle slurry and poultry manure(Chapter 2). The N recovery fraction was low when SCM was stored traditionally (i.e. stockpiling or composting) due to (i) loss of the initial mineral N content and readily degradable organic N compounds, and (ii) conversion of part of the remaining N into more stable forms as compared to that originally present before storage. Up to 31% of the initial total N from the stockpiled and 46% from the composted SCM heaps were lost during a period of about four months. Covering and roofing of SCM heaps reduced the losses down to 6 and 12%, respectively. Of the total N losses from each storage method, only about one fourth could be traced back as NH3-N and N2O-N emissions, and/or N leaching. The remainder could not be accounted for and constituted, in all probability, of harmless N2 gas. Of the total measured gaseous and liquid N losses together, N leaching contributed the most. The leaching N losses were reduced by almost three times through protection of SCM heap against precipitation either by its covering or roofing when compared to its stockpiling or composting in the open air. Although stockpiling of SCM under a roof significantly reduced overall total N losses, NH3 and N2O emissions were much higher as compared to stockpiling of SCM in the open air. Composting of SCM resulted in higher gaseous N emissions as well as N leaching with respect to the other storage methods. In view of these finding I conclude that covering of SCM heaps with an impermeable sheet is the best option to reduce storage N losses (Chapters 3 and 4). .