Identification of relevant environmental descriptors

Based on previous experiences and a literature review the most relevant environmental descriptors were selected and tested by means of field experiments. These included: (i) the temperature-humidity index (THI), (ii) the cattle stocking system (rotational stocking, continuous stocking or strip-grazing), (iii) the botanical composition of the grasslands, (iv) the net grassland productivity in terms of Net Energy (NE) and/or energy-corrected milk (ECM) per unit grassland area, and (v) the behaviour of dairy cows within grazing herds as recorded with SensOor® technology

The contribution of mineralization to grassland N uptake on peatland soils with anthropogenic A horizons

Peatland soils contain large amounts of nitrogen (N) in the soil and mineralization can contribute substantially to the annual mineral N supply of grasslands. We investigated the contribution of N mineralization from peat with respect to the total annual N uptake on grasslands with anthropogenic A horizons and submerged tile drains. The study included i) a pot experiment to determine potential N mineralization from the topsoil and the subsoil, ii) a 1-year field experiment to study herbage yields and N uptake under fertilized and non-fertilized conditions and iii) a 3-year field study where herbage yield and N uptake from the top 30 cm and the entire soil profile were monitored. The 3-year field study yielded an average N uptake of 342 kgha(-1) under non-fertilized conditions but the contribution of subsoil peat N mineralization to the total N uptake was found to be negligible. Our calculations demonstrate that peat N mineralization contributed only 10% to 30% to the total N-uptake, mainly coming from the top 30 cm. Most of the N uptake under unfertilized conditions appears to be largely the result of mineralization from long-term inputs of dung, ditch sludge, farmyard manure, cow slurry and non-harvested herbage

Laboratory and greenhouse assessment of plant availability of organic N in animal manure

Laboratory data (thermal fractionation, pepsin extraction, C:No ratio) of dung and manure were mutually compared and contrasted with plant-availability of organic N (No) as found in a greenhouse experiment according to the double-pot technique. Two types of fresh cow dung (one with a relatively wide and the other with a relatively narrow C:No ratio) and four types of manure (from poultry, sheep, pigs and cow) were compared with ammonium nitrate as chemical reference fertilizer. Relative effectiveness of organic N (REo) was used as characteristic; it was calculated as the fraction of organic N that has the same availability to plants as inorganic N. REo for poultry and sheep manure could not be assessed, probably because of NH3 volatilization causing direct damage to plants and N losses. REo values decreased in the order: dung with narrow C:No > dung with wide C:No > pig manure > cow manure. Thermal fractionation did not provide a suitable index of plant-availability of organic N. Pepsin extracted organic N gave a positive, and C:No ratio a negative relationship with REo. Also between pepsin extracted organic N and C:No ratio a negative relationship was found. As C:No ratio is relatively easy to determine, it is considered the most practical laboratory index for plant availability of organic N in animal manures low in ammonia. When using the double-pot technique, application rates of manure types high in ammonia should be restricte

The influence of feeding strategy on growth and rejection of herbage around dung pats and their decomposition

Fresh cattle dung from four farms with different feeding strategies was used to create artificial dung pats in a continuously grazed pasture in order to compare the rejection of herbage growing around the pats, the effect on undisturbed herbage growth under cages and pat decomposition. The first farm was an extensive organic farm (ORGE) with young steers grazing on a biodiverse sward. The second was an intensive organic farm (ORGI) with dairy cattle grazing on a grass/clover sward during the day and fed low-protein forages indoors. The third dung used was from an integrated farm (TNT), where the feeding strategy was aiming for high dung quality by including straw in the diet. The fourth examined dung was from a conventional farm (CONV) aiming for a high milk production per cow, where fertilized grazed grass was the main component of the diet. A human smell test was performed to rank the odour of the four dungs. After 6 weeks of continuous grazing with dairy cattle, herbage yield around TNT pats tended to be lowest, whilst undisturbed herbage yield in and around caged TNT pats was highest (

Charles Glenn: A Response

This paper was given in response to Dr. Glenn’s presentation

Adam\u27s Navel: A Natural and Cultural History of the Human Form (Book Review)

Reviewed Title: Adam’s navel: A natural and cultural history of the human form, by Michael Sims. New York: Viking, 2003. 342 pp

Great with Child: Reflections on Faith, Fullness, and Becoming a Mother (Book Review)

Reviewed Title: Great with Child: Reflections on Faith, Fullness, and Becoming a Mother, Debra Rienstra (Tarcher Putnam, 2002), 295 pp

Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen (Book Review)

Reviewed Title: MacDougall, Christopher. Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen. New York: Vintage Books, 2009. 304 pages. ISBN: 9780307279187

Perfecting Ourselves to Death: The Pursuit of Excellence and the Perils of Perfectionism (Book Review)

Reviewed Title: Perfecting ourselves to death: The pursuit of excellence and the perils of perfectionism, by Richard Winter, Downer’s Grove, IL: Intervarsity Press, 2005. 203 pages