Water, rather than temperature, dominantly impacts how soil fauna affect dissolved carbon and nitrogen release from fresh litter during early litter decomposition

Longstanding observations suggest that dissolved materials are lost from fresh litter through leaching, but the role of soil fauna in controlling this process has been poorly documented. In this study, a litterbag experiment employing litterbags with different mesh sizes (3 mm to permit soil fauna access and 0.04 mm to exclude fauna access) was conducted in three habitats (arid valley, ecotone and subalpine forest) with changes in climate and vegetation types to evaluate the effects of soil fauna on the concentrations of dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) during the first year of decomposition. The results showed that the individual density and community abundance of soil fauna greatly varied among these habitats, but Prostigmata, Isotomidae and Oribatida were the dominant soil invertebrates. At the end of the experiment, the mass remaining of foliar litter ranged from 58% for shrub litter to 77% for birch litter, and the DOC and TDN concentrations decreased to 54%-85% and increased to 34%-269%, respectively, when soil fauna were not present. The effects of soil fauna on the concentrations of both DOC and TDN in foliar litter were greater in the subalpine forest (wetter but colder) during the winter and in the arid valley (warmer but drier) during the growing season, and this effect was positively correlated with water content. Moreover, the effects of fauna on DOC and TDN concentrations were greater for high-quality litter and were related to the C/N ratio. These results suggest that water, rather than temperature, dominates how fauna affect the release of dissolved substances from fresh litter

Gromov-Hausdorff convergence of discrete transportation metrics

This paper continues the investigation of `Wasserstein-like' transportation distances for probability measures on discrete sets. We prove that the discrete transportation metrics on the d-dimensional discrete torus with mesh size 1/N converge, when $N\to\infty$, to the standard 2-Wasserstein distance W_2 on the continuous torus in the sense of Gromov-Hausdorff. This is the first convergence result for the recently developed discrete transportation metrics. The result shows the compatibility between these metrics and the well-established 2-Wasserstein metric.Comment: 22 pages, to appear in SIAM J. Math. Ana

The Influence of Initial Cow Weight on Progeny Performance and TDN Efficiency in Production of Slaughter Cattle

Data utilized in this study were from records (collected over a two-year period) of 45 Angus cow-calf pairs in which both the individual TDN consumption of the cows over a twelve month period and the individual TDN consumption of the calves from birth to slaughter (excluding TDN provided by milk) were recorded. The objectives of this study were to determine total digestible nutrient (TDN) consumed by cows of various sizes and weights, to determine the TDN intake of both cow and calf per unit weight of slaughter calves which varied in growth potential, to establish weights at which maximum TDN utilization occurred, and to establish relationships among characteristics of cows and calves, and overall TDN efficiencies for various periods. Cows were selected at weaning, confined to individual pens and individually fed to the following weaning. Cows selected ranged in weight from 835 lb. to 1,195 lb. In addition to initial weight, skeletal measurements and subcutaneous fat deposition between the twelfth and thirteenth ribs were recorded at the initiation of each trial. Milk production of the cows were made at 28-day intervals. (Abbreviated) These results indicated that TDN efficiency at weaning was primarily a function of size of both the dam and progeny while at point of maximum TDN utilization, size of the dam and progeny exhibited very little influence on TDN efficiency

Circular 68

Livestock rations should be balanced for many parameters including protein, and various minerals, and energy, to ensure that all required nutrients are present in the adequate amounts and proper relationships. Energy content is the primary consideration for balancing any farm animal’s diet because it is often the most limiting factor in animal performance. In Alaska, it is extremely important to test for major nutrients and then to balance rations because: 1) Alaska has longer, colder and wetter winters than those in the lower 48 states and consequently Alaskan animals have different nutrient needs. 2) Alaskan feedstuffs tend to be more variable in nutrient content than feeds grown in other states. After energy requirements, crude protein, calcium, phosphorus, and potassium are considered - and with the energy estimate - are the basis of the standard feed analyses performed by the Agricultural and Forestry Experiment Station (AFES) Service Laboratory feed testing section. Because all of these nutrients can vary greatly in the same feed, the Palmer Animal Sciences beef unit of AFES tracks the nutrient values of feed samples submitted to the AFES Service Laboratory. A summary of these values provides an indication of the types and values of feed available in Alaska. It also shows the variability in nutrient content of feedstuffs. Hopefully, this will stimulate the use of individual nutrient analyses for feeding livestock in Alaska