Experiments with Small Numbers of Observations

This is a report on part of an experiment that is under way having for its objective the determination of (a) the extent of divergence from theoretical values of probability in small samples, and (b) the extent of divergence from theoretical values of probability as computated by Student\u27s method if the sample is drawn from a non-normal distribution

Immediate effects of microclimate modification enhance native shrub encroachment

Shrubs have become more dense and expanded beyond their range all over the world for a variety of reasons including increased temperatures, overgrazing, and alteration of historical fire regime. Native shrubs have been encroaching on Virginia barrier island grasslands for over half a century for unknown reasons. Species composition, soil nutrients, leaf area index (LAI), and ground and air temperature were recorded across the shrub to grass transition and at free-standing shrubs in a coastal grassland in order to determine the effect of shrub encroachment on plant community and microclimate. Species richness was significantly lower inside shrub thickets. Soil water content, organic matter, nitrogen (N), carbon (C), and LAI were higher in shrub thickets and free-standing shrubs compared to grasslands. Summer and fall maximum temperatures were lower and more moderate where shrubs were present. Fall and winter minimum temperatures were highest inside shrub thickets. Native shrubs impact microclimate and species composition immediately upon encroachment. These shrubs lower overall species composition, increase soil nutrients and moisture, moderate summer temperature, and increase winter temperature, which has consequences on a larger scale. As barrier islands are critical for protecting marsh and mainland habitats, understanding this mechanism for shrub expansion is important to predict future encroachment of shrubs and displacement of grassland habitat

Some considerations on aggregate sample supports for soil inventory and monitoring

Soil monitoring and inventory require a sampling strategy. One component of this strategy is the support of the basic soil observation: the size and shape of the volume of material that is collected and then analysed to return a single soil datum. Many, but not all, soil sampling schemes use aggregate supports in which material from a set of more than one soil cores, arranged in a given configuration, is aggregated and thoroughly mixed prior to analysis. In this paper, it is shown how the spatial statistics of soil information, collected on an aggregate support, can be computed from the covariance function of the soil variable on a core support (treated as point support). This is done via what is called here the discrete regularization of the core-support function. It is shown how discrete regularization can be used to compute the variance of soil sample means and to quantify the consistency of estimates made by sampling then re-sampling a monitoring network, given uncertainty in the precision with which sample sites are relocated. These methods are illustrated using data on soil organic carbon content from a transect in central England. Two aggregate supports, both based on a 20 m 20 m square, are compared with core support. It is shown that both the precision and the consistency of data collected on an aggregate support are better than data on a core support. This has implications for the design of sampling schemes for soil inventory and monitoring

Effect of dietary supplement of sugar beet, neem leaf, linseed and coriander on growth performance and carcass trait of Vanaraja chicken

Aim: This study was planned to investigate the effect of sugar beet, neem leaf, linseed and coriander on growth parameters such as feed intake, body weight gain, feed conversion ratio (FCR), performance index (PI), and carcass characteristics in broiler birds. Materials and Methods: The experiment was conducted for a period of 42 days on Vanaraja strain of broiler birds. Different dietary supplement such as sugar beet meal, neem leaf meal, linseed meal and coriander seed meal were used in the basal diet. All day-old 150 male chicks were individually weighed and distributed into five groups having 30 birds in each. Each group was further sub-divided into triplicates having 10 birds in each. Group T1served as control and rest groups T2, T3, T4 and T5 as treatment groups. Birds in T1 group were fed basal ration only, however, T2 , T3, T4 and T5 groups were fed basal ration mixed with 2.5% sugar beet meal, neem leaf meal, linseed meal, and coriander seed meal individually, respectively. Results: Broilers supplemented with herbs/spices showed improvement in growth attributes and carcass characteristics. Broilers fed with herbs at the rate of 2.5% had higher feed intake except sugar beet and coriander seed meal fed group. The body weight and weight gain was also significantly (p<0.05) higher than control. Both FCR and PI were improved in supplemented groups in comparison to control. Dressing percentage was not significantly (p>0.05) affected. Average giblet percentage of all supplemented groups were significantly (p<0.05) higher than control and was found to be highest in neem leaf meal fed group. Average by-product percentage was found to be highest in linseed fed group. Conclusion: Various herbs such as sugar beet, neem leaf, linseed and coriander seed meals affected the growth performance, and carcass trait showed positive inclination toward supplemented groups in broilers. The exact mode of action of these herbs/spices is still not clear, however, one or more numbers of active compounds present in these supplements may be responsible