No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Climate change has become the most important global environmental problem we face today. Agriculture, forestry and the land use sector not only contribute to national economies but also provide a source of greenhouse gas (GHG) emissions as well as a carbon store, contributing approximately 20% but removing about 16%. Energy crops and associated increases in soil carbon sequestration from different ground covers through various land management strategies are examples of approaches that could be adopted to reduce GHG emissions. A number of these options have an associated economic cost to the land manager and it is important to understand what is economically and socially viable by understanding the link between energy crop adoption and a range of socio-economic factors. Agent-based modelling (ABMs) has been identified as providing a promising approach to integrate social, economic and biophysical processes. In the past these areas of research have been mainly studied separately but now there is an urgent need to address these areas in a combined way. Economic rationalisation is fundamental to farmers’ decision-making, although not wholly representative and non-economic factors were identified. The estimated GHG mitigation potential of bioenergy crops at current adoption levels is modest when taking Scotland’s national GHG emissions into account, however, more significant when considering the agricultural sector in isolation. This contribution can only increase with improved management practices and policy designed to encourage adoption and improve energy security. This work will contribute to a greater understanding of bioenergy land use strategies. This project used North East Scotland as the case study, with raw data collated by questionnaire, however, conclusions drawn add to the broader understanding of the link between socio-economic activity, bioenergy adoption and GHG emissions.

Doctor of Philosophy / Department of Agronomy / Mary Beth Kirkham / In Kansas, winter cover crops have a new interest with the development of summer crops for biofuel. When a crop is harvested for bioenergy, the residue is removed leaving the soil prone to erosion during the winter. It is possible that the use of winter cover crops may allow for more residue to remain in a field while keeping the soil from blowing. Therefore, the objective of this research was to determine the effect of two winter cover crops on the growth of two biofuel crops, corn (Zea mays L.) and forage sorghum [Sorghum bicolor (L.) Moench] in a corn-forage sorghum rotation. The two cover crops were a legume, Austrian winter pea (Pisum sativum var. arvense Poir.) and winter wheat (Triticum aestivum L.). Control plots were fallowed. The experiment was done for two years (2010 and 2011) at two locations: under rain-fed conditions in Manhattan in the northeastern part of Kansas, where the soil was a Belvue silt loam (coarse-silty, mixed superactive non-acid, mesic Typic Udifluvents) and under irrigated conditions in Tribune in the western part of Kansas, where the soil was a Richfield silt loam (fine, smectitic, mesic Aridic Argiustolls). Two levels of nitrogen were added to the soil: 0 and 101 kg ha[superscript]-1 N. Grain and stover yields of the corn and forage sorghum were determined at harvest of the crops in the fall, and dry matter production of the cover crops was determined at their termination in the springs of 2011 and 2012. Additional nitrogen fertilizer increased grain and stover yields in both growing seasons at both locations, except for Manhattan in 2010. During the second winter of the study, Austrian winter pea did not emerge in Manhattan, probably due to a combination of cold temperatures and drought. Austrian winter pea survived both winters at Tribune. Corn yielded more grain than did the forage sorghum in Manhattan in 2011 and in Tribune in 2011. This suggests that, under both rain-fed and irrigated conditions in Kansas, corn would potentially be more productive for bioenergy production than forage sorghum. The results of the study also showed that winter wheat for both Manhattan, Kansas, and Tribune, Kansas, should be the cover crop chosen, because of its ability to grow well during the off-season of the bioenergy crops and to provide soil cover during winter.

Thesis (M.A.)--Boston University

This thesis presents a statistical approach which incorporates pedigree information in the form of relationship matrices into the analysis of standard agricultural genetic trials, where elite lines are tested. Allowing for the varying levels of inbreeding of the lines which occur in these types of trials, the approach involves the partitioning of the genetic effect of lines into additive genetic effects and non-additive genetic effects. The current methodology for creating relationship matrices is developed and in particular an approach to create the dominance matrix under full inbreeding in a more efficient manner is presented. A new method for creating the dominance matrix assuming no inbreeding is also presented. The application of the approach to the single site analyses of wheat breeding trials is shown. The wheat lines evaluated in these trials are inbred lines so that the total genetic effect of each of the lines is partitioned into an additive genetic effect and an epistatic genetic effect. Multi-environment trial analysis is also explored through the application of the approach to a sugarcane breeding trial. The sugarcane lines are hybrids and therefore the total genetic effect of each hybrid is partitioned into an additive genetic effect, a heterozygous dominance genetic effect and a residual non-additive genetic effect. Finally, the approach for inbred lines is examined in a simulations study where the levels of heritability and the genetic variation as a proportion of total trial variation is explored in single site analyses. / Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2008