Kristine Nichols

Biochar: A Synthesis of Its Agronomic Impact beyond Carbon Sequestration

Biochar has been heralded as an amendment to revitalize degraded soils, improve soil carbon sequestration, increase agronomic productivity, and enter into future carbon trading markets. However, scientific and economic technicalties may limit the ability of biochar to consistently deliver on these expectations. Past research has demonstrated that biochar is part of the black carbon continuum with variable properties due to the net result of production (e.g., feedstock and pyrolysis conditions) and postproduction factors (storage or activation). Therefore, biochar is not a single entity but rather spans a wide range of black carbon forms. Biochar is black carbon, but not all black carbon is biochar. Agronomic benefits arising from biochar additions to degraded soils have been emphasized, but negligible and negative agronomic effects have also been reported. Fifty percent of the reviewed studies reported yield increases after black carbon or biochar additions, with the remainder of the studies reporting alarming decreases to no significant differences. Hardwood biochar (black carbon) produced by traditional methods (kilns or soil pits) possessed the most consistent yield increases when added to soils. The universality of this conclusion requires further evaluation due to the highly skewed feedstock preferences within existing studies. With global population expanding while the amount of arable land remains limited, restoring soil quality to nonproductive soils could be key to meeting future global food production, food security, and energy supplies; biochar may play a role in this endeavor. Biochar economics are often marginally viable and are tightly tied to the assumed duration of agronomic benefits. Further research is needed to determine the conditions under which biochar can provide economic and agronomic benefits and to elucidate the fundamental mechanisms responsible for these benefits.

Indirect Contributions of AM Fungi and Soil Aggregation to Plant Growth and Protection

Ecological and biological engineering contribute indirectly to the fitness of the soil environment and promote plant growth and protection. This engineering modifies soil physical, chemical, and biological attributes to enhance nutrient cycling, increase soil organic matter, and improve soil quality. Arbuscular mycorrhizal (AM) fungi, under most conditions, improve plant growth directly by providing greater and more efficient access via fungal hyphae for absorption of nutrients, especially P, and delivery of these nutrients to the plant. The AM symbiosis also augments disease resistance in host plants and suppresses the growth of non-mycorrhizal weeds. When plants moved from an aquatic to a terrestrial environment, mycorrhizal fungi were an integral part of their success by providing efficient nutrient absorption from the low organic matter mineral soil. In addition, AM fungi stabilize soil aggregates and promote the growth of other soil organisms by exuding photosynthetically-derived carbon into the mycorrhizosphere. Glomalin is a glycoprotein produced by AM fungi which probably originated as a protective coating on fungal hyphae to keep water and nutrients from being lost prior to reaching the plant host and to protect hyphae from decomposition and microbial attack. This substance also helps in stabilizing soil aggregates by forming a protective polymer-like lattice on the aggregate surface. AM fungal growth and biomolecules engineer well-structured soil where the distribution of water-stable aggregates and pore spaces provides resistance to wind and water erosion, greater air and water infiltration rates favorable for plant and microbial growth, nutrients in protect micro-sites near the plant roots, and protection to aggregate-occluded organic matter.

The Area IV Soil Conservation Districts Cooperative Research Farm: Thirty years of collaborative research to improve cropping system sustainability in the Northern Plains

Dryland cropping in the northern Great Plains of North America has long been viewed a risky endeavor (Sarvis and Thysell 1936). The regions unpredictable climate—characterized by short, erratic growing conditions and limited rainfall—has challenged farmers since the arrival of European settlers over 140 years ago (Padbury et al. 2002). Following the breaking of native prairie, cropping systems in the region have evolved considerably, from tillage-intensive wheat (Triticum aestivum L.)–fallow systems to dynamic cropping practices under no-till management (Tanaka et al. 2005). Yet, yield stability over time has been elusive and is frequently coupled with widely fluctuating environmental impacts (Hanson et al. 2007; Chen et al. 2004). Such climate-driven variability in agronomic and environmental outcomes is perhaps the most notable characteristic of dryland cropping systems in the northern Great Plains. This attribute also makes determining the sustainability of dryland cropping systems in the region challenging. Long-term cropping system studies serve as important “listening places,” where investigators document treatment responses through the measurement of key metrics consistently over time (Janzen 2009). Findings and interpretations generated from these measurements serve to inform the status and trajectory of ecosystem services (Robinson et al. 2011), while concurrently providing opportunities for further inquiry focused on basic…

LaTeX for Agricultural Extension Professionals

LaTeX is a free open source document preparation system for professional quality documents and presentation materials. Extension professionals, trying to reach their audience though various forms of printed and online resources, can benefit from the vast potential of LaTeX. Using LaTeX empowers the extension professionals to create their own documents from start to finish, with good timing and exceptional qualities. This article describes the typesetting process, obtaining and installing LaTeX, creating and running a simple document, creating a scientific journal paper as an example though a template, and other advanced features suitable for extension publications. Such advanced features as side-by-side and wrapped figures, background figures, minipages, oral presentation slides, conference posters, books, and newsletters that use appropriate LaTeX classes and packages were explained with examples, commands and principles involved. Sections of fully functional LaTeX codes and graphics to reproduce generated outputs were presented. Although there is some learning involved to use LaTeX, the benefits may outweigh the effort. With experience, professionals can create more sophisticated documents, automate several aspects of document preparation, and make it easy for others to use by creating templates. The impact of extension activities through publications might be ensured through the timely and professional quality output of LaTeX, as the role of typesetters can be eliminated and the authors can directly produce high-quality final output.