Changes in Organic Carbon and Physical Properties of Soil Aggregates Under Fiber Farming

Abstract

Interest in intensive forestry systems to produce woody fiber or Bfiber farming^(FF) is increasing because of high energy costs and the risks of global warming. The FF-induced changes in soil structural properties at the microscale or aggregate level important to soil organic carbon (SOC) sequestration and soil-water dynamics are, however, not well understood. Thus, we compared differences in soil physical properties and SOC concentrations in aggregates among tree species after 7 years of plantation establishment on an Onaway fine sandy loam (fine loamy, mixed, active, frigid Inceptic Hapludalfs) at the Upper Peninsula Tree Improvement Center near Escanaba, Mich. Soil samples from 16.8  16.8-m plots under six tree taxa and three rates of wood ash application (0, 9, and 18 Mg ha j1 ) were collected in May, 2005. The six tree taxa were European larch (Larix deciduas Mill.), hybrid aspen (Populus tremula  Populus tremuloides), and four poplar taxa: NE-222 (Populus deltoids  Populus nigra var. caudina), DN-5 (Populus euramericana, cv. BGelrica^), DN-34 (P. euramericana, cv. BEugenei^), and NM-6 (P. nigra  Populus maximowiczii). Tree species induced measurable changes in most soil aggregate properties. Larch and DN-34 increased aggregate mean weight diameter more than N-222 and NM-6. Macroaggregates contained 20% more SOC concentration than microaggregates. Ash application increased tensile strength, soil water retention, and SOC concentration, indicating the benefits of applying ash in FF systems. Within both macroaggregates and microaggregates, NM-6 had the highest SOC concentration, whereas aspen had the lowest of all tree species. The SOC concentration increased with increase in biomass input. Results show that differences in aggregate physical properties and aggregateassociated SOC concentration among tree species were relatively small and depended on the soil property. (Soil Science 2007;172:553-564)

Distribution of soil organic carbon in the light and heavy fractions for six shelterbelt species and their adjacent agricultural fields in Saskatchewan.

“…Results of our study suggest that tree species affect the distribution of SOC stocks into physical density fractions (Table 4). This observation is supported by other studies that observed the influence of tree species on physicochemical stabilization of OC within the size and density fractions of soil (Blanco-Canqui et al 2007;Woldeselassie et al 2012). The coniferous species, white spruce and Scots pine, led to a higher increase in SOC stocks of the labile light fraction, in contrast to hybrid poplar, Manitoba maple, green ash, and caragana that led to a higher increase in the stable heavy fraction for an equivalent increase in the sequestered SOC (Table 4).…”

“…Stability of SOC is affected by quantity and quality of litter inputs (Prescott et al 2000;Lorenz and Lal 2005) as well as diversity and abundance of soil microorganisms and macrofauna (González and Seastedt 2001;Hättenschwiler et al 2005;Hedde et al 2007), which, in turn are influenced by incorporation of trees (DeBellis et al 2006;Lamarche et al 2007;Laganière et al 2009). Planting trees also improves soil physical properties such as soil aggregation, which may enhance stabilization of SOC (Blanco-Canqui et al 2007;Sarkhot et al 2008). Some studies that have determined the effect of tree establishment on the stability of C, have reported a significant increase in only the labile C pools (Leite et al 2014;Baah-Acheamfour et al 2015); while other studies have suggested an increase in the stable C pools (Garten 2002;Teklay and Chang 2008;Youkhana and Idol 2011).…”

Black Spruce Soils Accumulate More Uncomplexed Organic Matter than Aspen Soils

“…To the best of our knowledge, this study is the first to specifically address the effect of forest types on SOC stabilization through soil aggregation and soil physical fractions in a natural ecosystem. The very few studies focusing on this topic took place in managed plantation systems (e.g., Blanco-Canqui et al, 2007;Gama-Rodrigues et al, 2010;Quideau et al, 1998;Saha et al, 2010;Sarkhot et al, 2008), where soil disturbance is high and naturally-associated understory is generally lacking. In addition, the tree species selected in these studies were mostly genetically improved species [e.g., loblolly pine {Pinus taeda L.) and hybrid poplar clones].…”

Corn stover harvest changes soil hydrology and soil aggregation

“…Historically, unless harvested as animal feed or bedding, crop residues were returned to the land (Johnson et al, 2006). On the land, crop residues provide surface cover, raw materials for building soil organic matter, and contribute directly and indirectly to aggregate formation (Blanco-Canqui et al, 2007;Pikul et al, 2009;Six et al, 2000), which in turn may interact with soil hydrological properties (Benjamin et al, 2008;Rawls et al, 2004) and other soil properties (e.g., Benjamin and Karlen, 2014;Blanco-Canqui and Lal, 2009;Johnson et al, 2011;Lal and Stewart, 2010). In 2014, commercial cellulosic-ethanol production became a reality (http://poet.com/pr/first-commercial-scale-cellulosicplant), which at least locally will increase the demand for cellulosic feedstocks and may result in potential environmental risk and soil degradation unless carefully managed to avoid overharvesting (Archer and Johnson, 2012).…”