Biomass Production In Soil Research Articles

Assessing soil biodiversity potentials in Europe

Soil is important as a critical component for the functioning of terrestrial ecosystems. The largest part of the terrestrial biodiversity relies, directly or indirectly, on soil. Furthermore, soil itself is habitat to a great diversity of organisms. The suitability of soil to host such a diversity is strongly related to its physico-chemical features and environmental properties. However, due to the complexity of both soil and biodiversity, it is difficult to identify a clear and unambiguous relationship between environmental parameters and soil biota. Nevertheless, the increasing diffusion of a more integrated view of ecosystems, and in particular the development of the concept of ecosystem services, highlights the need for a better comprehension of the role played by soils in offering these services, including the habitat provision. An assessment of the capability of soils to host biodiversity would contribute to evaluate the quality of soils in order to help policy makers with the development of appropriate and sustainable management actions. However, so far, the heterogeneity of soils has been a barrier to the production of a large-scale framework that directly links soil features to organisms living within it. The current knowledge on the effects of soil physico-chemical properties on biota and the available data at continental scale open the way towards such an evaluation. In this study, the soil habitat potential for biodiversity was assessed and mapped for the first time throughout Europe by combining several soil features (pH, soil texture and soil organic matter) with environmental parameters (potential evapotranspiration, average temperature, soil biomass productivity and land use type). Considering the increasingly recognized importance of soils and their biodiversity in providing ecosystem services, the proposed approach appears to be a promising tool that may contribute to open a forum on the need to include soils in future environmental policy making decisions.

Estimating genetic potential of biofuel forest hardwoods to withstand metal toxicity in industrial effluent under dry tropical conditions.

Biofuel tree species are recognized as a promising alternative source of fuel to conventional forms. Additionally, these tree species are also effective in accumulating toxic heavy metals present in some industrial effluents. In developing countries such as Pakistan, the use of biofuel tree species is gaining popularity not only for harvesting economical and environmentally friendly biofuel, but also to sequester poisonous heavy metals from industrial wastewater. This study was aimed at evaluating the genetic potential of two biofuel species, namely, Jatropha curcas and Pongamia pinnata, to grow when irrigated with industrial effluent from the Pak-Arab Fertilizer Factory Multan, Southern Punjab, Pakistan. The growth performances of one-year-old seedlings of both species were compared in soil with adverse physiochemical properties. It was found that J. curcas was better able to withstand the toxicity of the heavy metals present in the fertilizer factory effluent. J. curcas showed maximum gain in height, diameter, and biomass production in soil irrigated with 75% concentrated industrial effluent. In contrast, P. pinnata showed a significant reduction in growth in soil irrigated with more than 50% concentrated industrial effluent, indicating that this species is less tolerant to higher toxicity levels of industrial effluent. This study identifies J. curcas as a promising biofuel tree species that can be grown using industrial wastewater.

A novel life cycle impact assessment method on biomass residue harvesting reckoning with loss of biomass productivity

Second generation bioenergy such as cellulosic bioethanol is expected to become commercially available in the near future. Large scale production of this bioenergy will require secure and continuous supplies of raw materials. One promising source of materials is biomass residues that currently remain on the fields following harvest, a feedstock that does not compete with food. However, unsustainable removal of these residues may adversely affect soil quality and hamper future harvests. In order to assess this effect, an impact assessment method was developed within the life cycle assessment framework based on a specific system definition, i.e. decomposed biomass residues above soil surfaces resulted in net carbon flow into soil compartment. This soil organic carbon functions as an elementary flow to complete the overall carbon balance. The assessment method considers effects of soil organic carbon on soil biomass-productivity. This impact is expressed as loss of net primary production, a midpoint indicator. The impact assessment method follows the ISO-standard format, comprising a characterization factor and an input term representing changes in elementary flows. The operation of the proposed method was illustrated with a small case study. At 10% biomass removal, the impact is 7.16 g-carbon/m2.year loss in biomass productivity as compared to the undisturbed reference. We believe that the method has a good potential to be adopted and employed as metrics for assessing the sustainability of bioenergy systems, although data for spatially detailed implementation within bioenergy systems in various regions are to be supplemented.

Fungal biomass production and turnover in soil estimated using the acetate-in-ergosterol technique

We report the first attempt to estimate fungal biomass production in soil by correlating relative fungal growth rates (i.e., acetate incorporation into ergosterol) with fungal biomass increase (i.e., ergosterol) following amendments with dried alfalfa or barley straw in soil. The conversion factor obtained was then used in unamended soil, resulting in fungal biomass productions of 10–12 μg C g −1 soil, yielding fungal turnover times between 130 and 150 days. Using a conversion factor from alfalfa-treated soil only resulted in two times higher estimates for biomass production and consequently lower turnover times. Comparing fungal biomass production with basal respiration indicated that these calculations overestimated the former. Still, the turnover times of fungal biomass in soil were in the same range as turnover times estimated in aquatic systems. The slow turnover of fungal biomass contrasts with the short turnover times found for bacteria. The study thus presents empirical data substantiating the theoretical division of bacteria and fungi into a fast and a slow energy channel, respectively, in the soil food web.

Shoot-to-root ratios and root biomass of cool-season feed crops in a boreal Podzolic soil in Newfoundland

Barley (Hordeum vulgare L.) and oat (Avena sativa L.) crops are grown as feed grains by Newfoundland (NL) dairy farmers. The cereals are either grown as monoculture or intercropped with field pea (Pisum sativum L.) with or without N fertilization. Two experiments were conducted in both 2000 and 2001 to evaluate the shoot-to-root (S:R) weight ratios and root biomass in these production systems. Experiment 1 involved monocultures of pea sown at 150 kg ha-1, and barley and oat each sown at 170 kg ha-1. For pea-barley and pea-oat intercrops, pea was sown at 150 kg ha-1 and each cereal component was sown at either 85 and 170 kg ha-1. The seven treatments were referred to, respectively, as pea150, barley170, oat170, pea150-barley85, pea150-oat85, pea150-barley170, and pea150-oat170. Experiment 2 evaluated factorial combinations of two barley seeding rates of 107 kg ha-1 (low) and 157 kg ha-1 (high) and three N rates (0, 30 and 60 kg ha-1) applied at Zadok’s Growth Stage (ZGS 30). Root biomass was sampled from soil (30-cm depth) and determined at about the anthesis stage of oat and barley and the shoot biomass at maturity (ZGS 90). In exp.1, the S:R ratios of oat170 and pea150-oat85and pea150-oat170 ranged from 8.1 to 8.8 and were lower than barley170, pea150, pea150-barley85and pea150-barley170 which ranged from 10.0 to 12.5. Barley170 had the highest root biomass of 835 kg ha-1 followed by pea150-barley170 (745 kg ha-1) and pea150-oat170 (765 kg ha-1). Intercropping pea with cereals increased root biomas s by 31% for pea150-barley85and 48% for pea150-oat85compared to pea150. However, root biomass increased by 109% for pea150-barley170 and 104% for pea150-oat170, indicating that the cereal component of the intercrops contributed more to the root biomass than the pea at the higher seeding rate of the cereal crop. In exp. 2, the 0 kg N ha-1 rate produced the lowest S:R ratios irrespective of the barley seeding rate. When N was applied, both the shoot biomass and root biomass appeared to be increased at the high barley seeding rate. The feed grain production practice in Newfoundland could affect root biomass production in soil. High cereal seeding rates in either monoculture and intercrop systems are required to maximize root biomass production and therefore increase C inputs into the soil. Key words: Shoot-to-root (S:R) ratios, root biomass, intercrops, barley, oat, pea, seeding rate

Fungal presence in paired cultivated and uncultivated soils in central Iowa, USA

Amounts of fungal biomass in adjacent cultivated and uncultivated soils in central Iowa were estimated and compared by quantifying soil ergosterol concentrations and lengths of fungal hyphae present. Both indices of fungal biomass, with one exception, indicated that there was at least twice as much fungal biomass in uncultivated soil as in cultivated soil. Levels of microbial biomass carbon in uncultivated soils were also determined to be at least twice that in cultivated soils. Data collected in this study indicate that fungi may be more significantly affected by agricultural soil management practices than other components of the soil microbial community. For two of the soils examined, calculated estimates denote that fungal biomass carbon represented approximately 20% of the total microbial biomass carbon in cultivated soil and about 33% of the microbial biomass carbon in uncultivated soil. Results of this study indicate that conventional agricultural practices result in a significant reduction of fungal biomass production in soil. Implications of differences in fungal biomass between the soils are discussed.