The mineralization of commercial organic fertilizers at 8°C temperature

In organic production only organic fertilizers and soil conditioners can be used to supply the soil with nitrogen. The mineralization of these products is slow and so there can be problems with the supply of nitrogen, when the demand of the plants is high. The supply of nitrogen from organic products depends on the speed of their mineralization which is primarily influenced by the composition and formulation of their raw material. In apple production in the Alps-region especially during spring problems with nitrogen supply are common. In that period, the weather conditions are sometimes bad, the temperature in the soil is low and mineralization starts slowly - apple trees demand more nitrogen than the soil can deliver. To compensate the demand of the apple tree organic growers can not use mineral fertilizers but only organic fertilizers and soil conditioners whose mineralization rate is often unknown. There is a strong need in organic fruit production to receive more information about the behaviour of fertilizers in the soil especially concerning their N-release under different conditions. To acquire that information, incubation experiments under controlled conditions (temperature, type of soil, humidity of the soil) were carried out in the laboratory to determine the mineralization-rate of different organic fertilizers and soil conditioners which are available in our region

Examining the Effects of Urbanization on Soil Characteristics in Portland, Oregon\u27s Forest Park

Studies by Dr. Nancy Broshot in Forest Park, an urban forest in Portland, Oregon, have shown high tree mortality and low concomitant recruitment. Lichen surveys conducted in 2013 revealed a shift in the lichen community to one typified by nitrogen-tolerant and nitrogen-thriving species. To ascertain if nitrogenous air pollution could be a cause of low recruitment, soil samples were collected from 32 previously established study sites in Forest Park and at 3 control sites established in 2014 in the Mount Hood National Forest, a rural forest in the Clackamas River Basin. At each site, the soil O horizon depth was measured, and soil samples were collected from the A horizon, which were subsequently dried and sieved. The resulting soil samples were analyzed at the Central Analytical Laboratory at OSU to determine carbon and nitrogen concentration, as well as carbon to nitrogen ratios. The results of the soil analysis show that soil samples from the control sites had significantly higher concentrations of carbon and a significantly higher carbon to nitrogen ratio than the sites in Forest Park. These findings are quite exciting and suggest a number of possible avenues for further research

Plant and soil microbe responses to light, warming and nitrogen addition in a temperate forest

1. Temperate forests across Europe and eastern North America have become denser since the 1950s due to less intensive forest management and global environmental changes such as nitrogen deposition and climate warming. Denser tree canopies result in lower light availability at the forest floor. This shade may buffer the effects of nitrogen deposition and climate warming on understorey plant communities. 2. We conducted an innovative in situ field experiment to study the responses of co-occurring soil microbial and understorey plant communities to nitrogen addition, enhanced light availability and experimental warming in a full-factorial design. 3. We determined the effects of multiple environmental drivers and their interactions on the soil microbial and understorey plant communities, and assessed to what extent the soil microbial and understorey plant communities covary. 4. High light led to lower biomass of the soil microbes (analysed by phospholipid fatty acids), but the soil microbial structure, i.e. the ratio of fungal biomass to bacterial biomass, was not affected by light availability. The composition of the soil bacterial community (analysed by high-throughput sequencing) was affected by both light availability and warming (and their interaction), but not by nitrogen addition. Yet, the number of unique operational taxonomic units was higher in plots with nitrogen addition, and there were significant interactive effects of light and nitrogen addition. Light availability also determined the composition of the plant community; no effects of nitrogen addition and warming were observed. The soil bacterial and plant communities were co-structured, and light availability explained a large part of the variance of this co-structure. 5. We provide robust evidence for the key role of light in affecting both the soil microbial and plant communities in forest understoreys. Our results advocate for more multifactor global change experiments that investigate the mechanism underlying the (in) direct effects of light on the plant-soil continuum in forests

Soil Properties and their Influence on Grassland Production under Low Input and Organic Farming Conditions

End of project reportThis project set out to identify soil properties that most influence grassland production under low mineral nitrogen input conditions. Sixteen farms were selected in Counties Limerick and Clare and the soil sampled. Soil physical and chemical characteristics and soil biological aspects involved in the carbon and nitrogen cycles were studied in the laboratory. Nutrient additions to farms as well as the nature of grazing by livestock (numbers, types of grazing animals, grazing practices), grassland management, and production from the farms were recorded

High functional diversity is related to high nitrogen availability in a deciduous forest - evidence from a functional trait approach

The current study tested the assumption that floristic and functional diversity patterns are negatively related to soil nitrogen content. We analyzed 20 plots with soil N-contents ranging from 0.63% to 1.06% in a deciduous forest near Munich (Germany). To describe species adaptation strategies to different nitrogen availabilities, we used a plant functional type (PFT) approach. Each identified PFT represents one realized adaptation strategy to the current environment. These were correlated, next to plant species richness and evenness, to soil nitrogen contents. We found that N-efficient species were typical for low soil nitrogen contents, while N-requiring species occur at high N-contents. In contrast to our initial hypotheses, floristic and functional diversity measures (number of PFTs) were positively related to nitrogen content in the soil. Every functional group has its own adaptation to the prevailing environmental conditions; in consequence, these functional groups can co-exist but do not out-compete one another. The increased number of functional groups at high N-contents leads to increased species richness. Hence, for explaining diversity patterns we need to consider species groups representing different adaptations to the current environmental conditions. Such co-existing ecological strategies may even overcome the importance of competition in their effect on biodiversity

Soil Health Indicators and Sustainable Practices on Indy Urban Farms: An Investigation of Ecosystem Functionality

Urban agriculture is capable of restoring ecosystem services like food production, recreation, and clean soil and water to cities. Urban farms in particular can help relieve pressure for areas with limited food access, also known as food desserts. This is especially important to the community of Indianapolis because the city is tied for the most food desert areas within a U.S. metropolitan area. To help a community, an urban farm must have healthy, nutrient rich soils. Nitrogen is the most limiting nutrient for plants when it comes to growth and development. Plants cannot produce nitrogen; they acquire the mineral by external inputs (mulch, manure, fertilizer etc.) or internal N-fixing bacteria. If biological nitrogen fixation increases, the immediate and long-term nitrogen supply would increase, leading to an increase in ecological sustainability. In addition to nitrogen, carbon is another mineral that can tell researchers a lot about the health of a soil system. Organic carbon is a major factor for plants, it promotes the structure, of soil, and it also acts as a pH buffer. The goal of this project is to test if common urban farming management processes are increasing the health of the ecosystem at the level of the soil. To analyze this, we looked at multiple different health indicators including: organic matter composition, percentage of carbon and nitrogen, carbon nitrogen ratio, soil pH, and bulk density of the soil samples collected. It is hypothesized that soil samples retrieved from actively farmed land will have increased health indicators. If this is true, farmed samples will be more similar to naturally established ecosystems than controlled, unfarmed samples with regard to the indicators tested. The soils used were collected from multiple sites around the city. Because of this, the data collected can be analyzed in a larger context with the goal of helping farms across Indianapolis restore fundamental ecosystem functions and improve overall sustainability

Effect of Nitrogen Fertilization and Liming on Rye-Ryegrass Yield and Soil pH Dynamics

Using ammonium based nitrogen fertilizers in crop production has been shown to acidify soils. Lime used to correct soil pH is an important cost to producers. Recommendations of the optimal level of nitrogen to apply typically ignore the cost of lime created by nitrogen fertilization. This study was aimed to estimate soil pH change in response to nitrogen and lime application, and determine the effect of considering the cost of lime on recommendations about the optimal level of nitrogen. Yield response and pH functions were estimated and used to determine optimal levels of inputs. The effect of the cost of lime on recommendations about the optimal level of nitrogen was found to be marginal. Nitrogen acidification was found to be more severe with nitrogen application amounts above recommended rates than with nitrogen that is used by the plant.Lime, Nitrogen, Soil pH, Rye-ryegrass, Crop Production/Industries, Production Economics,

Litter Production in an Area of Amazonian Terra Firme Forest. Part I.Litter - fall, Organic carbon and total Nitrogen Contents of Litter').

In 1963 anð, L964 litter was collected in a terra firme forest near Manaus, oven-dried and shipped to Europè. The sampleswere subdivided intofour litterfractions (leaves, wood,'fruits, termite fraction), dried at 105o and weighed. Organic carbon and total nitrogen of these litter fractions were determined. Annual average litter production is 7.4 t/ha consisting in 5.6 t ofleaves, and 1.8 t ofother litter. 105,6 kg nitrogen return annually to the soil. Compared with data on litter production and nitrogen content of litter of other tropical forests, the Amazonian forest produces less litter and returns a lower amount of nitrogen to the soil

Ratio of natural isotopes of nitrogen. I. Primary results: soils of Dombes [Translation from: Revue d'Ecologie et de Biologie du Sol 14, 279-287, 1977]

Utilization of the heavy isotope of nitrogen as a tracer has found numerous applications in soil biology. It allows better definition of different stages of the nitrogen cycle, in particular the immobilization-mineralization cycle. In this work, the authors report the results of calculations of natural isotope ratios of nitrogen in samples of water, soil and vegetation prevailing in Dombes and discuss the possibilities of errors and coefficients of fractionation

Cover Crop Planting Date x Seeding Rate Trial

When corn silage is harvested in the fall, the entire plant is removed, leaving the soil exposed through the winter. Many farmers have started to plant cover crops following corn harvest because of the multitude of benefits cover cropping brings to soil health and fertility. The cover crop protects the soil from erosion, adds organic matter, and also scavenges excess soil nitrogen (N), releasing it again after cover crops are terminated in the spring. This keeps the nitrogen from potentially being lost through leaching, which, in addition to the soil benefits, provides a financial benefit to farmers – less nitrogen loss means less fertilizer needed in the spring. Farmers have asked about best practices for growing cover crops to maximize benefit to the soil, while protecting corn silage yield and quality. In particular, establishing a “last chance” planting date for cover crops is important in our region where the growing season is short and common adverse fall weather can delay planting. This study was intended to determine what planting dates and which seeding rates give the best cover crop performance