Common agricultural practices such as excessive use of agro-chemicals, deep tillage and luxury irrigation have degraded soils, polluted water resources and contaminated the atmosphere. There is increasing concern about interrelated environmental problems such as soil degradation, desertification, erosion, and accelerated greenhouse effects and climate change. The decline in organic matter content of many soils is becoming a major process of soil degradation, particularly in European semi-arid Mediterranean regions. Degraded soils are not fertile and thus cannot maintain sustainable production. At the same time, the production of urban and industrial organic waste materials is widespread. Therefore, strategies for recycling such organic waste in agriculture must be developed. Here, we review long-term experiments (3-60 years) on the effects of organic amendments used both for organic matter replenishment and to avoid the application of high levels of chemical fertilizers. The major points of our analysis are: (1) many effects, e.g. carbon sequestration in the soil and possible build-up of toxic elements, evolve slowly, so it is necessary to refer to long-term trials. (2) Repeated application of exogenous organic matter to cropland led to an improvement in soil biological functions. For instance, microbial biomass carbon increased by up to 100% using high-rate compost treatments, and enzymatic activity increased by 30% with sludge addition. (3) Long-lasting application of organic amendments increased organic carbon by up to 90% versus unfertilized soil, and up to 100% versus chemical fertilizer treatments. (4) Regular addition of organic residues, particularly the composted ones, increased soil physical fertility, mainly by improving aggregate stability and decreasing soil bulk density. (5) The best agronomic performance of compost is often obtained with the highest rates and frequency of applications. Furthermore, applying these strategies, there were additional beneficial effects such as the slow release of nitrogen fertilizer. (6) Crop yield increased by up to 250% by long-term applications of high rates of municipal solid waste compost. Stabilized organic amendments do not reduce the crop yield quality, but improve it. (7) Organic amendments play a positive role in climate change mitigation by soil carbon sequestration, the size of which is dependent on their type, the rates and the frequency of application. (8) There is no tangible evidence demonstrating negative impacts of heavy metals applied to soil, particularly when high-quality compost was used for long periods. (9) Repeated application of composted materials enhances soil organic nitrogen content by up to 90%, storing it for mineralization in future cropping seasons, often without inducing nitrate leaching to groundwater.

/pdf/long-term-effects-of-organic-amendments-on-soil-fertility-a-w170id51u9.pdf

Long-term effects of organic amendments on soil fertility. A review

Common agricultural practices such as excessive use of agro-chemicals, deep tillage and luxury irrigation have degraded soils, polluted water resources and contaminated the atmosphere. There is increasing concern about interrelated environmental problems such as soil degradation, desertification, erosion, and accelerated greenhouse effects and climate change. The decline in organic matter content of many soils is becoming a major process of soil degradation, particularly in European semi-arid Mediterranean regions. Degraded soils are not fertile and thus cannot maintain sustainable production. At the same time, the production of urban and industrial organic waste materials is widespread. Therefore, strategies for recycling such organic waste in agriculture must be developed. Here, we review long-term experiments (3–60 years) on the effects of organic amendments used both for organic matter replenishment and to avoid the application of high levels of chemical fertilizers. The major points of our analysis are: (1) many effects, e.g. carbon sequestration in the soil and possible build-up of toxic elements, evolve slowly, so it is necessary to refer to long-term trials. (2) Repeated application of exogenous organic matter to cropland led to an improvement in soil biological functions. For instance, microbial biomass carbon increased by up to 100% using high-rate compost treatments, and enzymatic activity increased by 30% with sludge addition. (3) Long-lasting application of organic amendments increased organic carbon by up to 90% versus unfertilized soil, and up to 100% versus chemical fertilizer treatments. (4) Regular addition of organic residues, particularly the composted ones, increased soil physical fertility, mainly by improving aggregate stability and decreasing soil bulk density. (5) The best agronomic performance of compost is often obtained with the highest rates and frequency of applications. Furthermore, applying these strategies, there were additional beneficial effects such as the slow release of nitrogen fertilizer. (6) Crop yield increased by up to 250% by long-term applications of high rates of municipal solid waste compost. Stabilized organic amendments do not reduce the crop yield quality, but improve it. (7) Organic amendments play a positive role in climate change mitigation by soil carbon sequestration, the size of which is dependent on their type, the rates and the frequency of application. (8) There is no tangible evidence demonstrating negative impacts of heavy metals applied to soil, particularly when high-quality compost was used for long periods. (9) Repeated application of composted materials enhances soil organic nitrogen content by up to 90%, storing it for mineralization in future cropping seasons, often without inducing nitrate leaching to groundwater.

Long-Term Effects of Organic Amendments on Soil Fertility

Effect of biochar on soil physical properties in two contrasting soils: An Alfisol and an Andisol

If moist food scraps are placed in a container and left to sit for a week or two, the end product is likely to be a smelly \" slop \" that attracts flies. Given the proper conditions, these same food scraps can be composted to produce a material that looks and smells like rich soil and can be used to enhance soil texture and productivity. So, what are these conditions that promote composting? The physical and chemical conditions that should be maintained in a compost heap seem logical if you think about what compost really is — a big pile of food for billions of minute organisms. These microorganisms have certain chemical requirements, primarily carbon for energy, nitrogen to build proteins, and oxygen for respiration. Interacting with these are physical requirements, such as aeration to maintain optimal oxygen levels while not depleting the moisture necessary for microbial growth. This chapter begins with an overview of the chemical, physical, and biological changes that occur during thermophilic composting, thereby providing an example of how several sciences can be integrated in the study of composting. This overview is followed by more detailed, separate sections on compost chemistry, physics, and biology. Much of the information in the chemistry and physics sections focuses on thermophilic composting. The biology section includes a discussion of the microbes that are present in all types of composting, and of the diversity of invertebrates that live in outdoor and some worm composting systems. The information presented here reflects the current body of scientific knowledge regarding composting. Much remains unknown, leaving a variety of intriguing questions for future research. Some of these questions are identified as Research Possibilities, sprinkled in italics throughout the text. We hope they will provide the inspiration for students to ask a much wider range of questions, and to design their own original research.

The Science of Composting

Presently, producers are striving to create products which contain a value added factor, such as dietary fibre or in more recent times, phytochemicals. The production and addition of such nutrients can be quite costly for the producer. In the fruit and vegetable industry, the preparation and processing procedures can lead to one third of the product being discarded. This can be costly for the manufacturer and also may have a negative impact on the environment. Research has shown that these by-products can have a high nutritional value. It has also been suggested, that they could be used as a food ingredient due to their functional abilities such as gelling and water binding. The focus of this review is on the nutritional and functional properties of the by-products of food processing and their potential applications as nutritional new ingredients in foods. Industrial relevance Processors are constantly trying to utilize as much of their product as possible, and this paper puts forward an alternative use for their ‘waste’ which would be of a significant benefit to their business.This new food ingredient contains a nutritional benefit, such as dietary fibre, vitamins and minerals and bio-actives such as flavonoids and lycopene.Due to the nature of the by-products, functionally they hold such properties as increased water holding and binding, gelling and thickening.This review suggests a solution for creating a cheaper value-added ingredient which in turn decreases the present ways of disposing these by-products (which can be harmful to the environment), while also saving the producer's money.Ingredient companies are continually looking for cheaper but value-added ingredients; this paper reflects the opportunity for fruit and vegetable byproducts.

Dietary fibre and phytochemical characteristics of fruit and vegetable by-products and their recent applications as novel ingredients in food products

https://biblio.ugent.be/publication/443927/file/450060.pdf

Soil biological quality after 36 years of ley-arable cropping, permanent grassland and permanent arable cropping

https://biblio.ugent.be/publication/370426/file/577473.pdf

The application of vegetable, fruit and garden waste (VFG) compost in addition to cattle slurry in a silage maize monoculture: Effects on soil fauna and yield

Compost and other organic amendments have been proven to improve the soil physical quality. In Flanders, vegetable, fruit and garden (VFG) wastes are collected selectively and composted. We studied the effects of the combined application of three different doses of VFG compost and cattle slurry and one treatment with only mineral N applied, during 9 years on a range of soil physical properties: aggregate stability, saturated hydraulic conductivity, bulk density, total pore volume and soil moisture retention. The organic amendments had a significantly beneficial impact (p<0.05) on all soil physical properties, except for the soil moisture retention which was hardly influenced by any of the treatments. The combined application of VFG compost and cattle slurry resulted in the best soil physical conditions. No significant differences were found in soil physical parameters between the unfertilized plots and plots that were fertilized with mineral N.

Effect of vegetable, fruit and garden (VFG) waste compost on soil physical properties

Reducing fertiliser N use by application of ley-arable rotations.

Pathways of the dominant follicle after exposure to sub-luteal circulating progesterone concentrations are different in lactating dairy cows versus non-lactating heifers.

Lydia Bommelé

Papers

Soil biological quality after 36 years of ley-arable cropping, permanent grassland and permanent arable cropping

The application of vegetable, fruit and garden waste (VFG) compost in addition to cattle slurry in a silage maize monoculture: Effects on soil fauna and yield

Effect of vegetable, fruit and garden (VFG) waste compost on soil physical properties

Reducing fertiliser N use by application of ley-arable rotations.

Pathways of the dominant follicle after exposure to sub-luteal circulating progesterone concentrations are different in lactating dairy cows versus non-lactating heifers.