Tag Archives: physical properties

1548-1561 I. Černá, J. Pecen, T. Ivanova and Z. Piksa
The dependence of the durability of digestate briquettes and sorption properties on represented particle sizes
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The dependence of the durability of digestate briquettes and sorption properties on represented particle sizes

I. Černá, J. Pecen, T. Ivanova* and Z. Piksa

Czech University of Life Sciences Prague, Faculty of Tropical AgriSciences, Department of Sustainable Technologies, Kamýcká 129, CZ 16521 Prague 6, Czech Republic
*Correspondence: ivanova@ftz.czu.cz

Abstract:

Digestate, a product of the anaerobic digestion process, is traditionally used as liquid fertiliser. Besides agriculture use, it became possible to dry its separated solid part and compress it into briquette or pellet form. In the context of the characterisation of briquettes, the description here largely covers the mechanical properties of texture components and the distribution of particles within the briquette space. In order to define these properties and understand the relations between the mechanical part and any influencing factors, researchers started to identify the relationship between particles size distribution in briquettes and sorption properties and therefore mechanical properties. The objective of the present research was to compare size distribution in particles in different digestate samples and to study the connection to water sorption by briquettes and the durability of briquettes that have been made from two kinds of digestate material. For a comparison, two types of digestate were used, for which particles were split into a few size files according to the sieve size. By using digital image analysis, the dimensions of particles were specified and compared with values that were measured by means of a calliper. Sorption properties were defined through experimentation: exposing briquettes to a water source with water adsorption being determined via moisture content. Other mechanical properties were represented by toughness and the rate of abrasion. As result, digestate is an appropriate sorption matter which can multiply its initial mass by a factor of five if the water supply is sufficient. In the case of a dimension measurement of particles, digestate texture is represented by particles with one prevalent dimension, in most cases this being length. The length of particles was between approximately 1mm to 9mm. The digestate has been proven to be a good water sorbent material and can be applied in various sectors of agriculture.

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211–218 A. Velykis and A. Satkus
Soil protection value of winter crops and reduced tillage on clay loams
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Soil protection value of winter crops and reduced tillage on clay loams

A. Velykis and A. Satkus

Joniskelis Research Station of the Lithuanian Institute of Agriculture, Joniskelis, LT-5240 Pasvalys District, Lithuania;
Tel/fax: 370-71-38224; e-mail: joniskelio_lzi@post.omnitel.net

Abstract:

Experiments to reduce soil physical degradation were carried out at Joniskelis Research Station of the Lithuanian Institute of Agriculture over the period 1998–2002. The soil of the experimental site is characterised as glacial lacustrine clay loam on silty clay (Gleyic Cambisol). The following was investigated: Factor A. Crop rotations with different proportions of winter and spring crops (1. Without winter crops; 2. Winter crops 25%; 3. Winter crops 50%; 4. Winter crops 75%; 5. Winter crops 100%), growing annual and perennial grasses, spring and winter wheat, triticale, and barley. Factor B. Soil tillage systems: 1. Conventional (primary soil tillage was performed by ploughing); 2. Sustainable (after grasses the soil was ploughed, after other preceding crops the soil was loosened without inverting the topsoil). Our experimental evidence suggests that increasing winter crops in the crop rotation reduced compaction of the topsoil from high to moderate, maintained up to 37.3% of higher productive moisture reserves, improved water to air ratio, and increased the crop rotation productivity up to 44.7%. The application of reduced primary tillage in a sustainable system had persistence of high soil compaction and 8.0% lower air-filled porosity at the bottom of the topsoil, but the whole topsoil reached physical maturity more evenly in the spring. The grain yield of cereals was 6.4% lower compared with the yield after conventional soil tillage. On these clay loam soils, spring cereals were more sensitive (poorer performance) to reduced soil tillage compared with winter cereals.

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