A. Huisz, T. Kismányoky, S. Hoffmann, T. Tóth, T. Németh. 2007. Organic
matter-induced changes in water-stable aggregation. Cereal Research
Communications. 35 (2) 497-500.

Abstract

The most important function of soil is that it is the basic media of crop production
(Varallyay, 2002). Consequently, sustaining and ameliorating of soil structure is crucial.
Decline of soil structure and degradation of its stability are frequently caused by tillage,
crop management and getting moist (Chan et al., 2003).
Soil structure is built up by groups of primary particles that cohere to each other, and
which are called aggregates (Kemper and Rosneau, 1986). (Di Gleria et al., 1957). Waterstability
is often investigated by wet sieving. Earlier reported methodological problems
were solved and circumstances affecting soil structure were standardized with the new
modified wet sieving method proposed by Six (2000). The Normalised Stability Index
(NSI) characterises aggregate stability by comparing the aggregate distribution after two
differently disrupting wetting methods. The two different wetting methods are: (1) fast
wetting, namely rapid immersion in water (Slaking (S)), which disrupts the aggregates to
the highest extent, therefore produce the lowest aggregate amount; and (2) slow wetting,
namely capillary wetting (Capillary (C)) to field capacity, which disrupts the aggregates
to the lowest extent and therefore achieves the highest aggregate amount. The capillary
wetting method was earlier tried by us to get different size fractions to evaluate the
distribution of soil organic matter in soils (Huisz et al., 2006).
In this paper our aim was to test the standardised wet sieving method proposed by Six
(2000). We investigated the effect of farmyard manure addition on soil structure and its
quality and on the stability of aggregates.