Soil structure stability and distribution of carbon in water-stable aggregates in different tilled and fertilized Haplic Luvisol

SIMANSKÝ, V. : Soil structure stability and distribution of carbon in water-stable aggregates in diff erent tilled and fertilized Haplic Luvisol. Acta univ. agric. et silvic. Mendel. Brun. , 2012, LX, No. 3, pp. 173–178 The infl uence of tillage and fertilization on soil structure stability and the distribution of carbon in water-stable aggregates of loamy Haplic Luvisol were studied. Soil samples from the locality of Dolna Malanta (experimental station of SUA Nitra) were collected (in 2007–2009) from a depth of 0–0.2 m in two tillage variants: (1. conventional tillage, 2. minimal tillage) and three treatments of fertilization: (1. without fertilization, 2. crop residues and NPK fertilizers, 3. NPK fertilizers). The minimal tillage system has a positive eff ect on both the aggregation processes and sequestration of carbon in size fractions of water-stable aggregates, as well as ploughing of crop residues together with NPK fertilizers. On the other hand, application of only NPK fertilizers had a negative eff ect on SOM content. Under the minimal tillage system and in treatment with crop residues together with NPK fertilizers, what has been observed is a statistically signifi cant increase in the total organic carbon contents by increasing size fractions of water-stable aggregates. Organic carbon did not infl uence the aggregation processes with dependence on tillage systems. Under conventional tillage as well as in treatment with ploughing crop residues with NPK fertilizers, a very important eff ect on aggregation had bivalent cations Ca2+ and Mg2+. soil structure stability, water-stable aggregates, organic matter, Luvisol Aggregation processes in soils are infl uenced by a large number of factors such as changes in soil organic matter (SOM), moisture content and microbial activity, crop type, root development, tillage and fertilization or liming implementation. The structural stability is dependent on particlesize distribution, soil organic matter, vegetation and soil micro-organisms and its stability is infl uenced by exchangeable cations and sesquioxides (Amezketa, 1999; Bronick and Lal, 2005). One of the most important binding agents for forming stable aggregates is soil organic matter (Tisdall and Oades, 1982). Organic materials are important soil additives to improve soil physical properties. Degradation of soil structure occurs mostly due to the decrease in soil organic matter caused by excessive soil cultivation (Grandy et al., 2002). For example, the conventional tillage may result in the disruption of soil structure and loss of soil organic matter compared with no-tillage (Beare et al., 1994). Several studies have shown that where crop residues are returned, no-till can enhance soil aggregation and increase soil organic matter (Havlin et al., 1990; Simanský et al., 2008). The objective of this study was: 1. to quantify the extent to which tillage and fertilization treatments aff ect soil structure stability and carbon distribution in water-stable macro-aggregates of a Haplic Luvisol, 2. to determine the relationship between quantity of soil organic matter, exchangeable cations and parameters of soil structure stability of Haplic Luvisol with dependence on soil tillage and