Effect of crop rotations with triticale (x Triticosecale Wittm.) on soil pore characteristics

Crop rotations with a high proportion of cereals, including monoculture, are typical in many countries in Europe. Although wheat is the most popular cereal as it is cultivated world-wide, in recent years a steady increase has been observed in triticale production. The objective of the study was to determine the effect of different crop rotations using triticale on soil air-water properties with a special focus on macroporosity. The following crop rotations were investigated during a long-term (2002-2010) field experiment: Norfolk crop rotation (NCR) with sugar beet, spring triticale, faba bean and winter triticale; Diculture (DCR) with spring triticale, winter triticale and oat; and Monoculture (MCR) with winter triticale and spring triticale. Undisturbed soil samples were collected in 2009 and 2010 to determine water retention parameters and morphometric characterization of soil pores. The soil moisture characteristic curve was determined in pressure chambers with ceramic plates according to Richards' method and they were expressed by the van Genuchten model. Macropore system for the investigated soil was characterized using image analysis on sections of soil samples hardened with polyester resin. The effect of the treatment applied has influenced the retention characteristics in the low water potential range, which corresponds mainly with large pores (transmission pores and fissures). The greatest differences between crops were observed in the NCR. The highest macropore volume was noticed for sugar beet. The increase in macroporosity of soil under sugar beet in the pore diameter classes ranged from 50 to 2000 mu m in comparison with both the spring and winter triticale. Sugar beet increases the volume of regular, irregular and elongated macropores, whereas other crops, such as faba bean, spring and winter triticale, did not significantly affect the shape of pores. Although there were some differences in size and shape of macropores, the influence of earthworm activity on soil porosity in the investigated soil was not statistically significant due to the tested crop rotations. The investigated crops in different crop rotations changed the water retention properties of the soil. The highest water retention in the range of available water was noticed for two treatments; one with spring triticale for the MCR and the second with winter triticale for the DCR. In this experiment, crop rotation had no long-term effects. The findings of the presented experiment showed that crop rotation did not play a significant role in soil structure modification. Particular crops could differ in terms of their impact on soil porosity but this effect is not permanent and is visible in the year when a particular crop is cultivated or sometimes remains until the following year. (c) 2013 Elsevier B.V. All rights reserved.