Soil & Water Res., 12, 2017 (2): 00–00 Original Paper doi: 10.17221/91/2016-SWR The Influence of Tillage and Crops on Particle Size Distribution of Water-Eroded Soil Sediment on Stagnosol Ivica KISIC, Igor BOGUNOVIC and Darija BILANDZIJA* Department of General Agronomy, Faculty of Agriculture, University of Zagreb, Zagreb, Croatia *Corresponding author: [email protected] Abstract Kisic I., Bogunovic I., Bilandzija D. (2017): The influence of tillage and crops on particle size distribution of water- eroded soil sediment on Stagnosol. Soil & Water Res. The influences of six different tillage treatments and five different crops on soil losses by water erosion were studied during a twenty-year period (1995–2014) on Stagnosol in central lowland Croatia. The aim of the study was to determine how the quantity of soil sediment, different tillage treatments and crops influence the particle size distribution (PSD) of soil sediment. During the studied period, total number of non-eroded soil samples was 60 and total number of soil sediments samples was 445. Significantly lower amounts of fine sand and higher amounts of clay and silt were determined in sediments compared to the non-eroded soil regardless of cover crop and tillage treatment, with the exception of bare cultivated soil. Generally, when quantities of soil sediments were higher, textural differences between non-eroded and eroded soil were lower. Very week negative correlation was determined between the quantity of soil sediment and the content of clay (r = –0.25) as well as the content of silt (r = –0.23). A very weak positive correlation (r = 0.23) was determined between the content of fine sand and the quantity of soil sediment, while non correlation (r = –0.02) was determined between the content of coarse sand and the quantity of soil sediment. Keywords: Croatia; soil loss; soil management; soil texture As a polydisperse system, soil is composed of par- previous studies have reported that eroded materials ticles of different sizes the composition of which were enriched in silt-sized particles and clay relative defines the soil texture. The proportion of textural to the non-eroded soil (Mannering & Bertrand classes contributes to the physical, chemical, and 1971; Alberts et al. 1983; Bašić et al. 2002; Zhao et biological properties of soil and thus the suscepti- al. 2011; Shi et al. 2012). Conversely, others (Packer bility of a particular soil type to erosion processes. et al. 1992; Martinez-Mena et al. 2000; Jin et al. Pieri et al. (2009) indicated that many factors 2009) concluded that there are no differences between affect sediment detachment and redistribution in- the non-eroded soil and soil sediments. However, cluding rainfall intensity, topography, land use, soil these investigations were carried out under different texture, soil organic matter content, soil moisture, agroecological conditions, on different soil types, and soil management, and tillage operations. Meyer et under different tillage treatments and cover crops. al. (1980) indicated that particle size distribution The aim of this study was to determine which (PSD) of eroded sediment has changed relatively particle size classes were predominantly transported little with major changes in rain intensity, continued along the slope under different tillage treatments erosion, and the presence or absence of crop canopy. and crops. This paper provides information on how Research results on this subject are contradictory. soil erosion processes affect PSD of eroded sediment Some researches (Lal 1976; Alberts et al. 1980; and whether there are some differences in sediment Ampontuah et al. 2006) demonstrate a higher per- yield and PSD that can be attributable to tillage and centage of larger soil particles in sediments. Many crop interaction. 1 Original Paper Soil & Water Res. doi: 10.17221/91/2016-SWR MATERIAL AND METHODS at the beginning of the research in 1995 (pH, soil organic matter, available phosphorus and potassium The experiment was carried out in Daruvar in content, and PSD). Soil samples were transported to central lowland Croatia (45°33'48''N, 17°02'06''E, the laboratory for determination of soil properties. altitude 133 m a.s.l.) on Stagnosol (IUSS 2006). Soil samples were prepared in accordance with ISO Six different tillage treatments (area of one treat- 11464 : 2006. Soil reaction (KCl) was determined 2 ment is 41.3 m , 22.1 m long and 1.87 m wide) on a according to HRN ISO 10390 : 2005, soil organic 9% slope were investigated: (i) Control plot (black matter content was determined according to HRN fallow, BF) tillage up and down the slope. Applied ISO 10694 : 2004, available phosphorus and pota- tillage practices included: ploughing to a depth of ssium content was determined according to Egner 30 cm and seedbed preparation with a harrow, but et al. (1960). Particle size distribution or texture the soil was kept bare at all time. The weeds were was determined according to ISO 11277:2009. The suppressed by total herbicides. This is the plot in determined texture classes were: coarse sand (2–0.2 which maximum soil loss was expected. (ii) Ploughing mm), fine sand (0.2–0.02 mm), silt (0.02–0.002 mm), up and down the slope to a depth of 30 cm (PUDS). and clay (less than 0.002 mm). Seedbed preparation and sowing were performed The crops on each experimental plot (apart from in the same direction. (iii) No-tillage (NT) included the control plot) were grown in a crop rotation that sowing with a special seeder – John Deere 750A (John is typical for this part of Europe: 1995, 2000, 2008, Deere, Mannheim, Germany) into the dead mulch and 2012 – maize (Zea mays L.); 1996, 2001, 2005, up and down the slope. 2–3 weeks before sowing, and 2009 – soybean (Glycine hispida L.); 1996/97, weeds were suppressed by total herbicides. From 2001/02, 2005/06, and 2012/13 – winter wheat (Triti- the beginning of this investigation no cultivation cum aestivum L.); 1997/98, 2002/03, 2006/07, and has been done. Plant residues were retained on soil 2010/11 – oil seed rape (Brasicca napus var. olei- surface. (iv) Ploughing across the slope to a depth fera L.) and double crop: 1998/99, 2003/2004, 2009/10, of 30 cm (PAS). (v) Very deep ploughing across the and 2013/14 – spring barley (Hordeum vulgare L.) slope to a depth of 50 cm (VDPAS). In contrast to with soybean. all other ploughing which was done with multi- Analysis of variance (ANOVA) was conducted using furrow ploughs, a single-bottom plough was used in the GLM procedure (SAS Institute, Version 9.1.3) this treatment. (vi) Subsoiling to a depth of 50 cm to evaluate the effects of tillage and crop on the (SSPAS). Subsoiling operation was performed with quantity of sediment and its PSD. An estimate of the tines spaced 50 cm apart. Very deep ploughing and least significant difference (Tukey’s LSD) between subsoiling were not applied every year, since their residual effect was taken into account. These practices were repeated every three to four years, in accord- ance with the crop rotation of investigated crops. In the last three tillage treatments seedbed preparation and sowing were performed across the slope. The experimental plot was fenced off with a tin fence that was removed before each tillage operation and then placed back into the soil for the remainder of the growing season. Filtration equipment was set up at the lower end of each plot and was designed for volume measurement of water and sediment transported by surface runoff (Figure 1). After each rainfall event that created soil loss, soil sediments were collected. During the studied period, total number of non-eroded soil samples was 60 and total number of soil sediments samples was 445 (133 on BF, 93 on PUDS, 52 on NT, 60 on PAS, 53 on VDPAS, and 54 on SSPAS). Also, some basic Figure 1. Measurement equipment for determining runoff soil properties were determined in each soil horizon and quantity of soil sediments (cited from Bašić et al. 2004) 2 Soil & Water Res., 12, 2017 (2): 00–00 Original Paper doi: 10.17221/91/2016-SWR treatments was obtained. Statistical differences were Table 1. Soil profile characteristics of the Stagnosol at the declared significant at P < 0.05. The value of the cor- experimental site (average value ± standard deviation) relation coefficient was ranked by Roemer-Orphal scale (0.0–0.10: no correlation, 0.10–0.25: very weak, Horizons 0.25–0.40: weak, 0.40–0.50: modest, 0.50–0.75: strong, Ap + Eg Eg + Btg Btg 0.75–0.90: very strong, 0.90–1.0: full correlation) Depth range (mm) 0–24 24–35 35–95 (Va silj 2000). pH in KCl 4.21 ± 0.15 4.20 ± 0.18 4.81 ± 0.23 Soil organic matter 16 ± 3.3 14 ± 4.2 6 ± 3.8 RESULTS AND DISCUSSION (g/kg) Available P O 2 5 172 ± 18 65 ± 4 244 ± 24 Soil properties of non-eroded soil. Parent material (g/kg) at this experiment site is loess of Upper Pleistocene Available K O 2 308 ± 6 123 ± 8 502 ± 12 origin – Riss, Würm (i.e. loess transformed into mot- g/kg) tled, non-carbonate loam). Soil texture throughout the Clay (< 0.002 mm) 154 ± 25 148 ± 44 196 ± 40 profile of non-eroded soil (0–95 cm) is a homogeneous (g/kg) loam. Soil was very acid in the arable layer and acid Silt (0.02–0.002 mm) 242 ± 35 260 ± 54 254 ± 32 in the Btg horizon. There was little organic matter (g/kg) in the arable layer, medium phosphorus availability, Fine sand 586 ± 37 571 ± 59 545 ± 69 and good potassium availability.