Soil physical properties under winter wheat grown with different tillage systems at selected locations

The aim ofthis research was to determine in 2006 and 2007 the effects of different tillage systems on the soil physical properties: bulk density, water content and stability. Analyses of physical properties of soil were performed on the long-term field experiment at the IUNG-PIB Experimental Station in Grabow (Mazowieckie voivodeship) on a heavy loamy sand and on a pri- vate farm in Rogow (Lublin voivodeship) on a silt loam soil. Winter wheat was grown in traditional and reduced tillage systems: 1) traditional tillage (TT) with surface mulching (chopped wheat straw) based on mouldboard ploughing (to 25 cm depth) and traditional soil management equipment, and 2) reduced tillage (RT) with surface mulching (chopped wheat straw) based on soil crushing-loosening equipment and a rigid-tine cultivator (to 10 cm depth). Soil physical properties were measured on samples coll- ected from the field throughout the growing season. These in- cluded: particle size distribution (hydrometer method), soil water content and bulk density measured using 100 cm 3 cylinder samples (after drying at 105C for 48 h). For the above, four replicates were collected from each of the following depths: 2-8, 13-18, 28-33, 47-53 and 67-73 cm. Soil stability was measured with a turbi- dimetric method using samples from 5-10, 15-20 and 30-35 cm depths. Soil stability was measured in terms of the content of readily-dispersible clay (RDC) in the soil samples. RDC was measured using a turbidimeter. Ten replicates were used for each soil and depth at each place. The effect of the tillage system on the values of the physical properties was significant at both sites. Reduced tillage resulted in increased water content throughout the whole soil profile at Rogow. However, at Grabow, this effect was found only at the top depth. Also reduced tillage increased bulk density in both soils, especially in the 2-8 and 13-18 cm depth layers in comparison with traditional tillage. Reduced tillage reduced the amount of RDC and therefore increased soil stability, especially in the top layer (5-10 cm) in comparison with traditional tillage. The results showed that the reduced tillage system created a more-friendly environment for soil physical properties - particularly soil stability than the conventional system.