The effect of tillage system and forecrop on the yield and values of LAI and SPAD indices of spring wheat

Catch crops cultivated for producing green manure are the reason for modifications in soil tillage. The objective of the present study was to determine the yields of two spring wheat cultivars, as well as the values of LAP and SPAD indices in relation to the method of tillage and use of a forecrop. A field experiment was carried out over the period of 2005-2007 at the Experimental Station in Prosy near Krakow (Poland). It included the following research factors: (i) a tillage system: simplified and conventional, (ii) forecrop: faba bean, stubble crop (white mustard) after faba bean, (iii) cultivars of spring wheat (Bryza and Zebra). These spring wheat cultivars reacted the same way to the tillage variants applied. Crop residue of faba bean and stubble crop leave the soil rich in mineral nitrogen; owing to this fact, it is possible to obtain high grain yield of spring wheat (6.71 Mg ha(-1)) with relatively low application of nitrogen fertilization (60 kg N ha(-1)). Cultivation of white mustard as a stubble crop after faba bean is a valuable solution not only in terms of protecting the soil environment by immobilizing nitrate nitrogen, but also because it results in a significant increase in wheat yields, especially under simplified soil tillage conditions. The simplified soil tillage resulted in a decrease in the wheat yield by 12.6% on average, while with the stubble crop incorporated it was possible to increase the wheat grain yield by 18.2%. (C) 2010 Elsevier B.V. All rights reserved.