THE EFFECT OF TWO DIFFERENT ROTATION SYSTEMS ON SOIL ORGANIC MATTER IN ORGANIC FORAGE CULTIVATION

Crop rotation has a key role in improving the soil and increasing the yield. Crop rotation with legumes, recycling of crop residues and the application of organic manure must form the basis of nutrient management in organic farming. Presence of legumes in rotation may serve as the primary source of nitrogen for subsequent crops. Most deficiencies in the soil are directly linked to low organic matter content. Organic matter has a very crucial significance for soil fertility improvement. The aim of this study was to determine the effects of some plants used in animal feeding on soil organic matter (SOM). For this purpose some certain plants have been selected and tested in two different rotation systems. This study was carried out in Menemen Plain, in Aegean Region, Izmir, Turkey during a period of 5 years between 2012 and 2016. Trial was set up in a randomized block design with four replications. According to the results of soil analysis, organic fertilizer containing 2 % N, 2.5 % P2O5, 2.5 % K2O, 60 % organic matter and 9/12 C/N was given to the plots. Fertilization was carried out so as not to exceed 170 kg / ha nitrogen as stated in the organic farming law. In the study, the fertilizer applications required by the plants were made considering the residual nitrogen from the plant roots. In the first rotation system Persian clover - silage maize, vetch/triticale mixture– cotton, Persian clover - silage maize, vetch/triticale mixture – cotton, in the second rotation system Persian clover - silage maize, triticale (grain) – second crop soybean, Persian clover - silage maize, triticale (grain) – second crop soybean were consecutively cultivated for five years. Soil organic matter (SOM) in soil samples taken from 0-20 and 20-40 cm in rotation system mentioned above was analyzed. According to analysis results, plant in the first rotation system affected SOM better than those of the second rotation system. It can also be stated that selected crops play an important role i