Effect of Organic Farming on Agrochemical Characteristics of Loamy Soil in Mid-Lithuania

Research of the effect of organic farming on the agrochemical soil characteristics was carried out in the period of 1997–2004 on the farm of organic production of the Agorecological center at Lithuanian University of Agriculture in the loamy soil of moderate heaviness Endohypogleyi-Eutric Planosols (PLe-gln-w). Tests were performed in a hexafield rotation field with the following sequence: winter wheat, summer crop, legume crops for seed an green fertilizer, summer grain, + additional seed sown into cereal crops, perennial grasses of the 1st year of use, perennial grasses of second year of use. In 1997 five monitoring areas of 100 m2 (10×10 m) were established, later each of them divided into four areas of 25 m2. Soil samples for analysis were taken from each area from four separate squares. Soil samples were taken with a soil drill out of the depth of 0–20 in 6–8 different places and the total sample was composed. No nitrogen, phosphorus and potassium fertilizers were applied to plants and legumes were grown to increase the nitrogen amount in the soil rotation. It was found that as the result of organic farming, the amount of organic carbon and total nitrogen decreased 0,33 and 0,009 percentual units, the amount of active phosphorus and potassium decreased 44,2 and 49,5 mg kg-1 respectively, the amount of calcium and magnum decreased 11,5 and 2,59 mgekv kg-1, however, the amount of active sodium increased 0,13 mgekv kg-1. Effective exchange acidity and effective sorption receptivity decreased in soil, however, potential exchange acidity and potential sorption receptivity increased. The sum of exchange cations decreased. pH value of soil decreases 0,20 units and base-richness of soil decreased 0,01 percentual unitsVytauto Didžiojo universitetasŽemės ūkio akademij