Effects of organic farming and crop rotations on crop productivity and nutrient amount in the soil
Voke Branch of the Lithuanian Institute of Agriculture, Žalioji aikštė 2, Trakų Vokė,LT-02232 Vilnius Lithuania; e-mail: email@example.com
The trials were carried out at the Voke Branch of the Lithuanian Institute of Agriculture during the period 2003–2007 and were designed to investigate the influence of organic (without fertilizers) and sustainable farming systems on plants (the plants were fertilized only with bonemeal as a source of phosphorus and magnesia of potassium as a source of potassium) and to explore their productivity, chemical properties of soil and balance of nutrients in the soil.The experiments were conducted in the trial field with 4 treatments, in various croprotations with the plants grown for green manure for the soil supply with nitrogen (the main nutritional element of sandy loam soil) without mineral fertilizers.The experimental results show that higher productivity was achieved when cultivatingplants after green manure of lupines and white mustard. We established negative nitrogen, phosphorus (except in the sustainable farming system) and potassium balance in the soil. The use of various crop rotations in all farming systems on sandy loam Haplic Luvisol showed that there was no definite effect on soil acidity but an increase in the total nitrogen and organic carbon content in the soil was observed. The amount of phosphorus increased and potassium decreased only in the organic farming system. Phosphorus and potassium amounts in the soil increased in the sustainable farming system.