Effects of organic farming and crop rotations on crop productivity and nutrient amount in the soil

E. Bakšienė, A. Ražukas and T.L. Nedzinskienė

Voke Branch of the Lithuanian Institute of Agriculture, Žalioji aikštė 2, Trakų Vokė,LT-02232 Vilnius Lithuania; e-mail: eugenija.baksiene@voke.lzi.lt

Abstract:

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.

Key words:

Influence of various farming systems on agrochemical indices and amount of microorganisms in Haplic Luvisol

E. Bakšienė¹, A. Ražukas¹, T.L. Nedzinskienė¹,O. Salina² and J. Repečkienė²

¹Voke Branch of Lithuanian Institute of Agriculture, Žalioji a. 2, Trakų Vokė,LT-02232 Vilnius; e-mail: eugenija.baksiene@voke.lzi.lt
²Institute of Botany, Žaliųjų Ežerų 49, LT-08406, Vilnius;e-mail: olga.salina@botanika.lt

Abstract:

The article presents data from a study comparing the influence on plant productivity of three different farming systems – ecological, sustainable and chemical – and the use of various plants grown for green manure. Crops were lupine, white mustard and red clover. Calculations of the nutritional content of the soil in the experiments show that various crop rotations (treatments) affect the phosphorus and potassium balance.The data indicate that productivity of plant rotations depends on the plants cultivated andthe applied farming system. In all farming systems, the highest yield was achieved cultivating plants after fertilization with green manure (lupines and white mustard). The results of the experiments show that crop rotations result in negative nitrogen, phosphorus (except in sustainable and chemical farming systems) and potassium balance in the soil.Crop rotations had no effect on the soil acidity and increased total nitrogen and organiccarbon content in the soil. The amount of phosphorus in the soil increased in all farming systems; potassium increased only in the sustainable and chemical farming systems.Data indicating the number of micromycetes, organic and mineral nitrogen assimilatingbacteria in the rizosphere soil of various grown plants are also presented.

Key words:

agrochemical properties, bacteria, farming systems, micromycetes, nutrients balance, soil, yield