Effect of fertilisation systems on the balance of plant nutrients and soil agrochemical properties
Joniskelis Research Station of the Lithuanian Institute of Agriculture Joniskelis LT-39301 Pasvalys district. Lithuania; e-mail: email@example.com
Clay loam soils are rich in available potassium, however, they contain a low or moderate content of phosphorus. At the Lithuanian Institute of Agriculture’s Joniskelis Research Station trials were carried out over the period of 1960–2000 on a Endocalcari-Endohypogleyic Cambisol (Cmg-n-w-can) – a clay loam soil in a five-course crop rotation, in which we investigated mineral, organic and organic-mineral fertilisation systems. Results of the sixth rotation showed that the annual application of mineral N56P48K60 fertilisers resulted in an increase of the content of available phosphorus in 5 mg kg-1 of the soil, and the reduction of potassium content in 3 mg kg-1 of the soil, compared with the initial level. In the organic fertilisation system, the application of only 80 t ha‑1 of farmyard resulted, compared with the mineral fertilisation system, in a humus content increase in the plough layer by 0.12 percentage units and that in the phosphorus content by 26.0 mg kg-1 and potassium content by 31.0 mg kg‑1. In this system the crop productivity, compared with unfertilised crops, increased by 34.1%, however, compared with the mineral fertilisation system, it declined by 14.1%. In the organic-mineral fertilisation system, the application of 40, 60 and 80 t ha‑1 of farmyard manure and NPK fertilisers in the same amount as in the mineral fertilisation system resulted in the following increases – soil humus content by 0.18; 0.24 and 0.21 percentage units, phosphorus content by 41.0, 61.0 and 61.0 mg kg-1, potassium content by 36.0; 46.0 and 54.0 mg kg-1, and crop rotation productivity by 6.2, 7.6 and 7.8, respectively, compared with the mineral fertilisation system.