The changes of nutrient content in soil in long-term fertilizer experiments
2015
Vigovskis, J., Latvia Univ. of Agriculture, Skriveri, Skriveri Municipality (Latvia). Research Inst. of Agriculture | Jermuss, A., Latvia Univ. of Agriculture, Skriveri, Skriveri Municipality (Latvia). Research Inst. of Agriculture | Svarta, A., Latvia Univ. of Agriculture, Skriveri, Skriveri Municipality (Latvia). Research Inst. of Agriculture | Sarkanbarde, D., Latvia Univ. of Agriculture, Skriveri, Skriveri Municipality (Latvia). Research Inst. of Agriculture
The paper describes the influence of long term (more than 30 years) fertilizer application to the changes of soil properties and identifies the influence of different fertilization rates to phosphorus, potassium, calcium and magnesium accumulation in soil. The experimental field was established with four rates of mineral fertilizers: without fertilizers, N45P30K45; N90P60K90 N135P90K135 calculated in form of P2O5 and K2O. Since 1994 a seven-year crop rotation has been organized: 1) winter triticale, 2) potatoes, 3) spring wheat, 4) spring oilseed rape, 5) spring barley + perennial grasses (red clover, timothy), 6) perennial grasses, 1st year of using, and 7) perennial grasses 2nd year of using. During the vegetation period all the required common agrotechnical measures were taken – treatment with herbicides, fungicides and insecticides. On a low background of fertilizers (N45P30K45) a small increase of mobile phosphorus in soil has only been observed in recent years. At the fertilizer rate N90P60K90 the content of available phosphorus and potassium in soil gradually begins to grow. Fertilization norm N135P90K135 caused a constant accumulation of nutrients in soil. In 30 years’ time the content of exchangeable phosphorus (calcium lactate – extractable) has increased more than 20 times (from 9 till 184 mg P2O5 kgE-1) and exchangeable potassium (calcium lactate – extractable) has increased more than 4 times (from 64 till 223 mg K2O kgE-1). There were no relation between different fertilizing rates and calcium and magnesium content in soil observed.
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