The effect of fertilization and liming on pH of soils and crop yields

At two sites of stationary experiments at Lipa (cambisol) and at Svitavy (Iuvisol) pH of soils, mineral and mineralizable N content in soils in spring and autumn period, yield of crops and N uptake of crops were evaluated. Different rates of fertilizers were applied at Lipa from 1974 and at Svitavy from 1980. The article evaluated three treatments (treatment 1 - unfertilized, treatment 2 - manure + NPK, treatment 3 - manure + NPK + liming). The following crops were cultivated during the period under study: 1991 - red clover, 1992 - winter wheat, 1993 - potatoes, 1994 - winter wheat, 1995 - spring barley. The results of investigations for the period 1991 to 1995 show that the yields were significantly affected by red clover, followed by manuring and fertilizing. Treatment 2 (manure + NPK) gave increase of the yield at Lipa by 62.3% compared with untreated treatment and treatment 3 (limed, in addition) by 84.1% and at Svitavy by 35.7% and 57.9%. Similar influence, but at lower level, was found in N uptake by crops. Fertilization affected the yield more than N uptake by plants. Different fertilization had an impact on pH of soils and mineral and mineralizable N in soils, hence also crop yields and N uptake by crops. Liming maintained favourable level of soil pH and increased the yields over five yields at Lips by 4.5 t and by 5.6 t of cereal units per 1 ha at Svitavy.