Effect of liming and mineral fertilization on the soil and plants in a 44-year long-term experiment in Nyirlugos.

摘要

One of the oldest long-term mineral fertilizer application experiments in Hungary was set up in Nyirlugos, Hungary, in 1963 on acidic sandy brown forest soil with thin interstratified layers of colloid and sesquioxide accumulation. Characteristics of the site: pH(KCl) 4.6, humus 0.5-0.7%, CEC 3-4 meq/100 g in the ploughed layer. The topsoil was poor in all five macronutrients (N, P, K, Ca, Mg) and the groundwater depth was 2-3 m. Fertilizers were applied in the form of Ca-ammonium nitrate, superphosphate, potassium chloride, powdered limestone and dolomite. Results showed that in response to long-term N fertilizer application, the pH(KCl) value dropped from 4.3 in the unfertilized control to 3.5, while the application of 1 tonne/ha/year CaCO< sub>3 caused it to increase to 6.4 in the ploughed layer, where the value of exchangeable Ca2+ rose from 0.13 to 2.18 meq/100 g. In contrast, the value of Al3+ declined from 0.68 to 0.40 and that of Fe2+ from 0.43 to 0.15 meq/100 g. As a result of liming, the cation exchange capacity of the soil (T value) rose from 3.3 to 3.6-3.8, the total exchangeable bases (S value) from 0.4 to 2.5 meq/100 g and the base saturation from 12 to 69%. The effect of mineral fertilizer application, liming and soil acidification was characterized as the NH< sub>4-acetate + EDTA-soluble element contents. On this strongly acidic soil, the Ca content rose from 87 to 767 mg/kg as the result of liming, the Mg content from 18 to 97 mg/kg as the result of Mg fertilizer application, the Mn content from 8 to 36 mg/kg, the Sr content from 0.4 to 2.7 mg/kg, the Co content from 0.15 to 0.53 mg/kg and the Ni content from 0.10 to 0.19 mg/kg. The fertilizer effects were time-dependent. In the first ten years of the experiment (1963-1972), substantial fertilizer effects (yield surpluses) were only observed for N fertilizer application. In the second decade (1973-1982), the N effects gradually declined to the unfertilized control level, and fertilizer effects were observed for the joint NP treatments in cereals and for the NK treatments in hoed crops. In the third decade (1983-1992), sunflower (Helianthus annuus) and tobacco (Nicotiana tabacum) responded well to the application of NPKCaMg. In the fourth decade (1993-2002), the maximum yields of continuous triticale were also recorded in NPKCaMg treatment. Over the last few years (2003-2006), practically no triticale plants have survived on soils treated with 100-150 kg/ha/year N alone, as the soil became extremely acidic and other elements were exhausted. Soil fertility can be preserved if AL-P< sub>2O< sub>5 and AL-K< sub>2O contents of 120-150 mg/kg are maintained in the topsoil or if rates of approximately 1 tonne/ha/year ground dolomite are applied to ensure a pH(KCl) of 5.5-6.0, together with satisfactory levels of N fertilizer. The quantities of N, K, P, Mn and Co increased in the straw and grain yields of triticale in the N< sub>3 treatment, which was strongly acidic and gave very low yields, while the Ca, Sr and Mo concentrations declined. In general, liming caused the opposite effect. The availability of Mo in particular increased, while that of Co decreased in the grain, each by an order of magnitude on the high pH soil.