engleski

The effect of acid soils liming on alfalfa mineral composition change

Soil acidification is a slow, continuous natural process resulting in acid soils being common in areas where soil development continued for long, geological periods of time and under climatic conditions which rainfall exceeds evapotranspiration. Soil acidification process may be accelerated by intensive agricultural production with fertilization as one of the main factors of intensification. The process of soil acidifications is aided by water leaching base cations to lower horizons and acid soils are widespread in the eastern Croatia. Consequently, in conditions of excessive soil acidity, numerous negative effects are present like hydrogen ions toxicity, toxicity of aluminum and manganese ions, phosphorus and molybdenum deficiency, reduction of microbiological activity and increased heavy metals availability. These unfavorable chemical properties of acid soils represent one of the main factors limiting the field crops yield. Alfalfa or lucerne (Medicago sativa L.) is the most widely used fodder legume in temperate regions. Soil acidity is one of the limiting factors affecting the production and sustainability of pastures and crops in many parts of the world. In Croatia, soil acidity is main limiting factor of field crops yield. Correcting soil pH by liming can influence plant nutrient availability and plant yield and quality. Alfalfa belongs to crops requiring a pH in the range of 6.5 to 6.8 or higher. Therefore the aim of the research was to determine the influence of liming, organic and mineral fertilization on alfalfa mineral composition change and above ground mass response, as well as impact on soil chemical properties. The pot experiment was conducted in field conditions, in eastern part of Croatia with two different acid soils of heavy and light textural class from Donji Miholjac and Magadenovac site. Acid soils were set up in plastic pots of 20 L volume with 10 liming and organic fertilization treatments in four repetitions according to random block design using alfalfa as the indicator plant. Lime material was added in two rates: 7, 5 and 15 t/ha of Mischkalk lime material (65 % CaO, ENV = 82, 5) as well as organic fertilization: 20 and 40 t/ha cattle manure and mineral fertilization 100:200:300 kg/ha N:P2O5:K2O. During each year, first cutting of alfalfa were sampled at the beginning of flowering stage by cutting whole above ground mass and analysed to determine mineral composition. Also, soil was sampled and analysed in a first year of investigation (2014.) and in second investigation year (2015.). A higher concentration of all investigated elements in the leaf and stalk was found in the first year, except of calcium, which concentration has increased in the second year because of the liming extension effect. However, in the second year was achieved higher total production of dry matter of alfalfa above ground mass. Liming significantly impacted on the increase in the number (8-14 %), height (4- 8 %) of alfalfa plants, and leaf dry matter yield (13-28 %), the stem (19-30%), and the total above ground mass (17 -29 %) and root mass (20-34 %). A higher concentration of all investigated microelements in the leaf and stalk was found in the soil which had a lower initial pH and higher concentrations of the same elements. Increasing doses of liming and fertilizer doses resulted with concentration increase of N, P, K and Ca in the leaf and stem of alfalfa, while liming reduced the concentration of Mg in the leaf. At the same time, increasing the doses of organic fertilizer impacted on the concentration increase of Fe, Mn, Zn and Cu in the leaf and stem of alfalfa, while liming resulted with the opposite effect where increment of lime rates reduced the concentrations of all investigated microelements in the leaf and in the stalk. Liming doses increment also resulted with positive effect on the concentrations increment of N, P, K and Ca in alfalfa root, and the with opposite effect on the concentration of Mg and microelements. At the same time, the impact of organic fertilization was smaller and slightly different on the root composition where organic fertilization significantly impacted on the concentration of N, K, Mn, Zn and Cu. So, liming of two acid soils positively impacted on alfalfa yield components and increased plant number and hight, as well as yield of above ground and root mass and also leaf and stalk dry matter yield. Moreover, liming and organic fertilization rates increment, increased concentrations of macroelements in alfalfa leaf and stalk, but decreased Mg leaf concentrations. Increment of organic fertilizer rates increased concentrations of micronutrients in alfalfa leaf and stalk, while liming showed the opposite effect and decreased micronutrients concentrations in alfalfa leaf and stalk by increament of lime rates.

acid soils ; liming ; alfalfa ; mineral composition

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