Tag Archives: limestone

415-420 V. Loide
Relieving the calcium deficiency of field soils by means of liming
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Relieving the calcium deficiency of field soils by means of liming

V. Loide

Estonian Research Institute of Agriculture, Teaduse 11, Saku 75501, Estonia;e-mail: valli.loide@mail.ee

Abstract:

Over 22% of Estonian field soils are calcium-deficient and acidificated, and are also among the poorest soils in Estonia in terms of humus; their average humus content remains below 2%. Low humus content in calcium-deficient soils results from either, a lesser generation of organic matter on acid soil, or its decomposition speed as affected by the micro fungi, which are dominant in calcium-deficient (Haplic Podzoluvisols) soils. The dissolved organic matter succumbs easily to leaching and transport caused by wind and water (erosion), whereby the fertility of the soil will decline. Thus, calcium plays an important role in ensuring the fertility and sustainability of soil; liming is used to relieve its deficiency. To eliminate calcium-deficiency in field soils, the quick-acting fine dusty limes with 5-year interval 5 t ha-1 are mainly used in Estonia. Paying attention to the dynamics of available calcium content in the soil limed with fine dusty lime fertilisers, it appeared that the calcium content remained at the optimum level in the ploughed layer for only 2–3 years, a considerably shorter period of time than expected. Since the level of fineness determines its ability to dissolve and the effect of lime on the available calcium content in soil, then to improve the effectiveness of liming and, from the aspect of an economical use of resources, it is advisable to use dusty limes with a shorter than 5-year interval and, respectively, in smaller quantities, which would guarantee a more stable calcium content in the soil with a better use of resources. For longer effect, limestone should sufficiently contain a coarser fraction, dissolving only in the 3rd–4th year.

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39–48 M. Järvan and P. Põldma
Content of plant nutrients in vegetables depending on various lime materials used for neutralising bog peat
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Content of plant nutrients in vegetables depending on various lime materials used for neutralising bog peat

M. Järvan¹ and P. Põldma²

¹Department of Field Crops, Estonian Research Institute of Agriculture, Teaduse 13, 75501 Saku, Estonia; e-mail: malle.jarvan@mail.ee
²Department of Horticulture, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: ppoldma@eau.ee

Abstract:

The trials were performed in the years 1998–2000 in Saku (59°18’N, 24º39’E) in greenhouse conditions. The aim was to establish how lime materials used for the neutralisation of bog peat acidity (oil shale ash, clinker dust, limestone meal, dolomite meal and their mixtures), which changed significantly the contents of available Ca, K and Mg in the peat substrata, affect the mineral composition of vegetable leaves (lettuce, cucumber, tomato, paprika) and the mutual relationships between elements (K, Ca, Mg, P). In the case of all vegetables, a strong Ca and Mg antagonism occurred. The Mg content of plants was very sensitive to the Ca:Mg ratio in the lime material used for peat neutralisation. In the case of limestone meal, the tomato plants contained Mg 0.18–0.24% and cucumber plants 0.36–0.40%; in the case of dolomite meal, 0.66–0.71% and 0.78–0.90, respectively. The Ca and K contents of vegetables were somewhat less affected by the difference of lime materials than the Mg content. Abundant Mg in lime material increased P content in plants, a synergism between Mg and P occurred.
Lettuce grown on substrata neutralised with mixtures of limestone and dolomite meal contained less nitrates than that grown on substrata with clinker dust and oil shale ash. Too high K content in the substrate neutralised with clinker dust had a negative effect on the carotene content of lettuce.

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29–37 M. Järvan
Available plant nutrients in growth substrate depending on various lime materials used for neutralising bog peat
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Available plant nutrients in growth substrate depending on various lime materials used for neutralising bog peat

M. Järvan

Department of Field Crops, Estonian Research Institute of Agriculture, Teaduse 13, 75501 Saku, Estonia; e-mail: malle.jarvan@mail.ee

Abstract:

In 1998–2000, the effect of local Estonian lime materials (oil shale ash, cement clinker dust, limestone meal, dolomite meal and their mixtures) used for neutralising acid bog peat on the contents of available plant nutrients (K, Ca, Mg) and on Ca:Mg, Ca:K, K:Mg ratios in peat substrate was investigated. The substrate were made on NPK and NP backgrounds. Lime materials, the Ca:Mg ratio of which varied between 3.4–16.7:1, were applied at a rate of 8 kg (in some variants 6 and 10 kg) per m³ peat. The substrate were analysed 2 and 4 weeks after their production.
The pHKCl of growth substrate became stable almost within 2 weeks. Dolomite meals neutralised peat acidity approximately by 0.5–0.7 units less than the same rate of dusty lime fertilisers. The higher the Mg-content in lime material, the weaker its neutralising effect. While using a 1:1 mixture of limestone and dolomite meal, the content of available Mg in the substrate was sufficient for plant growth and it was possible to leave out the application of Mg-fertiliser to the substrate. The Ca:Mg ratio in growth substrate was considerably broader than in lime materials and depended significantly on the type of lime. The content of available Ca in substrate increased relatively more than that of available Mg. Under the effect of dusty lime fertilisers the Ca:Mg ratio had shifted in favour of Ca by 1.2–1.4 times, in the case of carbonate rock meals the preponderance of Ca had increased by 3.6–3.9 times. The best variants for neutralising peat acidity in the given research were as following: 1:1 mixture of limestone meal and dolomite meal and 1:1 mixture of clinker dust and dolomite meal. In these cases the contents of Ca, Mg and K and their mutual ratios in the substrate corresponded in the best way to the limit values needed for the optimum growth of greenhouse vegetables.

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