Tag Archives: peat substrate

317-328 L. Āboliņa, A. Osvalde, and A. Karlsons
Effect of substrate moisture level on cloudberry seedling growth and development after propagation
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Effect of substrate moisture level on cloudberry seedling growth and development after propagation

L. Āboliņa¹²*, A. Osvalde¹, and A. Karlsons¹

¹University of Latvia, Institute of Biology, O. Vaciesa street 4, LV-1004 Riga, Latvia
²Latvia University of Life Sciences and Technologies, Faculty of Agriculture and Food technology, LV-3001 Jelgava, Latvia
*Correspondence: laura.abolina@lu.lv

Abstract:

Experimentation of cloudberry cultivation has recently started in Latvia. Propagation is an essential part of cloudberry cultivation strategy, and it is an important step to ensure cloudberry survival and high vitality in field conditions. Optimal moisture conditions have to be determined for seedling development in the greenhouse. Potted cloudberries, cultivar ‘Nyby’, were grown at four different relative moisture levels of the substrate (in percent of the full water-holding capacity of the peat) – 50%, 60%, 70%, and 80%. Physiological measurements were taken once every week, including the concentration of total a and b chlorophyll in SPAD units and stomatal conductance in mmol m-2s-1. Morphological parameters, such as the number of leaves per pot, leaf size (cm), number of winter buds and visual score (from 1 to 5) were measured at the end of the vegetation season. Results revealed significant differences between the substrate moisture treatments for chlorophyll content in leaves, winter bud development and visual scoring. The authors note that slightly higher results were found for all parameters for the 80% treatment, following the tendency of increased plant vitality in higher moisture levels. This study indicates that a relative moisture of at least 70% of the full water-holding capacity of the peat is necessary for successful cloudberry growth and development under greenhouse conditions.

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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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