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Radu Lăcătușu, Anca-Rovena Lăcătușu, Romeo Căpățână, Mihaela Lungu, Rodica Lazăr and Irina Ramona Moraru

Abstract

Aiming to increase the use of natural resources and unexplored opportunities in industrial and agricultural practices, the marine algae biomass, that causes serious environmental problems in the Romanian Black Sea coast, was used in association with another two organic wastes, farmyard manure from cattle-breeding farms and sewage sludge resulted from the waste water treatment, to produce a compost suitable as organic fertilizer for plant cultivation in ecologic farming systems. Four variants of compost, first representing equal parts (33.33%) of those three components, and the other three proportions of 50% of each component, the difference being ensured in a ratio of 25% of each of the other two components, have been tested in a field experiment to assess their effects, both on the agro-chemical properties of the soil and on the sunflower plants development and crops. Until the phase of sunflower calathidia formation, the compost containing 50% farmyard manure influenced the best plant development in terms of height and number of leaves, then, at the end of vegetation period, the best plant development took place under the influence of compost prevalent in marine algae. The mobile forms of N and P were statistically differentiated depending on the dose of compost, the maximum dose generating the lowest content levels in the soil, as a result of higher absorption of these chemical elements in plants. The content of P and Ca in sunflower leaves recorded significant differences.

Open access

Monica Dumitrașcu, Mihaela Lungu, Sorin Liviu Ștefănescu, Victoria Mocanu, Gabi Mirela Matei and Rodica Lazăr

Abstract

As low-input environmentally friendly agricultural practices are currently associated with the delivery of a wide range of public goods and socioeconomic benefits, the strategy of European Union in mitigating climate change effects, protecting environment and ensuring public health has, among others, focused around preserving the High Natural Value (HNV) areas. About a quarter of the land in Romania is potentially covered by HNV farming and eligible for associated support payments, mostly along the chain of the Carpathian Mountains. Since soil systematic data on HNV area are scarce, recent research developments currently undertake to build up a first national HNV soil data base.

Soil fertility state in a HNV payment eligible area of south-eastern Transylvania was studied in seven in-depth dug profiles and seven additional shallow dug profiles. Soil samples were taken by genetic horizons as well as agrochemical samples from the upper soil layers (0-20 cm). Physical, chemical, and microbiological analyses revealed that the studied soils have a medium clayey loamy texture, good fertility and are subject to an adequate HNV management in the area, as the analytical values mostly range in favorable intervals for plant growth and nutrition. Thus, soil reaction is moderately acid up to slightly alkaline in the presence of carbonates, the soil organic matter, generally well mineralized, reaches fair levels and the high and very high cation exchange capacity ensure good conditions for plants growth and nutrition whilst nitrogen and potassium supply is adequate. Phosphorus is the only element in short supply – a situation often encountered in Romania unfertilized soils. Soil bulk density and total porosity are also favorable for root growth and spreading and plant nutrition. Microorganisms’ activity is diverse and is also adequate for plant nutrition.