Under open environmental conditions, Trihodermin and BioMikss were used for trial purposes to study lettuce (Lactuca sativa L.) and strawberry (Fragaria x ananassa Duch) yields in 2008. Experiments were carried out in the Region of Riga at the farm 'Pukulejas'. The lettuce cultivar 'May King' and the strawberry cultivar 'Senga Sengana' were both used in the trial. The purpose of the trial was to evaluate the use of biological products when applied on the above mentioned trial plants. In the field trial, both Trihodermin and BioMikss in dry powder form in peat mixture were applied for soil treatment 10 kg haE-1. Trihodermin contains cells of microscopic fungus Trichoderma harzianum 8-21 and Trichoderma viride 1-5. BioMikss is a mixture of microorganisms, containing cells of seven various bacteria (Azotobacter chroococcum 23, Polyangium cellulosum 5-t, Polyangium 56, Pseudomonas putida 48-t, Rhizobium meliloti 15, Streptomyces griseoviridis P-t and Streptomyces cellulosae D) and cells of two various fungus (Trichoderma harzianum 7-t and Trichoderma viride A-L). Three times during the growing period Trichodermin and BioMikss water solution 100 g kgE-1 was applied on the trial plants. When compared to non-treated plants, significantly increased yield was observed on BioMikss-treated lettuce. A significantly increased yield was also observed on BioMikss-treated strawberries. The results of the experiments showed that in open environment, both strawberry and lettuce plants treated with BioMikss showed resistance to the grey mould, caused by a parasitic fungus Botrytis cinerea. The results prove that biological products, by environmentally friendly means, revitalize soils, protect plants, and enhance growth, immunity and productive potential.

Strawberries (Fragaria× Ananassa Duch.) are widely grown in Latvia, and it is the first berry crop that ripens in summer. In Latvia, climate conditions are very suitable for strawberry growing. Unfortunately, meteorological conditions have become very changeable in recent years. The short day (SD) strawberry cultivars are the most important ones for Latvia, as they initiate flower buds in autumn. For these cultivars it is important to initiate flower buds at the end of September till the end of October. The day length has to decrease less than 14 hours per day to begin this process. In Latvia, the day length below 14 hours per day is at the end of August. The second important limiting factor for initiation of flower buds is the average day temperature, which must be between 10 and 15 °C. The studies on strawberry flower bud initiation in Latvia were done long time ago, on a very small scale and fragmentary. The current paper analyzes the temperature regime during the period of previous ten years (2004 – 2013) in autumn in Dobele in relation to suitability of this climatic factor to the flower bud initiation and strawberry yield next year. The soil surface temperatures during the last ten years in August were about +20 °C, which means that the flower bud initiation could not occur as early as it was described in the previous study.

Legumes are becoming more popular in food and feed consumption. They are promoted by EU policy related to healthy lifestyle and environmental policy. Legumes can be grown in crop rotation as monocrop or in different kind of intercropping systems. It is a well-known fact that legumes play an important role in fixation of the atmospheric N, whereas their influence on other biological and chemical aspects of the soil ecosystem is only explored partially. The experimental trial was established at the Pūre Horticultural Research Centre with the aim of studying the influence of legumes on the soil properties in the intercrop with strawberries (Fragaria × ananassa Duch.). Different genotypes were included in the trial as intercrops: two local broad beans (Vicia faba var. major L.) genotypes, two pea (Pisum sativum L.) cultivars and clover (Trifolium hybridum L.). Two control treatments were included in the trial: with and without nitrogen fertilizer usage. Strawberries were planted in May of 2014 and maintained in the field for three years. Results showed that there were significant differences between treatments in soil respiration rate (SRR) and SRR dynamic throughout the experiment time. Dehydrogenase activity had similar results, though no significant differences between treatments were observed in the third year. No significant difference between treatments was found in the soil organic matter. Obtained data shows that legumes have a significant influence on the soil biological properties but not on biochemical properties. Further research needs to be carried out to determine legume influence on soil environment in more detail.

The experiment was carried out at the Research Centre of Organic Farming of Estonian University of Life Sciences in 2012 and 2013. The study was aimed to find out the effect of defoliation and humic acid application on the strawberry (Fragaria × ananassa Duch.) plant growth, yield, and on the ascorbic acid, total phenolic and anthocyanin contents in ‘Darselect’ yield. Defoliation decreased significantly the number of leaves and inflorescences in both experimental years, while the fertilization effect was only in one experimental year. Fruit weight ranged from 19 to 42 g, being significantly decreased by defoliation in 2012, but increased in 2013. Yield was decreased due to defoliation up to 40% in 2012 and up to 51% in 2013, but humic acid application increased the yield of the defoliated plants in both experimental years. Defoliation in combination with humic acids had a significant effect on strawberry ascorbic acid content, but the effect was different for different fruit order. Tertiary fruits contained up to 46% more of total phenolics due to defoliation in both experimental years. Defoliation increased anthocyanins in primary and secondary fruits, but decreased it in tertiary fruits; while fertilizing increased the content up to 45% in defoliated plants in primary, but decreased about 13% in tertiary strawberries.