Tag Archives: winter cover crops

xxx J. Kuht, V. Eremeev, E. Loit, M. Alaru, E. Mäeorg, L. Talgre and A. Luik
Changes in the content of soil organic carbon and total nitrogen in the organic and conventional cropping systems
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Changes in the content of soil organic carbon and total nitrogen in the organic and conventional cropping systems

J. Kuht*, V. Eremeev, E. Loit, M. Alaru, E. Mäeorg, L. Talgre and A. Luik

Estonian University of Life Sciences, Institute of Institute of Agricultural and Environmental Sciences, Kreutzwaldi 5, EE51006 Tartu, Estonia
*Correspondence: jaan.kuht@emu.ee

Abstract:

Maintaining and increasing the stock of soil organic carbon is of vital importance in maintaining the soil fertility. In present research the changes in the content of organic carbon (SOC) and total nitrogen (Ntot) in the soil are investigated. The data is collected from the long-term field experiment, which compares organic and conventional farming systems in a crop rotation (barley undersown with red clover, red clover, winter wheat, pea, potato) during 2014–2018. Based on the 5-year experiment, it was concluded that the cropping systems have a significant effect on the SOC content and a smaller effect on the Ntot content of the soil. The diversification of organic cropping systems with cover crops and composted cattle manure significantly increases the content of organic carbon in the soil. The results of the experiment indicate that the content of organic carbon was significantly lower (by 7.6–12.6%) in conventional systems, where pesticides had been applied and cover crops and manure had not been used, compared to the organic cropping systems. The correlations between the SOC contents of main crops and precrops were statistically more significant in organic farming system, compared to the conventional system. Highest SOC and Ntot values were observed in organic systems with cover crops and composted manure fertilization. Hence, it can be stated that in order to improve the soil fertility and fix more carbon and nitrogen, high amounts of organic material should be applied into the soil and the activity of soil microbes should be a priority. The organic cropping systems have more advantages for sustainable crop production.

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592-597 L. Talgre, V. Eremeev, E. Mäeorg and A. Luik
Diversified cropping systems for promoting the beneficial insects – ground beetles (Coleoptera: Carabidae)
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Diversified cropping systems for promoting the beneficial insects – ground beetles (Coleoptera: Carabidae)

L. Talgre*, V. Eremeev, E. Mäeorg and A. Luik

Estonian University of Life Sciences, Institute of Institute of Agricultural and Environmental Sciences, Kreutzwaldi 5, EE51006 Tartu, Estonia
*Correspondence: liina.talgre@emu.ee

Abstract:

In agro-ecosystems ground beetles – carabids (Coleoptera: Carabidae) are important as generalist predators of invertebrate pests and weed seeds and as prey for larger animals. This way they contribute to biodiversity and influence the most important ecological processes. Impacts of crop management practices on the carabids are not well described. Carabids were studied in winter wheat which is one crop in the rotation experiment (barley undersown with clover-clover-winter wheat-pea-potato). Carabids were collected with pitfall trap during one week at the end of June 2022. In laboratory, their species was identified. Trapping of carabids during the spiking phase of winter wheat has shown significant differences in carabids activity-density and diversity depending on five different cropping systems. In two conventional systems where pesticides were used the number of carabids was two times smaller in comparison with three organic systems. Activity-density and diversity of carabids was significantly higher in all organic systems and especially in Org II system where winter cover crops and composted manure where used for rotation diversification. The Shannon–Wiener index values, which takes into account the number of species and their relative abundance were 1.24–1.53 in conventional systems, but higher in diversified organic systems (1.60–1.78). Only in organic systems Org I and Org II there were very rare species present, like Acupalpus meridianus (Linnaeus) and Microlestes minutulus (Goeze). In diversified organic systems the higher activity-density and abundance of carabids could be explained by the diverse plant community as possible source for better food and microclimatic conditions.

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1934–1943 J. Kuht, V. Eremeev, L. Talgre, H. Madsen, M. Toom, E. Mäeorg, E. Loit and A. Luik
The content of weed seeds in the soil based on the management system
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The content of weed seeds in the soil based on the management system

J. Kuht¹*, V. Eremeev¹, L. Talgre¹, H. Madsen¹, M. Toom¹², E. Mäeorg¹, E. Loit¹ and A. Luik¹

¹Estonian University of Life Sciences, Kreutzwaldi 1, EE51014 Tartu, Estonia
²Estonian Crop Research Institute, J. Aamisepa 1, EE48309 Jõgeva, Jõgeva Vald, Estonia
*Correspondence: jaan.kuht@emu.ee

Abstract:

In 2008 an experiment was set up on the field in Eerika experimental station (Estonian University of Life Sciences) as a 5-field crop rotation: barley (Hordeum vulgare L.) with undersown red clover, red clover (Trifolium pratense L.), winter wheat (Triticum aestivum L.), pea (Pisum sativum L.), potato (Solanum tuberosum L.). The objective of the study was to measure the content of weed seeds in the soil and to evaluate the diversity of the species at the beginning of the period of organic production in 2011. In conventional farming systems without fertilizer (Con I) and conventional farming with mineral fertilizer (Con II) herbicides were used for weed control. All the crops in Con II system received P 25 kg ha-1 and K 95 kg ha-1, but the application rates of mineral nitrogen fertilizer differed. In organic systems (Org I – organic farming based on winter cover crop and Org II – organic farming based on winter cover crop and manure), the winter cover crops (ryegrass after winter wheat, winter oilseed rape after pea, winter rye after potato) were sown after the harvest and were ploughed into the soil as green manure in spring. Organic farming systems (Org II) had a negative effect on the content of weed seeds in the soil (2.0–22.7% less seeds than in other variants). The seeds of Chenopodium album were the most abundant among summer annual weeds and the seeds of Viola arvensis among winter weeds in the soil. Organic farming measures increased the domination of Chenopodium album – the dominance index D’ was increased by 0.09–0.14 compared to conventional variants. The content of seeds of winter weed Viola arvensis in Org II variant was decreased by 82%. The index of species evenness J’ and Shannon Wiener diversity index H’ were lower in organic plots by 0.10–0.18 and 0.60–0.19, respectively. Org II variants showed the best results based on the decrease of soil weed seed bank and distribution of the weed species.

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1372-1379 J. Kuht, V. Eremeev, L. Talgre, H. Madsen, M. Toom, E. Mäeorg and A. Luik
Soil weed seed bank and factors influencing the number of weeds at the end of conversion period to organic production
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Soil weed seed bank and factors influencing the number of weeds at the end of conversion period to organic production

J. Kuht*, V. Eremeev, L. Talgre, H. Madsen, M. Toom, E. Mäeorg and A. Luik

Estonian University of Life Sciences, Kreutzwaldi 1, EE51014 Tartu, Estonia *Correspondence: jaan.kuht@emu.ee

Abstract:

In 2008 an experiment was set up on the field in Eerika experimental station (Estonian University of Life Sciences) as a 5-field crop rotation: red clover, winter wheat, pea, potato and barley undersown with red clover. The objective of the study was to measure the content of weed seeds in the soil and to evaluate the diversity of the species at the end of the period of converting to organic production. In conventional farming systems without fertilizer (Conv I) and conventional farming with mineral fertilizer (Conv II) herbicides were used for weed control. All the crops in Conv II system received P 25 kg ha-1 and K 95 kg ha-1, but the application rates of mineral nitrogen fertilizer differed. In organic systems (Org I – organic farming based on winter cover crop and Org II – organic farming based on winter cover crop and manure), the winter cover crops (ryegrass after winter wheat, winter oilseed rape after pea, winter rye after potato) were sown after the harvest and were ploughed into the soil as green manure in spring. The content of annual weed seeds was the lowest in red clover that had 17.7% less weed seeds in the soil of Org II system compared to control (Conv I). In winter wheat the content of winter annual weed seeds was 50–76% higher compared to other crops. By the end of 2009 the content of organic carbon (Corg %) in the soil had increased significantly in both organic systems which results in higher activity of organisms that decrease the viability of weed seeds.

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