Browsing by Subject "vilja"
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(2020)Modern agriculture is based on intensive farming practices where plant production farms rely on external mineral fertilizers and carbon stocks of the soils are decreasing. At the same time, regional clusters of animal production farms are struggling with excessive manure that increases the risk of nutrient leaching from their fields. To overcome problems related to nutrient loss, eu-trophication of watersheds and greenhouse gas emissions from food production, several national projects aim to promote farmers to use recycled fertilizers. The latter are fertilizers or soil condi-tioners which can be processed from side products such as animal manure, green manure, mu-nicipal biowaste, by-products from food industry or sludges from wood industry. The aim of this study was to determine how different recycled fertilizer products affect grain yield and yield quality of oat as well as how the products perform in relation to nitrogen input. The field experiment was founded in southern Finland where oat was cultivated for three successive years in a five-year rotation. Liquid ammonium sulfate, meat and bone meal pellets and biogas sludge were compared with commercial mineral fertilizer. The control treatments were unfertilized plots and mineral fertilization treatments with three different nitrogen levels between 44–161 kg/ha. There were no statistically significant differences between treatments in terms of grain yield, except for favorable growing season 2017 when unfertilized plots produced the lowest yield. Nor were there differences in protein, starch, fiber or ash content of grains among recycled and min-eral fertilizers over the three years. The grain yield was positively correlated with the amount of soluble and total nitrogen. Having the lowest application level, meat and bone meal produced the highest yield per nitrogen input among fertilizer treatments. The yield results show that ammonium sulfate, meat and bone meal and biogas slurry can be as effective as mineral fertilizers in oat production, if they have the same amount of soluble nitro-gen. Good fertility of the research plot and drought stress during the two following years mitigat-ed differences among treatments so that nitrogen fertilization proved itself useful only in the grow-ing season 2017. To gather enough data and determine the long-term effect of recycled fertiliz-ers, further research should be distributed into several pilot farms. Moreover, the current Finnish fertilizer recommendations should be updated towards experimental nutrient balance models. This could encourage farmers to gather information of the yield-limiting factors and prevent over fertili-zation in poorly responsive soils.
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(2017)The soil mineral nitrogen content is affected by many factors such as nitrogen fertilizer, fertilization and cultivated plant species. The effects of these factors on soil mineral nitrogen content were examined and the research was conducted at the Viikki Research Farm during 2013–2015. The possibility of using soil mineral nitrogen content and nitrogen balance to optimise nitrogen fertilization was also studied as well as the leaching of mineral nitrogen during winter and the factors affecting leaching. The soil type of the experimental area was clay loam in topsoil and sandy loam in subsoil. Soil samples were taken in the spring before tillage and in the autumn before soil freezing from topsoil (0-20 cm) and subsoil (30-50 cm). Ammonium and nitrate were extracted from soil samples with 2 M KCl. Plant species and fertilization changed every year, but fertilization followed the regulations for the subsidies of agricultural environment and all the fertilizers and cultivars were commercially available in Finland. The nitrogen content of the seed and forage samples were determined. The actual nitrogen yield and nitrogen balance were calculated. The expected nitrogen yield and nitrogen balance were calculated with the common nitrogen contents of seeds published by the Finnish Agency for Rural Affairs and compared to the actual nitrogen yield and nitrogen balance, but no differences were found. Soil mineral nitrogen content, nitrogen balance and nitrogen yield varied a lot from year to year which was partly caused by the differences between the growing seasons and winters as well as the changes of cultivated plants and fertilization. The soil mineral nitrogen content was smaller in the spring (33 N kg/ha) than in the autumn (55 N kg/ha). Grass took more nitrogen than the other plant species. The soil nitrate content was smaller under growing grass than harvested plant stand in the autumn and the ammonium content was greater under growing grass than other plant species in the spring. The soil mineral nitrogen content was reduced and differences between treatments were moderated during the winter, which was probably caused by leaching. Fertilization had no direct effect on soil mineral nitrogen content. Increasing nitrogen fertilization increased nitrogen balance, but there was no correlation between nitrogen balance and soil mineral nitrogen content.
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