Browsing by Subject "savimaa"

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  • Alhonoja, Katja (Helsingin yliopisto, 2015)
    Phosphorus (P) plays a major role in cereal production. Total P content is high in Finnish soils but only a fraction of it is available to plants. This phenomena led to generous P fertilization since 1940 increasing the P concentration in fields as well as P balances. Reduced P fertilization since 1970 has decreased soil P concentration, resulting in negative P balances almost in entire Finland. Accumulation of P in the top soil is a result of chemical reactions occurring in the soil. Reactions of P in soils and the ability of the plants to take up P from soil affects the efficiency of P fertilization. P fertilization is most effective when the application rate replaces P removed from the soil in harvested yield. In this theses, results of the long-term fertilization trial (1973-2013) are compiled. The trial included spring wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and oat (Avena sativa L.). The data gathered was analyzed to investigate crop yield, P concentration of soluble P in soil and the effect of plant species on the concentration of soluble P in soil within 40 years. Rate of P fertilization and plant species affected soluble P concentration in soil. The higher the P fertilization rate was, the higher the soluble P concentration in soil was. The concentration of soluble P did not decrease during the years when the P fertilization rate was reduced. Among all cereals studied, the P balance decreased during the years following the decrease in P fertilization rates. Changes in P balance does not explain chances in soluble P concentration in soil.
  • Sarkala, Tero (Helsingin yliopisto, 2019)
    Tiivistelmä * Referat * Abstract Tutkimuksessa selvitettiin maan muokkausmenetelmien vaikutusta savimaalla. Tutkimus tehtiin Yara Suomen koetilalla Vihdissä. Siellä vuodesta 2007 käynnissä olleiden yhtäjaksoisten muokkauskokeiden jatkoksi haluttiin selvittää, miten muokkausmenetelmät ovat vaikuttaneet maahan. Kokeessa tutkittiin suorakylvetyn, sänkimuokatun ja kynnetyn maan eroja. Tutkimuksessa selvitettiin maan rakenteeseen liittyviä ominaisuuksia: maan kosteus keväällä, penetrometri läpäisevyys, lierojen kekolaskenta, maan orgaanisen hiilen pitoisuus, maan ravinneanalyysit sekä Peltomaan laatutesti. Mittaukset ja määritykset tehtiin kasvukauden 2015 aikana. Kokeista selvisi, että pitkäaikaiset muutokset muokkauksessa vaikuttivat maahan erilaisesti. Penetrometri mittauksissa kävi ilmi, että kynnetyn maan työntövastus oli pienin 0–25 cm syvyydessä, josta syvemmälle mentäessä kaikkien muokkaustapojen työntövastus oli lähes sama. Maan orgaanisen hiilen pitoisuus? 0–15 cm syvyydessä oli kevennetyillä muokkaustavoilla 26 % suurempi kuin kynnetyllä. Maan kosteus keväällä oli suorakylvetyssä maassa suurin ja kynnetyssä pienin. Lierolaskennassa kävi ilmi, että kynnetyllä maalla oli kekoja vähemmän kuin muissa muokkauksissa. Maan ravinneanalyyseissä ei löytynyt merkitsevää eroa eri muokkaustapojen välillä. Peltomaan laatutestissä tutkittiin maan ominaisuuksia fysikaalisesti ja biologisesti. Peltomaan laatutestin perusteella pintamaan vedenjohtavuus on kaikilla mailla hyvä, suorakylvetystä maasta ei löydy tiivistymää ja siinä on eniten lieroja. Lopuksi todettiin, että tämän tutkimuksen mukaan ei voida päätellä, mikä muokkaustavoista olisi paras savimaalla pohjoisissa olosuhteissa. Kuitenkin tutkimus viittaa siihen että, pitkään jatkunut suorakylvö saattaisi olla hyvä vaihtoehto savimaan viljelyssä.
  • Kangas, Jaakko (Helsingin yliopisto, 2015)
    New primary tillage methods have appeared alongside traditional ploughing. Objectives of primary tillage can nowadays be achieved with other methods such as by exploiting nature’s own processes or with chemical weed control. The endeavor of farmers to save time and money has caused conservation tillage to become more common. Different methods of conservation tillage and no-tillage has been replacing traditional ploughing. Conservation tillage has had various kinds of effects to achieved yields. Some international studies reported that conservation tillage had reduced yields. On the other hand, the rest of the studies point out that either the yield remained at the same level or at times, yield levels rose with reduced tillage. The aim of this study was to determine the profitability of different tillage methods. The profitability of three different primary tillage methods were compared at three farm sizes (50, 100 and 200 ha). Retail prices of farming machinery and Luke’s on-going field experiments on clay soil in Jokioinen were drawn on for data used in this study. Luke has been running no-tillage field experiments in Jokioinen since 2000. Yield data of spring barley from Jokioinen field experiment was used in this study. No-tillage was the most profitable tillage method on every farm size. The costs of no-tillage was 145?279 €/hectare lower than the costs with ploughing and 111?234 €/hectare lower than the costs with cultivation. The surplus of no-tillage was 93–226 €/hectare greater than surplus with ploughing and 69?192 €/hectare bigger than the surplus achieved with cultivation as a primary tillage. The profitability of cultivation was 16–34 €/hectare bigger than the surplus acquired through ploughing. No-tillage was more economically beneficial on a field which had less clay in its texture. The no-tillage’s surplus was 183?317 €/hectare bigger than the ploughing’s surplus and it was 161?284 €/hectare bigger than the cultivation’s surplus. Fields of similar size were used when analyzing the difference of profitability between ploughing and cultivation. This study asserts that the profitability of primary tillage method depends on machinery, weather conditions, soil type and the size of the farm. In this study, no-tillage was more profitable even though the yields produced were less than with traditional primary tillage. The profitability of the different primary tillage methods varied erratically between farms and for this reason, an unambiguous answer for profitability cannot be given.