Browsing by Subject "NUE"

Tiivistelmä - Referat – Abstract Acid sulfate soils are formed from sediment deposits containing sulfides, in which sulfur is present in the form of iron sulfides. In contact with air, the sulfur layer initiates a long-chain of biochemical and chemical reactions that increase the acidity of the soil and the amount of sulfate. Excessive acidity restricts plant development and growth. In acid soil, the aluminum solubility reaches a high level of toxicity for roots and slows down the microbiological degradation of organic matters, resulting in a reduction of nitrogen mineralization. Previous research results have shown that important liming has the potential to raise the pH of sulphate soils, and thereby reduce its acidity. With a high pH, the concentrations of ammonium and nitrate in the soil increase, facilitating nitrogen uptake and thereby also improving the efficiency of nitrogen uptake by plants. It has been speculated that, by increasing the nitrogen uptake efficiency and nitrogen utilization in plants, it will improve nitrogen use efficiency and so will reduce denitrification in sulphate soils and the resulting N2O emissions. However, to date, the studies on the effect of liming on plant nitrogen uptake (UPE) and utilization efficiency (UTE) and, consequently, on plant nitrogen utilization efficiency (NUE) have been minimal. The purpose of this study is to investigate how liming affects the yield formation and nitrogen uptake efficiency for barley (Hordeum vulgare L.) in unfertilized and fertilized acid sulfate soils. The field trial was established in Viikki, Helsinki, in the spring 2018. It followed split-plot design, in which the main plots were combinations of plant and nitrogen fertilization treatments (0 or 100 kg of nitrogen per hectare of fertilized barley (Kaarle) or unfertilized fallow) and lime treatments (0; 7,7; 15,3 t/ha) in four replicates. Liming raised the soil pH as expected and also increased nitrogen mineralization during the growing season, which is reflected in the nitrogen uptake. The effect of liming and fertilization on crop formation was small for barley biomass, yield component and grain yield. On the other hand, the liming effect reduced the nitrogen absorption efficiency and the nitrogen utilization efficiency and thereby the efficiency of nitrogen use. Fertilization also increased nitrogen uptake, but also decreased nitrogen utilization efficiency and nitrogen harvest index. The combined effect of liming and fertilization increased nitrogen mineralization. Liming treatment clearly increased nitrogen mineralization more in unfertilized soils than fertilized (there was no difference between liming levels). The drought in June and the low moisture limited the mobilization of nitrogen released from fertilizer in the soil, which would explain the effect of the nitrogen fertilizer treatment remaining relatively small. The drought also limited the development of the roots and thus the uptake of nitrogen and other nutrients. Lime treatment did not change NUE, UPE and UTE, but increased nitrogen mineralization and nitrogen uptake during the growing season, suggesting that under more favorable conditions the liming treatment could improve the efficiency and therefore improve the profitability and ecology of the barley crop. Further studies are needed as the results of studies performed elsewhere may not be valid under boreal conditions.

It’s urgent to increase per capita food production to meet the increasing population and its high demand while maintaining environmental stability. Aim to have higher yields as well as reduce harm to the environment, the most difficult problem is how to improve the nutrient use efficiency of plants. Thus using recycling fertilizers is more important in the agriculture practices, it can result in a long-term benefit of plants and environment. In order to explore the impacts of recycling fertilizers on grain yield and on fertilizer nitrogen use efficiency (NUE), an experiment was laid out with the randomized design with 4 replicates of 6 treatments. The objectives were: (1) to test a range of organic fertilizers in arable crop production, especially to find possible differences in nitrogen productivity (2) to find possible differences in nitrogen uptake and in uptake efficiency by rye between variable organic fertilizers and between organic and mineral fertilizers. In the experiment, biogas residual, chemical fertilization, vermicompost, meat and bone meal, sewage sludge compost and unfertilized control were compared. The rates of N application, as kg N/ha varied from one fertilizer to another. This thesis studied impacts on field rye (Secale cereale). There were significant improvements (p < 0.05) in SPAD value, N yield in biomass, total above-ground biomass, and grain yield with the application of the fertilizers, compared with non-fertilized plots. Especially biogas residual, sewage sludge compost and chemical fertilizers were effective. The highest, 33% nitrogen use efficiency was achieved with chemical fertilizer, while sewage sludge compost was the best among organic fertilizers. Recycling fertilizers can produce as high yields of rye as mineral fertilizers, with equal fertilizer nitrogen use efficiency. The critical factor for high yield is the amount of total nitrogen applied, and plant availability of the nitrogen and various organic fertilizers vary in NUE.

Vedenpuute rajoittaa viljojen kasvua ja ravinteiden hyödyntämistä maailmanlaajuisesti. Suomessa ongelmana on sateiden vähyys orasvaiheessa keväällä, jolloin kasvi on herkimmillään stresseille sadonmuodostuksen kannalta. Keväisellä sadetuksella voitaisiin mahdollisesti parantaa viljojen ravinteiden hyödyntämistä sekä satoa. Tämän tutkimuksen tavoitteena oli selvittää vaikuttaako keväinen sadetus kevätvehnäkasvuston (Triticum aestivum L. emend Thell ’Amaretto') typen käyttöön ja mihin vaikutus perustuu. Tutkimus toteutettiin kasvihuoneessa täydellisesti satunnaistettuna osaruutukokeena, jossa päätekijä oli sadetus (0 tai 32 mm) ja osatekijä typpilannoitus (0 tai 150 kg/ha). Kasvustosta mitattiin fotosynteesi, lehtialaindeksi (LAI), ilmarakojen johtavuus, lehden lämpötila ja SPAD-arvo. Kukintavaiheessa mitattiin lehtiala ja laskettiin fertiilien ja steriilien kukkien lukumäärä sekä määritettiin kasvin typpipitoisuus. Tuleentuneesta kasvustosta määritettiin satokomponentit ja jyvien valkuaispitoisuus. Kasvuston typen käyttöä tutkittiin jakamalla se typen käyttöön vaikuttaviin laskennallisiin komponentteihin typenkäytöntehokkuus (NUE), otontehokkuus (UPE), hyödyntämisen tehokkuus (UTE), agronominen tehokkuus (AE), kertyminen jyviin (GAE), sisäinen tehokkuus (IE), satoindeksi (NHI) sekä typpilannoitteen käytön tehokkuus (PFP) ja lannoitetypen hyödynnys (FNR). Näiden lisäksi laskettiin myös biomassantuotannontehokkuus (BPE) ja satoindeksi (HI). Sadetus lisäsi vehnän NUE:ta, UPE:ta ja UTE:ta. Sadetetun kasvuston NUE oli 35, kun ilman sadetutusta NUE oli vain 25. NUE:n lisääntymistä sadetuksen seurauksena selitti eniten UTE, joka oli sadetetussa kasvustossa 40 ja sadettamattomassa 33. Sadetus lisäsi myös kasvuston typen ottoa noin 20 kg/ha. Lisäksi FNR oli sadetetuissa kasvustoissa 60 %, kun se sadettamattomissa oli 40 %. Fytomassa runsastui sadetuksen seurauksena kuitenkin suhteessa enemmän kuin typen otto. Toisaalta vegetatiivinen massa runsastui enemmän kuin jyvämassa. Lisäksi havaittiin, että sekä fotosynteesi että ilmarakojen johtavuus tehostuivat sekä LAI oli suurempi sadetuksen seurauksena. Vehnän NUE:ta voidaan lisätä sadettamalla kasvustoa. Sadetuksen nettofotosynteesiä ja ilmarakojen johtavuutta tehostava vaikutus saattaa olla yksi vehnän typen käyttöä parantava tekijä.