Browsing by Subject "NUE"

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  • Huang, Qiuchen (Helsingin yliopisto, 2018)
    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.
  • Unnaslahti, Jenna (Helsingfors universitet, 2017)
    Water deficiency limits the growth of cereals and the utilization of nutrients worldwide. In Finland, the problem is lack of rain during vegetative growth in the spring. At that time plants are most sensitive to stresses. Irrigation in spring could improve yields and the utilization of nutrients in cereals. The aim of this study was to investigate whether spring irrigation affects the nitrogen use of spring wheat (Triticum aestivum L. emend Thell ’Amaretto') and what are the possible effective mechanisms. Study was conducted in the greenhouse as a completely randomized split-plot experiment where the main plot was irrigation (0 or 32 mm) and the sub-plot was nitrogen fertilization (0 and 150 kg/ha). The rate of photosynthesis, leaf area index (LAI), stomatal conductance, leaf temperature and SPAD value were measured from the crop. At flowering stage leaf area was measured and the numbers of fertile and sterile flowers were counted and plant nitrogen content was analysed. At maturity stage the yield components and nitrogen content of the grains were determined. The components of nitrogen use of wheat was investigated by calculating nitrogen use efficiency (NUE), uptake efficiency (UPE), utilization efficiency (UTE), agronomic efficiency (AE), grain accumulation efficiency (GAE), internal efficiency (IE), nitrogen harvest index (NHI) as well as nitrogen fertilizer partial factor productivity (PFP) and nitrogen fertilizer recovery (FNR). Biomass production efficiency (BPE) and harvest index (HI) were also calculated. Irrigation increased NUE, UPE and UTE. The NUE of irrigated wheat was 35 whereas the NUE was 25 without irrigation. The increase of NUE due to irrigation was explained for the most part by UTE which was 40 with irrigation and 35 without irrigation. Irrigation increased also the uptake of nitrogen by approximately 20 kg/ha. Additionally, FNR was 60 % and 40 % with and without irrigation, respectively. However, phytomass increased more than nitrogen uptake as a consequence of the irrigation and vegetative mass increased more than grain mass. Furthermore, it was observed that both the photosynthesis and the stomatal conductance became more effective and LAI was higher as a consequence of the irrigation. In conclusion, NUE of wheat can be increased by irrigation. One explanation for this could be that irrigation intensifies netphotosynthesis and stomatal conductivity.