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  • Rural Digital Europe
  • Open Access
  • 0105 earth and related environmental sciences
  • EMU DSpace

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  • Open Access
    Authors: 
    Kokin, Eugen; Pennar, Madis; Palge, Veli; Jürjenson, Kuno;
    Country: Estonia

    Article The aim of the study was to define the strawberry leaf surface and ambient air temperature differences in night frost conditions. The study was carried out at the commercial strawberry field in late autumn at a specific natural climatic situation, corresponding to night frost conditions. Thermal camera FLIR P660 was used for obtaining thermal images and corresponding visual colour images of the strawberry leaves. The images were taken at ten-minute interval. The ambient air temperature, relative humidity, dew point, solar radiation and wind speed data were obtained by Davis Vantage Pro2 weather station. It was estimated that the surface temperature of the specific leaf is comparatively similar at different parts of the specimen and changes noticeably with the variation of solar radiation intensity. The speed of temperature changes was also analysed. During all the measurement period, the considerable difference between the temperature of the leaf and the ambient air temperature was established, especially in absence of solar radiation. The difference of the leaf surface and ambient air temperature reached 8 °C. The study showed that in night frost conditions the plants might be endangered by low temperatures even at the air temperatures above 0 °C due to intensive energy loss by long wave radiation to the sky. It is suggested that the thermal imaging or infrared radiation measurement should be used simultaneously with air temperature measurements for more exact timing of night frost prevention measures at strawberry cultivation. http://dx.doi.org/10.15159/ar.18.010

  • Open Access
    Authors: 
    Mihkel Are; Tanel Kaart; Are Selge; Alar Astover; Endla Reintam;
    Publisher: Lithuanian Research Centre for Agriculture and Forestry
    Country: Estonia
    Project: EC | iSQAPER (635750)

    Soil water-stable aggregate (WSA) stability is one of the most important indicators of soil health, because it influences chemical, biological and other physical properties. At the same time, WSA formation, stabilization and degradation are also some of the most complex processes that occur in the soil, making them difficult to fully understand. In particular, there is a lack of research on WSA stability in the Baltic region. To gain a better understanding how aggregation occurs in Estonian pedo-climatic conditions, this study was conducted in 2014– 2015 in a sandy loam Stagnic Luvisol (LV-st) (WRB, 2014). Potato and barley plots were analysed in a three-year crop rotation (potato → spring wheat → barley) with straw removal. The nitrogen (N) fertilization treatments were 0, 40, 80, 120 and 160 kg ha-1 yr-1 N, both without and with 40 Mg ha-1 fermented cattle farmyard manure (FYM) application prior to potato planting in the previous autumn. WSA stability was determined by Eijkelkamp’s wet sieving apparatus from air-dried soil samples of less than 2 mm in diameter. The study revealed a negative correlation (r = −0.16) between increased N rates and WSA stability, regardless of FYM applications. Although soil organic carbon (SOC) content increased with additional N fertilization rates, the reduction in soil acidity (pHKCl) levels caused by N fertilization, most likely repealed the positive SOC content effect on WSA stability. In general, compared with sole N fertilization, FYM application had a positive effect on WSA stability. However, even though WSA stability did not always increase with FYM applications, it still had a positive effect on bulk density, SOC content and soil acidity levels. Further research is needed in Estonia due to the complexities involved in the soil aggregation process. This study was supported by the H2020 project iSQAPER-635750.

  • Open Access
    Authors: 
    Mihkel Are; Karin Kauer; Tanel Kaart; Are Selge; Alar Astover; Endla Reintam;
    Publisher: Pleiades Publishing Ltd
    Country: Estonia
    Project: EC | iSQAPER (635750)

    Soil formation on the human time scale is immensely time consuming, although it can be significantly accelerated through the effects of vegetation. The content of water-stable aggregates (WSAs) is a useful indicator for determining both the soil development level and the soil quality. However, in severely degraded soils, especially in the Baltic pedoclimatic region, the effects of vegetation on the aggregate stability have been poorly studied. Therefore, to obtain more knowledge about the impact of vegetation on WSA, and thereby knowing how to improve it, this study was conducted on a long-term soil formation experiment in Estonia near Tartu. In 1964, the initial soil from an area of 20 × 8 m down to 100 cm depth was replaced with a sandy loam calcareous glacial till. The experiment started on April 26, 1965, when plants were sown on the plot. The topsoil (0–20 cm) samples were analyzed in 1966, 2000, 2007, and 2014. The study indicated that perennial grasses (meadow fescue and common meadow-grass) fertilized with P40K75, compared to N150P40K75, decreased the WSA content, as well at the accumulation rate of soil organic carbon (SOC) and the total nitrogen content (Ntot). The hybrid alfalfa treatment resulted in the significantly highest SOC and Ntot accumulation, but not in the overall highest WSA content. Under barley, manure positively affected the WSA and SOC, though many other physical properties were not improved. Compared to the initial till under bare fallow, the SOC and Ntot contents were significantly higher under grown crops, but the WSA content remained the same. In addition, regardless of the grown crops, the WSA of larger (0.25–2 mm) aggregates was substantially higher than that of smaller (0.25–1 mm) aggregates. Also, as the relationship between WSA and SOC in the study was linear, the soil was far from C saturation and still in development. Overall, it can be concluded that the cultivation of perennial grasses and hybrid alfalfa on the severely eroded soil is the most rational option to improve the water stability of aggregates and increase the SOC and Ntot contents. However, because of the complexity of the aggregation process, further research is still needed. This study was supported by the Horizon 2020 project iSQAPER (project number 635750) and by the Estonian Research Council grant (PSG147).

  • Open Access
    Authors: 
    Antille, D.L.; Peets, S.; Galambošová, J.; Botta, G.F.; Rataj, V.; Macak, M.; Tullberg, J.N.; Chamen, W.C.T.; White, D.R.; Misiewicz, P.A.; +3 more
    Country: Estonia

    Article There is both circumstantial and direct evidence which demonstrates the significant productivity and sustainability benefits associated with adoption of controlled traffic farming (CTF). These benefits may be fully realised when CTF is jointly practiced with no-tillage and assisted by the range of precision agriculture (PA) technologies available. Important contributing factors are those associated with improved trafficability and timeliness of field operations. Adoption of CTF is therefore encouraged as a technically and economically viable option to improve productivity and resource-use efficiency in arable and grass cropping systems. Studies on the economics of CTF consistently show that it is a profitable technological innovation for both grassland and arable landuse. Despite these benefits, global adoption of CTF is still relatively low, with the exception of Australia where approximately 30% of the grain production systems are managed under CTF. The main barriers for adoption of CTF have been equipment incompatibilities and the need to modify machinery to suit a specific system design, often at the own farmers’ risk of loss of product warranty. Other barriers include reliance on contracting operations, land tenure systems, and road transport regulations. However, some of the barriers to adoption can be overcome with forward planning when conversion to CTF is built into the machinery replacement programme, and organisations such as ACTFA in Australia and CTF Europe Ltd. in Central and Northern Europe have developed suitable schemes to assist farmers in such a process.

  • Open Access
    Authors: 
    Väljaots, E.; Lehiste, H.; Kiik, M.; Leemet, T.;
    Country: Estonia

    Article Land based drone technology has considerable potential for usage in different areas of agriculture. Here a novel robotic soil sampling device is being introduced. Unmanned mobile technology implementation for soil sampling automation is significantly increasing the efficiency of the process. This automated and remotely controlled technology is enabling more frequent sample collection than traditional human operated manual methods. In this publication universal mobile robotic platform is adapted and modified to collect and store soil s amples from fields and measure soil parameters simultaneously. The platform navigates and operates autonomously with dedicated software and remote server connection. Mechanical design of the soil sampling device and control software is introduced and discu ssed.

  • Open Access
    Authors: 
    Gheorghe Stegarescu; Jordi Escuer-Gatius; Kaido Soosaar; Karin Kauer; Tõnu Tõnutare; Alar Astover; Endla Reintam;
    Publisher: MDPI
    Country: Estonia
    Project: EC | iSQAPER (635750)

    and water-stable aggregates (WSA). The functional groups of the plant residues and the soil were analyzed using Fourier transform infrared spectroscopy (FTIR) and a double exponential model was used to estimate the decomposition rates. The results show that the decomposition rate of fresh organic materials was correlated with the soil functional groups and the C/N ratio. Oilseed rape and rye, with lower C/N ratios than wheat straw residues, had faster decomposition rates and higher CO2 and N2O emissions than wheat straw. The CO2 and N2O flush at the start of the experiment corresponded to a decrease of soil aggregate stability (from Day 3 to Day 10 for CO2 and from Day 19 to Day 28 for N2O emissions), which was linked to higher decomposition rates of the labile fraction. The lower decomposition rates contributed to higher remaining C (carbon) and higher soil aggregate stability. The results also show that changes in the soil functional groups due to crop residue incorporation did not significantly influence aggregate stability. Soil moisture (SM) negatively influenced the aggregate stability and greenhouse gas emissions (GHG) in all treatments (oilseed rape, rye, wheat straw, and control). Irrespective of the water addition procedure, rye and wheat straw residues had a positive effect on water-stable aggregates more frequently than oilseed rape during the incubation period. The results presented here may contribute to a better understanding of decomposition processes after the incorporation of fresh crop residues from cover crops. A future field study investigating the influence of incorporation rates of different crop residues on soil aggregate stability would be of great interest. The decomposition of fresh crop residues added to soil for agricultural purposes is complex. This is due to different factors that influence the decomposition process. In field conditions, the incorporation of crop residues into soil does not always have a positive effect on aggregate stability. The aim of this study was to investigate the decomposition effects of residues from two different cover crops (Brassica napus var. oleifera and Secale cereale) and one main crop (wheat straw) on soil aggregate stability. A 105-day incubation experiment was conducted in which crop residues were mixed with sandy loam soil at a rate of 6 g C kg&minus 1 of soil. During the incubation, there were five water additions. The decomposition effects of organic matter on soil conditions during incubation were evaluated by determining the soil functional groups carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions soil microbial biomass carbon (MBC)