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Methodology adaptation and development to assess salt content dynamics and salt balance of soils under secondary salinization
199-206Views:187The effect of irrigation with saline water (above 500 mg L-1) is considered a problem of small-scale farmers growing vegetable crops with high water demand in the hobby gardens characteristic of the Hungarian Great Plain. In order to simulate the circumstances of such hobby garden, we set up an experiment including five simple drainage lysimeters irrigated with saline water in the Research Institute of Karcag IAREF UD in 2019. We regularly measured the electric conductivity (EC) of the soil referring to its salt content and the soil moisture content with mobile sensors. Before and after the irrigation season, soil samples from the upper soil layer (0-0.6 m) were taken for laboratory analysis and the soil salt balance (SB) was calculated. The actual salt balance (SBact) was calculated of the upper soil layer (0-0.6 m) based on the salt content of the obtained soil samples. The theoretical salt balance (SBth) was calculated by the total soluble salt content of the irrigation water and leachates. During the irrigation season, we experienced fluctuating EC in the topsoil in close correlation with the soil moisture content. Based on the performed in-situ EC measurements, salts were leached from the upper soil layer resulting in a negative SB. Combining SBact and SBth of the soil columns of the lysimeters, we estimated the SB of the deeper (0.6-1.0 m) soil layer. We quantified 12% increase of the initial salt mass due to accumulation. We consider this methodology to be suitable for deeper understanding secondary salinization, which can contribute to mitigating its harmful effect. By repeating our measurements, we expect similar results proving that saline irrigation waters gained from the aquifers through drilled wells in Karcag are potentially suitable for irrigation if proper irrigation and soil management are applied.
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Climatic water balance in Hamelmalo, Eritrea
69-76Views:197Agricultural production is an important sector for peoples to live, but it is highly affected by climate change. To have a good production we need to understand the climatic parameters which adversely affect production. Hamelmalo, which is located in the semi-arid area of Eritrea, is vulnerable to climate change and this is realised in the total production loss. Nevertheless, there is no concrete reference about the climate of the region due to lack of data for a long time. Changes in precipitation (P), evapotranspiration (ET) and, implicitly, in the climatic water balance (CWB), are imminent effects of climate change. However, changes in the CWB, as a response to changes in P and ET, have not yet been analysed thoroughly enough in many parts of the world, including Eritrea. This study also explores the changes of the CWB in the Hamelmalo region, based on a wide range of climatic data (P, relative air humidity and evaporation pan necessary for computing potential evapotranspiration (PET) with the pan evaporation method) recorded at Hamelmalo from 2015-2019. This analysis shows that the annual cumulative CWB for Hamelmalo is negative in 67% of the years. The dry season without precipitation leads to negative CWB and the change in CWB only starts from the raining or crop season. Based on this recent study, 2015 had the highest PET and lowest P, and this resulted in the lowest CWB in the investigated period. Opposite to this, 2019 had lower PET and highest P, which led to the highest CWB. However, the monthly values of CWB did not correlate with the annual P or ET. On the base of our study, it can be concluded that PET and P were very variable in the investigated years and P was the most influential elements of CWB.
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Mitigation of the effect of secondary salinization by micro soil conditioning
115-119Views:208This research has the general goal to meet the customization of agriculture in small scale farming. We are developing a technique using micro doses of soil conditioners and organic material applied in the root zone of vegetable crops. We expected to change the physical and chemical properties of the affected soil, which has been irrigated with salty water. Two different soil conditioners were tested. A lysimeter experiment including 8 simple drainage lysimeters was set up in the Research Institute of Karcag IAREF University of Debrecen in 2017. The main goal was to study the effect of different soil conditioners on the soil endangered by secondary salinization induced by irrigation with saline water. In order to compare the difference between the treatments, we collected soil samples, water samples, and determined the yields. Chili pepper (Capsicum annuum) was used as an indicator crop during one specific agricultural season. The technique called micro soil conditioning is rational because several reasons. The roles of the technique are various, for example it can serve as a source of carbon or a container for soil amendments and can minimize evaporation. We found this technique not to interfere with the chemical reaction or the interaction with the plants. However, the micro doses of soil amendments had the role to minimize the risk of soil degradation and do not significantly influence soil respiration. In addition, by improving soil properties, soil conditioning increases the leaching of the excess of salts from the root zone. In fact, this technique can decrease the cost of the inputs and improves the production of vegetables, and at the same time mitigates the effect of secondary salinization.