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Energy Potential of Greenhouse Plant Residue: The Cases of Turkey and Poland
The search for waste management opportunities is crucial for achieving environmentally friendly waste practices and ensuring the country’s energy security. This research aimed to valorize biomass and waste generated in greenhouses and to analyze the potential for electricity production from this waste. The analyses compared the situations in Turkey and Poland, where greenhouse production of vegetables is developing and constitutes an important link in agricultural activities, despite differences in climatic conditions. The cultivation of vegetables and flowers under cover is rapidly expanding in both countries and, with changing climatic conditions, is expected to shape the future of agriculture. In addition to estimating the energy that can be obtained, the study also evaluated the economic benefits of such a solution and the volume of avoided CO2 emissions from fossil fuels. The issue of utilizing these wastes is significant because current methods of their management do not lead to energy production, so their considerable energy potential is wasted, as highlighted in this study. Moreover, there is a lack of similar studies in the literature. The plant species chosen as materials in this study were tomatoes, peppers, eggplant, watermelon, and melon in the case of Turkey. For Poland, the analysis was conducted for tomatoes and greenhouse cucumbers. These crops represent the largest cultivated areas under cover in the respective countries. Results indicated that the average yearly amount of vegetable residue is approximately 463 thousand Mg in Turkey, and 77 thousand Mg in Poland. The estimated annual electricity potential is 430 GWh in Turkey and 80 GWh in Poland. Considering the efficiency of power generation in a typical power plant, the real amount of electricity to be obtained is 0.46 MWh per Mg of waste in Turkey and 0.52 MWh in Poland.
The Effect of Drip Irrigation and Nitrogen Levels on the Oil and Fatty Acid Composition of Sesame and Its Economic Analysis
One of the oldest oilseed crops is sesame, which is mainly cultivated due to its valuable oleic/linolenic fatty acid ratio. The application of precise irrigation and fertilisation is crucial to ensure the continuity and productivity of sesame production, especially in arid and semi-arid regions. This study aimed to determine the effect of drip irrigation and nitrogen levels on sesame’s oil and fatty acid composition. For this purpose, four nitrogen doses (N0: 0 kg ha−1, N30: 30 kg ha−1, N60: 60 kg ha−1 and N90: 90 kg ha−1) and three different irrigation water levels (I50, I75 and I100, which correspond to 50, 75 and 100% evaporation levels from the evaporation of the Class A pan) were applied. The highest oleic acid content (43.06%) was obtained for the I75N90 treatment. In the case of linoleic fatty acid, the greatest value (43.66%) was for I50N0 treatment. The effects of irrigation and nitrogen doses on oleic acid and linoleic acid content were inverse of each other. An increase in applied irrigation water increased the linoleic acid content. However, it caused a decrease in oleic acid content. Increasing the nitrogen dose increased the oleic acid content and caused a decrease in linoleic acid content. Furthermore, this study showed that the I50N60 treatment (50% Epan and a rate of 60 kg N ha−1) is the most effective for achieving high grain and oil yields in sesame cultivation. The results obtained provide practical guidance for farmers in sesame cultivation.
Assessment of the Crop Water Stress Index for Green Pepper Cultivation Under Different Irrigation Levels
The objective of this study was to evaluate the effects of different water levels on yield, morphological, and quality parameters, as well as the crop water stress index (CWSI), for pepper plants under a high tunnel greenhouse in a semi-arid region. For this purpose, the irrigation schedule used in this study includes 120%, 100%, 80%, and 60% (I120, I100, I80, and I60) of evaporation monitored gravimetrically. In this study, increasing irrigation levels (I100 and I120) resulted in increased stem diameter, plant height, fruit number, leaf number, and leaf area values. However, these values decreased as the water level dropped (I60 and I80). At the same time, increased irrigation resulted in improvements in fruit width, length, and weight, as well as a decrease in TSS values. While total yield and marketable yield values increased at the I120 water level, TWUE and MWUE were the highest at the I100 water level. I80 and I120 water levels were statistically in the same group. It was found that the application of I100 water level in the high tunnel greenhouse is the appropriate irrigation level in terms of morphology and quality parameters. However, in places with water scarcity, a moderate water deficit (I80) can be adopted instead of full (I100) or excessive irrigation (I120) in pepper cultivation in terms of water conservation. The experimental results reveal significant correlations between the parameters of green pepper yield and the CWSI. Therefore, a mean CWSI of 0.16 is recommended for irrigation level I100 for higher-quality yields. A mean CWSI of 0.22 is recommended for irrigation level I80 in areas where water is scarce. While increasing the CWSI values decreased the values of crop water consumption, leaf area index, total yield, marketable yield, total water use efficiency, and marketable water use efficiency, decreasing the CWSI increased these values. This study concluded that the CWSI can be effectively utilised in irrigation time planning under semi-arid climate conditions. With the advancement of technology, determining the CWSI using remote sensing-based methods and integrating it into greenhouse automation systems will become increasingly important in determining irrigation times.
Use of Rainwater Harvesting from Roofs for Irrigation Purposes in Hydroponic Greenhouse Enterprises
This study was conducted to determine the irrigation water demand due to solar radiation in high-tech greenhouses using hydroponic systems in Turkey’s Mediterranean and continental climates, and to determine the annual water consumption and storage capacity with harvested rainwater. Intensive greenhouse cultivation and the recent increase in modern greenhouse cultivation were important factors in selecting the provinces for the study. The chosen provinces were Antalya and Adana, with a Mediterranean climate, and Afyonkarahisar and Kırşehir, with a continental climate. In this research, depending on the production period, the amount of water consumed per unit of area in greenhouses in Antalya, which has a Mediterranean climate, was determined to be 1173.52 L m−2 per yr−1, and in Adana, it was 1109.18 L m−2 per yr−1. In the provinces of Afyonkarahisar and Kırşehir, where a continental climate prevails, water consumption was calculated to be 1479.11 L m−2 per yr−1 and 1370.77 L m−2 per yr−1, respectively. Storage volumes for the provinces of Antalya, Adana, Afyonkarahisar and Kırşehir were found to be 438.39 L m−2, 122.71 L m−2, 42.12 L m−2 and 43.65 L m−2, respectively. For the provinces of Antalya, Adana, Afyonkarahisar and Kırşehir, the rates of rainwater harvesting and meeting plants’ water consumption were calculated to be 80.79%, 54.27%, 27.47% and 25.16%, respectively. In addition, the amount of water fee savings that could be achieved by rainwater harvesting was calculated to be USD 901.3 per yr−1 for Antalya, USD 835.3 per yr−1 for Adana, USD 247.6 per yr−1 for Afyonkarahisar and USD 210.2 per yr−1 for Kırşehir. As a result, rainwater harvesting will not only provide economic gain to enterprises but will also be important in reducing the negative effects of irregular rainfall regimes caused by climate change on underground and surface water resources. It was also concluded that enterprises should focus on popularizing rainwater harvesting.