Browsing by Author "Oztas, Taskin"

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Co2 Emission From Soil in Silage Maize Irrigated With Wastewater Under Deficit Irrigation in Direct Sowing Practice
(Elsevier, 2022) Yerli, Caner; Sahin, Ustun; Oztas, Taskin
It is necessary to understand and measure the impact of tillage and irrigation practices on CO2 emissions from the soil with an environmental sensitivity, while wastewater irrigation increases crop biomass yield. The main objective of the present study was to investigate the changes and reasons in CO2 emissions from soil conventional and conservative tillage under different levels of wastewater irrigation. The CO2 emission from tillage-sowing to harvest over the regular measurements with a EGM-5 infrared gas analyzer device was investigated with three replicates in three deficit irrigation levels (0%, 33%, and 67%) of domestic recycled wastewater in conventional tillage and direct sowing practices. Binary relationships of CO2 emissions with H2O emission, air temperature, and the soil temperature and moisture measured at three different depths (5 cm, 10 cm, 20 cm) were also investigated and strong (p < 0.01) positive linear correlations were determined. Wastewater irrigation and conventional tillage significantly increased CO2 emissions compared to freshwater irrigation and direct sowing practice, while deficit irrigation practice decreased it. The direct sowing reduced seasonal CO2 emissions 25.1% and 26.1% for per unit area (1 ha) of silage maize and per unit of fresh silage yield (1 kg), respectively, compared to conventional tillage. The lowest CO2 emission per unit area and yield was determined in full irrigation treatment with freshwater in direct-sowing, while, in wastewater applications, it was determined in irrigation levels 33% per unit area and 67% per unit yield, under direct sowing. Thirty-three percent and 67% treatments in direct sowing resulted in less seasonal CO2 emissions as 38.7% per unit area and 13.8% per unit fresh silage yield, respectively compared to full irrigation treatment with freshwater in conventional tillage. Mean CO2 emissions in these treatments were found lower 17.9% per unit area and higher 17.8% per unit fresh silage yield compared to the full irrigation treatment with freshwater in direct-sowing. It was concluded that CO2 emissions per unit yield could be decreased with 33% water saving under wastewater irrigation conditions, and could be achieved environmental additional benefits from more decreasing CO2 emission by direct sowing also.
Deficit Irrigation With Wastewater in Direct Sowed Silage Maize Reduces Co2 Emissions From Soil by Providing Carbon Savings
(Iwa Publishing, 2022) Yerli, Caner; Sahin, Ustun; Kiziloglu, Fatih Mehmet; Oztas, Taskin; Ors, Selda
Direct sowing and deficit irrigation practices can reduce the effect of wastewater on CO2 emissions from soil by providing carbon savings. Therefore, the effect of domestic recycled wastewater uses at different levels in irrigation under conventional tillage and direct sowing practices on the CO2 emission from soil at the end of the vegetation period of silage maize was investigated by comparing it with full irrigation of fresh water. Both organic carbon and CO2 emissions in the second year in fully irrigated treatments were higher than those in the first year. The CO2 emission in the full irrigation with wastewater (0.263 g m(-2) h(-1)), compared to full irrigation with fresh water and 33 and 67% deficit irrigations with wastewater, was higher at 23.4, 25.0, and 59.3%, respectively. Direct sowing practice also (0.193 g m(-2) h(-1)) resulted in 17.0% less CO2 emission as compared to conventional tillage. The positive linear relationships of H2O emission and the soil moisture content at different depths (5, 10, and 20 cm) with CO2 emission were significant, and the negative relationships with the soil temperatures were also found. It has been concluded that deficit irrigation and direct sowing applications can be practical for reducing CO2 emissions from soil in wastewater irrigation conditions.
Fertility and Heavy Metal Pollution in Silage Maize Soil Irrigated With Different Levels of Recycled Wastewater Under Conventional and No-Tillage Practices
(Springer, 2025) Yerli, Caner; Sahin, Ustun; Oztas, Taskin; Ors, Selda
Irrigation with recycled domestic wastewater has been known to obtain positive effects on improving soil fertility, but it may also become a risk factor in case of causing an increase in soil salinity and/or heavy metal concentration of soil. No-tillage can retain soil moisture, helping to reduce irrigation water necessity, and thus lower amounts of heavy metals and salts are added to soil under wastewater irrigation conditions. The objective of this study was to analyze the effects of wastewater irrigation at different levels of on silage maize cultivation under conventional tillage and no-tillage conditions by comparing to full irrigation with fresh water. The two-year experiment was planned according to the split-plots design in the random blocks with three replications. The results indicated that full irrigation with wastewater increased soil salinity, organic matter content, total nitrogen, plant available phosphous, exchangeable cations, exchangeable sodium percentage and soil essential and non-essential heavy metal contents, but decreased soil pH and lime content. Increasing rates in organic matter content, total nitrogen, plant available phosphorus and exchangeable potassium were higher, but in electrical conductivity, and heavy metal accumulation were lower in soil under no-tillage as compared to conventional tillage. Contamination and enrichment factors and geographic accumulation index showed that non-essential heavy metal contamination due to cadmium and nickel, increased in full irrigation with wastewater. Irrigation with wastewater also increased heavy metal accumulation in silage maize. No-tillage can be a recommendable water management practice considering that the risks of soil salinity and heavy metal accumulation can be reduced and that soil fertility can be increased. Also, in reducing the risk of accumulation of cadmium and nickel in soil, 33% deficit irrigation with wastewater can make no-tillage more available.