Soil organic matter (SOM) is a heterogeneous mixture of materials ranging from fresh plant tissues to highly decomposed humus at different stages of decomposition. Soil organic carbon (SOC) status is directly related to the amount of organic matter in soil and therefore is generally used to measure it. Soil carbon sequestration refers to the removal of carbon (C) containing substances from the atmosphere and its storage in soil C pools. The soil microbial community (SMC) plays an important role in the C cycle, and its activity is considered to be the main driver of differences in C storage potential in soil. The composition of SMC is crucial for maintaining soil ecosystem services, as the structure and activity of SMC also regulate the turnover and distribution of nutrients, as well as the rate of soil organic matter (SOM) decomposition. Here, we applied fungi on the soils taken from two fields, one used as a pasture and one for agriculture (wheat cultivation), in a histosol in the eastern part of Türkiye and investigated the changes in the organic carbon and enzyme activity contents of the soils at the end of the 41-day incubation period. In the study, four different fungal species (Verticillium dahliae (SOR-8), Rhizoctonia solani (S-TR-6), Fusarium oxysporum (HMK2-6), and Trichoderma sp.) were used and catalase, urease, and alkaline phosphatase activities were examined. Results showed that the values of SOC were V. dahliae (7.46%), Trichoderma sp. (7.27%), R. solani (7.03%), Control (6.97%), and F. oxysporum (6.7%) in pastureland and were V. dahlia (4.72%), control (4.69%), F. oxysporum (4.65%), R. solani (4.37%), and Trichoderma sp. (4.14%) in agricultural land, respectively. SOC and soil enzyme activities were significantly affected by land use types (p < 0.05). The higher SOC and enzyme activities were observed in pastureland. Finally, it was determined that soil organic carbon and soil enzyme activities were affected by fungi. This study is important in terms of revealing that the effects of fungi on soil organic carbon and enzyme activities are different in various land types.

The foothill areas of eastern Turkey are an arid and semiarid region with natural salinization, where calcareous alluvial saline soils (Calcaric Fluvisols) are circulated as a result of floods of the Aras River. In this study, the effects of salinity and alkalinity on soil aggregate size distribution and enzyme activities at different aggregate size were investigated. For this purpose, soil samples were collected with three replicates at saline, alkaline, saline-alkaline and non-saline–alkaline areas and passed through into different sieves (2, 1, 0.850, 0.425, 0.106 and 0.02 mm) by dry sieving method for determining aggregate weight distribution in each macro (2–0.45 mm) and micro (0.45–0.02 mm) aggregates. For determining aggregate size distribution, sieves were shaken using a horizontal shaking machine (Retsch, AS 200 basic, Haan, Germany). The soil enzymes were determined in these aggregate sizes (2–1, 1–0.850, 0.850–0.425, 0.425–0.106, 0.106–0.02 mm) for all soil types. All soils belonged to the clay loam with the carbon content in the range of 0.5–0.8%, while the percentage of exchangeable sodium for the non-saline–alkaline and alkaline–saline soils was from 3.5 to 22%, but the pH diapason from 8.3 to 8.9. Results showed that soil salinity and alkalinity decreased the weight of macro aggregates and increased the weight of micro aggregates, besides soil salinity and alkalinity decreased soil enzyme activities. But soil salinity decreased enzyme activity more than alkalinity. Furthermore, the highest urease and catalase activities were in macro aggregates (0.850–0.425 mm aggregate size) for all soil types. The reason may be that macro aggregates contain higher organic matter and organic carbon than micro aggregates. Consequently, the highest enzyme (urease and catalase) activities were detected in macro aggregates.

Soil management systems such as conservation tillage practices and the cultivation of cover crops have various positive effects on soil environment. These practices help to increase or maintain an adequate level of soil organic matter, thus improve soil properties. The aim of the study was to determine the effects of cover crops and tillage systems on soil enzyme activity (urease, alkaline phosphatase, catalase) at different soil depths following wheat. According to the results, the cover crops affected all the enzyme activities while tillage systems affected only urease activity in the soil. The highest urease (8.09 and 6.90 μg g N soil-1 h-1), alkaline phosphatase (74.53 and 69.08 μg g p-nitrophenol soil-1 h-1) and catalase (41.56 and 48.62 ml O2 3 min-1 g soil-1) activities were observed in common vetch plots in minimum and conventional tilled plots. Another observation was that enzyme activities were decreased with the increase of soil sampling depths. These results showed that the incorporation of cover crops into rotations may increase soil enzyme activities and common vetch can be used as an alternative cover crop.

The thermal properties (thermal diffusivity, thermal conductivity, damping depth, heat absorption and heat flux) of soils were determined using different models (Amplitude, Arctangent, Logarithmic, Phase and Improved method) to select the adequate model according to the model selection criteria and to determine under which application (no-tillage, conventional tillage) the thermal properties of the soils are better. The study was conducted on loamy calcareous alluvial soils (Calcic Fluvisols) which were formed as a result of floods of the Aras River in the foothill areas of eastern Turkey. In the experiment, temperature sensors were placed in different depths of the soil (5, 10, 20 and 30 cm) at both tillage systems during the growth season of wheat. Temperature data were collected from sensors hourly. The thermal properties of the soils were calculated with different models by using the recorded data. As a result, it was determined that the adequate model was the arctangent. Because of the high average temperature under conventional tillage and the difference in soil texture, the thermal properties of the soils were higher under conventional tillage.

Cover crops and minimum tillage or zero- tillage practices are the soil conservation management practices. These practices improve or sustain soil properties especially soil organic matter. In the study, we investigated the effects of cover crops and tillage practices on soil urease, alkaline phosphatase and catalase activities at different soil depths following corn. The corn was planted in May, and the cover crops (common vetch, fodder beet, mix of common vetch and fodder beet) were planted in late summer under minimum and conventional tillage. Soil samples were collected at 0-10, 10-20 and 20-30 cm soil depths in 2018. With respect to results of the study, cover crops affected all the enzyme activities while tillage systems affected urease and catalase activities in soil. The highest urease (9.91 and 7.48 µg g N soil-1 h-1), alkaline phosphatase (99.29 and 84.61 µg g p-nitrophenol soil-1 h-1) and catalase (58.73 and 64.82 ml O2 3 min-1 g soil-1) activities were in common vetch plots in minimum and conventional tilled plots and all the enzyme activities were decreased with increasing soil depth. The results suggest that cover crops and minimum tillage practices increase soil enzyme activities.

Arazi kullanımı/örtü (AK/AÖ) değişimlerinin milli ve milletlerarası seviyede doğru olarak izlenmesine, analizine ve hesaplanmasına imkân veren, uzaktan algılama (UA) ve coğrafi bilgi sistemlerinden (CBS) yararlanan yeni dijital veri kümeleri kullanımı yaygınlaşmıştır. Bu dijital veri kümelerinden birisi Avrupa ölçekli çevre ile ilgili veri elde etme görevini yürüten Avrupa Çevre Ajansı’nın (European Environment Agency-EEA) yöntemini geliştirdiği ve Türkiye’nin de dahil olduğu 39 ülke tarafından kullanılan CORINE izleme sistemidir. Bu çalışmada Çevresel Bilgi Koordinasyonu (Coordination of Information on the Environment-CORINE) izleme yöntemine göre Iğdır ili için 2000-2006-2012-2018 yıllarında arazi kullanımı/örtü mevcut durumu ve meydana gelen değişikliklerin alan ve oran olarak hesaplanması, değişimin sebeplerinin belirlenmesi hedeflenmiştir. Iğdır ili için CORINE yöntemine göre; AK/AÖ çeşitleri 1. düzeyde yer alan 5 ana başlık altında (yapay yüzeyler, tarım alanları, ormanlık ve doğal alanlar, sulak alanlar ve su kütleleri), 2. düzeyde 12 ve 3. düzeyde 23 farklı izleme sınıfı olarak belirlenmiştir. Bu sınıfların her altı yıllık dönemi için alansal ve oransal hesaplamaları yapılarak 2000-2018 döneminde arazi kullanımı/örtü durumundaki değişimler, yapay yüzeylerde 358.9 ha, tarım alanlarında 1850.8 ha, su kütlelerinde 18.5 ha artış; ormanlık ve doğal alanlarda 2187.9 ha, sulak alanlarda 153.6 ha azalış olarak belirlenmiştir. İl arazisi üzerinde en yaygın arazi kullanımı/örtü sınıfını (16407.6 ha) ve artışını (4165.6 ha), seyrek bitki örtüsü ile kaplı eğimli, sığ ve düşük verimli alanlar oluşturmaktadır.