Long-term addition of manure increases soil organic carbon (SOC), provides nutrient supply, enhances soil quality and crop yield (CY), but may also increase global warming potential (GWP). In this study, a long-term experiment was conducted to investigate impacts of organic dairy manure and inorganic fertilizer on the spatial distribution of soil quality indicators in field scale. The experiment was initiated in 2008 (seven years), and includes three manure and two inorganic fertilizer treatments along with a control (no manure or no inorganic fertilizer addition). The study was set into a randomized complete block design with six treatments and four replications in a total of 24 plots with an equal size each of 6 × 18 m (108 m²). Soil physical, chemical and biological properties (total 26 properties) were considered as the total data set and principal component analysis (PCA) was used to determine long-term organic and inorganic fertilizer-induced changes in soil quality. Ordinary kriging interpolation methods were used to predict the spatial distributions of soil quality index (SQI) and mean soil quality values were compared with fertilization treatments by using Duncan’s test. Results showed that most measured soil quality index parameters showed significant differences (p < 0.05). The long-term dairy manure applications had positive impacts on soil quality index parameters where overall SQI scores were higher under high manure (HM) compared to medium manure (MM), low manure (LM), medium fertilizer (MF), high fertilizer (HF), control (CK) by 25%, 27%, 47%, 55% and 92%. A similar trend was observed for CY and GWP. This indicates that long-term dairy manure can be an option to increase SQI values and provide higher CY, however, this may lead to greater GWP.

The study identifies the soil physical properties most influenced by long-term fertilizer application, offering valuable insights into sustainable agricultural practices. Therefore, the aim of this study is to determine the effects of fertilizer application on soil physical properties by identifying key properties that require monitoring for improvement. A long-term field experiment was initiated (in 1996) on the Typic Xerofluvents soil series, which is generally low in organic carbon contents, and high in soil pH and calcium carbonate. The experiment was established under wheat-maize crop rotations with three replicates in which control (CO), mineral fertilizer (MF), animal manure (M25), compost (C25), compost and arbuscular mycorrhiza fungi (C10 + AMF) were applied. After the harvest, soil samples at 0–15 cm and 15–30 cm were collected and analyzed. Organic fertilizers such as M25, C25, and C10 + AM significantly increased soil organic matter (SOM) by 2.47, 2.19 and 1.86%, water stable aggregates (WSA), and air permeability (k _a ) at both depths. The organic fertilizer treatments significantly increased field capacity (FC), permanent wilting point (PWP_v), available water content (AWC_v) at 0–15 cm; bulk density (ρ_b), and total porosity (TP) at 15–30 cm. Furthermore, fertilizer application significantly improved crop yield. WSA had a strong positive correlation with SOM, while the principal component analysis showed that FC_v, PWP_v, AWC_v, MiP, and MaP explained the highest variation, whereas ρ_b, TP, and k _a made lesser contributions. In terms of k _a , hydraulic conductivity (K), SOM, WSA, and other soil parameters, CO outperformed MF; however, it fared badly when compared to organic fertilizers. Compost enhanced k _a and K, whereas manure improved SOM, ρ_b, and soil moisture; suggesting that if one of these properties is to be improved, a decision must be taken.

The stability of aggregates plays a vital role in preserving and long term storing of soil organic carbon (SOC). In this study, the long-term (2006-2014) effects of six tillage systems on aggregate-associated SOC were investigated in a field experiment conducted under Mediterranean conditions. The tillage treatments were; c onventional tillage with residue incorporated in the soil (CT1), conventional tillage with residue burned (CT2), reduced tillage with heavy tandem disc-harrow (RT1), reduced tillage with rotary tiller (RT2), reduced tillage with heavy tandem disc harrow fallowed by no-tillage (RNT) for the second crop, and no tillage (NT). The most frequently encountered aggregates in all tillage systems were at 4.0-2.0 mm size and the least frequently found aggregates were 1.0-0.5 mm. The mean weight diameter (MWD) value increased in the NT compared to the conventional tillage practices at the rates of 137% and 204%, respectively at 0-15 cm soil depth. Aggregate-associated SOC contents in 0-15 cm depth were higher under conservation tillage systems. However, the highest SOC at 15-30 cm depth were greater mainly in conventional tillage systems as 9.4% for both CT1 and CT2. The results indicated that conservation tillage systems had greater aggregation and carbon storage at the soil surface.

Research on microplastics (MPs) in soils has been widespread, but their impact on soil quality and the effects of mulching duration are still unclear. Therefore, the aim of this study is to determine how MP accumulation in mulched agricultural soils affects soil quality across three different mulching durations. Soil samples were collected from two depths (0–10 and 10–20 cm) at 15 agricultural sites in Adana, Türkiye, representing mulching durations of 5, 10, and 30 years. Microplastics were extracted using density separation and identified with ATR-FTIR. Soil physical, chemical, and biological properties were analyzed, and Soil Quality Index (SQI) was assessed with the Soil Management Assessment Framework (SMAF), which considers soil taxonomy, climate class, slope, sampling time, texture, mineralogy, organic matter, and analytical techniques to estimate the functional potential of each soil, considering the relevant soil indicators under MP accumulation. In this study, the evaluated soil indicators included physical properties such as bulk density (BD), aggregate stability (AS), available water content (AWC), and water-filled pore space (WFPS); chemical properties such as soil pH, electrical conductivity (EC), available phosphorus (P), and exchangeable potassium (K); and biological properties such as soil organic carbon (SOC), microbial biomass carbon (MBC), and potentially mineralizable nitrogen (PMN). Our data showed clear differences in both MPs and SQI across the three mulching periods, allowing the observed patterns to be better understood. The results showed that prolonged mulch application substantially increased MP accumulation and negatively affected key physical and biological soil indicators. Long-term mulching consistently reduced SQI values, indicating a cumulative decline in soil health and ecosystem functioning. At 0–10 cm depth, MP abundances were 69.3 ± 18.2, 64.0 ± 14.39, and 48.0 ± 9.53 particles kg ^− 1 for short-, medium-, and long-term durations, respectively, while at 10–20 cm depth, the values were 37.33 ± 6.18, 48.0 ± 9.75, and 78.66 ± 27.76 particles kg ^− 1 . These depth-specific patterns were accompanied by increases in bulk density (10%), substantial reductions in aggregate stability (48%), nitrogen mineralization (24%), and microbial biomass carbon (14%) with increasing plastic use (from S to L) at 0–10 cm depth. Overall, these analytical outcomes corresponded with a 17% reduction in SQI under long-term mulch application. These findings provide a solid foundation for predicting and monitoring MP contamination in agricultural soils with different mulch durations. The main limitation of this study is that, as a field-based investigation conducted under real agricultural conditions, it lacks full control over environmental and management variability, which should be considered when interpreting the results.

Tr en Çukurova koşullarında yaklaşık % 50 oranında kil içeren bir toprakta uzun süreli (2006-2014) buğday-mısır ve buğday-soya rotasyonu altında altı farklı toprak işleme yönteminin iki farklı derinlikte (0-15 ve 15-30 cm) agregatlara bağlı toplam karbon ve azot içeriğine etkileri araştırılmıştır. Toprak işleme uygulamaları olarak; Anızlı geleneksel toprak işleme (Gİ–1), Anızları yakılmış geleneksel toprak işleme (Gİ–2), Ağır diskli tırmıklı azaltılmış toprak işleme (ATİ–1), Rototillerli azaltılmış toprak işleme (ATİ–2), Ağır diskli tırmıklı azaltılmış sıfır toprak işleme (ASTİ) ve Doğrudan ekimli sıfır toprak işleme (STİ) yöntemleri kullanılmıştır. Her bir işleme yöntemi 480 m²’lik alana uygulanmakta ve 3 tekerrürlü tesadüf parselinden oluşmaktadır. 0-15 cm derinlikte bütün agregat boyutlarında (>4.0 mm, 4.0-2.0 mm, 2.0-1.0 mm ve 1.0-0.5 mm) toplam karbon değerleri geleneksel işleme yöntemlerine kıyasla korumalı işleme uygulamaları altında daha yüksek değerler elde edilmiştir. Derinlikteki artışla birlikte korumalı işleme yöntemleri altındaki agregatlarda bulunan toplam karbon değerleri azalmıştır. Her iki derinlikte (0-15 cm ve 15-30 cm) ve bütün agregat boyutlarında (>4.0 mm, 4.0-2.0 mm, 2.0-1.0 mm ve 1.0-0.5 mm) en yüksek toplam azot değerleri ATİ-1 işleme yöntemi altında belirlenmiştir. Korumalı işleme yöntemleri, geleneksel işleme yöntemlerine kıyasla agregatlar içerisinde toplam karbonun bağlanmasında önemli iyileşmeler sağladığı belirlenmiştir. ATİ-1 hariç diğer korumalı işleme yöntemlerinde (STİ, ASTİ ve ATİ-2) geleneksel işlemelere göre daha düşük toplam azot değerleri belirlenmiştir. The effect of six different tillage methods under long-term (2006-2014) wheat-maize and wheat-soy rotations on aggregate-assosicated total carbon and nitrogen content in two different depths (0-15, 15-30 cm) were studied under Çukurova conditions in approximately 50 % clay containing soil. The tillage systems consisted of conventional tillage with stubble (CT-1), conventional tillage with stubbles burned (CT-2), heavy disc harrow reduced tillage (RT-1), rototiller reduced tillage (RT-2), reduced tillage with heavy tandem disc harrow fallowed by no-tillage (RNT), and no-till (NT). Each tillage method applied at 480 m² plot and replicated three times in randomly distributed plots. Aggregate-associated total C contents in 0-15 cm depth were obtained higher in conservation tillage treatments compared to traditional tillage techniques at all aggregate sizes (>4.0 mm, 4.0-2.0 mm, 2.0-1.0 mm and 1.0-0.5 mm). Aggregate-associated total C values under conservation tillage methods decreased with increasing soil depth. In both depths (0-15, 15-30 cm) and at all aggregate sizes the highest total nitrogen concentration values were determined in RT-1 tillage treatment. Significant enhancements of total carbon bounding in aggregates were observed in conservation tillage methods compared to traditional tillage methods. Except for RT-1 in other conservation tillage methods (NT, RNT and RT-2) total nitrogen values were lower compared to conventional tillage methods.