Soil organic matter mineralization under different temperatures and moisture conditions in Kızıldağ Plateau, Turkey

Drought by climate change in East Mediterranean Region will change soil temperature and moisture that lead to alter the cycling of biological elements like carbon and nitrogen. However, there are few studies that show how sensitivity of soil organic matter mineralization to temperature and/or moisture can be modified by changes in these parameters. In order to study how these changes in temperature and moisture affect soil carbon and nitrogen mineralization, a laboratory experiment was carried out in two depths (0-5 and 5-15 cm) of soils of Onobrychis beata and Trifolium speciosum being common annual plants in Turkey that was taken from Kızıldag Plataeu (Adana city). Some soil physical and chemical properties and as well as rate of carbon and nitrogen mineralizations were determined for both depths of soils. These soils were incubated for 42 days under different field capacities (FC 60, 80 and 100%) and temperatures (24, 28 and 32°C). Cumulative carbon mineralization (Cm), potential mineralizable carbon (C0) and rate of carbon mineralization of all soils were increased with rising temperatures. Rate of carbon mineralization in O. beata soil were lower than T. speciosum soil. NH4-N and NO3-N contents at 42nd day were higher than initial levels of soils and also increased with temperatures and field capacities. In summary, sensitivity of soil organic matter mineralization to temperature was higher at 32°C in upper layer and lower at 24°C in deeper layer of both soils

Imazamox'un İki Farklı Nem Koşulları Altında Toprak Karbon ve Azot Mineralizasyonuna Etkisi

Imazamox, Türkiye'nin Akdeniz ikliminin etkisi altındaki Osmaniye yerfıstığı tarla topraklarında oldukçayaygın bir biçimde kullanılan bir herbisittir. Bu çalışmada, iki tip toprak seçilmiş olup, birincisi dahaönceden imazamoxla muamele edilmemiş olan toprak ve ikincisi de imazamox ile muamele edilmiş fıstıktoprağıdır. Bu herbisitin önerilen tarla dozu (40 g L-1etken madde) ve bu dozun 2 ve 4 katı dozları, öncedenimazamoxla muamele edilmiş ve edilmemiş topraklara ilave edilmiştir. Toprakların mikrobiyal aktivitesifarklı nem koşulları altında (tarla kapasitesinin %60 ve %80'i oranında) karbon ve azot mineralizasyonuylaölçülmüştür. Karbon mineralizasyonu 45 gün boyunca 30°C'de CO2respirasyon yöntemiyle ölçümüştür.Tarla kapasitesinin %60'ı ve %80'i ile nemlendirilmiş ve imazamoxun tüm dozlarıyla muamele edilmiş fıstıktoprağındaki karbon mineralizasyon oranları, herbisitle muamele edilmemiş toprakların diğer bütün doznem kombinasyonlarından daha anlamlı bulunmuştur (P<0.001). NH4-N'e rağmen, NO3-N içerikleribakımından bu iki toprak arasındaki farklılıklar anlamlıdır (P<=0.05). Bu sonuçlara göre nitrat bakterileritoprağa eklenen yabancı maddelere karşı hala duyarlı olduğunu göstermiştir. Çalışmanın sonuçlarına göretoprak mikroorganizmaları farklı nem koşullarından etkilenmeksizin imazamozu karbon ve /veya azotkaynağı olarak kullanmıştır.Imazamox, is a herbicide intensively used in the peanut field soils of Osmaniye, Turkey with Mediterraneanclimate conditions. In this study, two types of soils were selected, first not exposed (NE) to Imazamoxpreviously and the second Imazamox treated peanut soil (P). The recommended field dose [(RFD), 40 gL-1active ingredient], 2 x RFD, and 4 x RFD of this herbicide were added to the NE and P soil. Themicrobial activities of the soils were measured by carbon and nitrogen mineralization under two differenthumidity conditions [60% and 80% of field capacity (FC)]. Carbon mineralization was determined by theCO2respiration method at 30°C over 45 days. Mineralization ratios (%) of carbon in all herbicide doses ofP humidified at 60% and 80% FC were significantly higher than all the other dose-humidity combinationsof NE soils (<0.001). Despite the NH4-N, there were significant differences between the NO3-Ncontents of these two soils (<=0.05). These results showed that nitrate producing bacteria were still verysensitive to foreign compounds added to the soils. These results suggest that soil microorganismsconsumed the Imazamox as C and/or N sources without being effected by different humidity conditions

Is parent material an important factor in soil carbon and nitrogen mineralization ?

WOS: 000451499300008Conversion of rocks and organic inputs to parent material and soil is a dynamic process controlled by physical, chemical and biological factors. Soil samples were taken from different parent materials (gypsum, marl and serpentine) in Ankara, Turkey to observe how the properties of parent material reflect on some soil characteristics. Their carbon (C) and nitrogen (N) mineralization were respectively determined by CO2 respiration method and the Parnas-Wagner method under the controlled laboratory conditions for 42 days (28 degrees C, 80% of field capacity). Soil CO2 respiration showed that there were significant differences between each parent material after 42 days of incubation as following: marl > gypsum > serpentine. Soil C mineralization rate in marl was the highest among the other two soils. NH4-N contents and net N mineralization of soils were significantly highest at the 11th day compared to 26th and 42nd days in all soil types (P < 0.05). NO3-N contents were statistically different from each other in the serpentine soil at all of three times (P < 0.05). Generally, no significant differences were found between soils in all N mineralization parameters in each time of incubation. Our findings showed that soil carbon mineralization was affected by the differences in parent materials, their physical and chemical properties such as texture, pH, CaCO3, C and N contents. It can be concluded that response of soil microorganisms in carbon mineralization is more active than in nitrogen mineralization in all soil types due to a low nitrogen content