1Department of Biology, Faculty of Arts and Science, Çukurova University, 01330 Adana, Turkey
2Department of Biology, Faculty of Arts and Science, Osmaniye Korkut Ata University, 80000 Osmaniye, Turkey *Corresponding author: [email protected]
Some soil properties and microbial biomass of Pinus
maritima, Pinus pinea and Eucalyptus camaldulensis
from the Eastern Mediterranean coasts
Eurasia J Biosci 6, 121-126 (2012) DOI:10.5053/ejobios.2012.6.0.15
World-wide, approximately 10 million km2of land is affected by salt. Salt accumulates when the loss of salt via leaching is less than the addition of salt from rainfall or irrigation, or as a result rising saline groundwater. Salinity may be an important problem for soils. It disrupts soil productivity and ecological balance by affecting physical, chemical, and biological properties of soils (Flowers and Yeo 1995). Salinity (Na and Cl) reduces the activity of microorganisms as a result of low water availability and ion toxicity (Marschner 2012). Salinity stress can kill sensitive microorganisms and decrease the activity of surviving microorganisms due to the metabolic burden imposed by salt tolerance mechanisms (Wichern et al. 2006, Chowdhury et al. 2011, Li et al. 2012).
Carbon and nitrogen mineralization, which are crucial for the decomposition of organic matter and
release of nutrients required to sustain soil productivity, are inhibited by a high salinity (Frankenberger and Bingham 1982, Bandyopadhyay and Bandyopadhyay 1983, McClung and Frankenberger 1987, Nelson et al. 1996, Zahran 1997, Pathak and Rao 1998, Ghollarata and Raiesi 2007, Tripathi et al. 2007).
Ammonification is stimulated at low salt concentrations and inhibited at higher concentrations but, nitrification is very sensitive to salinity (Westerman and Tucker 1974, McClung and Frankenberger 1987). Laura (1974) and Laura (1976) observed that C mineralization from added green manure was inhibited by salinity and increased from 0.1 to 5.1% NaCl but, ammonification continued to increase at the same rate. The author hypothesized
Received: December 2012 Accepted: December 2012
Printed: December 2012
INTRODUCTION Abstract
Background: Salt-affected soils occupy wide areas that have ecological importance in semi-arid and
arid regions. Excessive amounts of salt have adverse effects on soil physical and chemical properties and also on the microbiological processes. The soils of Pinus maritima, Pinus pinea, and Eucalyptus
camaldulensis were found to be under salinity stress in the present study area. Thus, the carbon,
nitrogen, phosphorus contents, microbial biomass, and carbon mineralization were determined in the soils sampled from the Tarsus-Karabucak Forest of the Eastern Mediterranean Region (Turkey).
Method: Carbon mineralization of all samples was measured by the CO2respiration method over 30 d at 28°C and constant moisture.
Results: There were no significant differences in the carbon mineralization among the soils. The
average fungi count in 1 g of air dried soils of P. maritima, P. pinea, and E. camaldulensis were found to be a 72000 colony forming unit (cfu)/g, 25300 cfu/g, and 28500 cfu/g, respectively. The total bacterial counts were 4x103cfu/g, 10x103cfu/g, and 7x103cfu/g and the counts of anaerobic bacteria
were 17800 cfu/g, 42900 cfu/g, and 27300 cfu/g, respectively.
Conclusions: It is possible to conclude that salt, as an ecological factor, had no effect on microbial
activity. This may be as a result of heavy rains which decreased the salt concentrations of the soil in the sampling region.
Keywords: Eucalyptus camaldulensis, microbial activity, Pinus maritima, Pinus pinea, soil salinity.
Kizildag N, Aka Sagliker H, Kutlay A, Cenkseven S, Darici C (2012) Some soil properties and microbial biomass of Pinus maritima, Pinus pinea and Eucalyptus camaldulensis from the Eastern Mediterranean coasts. Eurasia J Biosci 6: 121-126.
DOI:10.5053/ejobios.2012.6.0.15
Nacide Kizildag1, Hüsniye Aka Sagliker2*, Ahu Kutlay1,
Şahin Cenkseven1, Cengiz Darici1
that this mineralized N was not biological but physicochemical in origin, caused by the proteolytic action of water on organic nitrogenous constituents of soil organic matter (Laura 1975).
Determination of the carbon mineralization and microbial biomass in the soils of Pinus maritima L.,
Pinus pinea L., and Eucalyptus camaldulensis Dehn., which grow in saline areas, would provide valuable information about the ecological tolerance limits and functions of similar areas. Additionally, characterization of soils under salinity stress would serve for the protection and surveillance of healthy soils.
This study was carried out in the Tarsus-Karabucak Forest of the Eastern Mediterranean region of Turkey. A summary of the weather data for 1950-1996 indicates that the average annual precipitation and temperature for this site was 611 mm and 18.5°C respectively (Anonymous 2007).
The research materials were collected from Pinus
maritima L., Pinus pinea L., and Eucalyptus
camaldulensisDehn., soils under salinity stress. Soil samples were taken from a 10 cm depth under each of the three plants chosen after removing recognizable plant debris, in April 2012 (Weather was rainy at the time of sampling). These samples were air-dried and sieved through a 2 mm mesh sieve before analysis. After mixing each sample thoroughly the three subsamples were taken for analysis. The soil texture was determined using the Bouyoucos (1951) hydrometer and the field capacity (%) by applying 1/3 atmospheric pressure with a vacuum pump (Demiralay 1993). The pH and salinity were measured in a 1:2.5 soil-water suspension with a pH meter (Jackson 1958) and salinity meter (Anonymous 1954). The organic carbon content (%) was determined by the Anne Method, total nitrogen content (%) by the Kjeldahl Method (Duchaufour 1970), and the phosphorus content by the Olsen Method (Olsen et al. 1954).
The moisture of soil was adjusted to 80% of the field capacity before incubation. Carbon mineralization was determined by CO2respiration at
28°C over a 30 d period (Duchaufour 1970). Carbon mineralization rates were calculated by dividing the cumulative C(CO2) values to total organic carbon.
The microbial biomass was determined by the serial dilution methods. The counts of total bacteria (PCA), anaerobic bacteria (Brewer), and fungi (PDA) were also determined by using Merck, 1.10130 (Anonymous 1978, Atlas 2005).
SPSS 16.0 software was used for the statistical analysis of the data. The mean differences among the carbon mineralization and among the trees was determined by analysis of variance and the multiple comparison Tukey HSD test (Kleinbaum et al. 1998). The differences in the analysis of variance were shown as being significant at P≤0.05.
The soils are classified as sandy and the pH levels were low in all the soil samples (6.8-6.9). Soils of the three plants were slightly saline 0.15% in P.
maritima, 0.13% in P. pinea, and 0.19% in the E.
camaldulensissoils (Table 1). The salinity level of E.
camaldulensis soils was significantly higher than both the P. maritima and P. pinea soils (P≤0.05). A significant difference in the soil carbon contents was found only between P. pinea (0.30%) and E.
camaldulensis (0.56%) (P≤0.05). The soil carbon dynamics may also be markedly affected by the composition and amount of organic matter in the soil and difference of plant species (Aggangan et al. 1999). There was no significant differences among the three plants however, other differences were found between the other parameters determined (P>0.05) except for phosphorus.
The phosphorus (P2O5) contents of P. maritima, P.
pinea, and E. camaldulensis soils were 13.0, 9.25, and 18.4 kg/da which were in sufficient levels (Alpaslan et al. 1998) and the difference among them was statistically significant (P≤0.05). The leaf phosphorus levels (%) in P. maritima, P. pinea, and E.
camaldulensiswere 0.72, 0.44 and 0.68 respectively and were only significant between P. maritima and P.
pinea(P≤0.05, Table 1).
There were no statistical differences among the carbon mineralization of the soils which were 9.30,
MATERIALS AND METHODS
9.17, and 10.3 for P. maritima, P. pinea, and E.
camaldulensis, respectively (Fig. 1). There were also not significant differences among the P. maritima, P.
pinea, and E. camaldulensis soils concerning carbon mineralization ratios (Fig. 2). It is possible to conclude that salt, as an ecological factor, had no effect on the microbial activity. This may be as a result of heavy rains which decreased the salt concentrations of the soils in the sampling region.
Carbon mineralization curves of all three species showed a time dependent increase, E. camaldulensis having a steeper curve which reflects the decomposition suitability of its organic matter. The lowest mineralization rate, however, was in the E.
camaldulensis soil, probably due to the higher carbon content of its soil (Table 1).
The average fungi count in 1 g of air dried soil was found to be 72000 cfu/g, 25300 cfu/g, and 28500
Table 1. Some physical and chemical properties of P. maritima, P. pinea, and E. camaldulensis soils and plants leaves (mean±S.E., n=3).
Fig. 1.Cumulative C respired (mean±S.E., n=3) in P. maritima, P. pinea, and E. camaldulensis soils at an incubation time of 30 d. Different letters denote significant differences among the three plants (P≤0.05, multiple comparisons by Tukey’s HSD test).
cfu/g in P. maritima, P. pinea, and E. camaldulensis respectively. The total bacterial counts were 4x103, 10x103, and 7x103 and the counts of anaerobic bacteria were 17800, 42900, and 27300 in this respect (Table 2). The higher fungi count in E.
camaldulensis can be explained by litter quality. The decreased count of anaerobic bacteria in the soils of this species might reflect a better aeration and homogenous distribution of organic matter in its soils. In fact, the anatomical structure and chemical composition of the leaves of the two other pine species restrict fungi development on their surface and hence fungi counts on these two species were lower at a ratio of 1/3 compared with E.
camaldulensis. The higher counts of total and anaerobic bacteria in P. pinea were in accordance. Higher counts of anaerobic bacteria found in its soil can be explained by the anaerobic bacterial development due to longer periods of submergence of this plants soil, anaerobic conditions aroused by the formation of thicker litter, and heterogeneous mixture of this litter into the soil.
Authors thank Prof. Dr. Sadık DİNÇER, Çukurova University, for his informative discussions and guidence.
ACKNOWLEDGEMENTS
Table 2.Counts of fungi, total bacteria, and anaerobic bacteria in the soils of the three plants.
Fig. 2.Organic carbon mineralization ratio (Rm, %) of P. maritima, P. pinea, and E. camaldulensis soils (mean±S.E., n=3), at the end of the incubation period (30 d).
There were no significant differences among the organic carbon mineralization ratio of three plants (P>0.05).
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Anonymous (2007) Ortalama ve ekstrem kıymetler. Meteoroloji Müdürlüğü Yayını, Ankara.
Atlas MR (2005) Handbook of Media for Environmental Microbiology. Taylor & Francis, New York.
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Doğu Akdeniz’de Kumul Alanlarda Yetişen Pinus maritima, Pinus pinea ve Eucalyptus
camaldulensis’in Bazı Toprak Özellikleri ve Mikrobiyal Biyoması
Özet:
Giriş: Kurak ve yarı kurak bölgelerde tuz etkisinde kalmış topraklar ekolojik öneme sahip olup geniş alanları
kaplamaktadır. Tuzun aşırı miktarı toprağın fiziksel ve kimyasal özellikleri ile mikrobiyolojik süreçlerini olumsuz etkilemektedir. Doğu Akdeniz Bölgesi (Türkiye) Tarsus-Karabucak Ormanında yetişen Pinus maritima (Sahil çamı), Pinus
pinea (Fıstık çamı) ve Eucalyptus camaldulensis (Ökaliptus)’in tuz stresi altında olan topraklarından örnek alınmış,
karbon, azot, fosfor içerikleri ile mikrobiyal biyomas ve karbon mineralizasyonları belirlenmiştir.
Metot: Örneklerin karbon mineralizasyonu 30 gün boyunca 28°C ve sabit nemde CO2 respirasyon yöntemi ile ölçülmüştür.
Bulgular: Topraklar arasında karbon mineralizasyonu açısından anlamlı farklılıklar bulunmamıştır. P. maritima, P. pinea,
ve E. camaldulensis’in 1 g hava kurusu topraklarında ortalama mantar sayısı sırasıyla 72000 koloni oluşturan birim (kob)/g, 25300 kob/g ve 28500 kob/g koloni oluşturan birim olduğu tespit edilmiştir. Toplam bakteri sayısı sırasıyla 4x103kob/g, 10x103kob/g, 7x103kob/g ve anaerobik bakteri sayısı 17800 kob/g, 42900 kob/g ve 27300 kob/g’dır.
Sonuç: Bu çalışma için, ekolojik faktör olarak tuzun incelenen toprakların mikrobiyal aktivitelerine etkisinin olmadığı
ileri sürülebilir. Bu durum örnekleme zamanından önce bölgedeki yoğun yağmurlar nedeniyle toprakların tuz konsantrasyonunun azalması ile açıklanabilir.
