Effects of co-addition of ammonium, nitrite, and glucose with methionine on soil nitrogen.

Methionine is one of the many amino acids in the soil. In order to study the role of methionine in acidic forest soil, the effect of methionine (Met) was compared with control together with addition of ammonium (Met + A), nitrite (Met + N), and glucose (Met + C) under 60% or 90% water holding capacity (WHC), because ammonium and nitrite are important factors in nitrification, and glucose affect the heterotrophic nitrification and nitrogen immobilization. We found that methionine addition significantly reduced NO3- concentration in acidic forest soil. Compared to Met, Met + A and Met + N treatments non-significantly enhanced nitrification; however, Met + C treatment decreased NH4+ concentration which suggested that soil autotrophic and heterotrophic nitrification were limited in the presence of methionine at 60% WHC. Further, our findings of 15N-labeled treatment showed the impact and priming effect of methionine was negative for NO3- concentration and positive for N2O emission, which were observed mainly from the soil N source rather than methionine. At 90% WHC, Met + C treatment significantly lessened concentrations of NH4+ and NO3-, nonetheless improved N2O compared to Met treatment. Therefore, besides the denitrification and dissimilatory NO3- reduction to ammonia, the immobilization might be the key factor to explain this decrease in NO3- concentration at 90% WHC, while these processes were induced with the C addition. This study indicated that the positive role of amino acids in soil N cycling might be overrated.

Role of soluble and exchangeable nitrogen pools in N cycling and the impact of nitrogen added in forest soil.

Nitrogen (N) cycle in forest soils is altered by water, salt, or acid solutions, and its internal transfers to and from each existing inorganic pools are not known comprehensively. To evaluate the soluble and exchangeable N pools, bulk soil (B soil), water-extracted soil (W soil), and the 0.5 mol L-1 K2SO4-treated soil (K soil) were incubated for up to 48 days to comprehend the dynamics of inorganic (NH4+ and NO3-) and soluble organic N (SON) in water-soluble, exchangeable, 2.5 mol L-1 H2SO4 (labile pool I, LPI) and 13 mol L-1 H2SO4 (labile pool II, LPII) pools. To test the N deposition effects, additional NH4NO3 solution was added to B, W, and K soils at amount of 40 mg N kg-1 soil. The results showed that though there was more NO3- removed when W soil was prepared, the similar net nitrification rate in W soil to B soil and more than 20 mg N kg-1 water-soluble NO3- were observed in W soil, which indicated that the loss of NO3- would be enhanced. In contrast, there was more water-soluble and exchangeable NH4+ for K soil compared with B soil. The different dynamic of NO3- between W and K soil suggested that nitrifiers might dominate in the soil matrix rather than the soil solution. After incubation, each N form in the LPI decreased, which can be attributed to the allocation of remaining N into the recalcitrant pool, except the increase of NH4+ for B soil and NO3- for K soil, and NO3- in LPII for B soil. Compared with control, N addition increased mineralization of exchangeable SON to promote nitrification regardless of soils, but weakened the immobilization of NO3-. In addition, N in LPI and LPII pools have increased, which might be related to decomposition of recalcitrant organic matter induced by N addition to transform when the water-soluble and exchangeable N was removed. Therefore, the changes of soluble and exchangeable nitrogen pools impact the N cycling. Our findings can give some explanation for whole soil N transformation responses to N deposition.

Scale-dependent intraspecific competition of Taurus cedar (Cedrus libani A. Rich.) saplings in the Southern Turkey.

Better understanding of the competitive interaction at the early development stages of the stand is crucial to help schedule silvicultural treatments for young stands and for the better management of the future stands. We used scale-dependent analysis to improve our understanding of sapling dynamics in the pure Taurus cedar (Cedrus libani A. Rich.) stands in Southern Turkey. Using data from nine plots established at the western Taurus Mountains, diameter, height, and crown radii of saplings were compared, and spatial point pattern analyses were performed. We found significant differences for the mean diameter and height, and crown radii of saplings among the plots. Univariate pair correlation function showed that sapling pattern was regular only at small scales (r < 0.4 m) but was predominantly random. Bivariate pair correlation function revealed no evidence of spatial interaction between tall saplings and short saplings. Univariate mark correlation function revealed that strong intraspecific competition was detected at small scales (up to 0.55 m). This distance is reasonable for the juvenile age tending of Taurus cedar saplings and should be under consideration during silvicultural treatments to use the site productivity more efficiently.

Studies on the chorology, ecology, morphology and conservation strategies of Orchis anatolica Boiss (Orchidaceae).

Orchis anatolica Boiss. is one of the Mediterranean species, which has wide distribution in Turkey. In this study, plant and soil samples of O. anatolica were taken from 26 natural populations in Turkey. There were one hundred ninety locality records in the Mediterranean region of Turkey, but we recorded two hundred sixteen localities thus adding twenty six new localities to the list. Twenty morphological parameters of O. anatolica were evaluated. The correlation coefficients between generative characters and vegetative characters were lower than the character groups of correlation coefficients between themselves. It is found from sea level upto 1700 m. Most common habitats of O. anatolica are macchie, forest lands and stony soils. The soils are loamy, clayey- loam and sandy-clayey- loam and rich in organic matter. The pH of the soils varies from 5.87 to 7.92. Although O. anatolica has wide distribution in Turkey, different types of land uses are posing a threat for it and restricting its distributional area. Lacking the legal regulations about conservation of the O. anatolica populations is one of the most striking requirement.

Morphological, anatomical and ecological studies on some Orchis (Orchidaceae) taxa of Mediterranean region, Turkey.

In this study, nine species mainly distributed in Mediterranean (+ Aegean region) region of Turkey were investigated in terms of 15 morphological, 16 anatomical and 5 ecological characteristics. Those species are Orchis anatolica Boiss., Orchis italica Poiret, Orchis laxiflora Lam., Orchis morio L. subsp. morio, Orchis provincialis Balbis ex DC., Orchis purpurea Hudson, Orchis sancta L., Orchis simia Lam., Orchis tridentata Scop. In conclusion, we found that O. laxiflora was characterized by the longest plant height and O. purpurea had the biggest tuber; whereas O. italica was identified by the highest number of leafs and O. purpurea had the longest leaf length and widest leaf width. Additionally, the other species which were characterized by different morphological and anatomical parameters are as follow: O. sancta with the longest bract length, O. italica and O. simia with the longest sepal lengths, O. laxiflora with the shortest and widest labellum, O. simia with the longest petal length, O. sancta with longest caudiculum length, O. anatolica with the longest spur length and O. provincialis with the longest ovary length. Particularly, O. laxiflora and O. purpurea species present essential divergence from the aspect of anatomical features of leaf surface in comparison with the other species. Morphological and anatomical traits of the species were attributed to the habitat selections of the species since that character differs along with each species.

Land use pattern at Alacam mountainous range land (submediterranean-Turkey) due to edaphic and physiographical factors.

Soil degradation is perceived as a major threat in the Mediterranean region due to land use pattern and projected climate change. As the high altitudinal mountainous lands are sensitive lands, the land use patterns atAlaçam mountains were investigated in this study. The assessment of land use distribution is arranged with the altitude, exposure, slope and bedrock parameters. The spatial database of project was created using GRASS GIS open source software (GRASS Development Team, 2008). The scanned land use and main rock map of the project area rectified, digitized, and attributes of land use and bedrocks were entered into the database tables. Also raster SRTM3 data were imported into these databases for making physiographical factor (elevation, slope, aspect) maps. Our findings illustrated thatthe whole area of Alaçam mountains is 282 480 ha where most of the area of the mass is located between 700-1300 m asl with 200 585 ha corresponding to 71% of the whole area. We detected two kinds of mis-land use; (1) agricultural activities applied at the slopes above 17% (representing 35 220 ha) and agricultural activities applied on metamorphic rocks (representing 872 ha). Total misuse of lands reached 36 092 ha comprised 12.77% of the whole area.

Heating induced changes in mineral nitrogen and organic carbon in relation with temperature and time.

Heating effects on carbon and mineral nitrogen contents of soils within different land use types were investigated in this study. With this intention we collected soil samples from 3 different land use types which are abandoned agricultural lands (AAL), shrub land (SL) and Oak forest land (OFL) and are in neighborhood with each other. The sampling was made at mid-summer to provide a better correspondence between factual buming conditions as well. Soils are slightly acidic (pH between 4.60-5.72) and sandy, sandy loamy textured. At the study site the vegetation type is pasture at AAL, Cystus and Rubus sp. dominated shrubs at SL and mixture of Oak species such as Quercus petrea, Q. robur Q. cerris and Q. frainetto at OFL. The results we found revealed that heating temperature has more remarkable effect on C losses and soil NH4+-N re-mineralization and losses of NH4+-N. Besides we could not detect remarkable differences between total N and NO3- amounts. Heating time created significant differences between NH4+-N amounts for different land use types where SL soils showed significant difference for all temperature levels. Heating soils at 100 degreesC created only slight differences at C and NH4+-N budgets but heating at 200 degreesC caused to striking results at NH4+-N budgets and heating at 350 degreesC led to only slight increase at NH4+-N budget. As the temperature increased the C loss also increased linearly.

Comparison of soil and forest floor properties of floodplain and surrounding forests in Igneada, Turkey.

In this study some soil and forest floor characteristics of floodplain forest, thermophile forest and sand dune were investigated at Igneada, Turkey. In this context, surface soil samples were analyzed and compared to each other in the extension of soil physical, chemical properties and as plant nutrition environment. To investigate the soil characteristics soil samples were collected from 48 sampling point. The distribution of the soils revealed that remarkably physical soil properties figure the ordination of soils in principal component analysis (PCA). We concluded that floodplain forests have quite different soil properties from the thermophile forest and sand dunes under the continuous effect of surrounding thermophile forest land with less sandy proportion to soil texture 52.4 at floodplain forest, 64.0% at thermophile forest and 91.0% at sand dunes and highly organic carbon 5.619, 4.191 and 0.478% respectively at 0-5 cm depth and total nitrogen content 0.213, 0.078 and 0.056% for floodplain forest > thermophile forest > sand dune soils, respectively. Weight and organic matter contents of forest floor were significantly higher in the thermophile forests.