Effects of cultural practices on soil respiration in hazelnut orchards and a comparison with an adjacent natural oak forest.

Soil respiration (RS) is one of the largest terrestrial sources of CO2 causing global warming and may vary according to land use and vegetation type. Türkiye is in the first place in the world in terms of area of hazelnut orchards that are generally converted from natural forests. The aim of this study was the comparison of the effects of cultural practices (pruning, fertilizing, and pruning+fertilizing) on RS in hazelnut orchards and that of the adjacent natural oak forest. Every trial site had a statistically similar annual mean RS, which ranged from 0.15 to 1.55 g C m-2 day-1. The RS on the sites was different only in the spring season and was similar in the other seasons. The RS of the pruned and fertilized hazelnut orchard (Hpf) in the spring was 58% greater than the unmaintained hazelnut orchard (Hc) and oak forest and 28% greater than the only fertilized hazelnut orchard (Hf). The RS of Hpf was also greater than other sites in most monthly measurements. While the positive correlation between soil moisture and RS was on an annual basis (r = 0.44), it was higher in summer (r = 0.61) and autumn (r = 0.55) seasons. The negative correlation between soil temperature and RS in the summer and autumn seasons evolved positively in winter. The results of the study suggest that the maintenance practices applied in the hazelnut garden could increase RS in the spring when soil moisture and temperature are optimal but have no effect in other seasons or on an annual basis.

Damage severity of wood-destroying insects according to the Bevan damage classification system in log depots of Northwest Turkey.

The aim of the study was to determine damage severity of wood-destroying insects on logs stored in forest depots. The Bevan damage classification (BDC) system, developed in 1987, was utilized to determine damage severity in log depots in 21 locations throughout seven provinces in Turkey. Pheromone traps were placed in those locations at the beginning of April in 2015 and 2016. Furthermore some stored wood within the log depots were checked and split into small pieces to collect insects that damage wood. The BDC system was used for the first time to measure the severity of insect damage in log depots. Twenty-eight families, 104 genera and 123 species were identified in this study. Based on the BDC system, the highest damage was found from the Cerambycidae and Buprestidae families. Arhopalus rusticus was determined as the insect responsible for the highest amount of damage with 8.8% severity rating in the pheromone-trapped insects group. When the stored wood material was considered, Hylotrupes bajulus was found to be the cause of the highest damage. The lowest damage values were among the predator insects (Cleridae, Trogossitidae, Cantharidae) and those feeding on fungi colonized on the wood (Mordellidae, Cerylonidae, Nitidulidae). Some other predator insects of the Tenebrionidae family (Uloma cypraea, Uloma culinaris, Menephilus cylindricus) and Elateridae family (Lacon punctatus, Ampedus sp.) exhibited relatively higher damage severity values since they had built tunnels and made holes in the stored wood material. When the environmental factors were considered, the Buprestidae family exhibited a very strong positive relationship (p < 0.005) with insect frequency distribution (r = 0.922), number of species (r = 0.879) and insect density (r = 0.942). Both families showed the highest number and frequency during July and August, highlighting the importance of insect control and management during these months.

Soil respiration in apple orchards, poplar plantations and adjacent grasslands in Artvin, Turkey.

In this study influence of land-use type on soil respiration was investigated in poplar plantation, apple orchard (apple trees with understory grasses) and adjacent grassland sites in Seyitler Area, Artvin, Turkey. Soil respiration was measured approximately monthly in three sampling plots in each land use type from January 2005 to November 2005 using the soda-lime technique. Mean daily soil respiration ranged from 0.63-3.59 g Cm(-2) d(-1). Mean soil respiration in apple orchard, poplar plantation and grassland sites were 1.98, 1.45 and 1.12 g C m(-2) d(-1), respectively. Mean soil respiration was significantly greater in apple orchard than in poplar plantations and grasslands. Seasonal changes in soil respiration were related to soil moisture and temperature changes. Mean soil respiration rate correlated strongly with subsurface soil (15-35cm) pH (R = -0,73; p < 0.05), sand content (R = 0.96, p < 0.001), soil silt content (R = -0.75; p < 0.05), soil clay content (R = -0.83; p < 0.001) and organic matter content (R = 0.88; p < 0.001). No significant correlations were observed between soil respiration and surface (0-15 cm) soil properties and root biomass. Overall, our results indicate that apple orchards with understory grasses have higher soil biological activity compared to poplar and grassland sites.