Agricultural drainage ditches, their biological importance and functioning

We reviewed studies on the biological state of agricultural drainage ditches in the temperate and boreal zones of the Northern Hemisphere. We looked at the relative importance of ditches for farmland biota as compared to that of other habitats, and assessed the degree to which biological communities of ditches contribute to the provisioning of ecosystem services. We evaluated impacts pertaining to replacement of open drains by subsurface drainage, removal of main ditches, rehabilitation of old drainage systems, and maintenance of ditches. Most ditches support species also common elsewhere. Whenever comprehensive surveys were conducted, ditches were shown to provide valuable wet vegetated non-cropped habitats to both aquatic and terrestrial taxa, supply food resources lacking in otherwise dry and intensively managed cropland, and perform connectivity functions within a wider landscape. Regionally ditches were shown to harbour rare species or species not found presently in other farmland habitats. Some functions of drainage ditches, such as regulating water flow and nutrient retention, are likely to depend on the composition and structure of biological communities of ditches, though the issue remains poorly explored. The biggest threat to the quality of ditch networks as ecosystems is presented by a severe runoff from the fields, management in disregard of a habitat value of ditches, and removal of ditches.     

An investigation of the concentrations of selected Fusarium mycotoxins and the degree of mold contamination of field-dried hay

The levels of selected mycotoxins and mold contamination of Ontario field-dried hay from 10 performance horse farms were examined. The farm owner, trainer or manager was questioned regarding their opinion of the quality of the hay. Half of the hay sampled showed potentially significant levels of mycotoxins, mold and actinomycete contamination. Subjective opinion did not correlate to objective analysis. Deoxynivalenol (vomitoxin), T 2 toxin and zearalenone were measured with vomitoxin present in the highest amounts. Vomitoxin is among the mycotoxins most frequently found as contaminants in cereal crops, in temperate climates, in North America. It can be concluded that the levels found in this study could potentially have an influence on the health of horses consuming such hay.     

Tail-in-mouth behaviour in slaughter pigs,in relation to internal factors such as: age,size, gender,and motivational background

Tail-in-Mouth (TIM) behaviour has occasionally been observed among pigs living under semi-natural conditions. It is therefore considered to be a normal, low-frequency behaviour. Under certain conditions, TIM behaviour may increase in frequency and progress into tail biting per se. Several factors, such as age, gender, and size, are believed to enhance this development. This study aimed to elucidate the frequency of TIM behaviour among slaughter pigs, specifically in relation to age, gender, size, and group composition regarding gender. Similarly, we intended to characterize the motivational context in which TIM behaviour occurs. Two batches consisting of 24 pigs each, weighing between 40 and 50 kg, were allocated into 3 groups: 1) Eight female pigs; 2) Eight castrated male pigs; 3) Four female and four castrated male pigs (mixed-gender group). Observation was performed by video recording 4 h per day, 1 day per week, for four consecutive weeks. The pigs were weighed once a week during the experiment. The number of TIM events (counts) as well as the identity of the performer and the receiver of TIM behaviour was recorded. The results showed that the frequency of TIM behaviour in the male group was significantly lower than in the female and mixed-gender groups (P=0.003). Size expressed as weight or growth rate did not influence the amount of TIM behaviour performed or received. TIM behaviour was positively related to social exploration and environmental exploration (P<0.001). Finally, TIM behaviour was most often performed while the pigs were standing still or lying down (P<0.001).     

A non-linear hierarchical mixed model to describe tree height growth

A non-linear hierarchical mixed model approach is used to describe height growth of Norway spruce from longitudinal measurements. The parameter variation in the model was divided into unknown random effects, fixed effects and covariate-dependent effects in order to model tree height growth. The values for fixed effect parameters and the variance–covariance matrix of random effects were estimated. Covariates could only explain up to 10% of parameter variability. Height curves were calibrated by means of BLUPs for the unknown random effects using prior height measurements and evaluated using a separate dataset. The resulting curves had a small error variance and plausible shapes.     

Framework for designing and applying peak runoff control structures for peatland forestry conditions

Drainage-induced diffuse pollution and erosion are key water quality problems in peatland forestry. A major part of the pollutant load is transported during peak runoff periods after snowmelt or intense rainfall. This study investigated possibilities to increase retention time of runoff waters in drained peatland catchments on purpose to diminish peak runoff and improve settling conditions of suspended solids (SS). To create retention, a peak runoff control (PRC) structure was developed and its functioning, dimensioning and practical applications were studied in five partly or completely ditch-drained catchments in Central Finland. The method reduced runoff peaks by 10–73% or 5.07–57.63 l⁻¹ s⁻¹ km⁻², and functioned especially well during largest runoff peaks. The effectiveness of the PRC method depended on (i) catchment topography (slope) and available detention volume, (ii) dimensioning and location of the PRC structure, and (iii) runoff rates. The PRC structure is cheap and can easily be created with forest drainage machinery during the ditching and ditch network maintenance operations. Different issues relating to the structural design, water quality benefits, and impacts on forestry are discussed.     

Soil–water content and air-filled porosity affect height growth of Scots pine in afforested arable land in Finland

We examined the soil–water content (SWC) and air-filled porosity (AFP) of afforested arable land in situ and related them with tree growth, which was expressed as the total length of 5-year-height growth above 2.5 m stem height. A total of 34 randomly selected sites in western Finland afforested with Scots pine (Pinus sylvestris L.) were sampled and SWC was measured using time domain reflectometry (TDR). Increasing AFP up to 30% and correspondingly decreasing SWC significantly increased tree growth while concentrations of foliar nutrients and contents of soil nutrients had no effect. Increasing organic matter content (OMC) and decreasing bulk density (BD) were accompanied by increasing SWC and decreasing AFP in the 0–10 cm soil layer. SWC values above 70% indicated critical AFP below 10%. It was found that 44% of the studied sites had mean AFP lower than 10%. The results obtained indicate that the afforested Finnish arable land with high soil OMC is commonly characterized by high SWC and low soil aeration, which can limit tree growth.     

Uncertainty of 21st century growing stocks and GHG balance of forests in British Columbia, Canada resulting from potential climate change impacts on ecosystem processes

Over the coming decades, climate change will increasingly affect forest ecosystem processes, but the future magnitude and direction of these responses is uncertain. We designed 12 scenarios combining possible changes in tree growth rates, decay rates, and area burned by wildfire with forecasts of future harvest to quantify the uncertainty of future (2010-2080), timber growing stock, ecosystem C stock, and greenhouse gas (GHG) balance for 67 million ha of forest in British Columbia, Canada. Each scenario was simulated 100 times with the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3). Depending on the scenario, timber growing stock over the entire land-base may increase by 14% or decrease by 9% by 2080 (a range of 2.8 billion m³), relative to 2010. However, timber growing stock available for harvest was forecast to decline in all scenarios by 26-62% relative to 2010 (a range of 1.2 billion m³). Forests were an annual GHG source in 2010 due to an ongoing insect outbreak. If half of the C in harvested wood was assumed to be immediately emitted, then 0-95% of simulations returned to annual net sinks by 2040, depending on scenario, and the cumulative (2010-2080) GHG balance ranged from a sink of −4.5 Pg CO₂e (−67 Mg CO₂e ha⁻¹) for the most optimistic scenario, to a source of 4.5 Pg CO₂e (67 Mg CO₂e ha⁻¹) for the most pessimistic. The difference in total ecosystem carbon stocks between the most optimistic and pessimistic scenarios in 2080 was 2.4 Pg C (36 Mg C ha⁻¹), an average difference of 126 Tg CO₂e yr⁻¹ (2 Mg CO₂e yr⁻¹ ha⁻¹) over the 70-year simulation period, approximately double the total reported anthropogenic GHG emissions in British Columbia in 2008. Forests risk having reduced growing stock and being GHG sources under many foreseeable scenarios, thus providing further feedback to climate change. These results indicate the need for continued monitoring of forest responses to climatic and global change, the development of mitigation and adaptation strategies by forest managers, and global efforts to minimize climate change impacts on forests.     

Agroecology as a Climate Change Adaptation Strategy for Smallholders of Tehri-Garhwal in the Indian Himalayan Region

Climate change is expected to increase temperatures and rainfall in the Himalayan region and place stress on local livelihoods by affecting agro-biodiversity, crop yield, cropping patterns and the species composition of forests. This paper reports findings of a survey of farmers into the role of agroforestry or ‘agroecological intensification’ for reducing climate change vulnerability. The survey was conducted in the Tehri-Garhwal district of Uttarakhand, a Himalayan State of India. Existing traditional agroforestry was found to provide ecosystem services to farmers at various scales ranging from the global to household level, contributing to the livelihoods and resilience of the farmers to climate change. The strategies of farmers for adaptating to climate change include adoption of agroforestry due to its diversified agricultural and forest products and services. The analysis suggests that policies should consider agroforestry as a tool for improving the livelihood and resilience to climate change of farmers.     

Influence of different nursery container media on rooting of Scots pine and silver birch seedlings after transplanting

Scots pine (Pinus sylvestris L.) and silver birch (Betula pendula Roth.) seedlings were grown in containers filled with growth media based on medium-textured sphagnum peat, coarse perlite and fine sand. The seedlings were then planted into fine and coarse sandy soils in 2.2 l pots, which were subjected to two water-content treatments (only one for birch). After the seedlings had grown five weeks in a greenhouse, rooting into the surrounding soil and shoot growth were measured. Addition of perlite and sand to peat medium slightly affected rooting; thus suggesting minor effects on seedling establishment. However, nitrogen concentration of the seedlings varied between growth media and correlated positively with rooting into the soil. The particle size and water content of the soil affected considerably rooting of the seedlings. Seedling height at the time of planting did not affect rooting or shoot growth. The fact that the fewest out-grown roots occurred in the dry fine sandy soil, suggests that dry soil together with high strength and resistance to root penetration reduce rooting and water uptake by container seedlings most and may thus cause water and nutrient stresses to seedlings after outplanting.     

Irrigation regime affects water and aeration conditions in peat growth medium and the growth of containerized Scots pine seedings

Containerized Scots pine seedlings growing in light Sphagnum peat growth medium in a greenhouse were subjected to three irrigation treatments. The seedlings were irrigated by saturating the growth medium with a nutrient solution (i) daily or when (ii) –5 or (iii) –10 kPa medium matric potential was achieved. In general, the nutrient concentrations in the foliage of the seedlings were rather similar for all irrigation treatments. In the wet (daily) irrigation treatment, however, the foliar concentration of N was lower and the foliar concentrations of P, Ca, S, Mn and Na were higher than in the other two treatments. In the wet irrigation treatment, height growth was lower than that in the other treatments. In this treatment the shoot to root ratio and several other morphological characteristics were also reduced, while the number of root lenticels and seedling mortality were increased compared to the other treatments. Rapid growth was obtained by irrigating at –5 to –10 kPa matric potential. In the wet irrigation treatment, the median matric potential and air-filled porosity of the peat medium were –0.4 kPa and 11%, respectively, which indicated waterlogging and very suboptimal aeration to the seedlings. The respective values for the irrigations at –5 and –10 kPa were –2.7 to –3.3 kPa and 39 to 43%, which were considered to cover the range from optimum to slightly suboptimum for average water availability and aeration.