Growth and yield of spring cereals during transition to zero tillage on clay soils

Due to the high cost of fuel and labour associated with conventional tillage, and because of their advantageous environmental consequences, interest in reduced and zero tillage systems has increased. Direct drilling into zero tilled (ZT) soil of two spring barley (Hordeum vulgare L.) cultivars (six-rowed Rolfi and two-rowed Saana), spring oats (Avena sativa L., cultivar Roope), and spring wheat (Triticum aestivum L., cultivar Kruunu) was compared with conventional tillage (CT) and drilling into ploughed soil. Two field experiments were conducted on clay soils (clay content > 50%) between latitudes 60° and 61° N. Seed and fertilizer were placed in the same row in ZT and in separate rows in CT. Oats was the most productive spring cereal species in ZT. Establishment of spring wheat was often poor. Barley was most vulnerable to water surplus during early growth and drought during late growth. High levels of crop residues caused problems in soil drying in spring and growth of monocultures of oats and wheat. A higher seeding rate was advantageous in zero tilled clay soil. The substantial grain yield decrease suggests need for improving ZT.Long-term trials are required to determine whether ZT suits clay soils as soil structure can change over time and weather conditions play a major role in the productivity of differently tilled soils.     

Effect of clear-cutting and site preparation on the level and quality of groundwater in some headwater catchments in eastern Finland

The impact of forest management (clear-cutting and site preparation) on stream hydrology has been studied in five small catchments in eastern Finland from 1991 and on groundwater levels and quality from 1994. The period 1992–1996 was a calibration period and in the autumn of 1996, 10% and 30% of the area of two of these catchments were clear-cut according to the forest management plan. Regeneration was carried out by disc-plowing in the autumn of 1998 and planting with Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) seedlings in the spring of 1999. The depth and quality of groundwater was monitored with four to nine groundwater wells installed in each catchment. There were 32 wells in all, 16 on upland mineral soils and 16 on peatlands (the perforated part of the pipe was totally put into the underlying mineral soil at eight sites). Sampling was made monthly during spring (March–May) and autumn (November–December) and bimonthly during summer (June–October). The samples were chemically analyzed for pH, electrical conductivity, and concentrations of total P and Fe (before filtration), and total N, NO₃⁻-N, NH₄⁺-N, total P, PO₄³⁻-P, SO₄²⁻-S, Ca²⁺, Mg²⁺, K⁺, Na⁺, Mn, Zn, Fe, Al³⁺, Cl⁻ (after filtration through 0.45 μm membrane filter). Data collected until the end of 2001 are reported. Groundwater was found in the down-slope wells in lower-lying areas, but not in those installed on the slopes with a thin (1–2 m) soil layer. Clear-cutting did not significantly affect groundwater levels in the wells. Nitrate N concentrations increased from 0.03 mg L⁻¹ level after clear-cutting and again after site preparation in the wells on upland soils and peatlands receiving water from the managed parts of the catchment. In one well at the lower edge of the managed area NO₃⁻-N concentrations reached 1–1.4 mg L⁻¹ in 2001 (fifth year after clear-cutting, third after disc-plowing), but mean concentrations remained <0.3 mg L⁻¹. Chloride concentrations also increased (50–100%) after treatments but the concentrations of other solutes showed no significant effect of treatment. It was concluded that changes in groundwater quality and quantity related to the clear-cutting were small and did not represent a danger to water quality or quantity.     

Effects of site preparation on soil properties and on morphology of Pinus sylvestris and Picea abies seedlings sown at different dates

The aims of the study are to find out the effects of site preparation on soil properties and on the morphology of three-year-old Pinus sylvestris L. and Picea abies (L.) Karst. seedlings sown at different dates along a slope with variation in soil texture, water, and fertility. Based on the hypothesis that soil texture affects soil water content, water retention capacity, and nutrient content, we studied site preparation of varying intensities: exposed C horizon, mounds (broken O/E/B horizons piled over undisturbed ground), and exposed E/B horizon. Though the growing time difference between sowings was about one month, after three growing seasons, spring-sown seedlings were larger than summer-sown seedlings. P. sylvestris seedlings were largest with mounds and smallest with exposed C horizon, but site preparation did not affect the morphology of P. abies seedlings.     

Unfecund, gigantic mutant of oats (Avena sativa) shows fecundity overdominance and difference in DNA methylation properties

Summary The fecundity heterosis of the gig/+oats (Avena sativa) was examined in a population showing segregation of the gene under the long photoperiods in S Finland. Segregating isolines of cv Hannes and of cv Kyrö were raised at two plant densities and the grain yield of heterozygotes and nonmutant homozygotes were evaluated. The heterozygotes in mean outyielded the homozygotes. The overdominance of grain number explains the persistance of this mutant at a relatively high frequency in oats in Finland, though the fecundity of the extremely late homozygous mutant is zero. Previous and current data indicate that the heterozygotes show heterosis of fecundity depending on genetic background, season or other environmental conditions. Grafting of cut stems of nonmutants onto wounded nodes of mutants did not transfer any observable florescence inductor. Hypomethylation of DNA, as revealed with HpaII digestion, occurred in topmost leaves of non-mutants, being absent or occurring to a lesser extent in the comparative leaves of mutants.     

Chemical moieties and interactions involved in the binding of zearalenone to the surface of Lactobacillus rhamnosus strains GG

Viable, heat-and acid-killed Lactobacillus rhamnosus strain GG (LGG) has shown high binding properties with zearalenone (ZEN). To identify the type of chemical moieties and interactions involved in binding with the ZEN, LGG was subjected to different chemical and enzymatical treatments, prior to the binding experiments. Pretreating the viable, heat- and acid-killed bacteria with m-periodate significantly decreased ZEN binding, suggesting that ZEN binds predominantly to carbohydrate components. Pretreatment with Pronase E had no effect on the ability of viable cells to bind ZEN, however, a reduction in the binding of ZEN by heat- and acid-killed cells, suggesting that the new binding sites exposed by heat or acid are proteins in nature. Pretreatment with urea also decreased binding, suggesting that hydrophobic interactions play a role in ZEN binding. The binding of ZEN in concentrations ranging from 0.79 to 62.82 microM and its subsequent dissociation by repetitive aqueous washes was also studied. The binding sites of the bacteria were not saturated by the maximum ZEN concentration studied.     

Microbial communities, biomass, and activities in soils as affected by freeze thaw cycles

Two Finnish agricultural soils (peat soil and loamy sand) were exposed to four freeze-thaw cycles (FTC), with a temperature change from −17.3±0.4 °C to +4.1±0.4 °C. Control cores from both soils were kept at constant temperature (+6.6±2.0 °C) without FTCs. Soil N₂O and CO₂ emissions were monitored during soil thawing, and the effects of FTCs on soil microbes were studied. N₂O emissions were extremely low in peat soil, possibly due to low soil water content. Loamy sand had high N₂O emission, with the highest emission after the second FTC. Soil freeze-thaw increased anaerobic respiration in both soil types during the first 3-4 FTCs, and this increase was higher in the peat soil. The microbial community structure and biomass analysed with lipid biomarkers (phospholipid fatty acids, 3- and 2- hydroxy fatty acids) were not affected by freezing-thawing cycles, nor was soil microbial biomass carbon (MIB-C). Molecular analysis of the microbial community structure with temperature gradient gel electrophoresis (TGGE) also showed no changes due the FTCs. These results show that freezing and thawing of boreal soils does not have a strong effect on microbial biomass or community structure.     

Nitrous oxide emissions from agricultural soils at low temperatures: a laboratory microcosm study

We studied in laboratory microcosms (intact soil cores) N₂O and CO₂ emissions from four different agricultural soil types (organic soil, clay, silt and loam) at low temperatures with or without freezing-thawing events. When the temperature of the frozen soil cores was increased stepwise from −8 °C the N₂O emissions began to increase at −0.5 °C, and peaked at −0.1 °C in the organic, clay and silt soils, and at +1.6 °C in the loam soils. However, a stepwise decrease in soil temperature from +15 °C also induced an increase in the N₂O emissions close to the 0 °C. These emissions peaked between −0.4 and +2.5 °C depending on the soil type and water content. However, the emission maxima were from 2 to 14.3% of those encountered in the experiments where frozen soils were thawed. Our results show that in addition to the well-documented thawing peak, soils also can have a maximum in their N₂O emission near 0 °C when soil temperature decrease. These emissions, however, are less than those emitted from thawing soils. The correlations between the N₂O and CO₂ emissions were weak. Our results suggest that N₂O is produced in soils down to a temperature of −6 °C.     

Structure and function of microbial communities in the rhizosphere of Scots pine after tree-felling

We evaluated changes occurring in the rhizosphere microbial communities of Scots pine (Pinus sylvestris L.) due to tree-felling and decrease of the photosynthetic C flow into the soil under field conditions over one growing season. Samples were taken from tree rhizospheres, freshly felled stump rhizospheres and bulk soil. We used culture dependent (CFU counts, community level physiological profiles, CLPPs) and independent methods (fluorogenic MUF-substrates, PLFA pattern and PCR-DGGE) to monitor the microbial communities in soil samples. The numbers of cultivable bacteria and amounts of phosphatase activity in the rhizosphere of trees were significantly higher compared with those in the bulk soil. The organic C consuming community measured by CLPP was stimulated directly after the tree-felling in stump rhizospheres; utilization of the disintegration components of cellulose, hemicellulose and chitin increased. Furthermore, bacterial and fungal biomass as well as chitin decomposers (CFU) increased in the stump rhizosphere. After 11 weeks of tree-felling the stump rhizosphere soluble PO₄-P and NH₄-N as well as amounts of total C and N began to resemble the concentrations measured in the bulk soil. However, the stump rhizosphere community structure detected by PLFA and PCR-DGGE still resembled that of the tree rhizosphere.     

Organisms,decomposition, and growth of pine seedlings in boreal forest soil affected by sod cutting and trenching

In an experiment with factorial design performed in a mature, mixed Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) stand in central Finland, we studied the effects of sod cutting (exposing the mineral soil simulating mechanical site preparation) and trenching the study plot (excluding root-mycorrhizal connections) on soil organisms, decomposition rate and pine seedling performance. During two growing seasons after sod cutting, the growth of pine seedlings was significantly enhanced compared to plots with the organic layer left intact. Some epiedaphic soil animals, such as ants, spiders and certain entomobryid collembolan, were more active (pitfall sampling) on sod-cut plots. By the end of the second growing season numbers of enchytraeids were greater in the exposed mineral soil than in the mineral soil under the forest floor. Trenching induced changes in microbial phospholipid fatty acid (PLFA) pattern and collembolan community structure with decreased numbers of collembolans and biomass of fungi in organic soil of uncut plots. In addition, N content of pine seedlings increased after trenching. Overall, the effects of trenching on the measured variables were similar in sod-cut and uncut plots. We conclude that the effects of mechanical site preparation on decomposers and decomposition processes can be explained partly by exclusion of mycorrhizal-root connections and partly by a decrease in unfavourable conditions created by the organic soil layer and ground vegetation.     

The development of skin,claw and teat lesions in sows and piglets in farrowing crates with two concrete flooring materials

Abstract

The aim of the study was to investigate lesions in sows and their piglets kept on two flooring materials – bare concrete and concrete coated with polyurethane containing sand. In total, 13 lactations on concrete and 11 on polyurethane were evaluated. The severity of skin lesions was scored and teat and claw lesions were recorded. The sand-filled coating was rougher compared to the concrete floor. Larger litter sizes were associated with a higher proportion of wounded teats in sows. Only seven of the 230 piglets had no skin lesions. The piglet skin lesions generally healed, since the number of more severe lesions decreased (p<0.001) and the number of less severe lesions (p<0.001) increased over time. Piglet lesions were associated with daily weight gain and litter size. The number of skin lesions on sows and piglets did not differ between animals kept on concrete and polyurethane-covered flooring. However, piglets kept on the latter flooring had more frequent claw lesions. On both types of flooring the majority of the piglets had skin lesions. Piglets had more claw lesions on polyurethane coating due to its roughness. In addition to the possibility of lower weight gains in piglets due to severe lesions, pig skin lesions are themselves a severe welfare problem in this type of housing system.