Structure of clay topsoil affected by tillage intensity

On the clay loam soil in 0-0,05 m layer, the average dry bulk density of ploughed soil was greater than that of reduced tilled soils. This was probably due to the higher organic matter content of reduced tilled plots. On the clay soil, the differences in soil dry bulk density were, however, small. In the 0-0,05 m layer, the differences in macropore size distribution were small on both fields

Phosphorus and nitrogen uptake of spring cereals in different tillage systems

On the clay soil, the mean grain yield of stubble cultivated and direct drilled treatments was 3 and 18 % less, respectively, than that of ploughed treatment. The relative reductions in P and N uptake were the same magnitude than the grain yield reductions

Variability in Herbage Mass and Chemical Composition within a Timothy Sward

Variability in herbage mass (HM) and chemical composition of timothy (Phleum pratense L.) sward was studied in a three-hectare field. The field, which was flat, was divided into twelve sections and a sampling site was randomly selected in each. The study was carried out in Sotkamo (64o 01’N, 28o22’E) research station in Finland. Snow depth and frost conditions were measured in winter and soil water content was monitored in the growing season at each sampling site. Observations on the crop included assessment of herbage ground cover and winter damage percentage, stand height and HM and analysis of neutral detergent fibre (NDF) and nitrogen concentration. Forage was harvested twice during the experiment and the first cut was made at ear emergence. Winter damage varied from 0 to 68% and herbage ground cover in spring from 30 to 100%. Variability in HM was higher at the first cut (from 1767 to 4390 kg DM ha-1) than at the second cut (from 3890 to 4348 kg DM ha-1). NDF content varied from 601 to 688 g kg-1 at the first cut and from 582 to 632 g kg-1 from at the second cut. The 95% confidence limits for NDF at the first cut were from 635 to 663 g kg-1 and at the second cut from 589 to 604 g kg-1

Subsoil compaction due to wheel traffic.

The article reviews those major soil properties and traffic factors, which together influence subsoil compaction resulting from the passage of agricultural vehicles. Likewise, the effects of subsoil compaction on soil properties, processes and crop growth are discussed on several levels, from methods of measuring to the persistence of compaction effects. The risk of subsoil compaction exists whenever moist soils are loaded with heavy axle load and moderate to high ground contact stress. Subsoil compaction tends to be highly persistent. To avoid the risk of long-term deterioration, limits for the induction of mechanical stresses in the subsoil should be established through international teamwork.;Maataloudessa käytettävien koneiden tehot ja painotovat kasvanut viime vuosikymmenien aikana jatkuvasti. Tämä on lisännyt pohjamaan tiivistymisriskiä. Tässä kirjoituksessa tarkastellaan, miten maan ominaisuudet ja peltoajoon liittyvät tekijät vaikuttavat pohjamaan tiivistymiseen. Lisäksi selvitetään, miten pohjamaan tiivistymisen vaikuttaa maahan, peltoviljelyyn, satoon ja ympäristöön. Pohjamaan tiivistymisriski on suuri, kun kostealla pellolla ajetaan raskaalla kalustolla, jonka pintapaine on kohtalainen tai suuri. Tiivistymisen ehkäisemiseksi on annettu yksittäisiä suosituksia akselipainon, pintapaineen ja maassa 0,50 metriin ulottuvan jännityksen ylärajaksi. Tekniset suoditukset pitkäaikaisten tiivistymishaittojen ehkäisemiseksi tulisi kuitenkin laatia kansainvälisenä yhteistyönä. Ennen suositusten laatimista on tutkittava mm. pohjamaiden kuormituksen kestävyyttä vaihtelevissa olosuhteissa. Pohjamaan tiivistyminen vaikuttaa lähes kaikkiin maan fysikaalisiin, kemiallisiin ja biologisiin ominaisuuksiin ja prosesseihin. Se on todettu pienentävän myös kasvien satoa ja typenottoa. Tutkimusten mukaan pohjamaan tiivistymisen vaikutukset säilyvät pitkään. Karkeissa maissa ne voivat olla jopa pysyviä

Subsoil compaction due to wheel traffic.

The article reviews those major soil properties and traffic factors, which together influence subsoil compaction resulting from the passage of agricultural vehicles. Likewise, the effects of subsoil compaction on soil properties, processes and crop growth are discussed on several levels, from methods of measuring to the persistence of compaction effects. The risk of subsoil compaction exists whenever moist soils are loaded with heavy axle load and moderate to high ground contact stress. Subsoil compaction tends to be highly persistent. To avoid the risk of long-term deterioration, limits for the induction of mechanical stresses in the subsoil should be established through international teamwork.