Variability of topsoil properties at the southern coast of Finland and the number of  soil samples needed for the estimation of soil properties

Biological nitrogen fixation (BNF) plays a crucial role in organic farming and red clover (Trifolium pratense) is cultivated widely in boreal grasslands for BNF. A geostatistical method, model-based kriging, was used to determine the spatial variation in yield, clover content and BNF of clover-grass leys as well as soil chemical properties throughout two fields in 2004−2006. Based on this variation, principal component analysis (PCA) was used to determine the similar patterns of variation. On one location, total dry matter yields of the leys decreased over three production years from 9 700 to 4 100 kg ha -1 , clover content from 53 to 26% and BNF from 150 to 40 kg N ha -1 , whereas on the other location the yields increased from 6 500 to 7 100 kg ha -1 , clover content from 52 to 62% and BNF from 100 to 120 kg N ha -1 . Nutrient concentrations in soil also varied greatly within the fields, although this depended on the nutrient species. Kriging combined with PCA described the spatial variation of ley parameters very informatively, but was not as powerful for describing the pattern of nutrients. Based on the spatial dependence determined in the two fields investigated, it seems that the sampling distance should be 80 m for soil nutrients, 100 m for yield and 60 m for clover content and BNF determination, respectively.

Section: Discussionsupporting

confidence: 80%

Field-scale spatial variation in yields and nitrogen fixation of clover-grass leys and in soil nutrients

Nykänen¹,

Jauhiainen²,

KEMPPAINEN³

2008

“…In an earlier study (Jokinen 1983), the number of soil samples needed for the accurate estimation of soil characteristics was calculated for the topsoil material on the basis of the coefficient of variation (w), Student's t-value (t) and allowable error (p) according to the equation n = t 2w If this equation were applied to subsoils, the number of samples needed would be greater than for topsoil because of the higher w-values in the subsoil. The subsoil seemed to be more heterogenic than the topsoil.…”

Section: Discussionmentioning

confidence: 91%

“…The method of systematic sampling has been reported previously by Jokinen (1983). The present material consisted of topsoil (0-25 cm) and subsoil (30 -50 cm) samples from 382 sampling sites.…”

Section: Methodsmentioning

confidence: 99%

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Comparison of and correlation between the characteristics of agricultural topsoil and subsoil at the southern coast of Finland

Jokinen

1984

Self Cite

Topsoil and subsoil samples were taken at 382 sites from the agricultural area of Viikki Experimental Farm, University of Helsinki. The samples were determinated for particle size distribution, pH(CaCI2), organic C %, at pH 7 exchangeable Ca, Mg and K, effective cation exchange capacity (ECEC), exchange acidity (AI + H) and plant available (Bray 1) P. The differences between topsoil and subsoil were studied taking into consideration the fertilization and liming during the past ten years before sampling. The correlations between soil characteristics were also studied.The clay (< 2 /un) and silt (2 -20 fim) contents, exchangeable Mg and exchange acidity were lower in the topsoil than in the subsoil; as for the remaining characteristics, the values for topsoil were higher than those for subsoil. The subsoil seemed to be more heterogenic than the topsoil.There was a closer correlation between exchangeable Ca, Mg and K and the clay content in the subsoil than in the topsoil. In Litorina soils, there was a weak correlation between exchangeable cations and clay. It is more difficult to predict the cation contents on the basis of soil particle size distribution in soils cropped intensively, since fertilization and liming have changed the original contents.Vertical movement of applied Ca occurred slightly, possibly because the topsoils were rich in organic C. There was some correlation between organic C and exchangeable Mg or K, indicating a minor effect of organic matter on the leaching of these cations. The plant available P content of the subsoil was about 10 % of that of the topsoil irrespective of the amount of P applied.Clay and organic C contents were the main constituents of effective cation exchange capacity in the topsoil; in the subsoil the significance of clay was greatest.

“…Usually one sample composed of 7-8 sub-samples represents 1-2 ha of acreage. The samples were taken from the top-soil in a standardised procedure (see Lakanen 1969, Jokinen 1983, Peltovuori 1999 and analysed according to the routines described by Vuorinen and Mäkitie (1955). Soil sampling was carried out within a five-year period prior to our survey.…”

Section: Soil and Herbage Datamentioning

confidence: 99%

Variability of herbage production in mixed leys as related to ley age and environmental factors: a farm survey

Riesinger¹,

Herzon²

2008

Influences of ley age, soil properties, and geographical location on the herbage production of red clover-grass leys were determined under practical conditions on 27 organic farms located in the southern and in the northwestern coastal regions of Finland. Averaged over one-, two-, and three-year-old leys the accumulated first and second cuts produced 7.12 t dry matter herbage ha-1 year-1, with a clover proportion of 34.8%. Herbage production declined with increasing ley age. The average proportion of clover increased from 26.4% in the first to 43.7% in the second cut but decreased with ley age. Within- and between-field variations of clover proportions markedly decreased from the first to the second cut and strongly increased with ley age, while changes in the variations of herbage production were less pronounced. Within-field variations of clover proportions in the first and in the second cuts were higher at lower proportions of clover. Herbage production was positively related with clover proportion. Soil properties had a major impact on clover proportion and herbage production, largely explaining also regional differences in ley growth. Amelioration of fields and, not at least, of less fertile sites within the same field seems to be a crucial requirement for higher and more even clover proportions and herbage yields.;