Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2003
Forfattere
Erland Kjesbu Lill-Ann Gundersen Anne Moxnes JervellSammendrag
Det er ikke registrert sammendrag
Forfattere
B. RosselandSammendrag
Det er ikke registrert sammendrag
Forfattere
Randi Holme Ann NorderhaugSammendrag
Målsetninger, metoder og gjennomføringen av Storfjordprosjektet. Diskuterer foreløpige resultater i et forvaltningsperspektiv.
Forfattere
Tron EidSammendrag
Det er ikke registrert sammendrag
Forfattere
Tron EidSammendrag
Det er ikke registrert sammendrag
Forfattere
Ketil KohmannSammendrag
Det er ikke registrert sammendrag
Forfattere
Johanne Kjuus Nils Øyvind BergsetSammendrag
Det er ikke registrert sammendrag
Forfattere
Johanne Kjuus Nils Øyvind BergsetSammendrag
Det er ikke registrert sammendrag
Sammendrag
.Precision agriculture (PA) may be defined as using the best available technologies to tailor soil and crop management to fit the specific conditions found within an agricultural field or tract (Johannsen, 2001). Knowledge about soil variation within fields is thus a prerequisite for optimum PA. The use of sensors which measure electrical conductivity (EC) has been introduced as a promising way of mapping within-field variation in soil properties. In this paper we present relationships found between EC and both clay content and ignition loss (SOM) of some morainic loam soils in SE Norway. Measurements of EC at Møystad (60°47"N, 11°10"E, altitude ca.150 m) correlated well with clay content. Despite the rather narrow range of clay content at Møystad (11-17%), EC measurements accounted for about 70% of the variation. The use of EM38 in the horizontal position gave the best prediction in the upper two layers, whereas measurements in the vertical position fitted best to data from the deepest layer (40-60 cm). This is reasonable, since the instrument has its deepest range in the vertical position. Ignition loss in the upper layer was 5-8% at Møystad. There was no significant relation between EC and ignition loss in the upper layer, when EC was measured with EM38 in the vertical position. When EC was measured horizontally, about 24% of the variation in ignition loss was reflected by the EC of the soil. One should, however, take into account that ignition loss and clay content were positively correlated with each other (r=0.382), so that the result may in fact have been due to variation in clay content. We also measured EC at Kise Research Station (60°46"N, 10°48"E, altitude ca.130 m), where we selected five points across a field with a particularly large gradient in ignition loss. Here EC correlated positively with clay content, but this was not statistically significant (R2=0.576, p=0.137). With ignition loss, however, EC showed a strong positive correlation (R2=0.878, p=0.019). Inclusion of both clay content and ignition loss in a two-predictor regression model, with EC as the dependent variable, showed that the conductivity measurements depended almost completely on clay content and ignition loss for the selected points at Kise (R2=0.981, p=0.019). However, the predictors were positively intercorrelated here as well (r=0.517), which may make the statistical approach questionable. We also admit that the number of data points was very low. Nevertheless, the results clearly illustrate the potential of EC measurements for mapping soil variation.
Forfattere
Audun KorsæthSammendrag
.Dense datasets are required to describe within field variation precisely. Sensor techniques appear to be promising to reduce labour, time and costs compared to traditional methods of sampling and analysis. Relationships found between soil apparent electrical conductivity (ECa) and available N, pH and soil moisture under spring barley on morainic loam in SE Norway are presented. Measurements were conducted in a 160 m long field trial, established in barley in 2002 at Kise Research Station (60°46"N, 10°48"E, 130 masl). The trial had 20 replicate blocks containing five N-level treatments (0, 60, 90, 120 and 150 kg N ha-1, given as calcium ammonium nitrate). Each plot was 1.5 x 8 m. Soil samples were taken from all five treatments in three selected blocks at 0-15 cm depth, shortly before fertilizing/sowing (10.05.02) and then at two week intervals until the beginning of July (23.05, 06.06, 20.06 and 04.07). Analyses comprised nitrate-N, ammonium-N, pH and water content. At each sampling, ECa was measured in the same plots, using a magnetic dipole soil conductivity meter (EM38, Geonics Ltd., Canada). The device was operated manually in both horizontal (EMh) and vertical (EMv) modes. Linear regressions showed that both EMh and EMv correlated well with the measured variables. All the relations were significant (p