lecture 10 Flashcards
what are the 4 sampling techniques
- traditional composite sampling
- benchmark soil sampling
- grid soil sampling
- soil and landscape direct sampling
describe traditional composite sampling
random sampling, best on fields that are flat with relative soil uniformity
what do do if you have hilly fields using traditional sampling
if samples are from hills take sample from mid slope
describe benchmark soil sampling
selecting 1/4 acre benchmarks areas
where to use benchmark soil sampling
good to use on fields where soil properties somewhat vary
how to analyze benchmark sampling
combine all sites and create a sub sample. unless interested in variable rate fertilizer applications, the analyze separately
other than field observation what else should you take into account when using benchmark soil sampling
- past growers experience
- yield monitors and maps
- soil surveys
- remotely sensed images
describe grid sampling
mapped out spots on a grid for soil sampling
cons of grid sampling
time consuming, and very expensive if done correct
describe variability sampling
defines zones on your field according to variability in texture, moisture, organic matter, erosion, history of manure use
process of all 4 techniques
- mix all samples from 0-6 inches deep
- subsample the combined soil
- submit this sample for analysis
- repeat for depths of 6-12 inches and 12-24 inches
pros to traditional sampling
good choice when soil is mostly uniform, don’t need much background on field
pros of benchmark
only good when you know your field
pros of grid
interesting, use this if you want to know your fields very well
pros of land scape
good alternate to grid and benchmark sampling
