Dw. James et Rl. Hurst, SOIL SAMPLING TECHNIQUE FOR BAND-FERTILIZED, NO-TILL FIELDS WITH MONTE-CARLO SIMULATIONS, Soil Science Society of America journal, 59(6), 1995, pp. 1768-1772
Band application of P fertilizer in no-till fields results in extremel
y variable soil test P (STP) along lines perpendicular to the bands. T
his variation may be represented by two interlaced populations, each w
ith a unique STP mean and standard deviation. The objectives of this r
esearch were to: (i) characterize STP populations in a band-fertilized
field; (ii) use these population characteristics to calibrate a Monte
Carlo based model to simulate STP populations; and (iii) use simulate
d STP populations to evaluate different soil sampling procedures. A co
rn (Zea mays L.) field was band fertilized with P, and 1 yr later STP
(mg P kg(-1)) was measured on individual soil cores with the bicarbona
te extraction procedure. Out-band STP mean and standard deviation (SD)
were 13.9 +/- 4.75, in-band STP mean and SD were 127.4 +/- 29.7, and
composite STP mean and SD mere 23.3 +/- 28.69. A computer simulation m
odel based on the Monte Carlo technique reproduced the observed popula
tions very closely. The results show that the number of completely ran
dom soil cores needed to represent a band-fertilized field is prohibit
ive. Rapid collection of a single representative composite sample with
equipment capable of taking a slice of soil across the fertilizer ban
d and accurately weight in-band and out-band STP by volume is recommen
ded.