In our polyfactorial 4-year long experiment, which was carried out on chern
ozem soil with lime deposits at the Experimental Farm of Debrecen Universit
y of Agricultural Sciences, we wanted to find out that out of four differen
t plant densities (N1=60, N2=70, N3=80, N4=90 thousand plant ha(-1)) beside
s a fixed and most advantageous manuring level and tillage method, which on
e is the most favourable in irrigated and non irrigated treatment. Our aim
was to choose the plant density by which a favourable yield can be achieved
and the yield risk of which is acceptable for the decision maker. By using
both mean (E) - variance (V) and stochastic dominance (SD) criteria we cam
e to the same conclusion. In non-irrigated treatment N1 and N2 gave the bes
t results for risk-averse decision makers but on the basis of neither crite
rion could we decide an order between the two plant densities. In the case
of irrigated cultivation both criteria proved that the most advantageous pl
ant density with regard to yield and its risk was N2 with 70 thousand plant
ha(-1).
With the E-V criterion we use only mean value and variance parameters to de
scribe the effects of plant density, while with the SD criteria it is possi
ble to make comparisons on the whole range of the crop. With smaller number
of data the use of the E-V, while with larger data number the use of the S
D criterion is suggested. We will get the same results from the use of the
two criteria only if the factors and conditions of cultivation are well rep
resented in our database.