The Longerenong Wrap

The Longerenong Cropping challenge gives local advisors the opportunity to put their agronomic skills on show by managing a crop within a three year cycle of canola, wheat and then chickpeas. The plots were all replicated and outcomes assessed annually on the basis of yield, quality and returns. Twelve groups participated in the challenge and while seasonal conditions - as always - varied from year to year, the average financial return for the challenge was $857/ha. The financial returns were highest in the canola and lowest in the wheat crops, which largely reflected the seasonal conditions for each. The highest gross margin was achieved by a group of current students at Longerenong College with a return of $959/ha per year over the three years.

A cropping system experiment such as this also allows some estimates to be made of nutrient use. Phosphorus rates used by the groups varied from 7 kg P/ha/y to 13 kg P/ha/y. There was a weak relationship between P application rate and return. The partial factor productivity for P averages 306 (+/- 56) kg grain/kg P combined over the three crops in the rotation, even though the Colwell P status of the site was considered moderate to high depending on crop. The partial nutrient balance for P over the three years (amount of P removed in grain divided by the amount of fertilizer P added) was nearly always positive, and averaged 1.2 kg P removed for each kg P applied.

Table 1 shows the results by group for financial return as well as the P balance data and P use efficiencies as measured by partial factor productivity (PFP) and partial nutrient balance (PNB) for the groups over the three years of the challenge.

Group	Means P rates	P Balance kg P/ha	PNB kg grain/kg P	PFP kg Grain P/kg Fertilizer P	Gross Margin $/ha
Agritech	13	-2	0.94	234	845
BCG	8	6	1.22	313	759
DPI	10	6	1.20	313	923
IPL 9P20N	13	-1	0.96	244	803
Green Machine	13	3	1.08	283	915
Longy Lecturers	9	6	1.22	342	794
Longy Students	10	9	1.29	306	959
Pacific Seeds	11	3	1.10	280	901
Raging Reds	11	8	1.24	317	892
SMS Rural	9	9	1.31	326	883
Tylers /Agwise	12	0	0.99	264	781
VTNFA	7	15	1.70	448	825