Results of 2015 HRZ Nutrition Experiments

Summary of results

The 2015 wheat trials at Bool Lagoon and Glenthompson showed an early biomass response to N and P by anthesis, but this did not translate into higher grain yield (see Table). There was evidence that additional P led to a reduced harvest index and lower grain size, which is consistent with the crop haying off under dry soil conditions during the grain-fill period. The 2015 canola trials showed a strong response in all measured parameters to additional N at Frances and both N and P at Inverleigh. There were positive grain yield and HI responses to S in wheat at Bool Lagoon in 2015, but negative responses to S at anthesis in wheat at Glenthompson (2015). Across all sites there wa only one significant response to micronutrients, which was for wheat (grain) at Glenthompson, and did not translate to a higher grain yield.

Summary of significant effects of applied nutrients in the 2015 omission trials. Values separated by different letters are significantly different at the 5% level. For N effects, 2 lsd’s are shown. The first is for comparison between the lowest and middle rate, the second for comparisons between the middle and highest rate. This is because the lowest N rate was only applied to the Nil and +all treatments, whereas the middle and highest N rate were applied to all treatments.

Site	Parameter	Response to…	Description of significant differences		5% lsd
Frances (canola)	Grain yield (t/ha, 100 C drying)	N	18 kg N/ha	0.64b	0.163
			95 kg N/ha	0.89a	0.126
			174 kg N/ha	0.94a
	Biomass – 11 September (kg/ha)	N	18 kg N/ha	2326b	660
			95 kg N/ha	2632b	461
			174 kg N/ha	3396a
	Harvest Index	Not significant		0.243
	Biomass at grain harvest (t/ha)	N	18 kg N/ha	2.76c	0.52
			95 kg N/ha	3.62b	0.40
			174 kg N/ha	4.04a
Bool Lagoon (wheat)	Grain yield (t/ha, 100 C drying)	N, S	18 kg N/ha	3.50a	0.459
			64 kg N/ha	3.05b	0.320
			149 kg N/ha	3.45a
			0 kg S/ha	3.12b	0.356
			23 kg S/ha	3.55a
	Visual rating 28 Oct (scored 1-5)	N, P	18 kg N/ha	1.50c	0.334
			64 kg N/ha	1.76b	0.233
			149 kg N/ha	1.99a
			0 kg P/ha	1.54b	0.260
			25 kg P/ha	1.97a
	Biomass at grain harvest (t/ha)	P	0 kg P/ha	7.67b	0.396
			25 kg P/ha	8.42a
	Harvest index	P, S	0 kg P/ha	0.456a	0.0337
			30 kg P/ha	0.421b
			0 kg S/ha	0.377b	0.0337
			23 kg S/ha	0.439a

Site	Parameter	Response to…	Description of significant differences		5% lsd
Glenthompson (wheat)	Grain yield (t/ha, 100 C drying)	Not significant	4.32
	Harvest Index	Not significant	0.41
	Grain protein (%)	Not significant	13.0
	Grain weight (g/1000 grain)	P (P = 0.09)	0 kg P/ha	33.2a	1.53
			25 kg P/ha	31.9b
	Anthesis biomass – 23 October (kg/ha)	N, P S (P = 0.08)	18 kg N/ha	9369b	438
			77 kg N/ha	9807a
			0 kg P/ha	9033b	534
			25 kg P/ha	9688a
			0 kg S/ha	10007	534
			23 kg S/ha	9449
	Ear density – 23 October (ears/m2)	P	0 kg P/ha	425b	30.3
			25 kg P/ha	463a
	Flag leaf mass – October (g/m2)	N	18 kg N/ha	18.7b	1.31
			77 kg N/ha	21.5a
	Biomass at grain harvest (t/ha)	Micronutrients (P = 0.1)	None	10.6	0.69
			+Cu, Zn	11.2
Inverleigh (canola)	Grain yield (t/ha, 100 C drying)	N, P	18 kg N/ha	1.34b	0.252
			75 kg N/ha	1.60a	0.173
			146 kg N/ha	1.69a
			0 kg P/ha	1.38b	0.196
			25 kg P/ha	1.69a
	Biomass at grain harvest (t/ha)	N, P	18 kg N/ha	5.16b	0.770
			75 kg N/ha	5.72ab	0.527
			146 kg N/ha	6.02a
			0 kg P/ha	5.12b	0.599
			25 kg P/ha	6.00a
	Harvest Index	N, P (P = 0.07)	18 kg N/ha	0.279	0.0336
			75 kg N/ha	0.292	0.0199
			146 kg N/ha	0.293
			0 kg P/ha	0.282	0.0218
			25 kg P/ha	0.294

	Oil content (% oil at 6% moisture)	N, P	18 kg N/ha	46.04a	0.529
			75 kg N/ha	43.49b	0.362
			146 kg N/ha	42.63c
			0 kg P/ha	42.39b	0.411
			25 kg P/ha	43.41a
	Oil yield (t/ha)	N, P	18 kg N/ha	0.690b	0.1248
			75 kg N/ha	0.777ab	0.0853
			146 kg N/ha	0.806a
			0 kg P/ha	0.652b	0.0970
			25 kg P/ha	0.818a
	Protein content (%, 6% moisture)	N, P	18 kg N/ha	36.6c	0.844
			75 kg N/ha	40.2b	0.577
			146 kg N/ha	41.9a
			0 kg P/ha	42.2a	0.656
			25 kg P/ha	40.5b
	Protein yield (t/ha)	N, P	18 kg N/ha	0.282c	0.0600
			75 kg N/ha	0.386b	0.0241
			146 kg N/ha	0.431a
			0 kg P/ha	0.358b	0.0467
			25 kg P/ha	0.412a