Lookup Tables for Fertilizer/Crop Combinations

Interpreting SBU and crop safety

PLEASE NOTE –

· THAT THESE SAFE RATES ARE DERIVED FROM MAINLY US DATA AND ARE FOR MOIST SEEDBEDS.
· THE VALUES GIVEN ARE IN KG PER HECTARE OF FERTILIZER
· THE SAFE RATES ASSUME THAT A 15% REDUCTION IN PLANT DENSITY IS ACCEPTABLE.
· THESE ARE INDICATIVE RATES ONLY AND SHOULD BE INTERPRETED IN THE LIGHT OF LOCAL SOIL TYPES, PREVAILING SOIL MOISTURE AND EQUIPMENT OPERATING METHODS.

ALSO – There were no data available on safe rates for Ammonium Sulphate on wheat, although it would be expected that wheat would be more tolerant of this fertilizer than canola.



Other fertilizer/crop/SBU can be estimated using the tool developed in the US by Dr Ron Gelderman of South Dakota State University for “Estimating the potential for crop from seed placed fertilizer”.

Table 1 – For wheat & urea – approximate safe fertilizer rates (kg of urea/ha) for in-furrow application for two seeders at three row spacings on three soil types. This assumes a moist seedbed.

Opener type	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	36	31	28	65	53	45
Medium (loam/clay loam) texture	56	51	48	90	73	65
Heavy (clay) texture	67	61	58	105	85	71

Table 2 – For canola & urea – approximate safe product rates (kg of urea/ha) for in-furrow application for two seeders at three row spacings on three soil types. This assumes a moist seedbed.

Opener type	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	12	0	0	45	28	20
Medium (loam/clay loam) texture	21	16	14	60	41	30
Heavy (clay) texture	34	26	21	80	58	45

Table 3 – For wheat & DAP – approximate safe fertilizer rates (kg product as DAP/ha) for in-furrow application for two seeders at three row spacings on two soil types. This assumes a moist seedbed.

	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
Opener type and row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	80	50	40	240	160	120
Medium (loam/clay loam) texture	120	80	60	360	250	150

Table 4 – For canola & DAP - approximate safe fertilizer rates (kg product as DAP/ha) for in-furrow application for two seeders at three row spacings on two soil types. This assumes a moist seedbed.

Opener type	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	30	20	15	100	60	50
Medium (loam/clay loam) texture	50	30	25	150	100	70

Table 5 – For wheat & MAP – approximate safe fertilizer rates (kg product as MAP/ha) for in-furrow application for two seeders at three row spacings on two soil types. This assumes a moist seedbed.

Opener type	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	120	80	60	350	250	180
Medium (loam/clay loam) texture	180	120	90	500	370	270

Table 6 – For canola & MAP - approximate safe fertilizer rates (kg product as MAP/ha) for in-furrow application for two seeders at three row spacings on two soil types. This assumes a moist seedbed.

Opener type	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	50	35	25	150	100	75
Medium (loam/clay loam) texture	75	50	40	230	150	110

Table 7 – For wheat & Muriate of Potash (MOP) – approximate safe fertilizer rates (kg product as MOP/ha) for in-furrow application for two seeders at three row spacings on two soil types. This assumes a moist seedbed.

Opener type	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	50	40	30	170	110	80
Medium (loam/clay loam) texture	80	50	40	250	170	120

Table 8 – For canola & Muriate of Potash (MOP) - approximate safe fertilizer rates (kg product as MOP) for in-furrow application for two seeders at three row spacings on two soil types. This assumes a moist seedbed.

Opener type	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	30	20	15	100	65	50
Medium (loam/clay loam) texture	50	35	25	150	100	75

Table 9 – For canola & ammonium sulphate - approximate safe fertilizer rates (kg product as Ammonium sulphate) for in-furrow application for two seeders at three row spacings on three soil types. This assumes a moist seedbed.

Opener type	Inverted T or similar narrow point/opener (2.5 cm spread)			Share or similar mixing point (7.5 cm spread)
row spacing (cm)	15	22.5	30	15	22.5	30
Light (sandy loam) texture	48	24	14	175	107	75
Medium (loam/clay loam) texture	85	59	45	245	162	125
Heavy (clay) texture	131	98	85	325	227	180

The tables above were adapted from the IPNI tool - which can be downloaded from the IPNI "Software Applications Site" by selecting the "Seed Placed Fertilizer Decision Aid". This spreadsheet tool was developed by Ronald Gelderman of South Dakota State University to assist with selecting safe in-furrow application rates for various fertilizer, crop, machinery and environment situations. An Australian version is being developed.

Rates in the spreadsheet tool are given in imperial units and as oxides for P (P₂O₅) and K (K₂O), and these values can be converted to metric units as follows:

Imperial (US) to Metric		Metric to Imperial (US)
1.00 lb/acre	1.12 kg/ha	1.00 kg/ha	0.89 lb/acre
1.00 US gal/acre	9.35 l/ha	1.00 l/ha	0.11 US gal/acre
1.00 inch	25 mm	1 mm	0.04 inches
1.00 lbs/acre N	1.12kg/ha N	1.00 kg/ha N	0.89 lb/acre N
1 lbP2O5	0.44 kg P	1.00 kg P	2.27 kg P2O5
1.00 lbs/acre P2O5	0.49 kg/ha P	1.00 kg/ha P	2.05 lb/acre P2O5
1.00 lb K2O	0.83 kg K	1.00 kg K	1.20 lb K2O
1.00 lbs/acre K2O	0.93 kg/ha K	1.00 kg/ha K	1.08 lb/acre K2O
1.00 lb/acre S	1.12 kg/ha S	1.00 kg/ha S	0.89 lb/acre S
1.00 lb/acre Mg	1.12 kg/ha Mg	1.00 kg/ha Mg	0.89 lb/acre Mg