Environmentally Smart Nitrogen Performance in Northern Great Plains’ Spring Wheat Production Systems

Table 7

Simple effects of two-way interactions of source by at-seeding and topdress N rates for N uptake from selected site-years where interaction effect was significant at least at .

Site-year	⁢At-seeding N rate, kg ha^−1	Source
		Blend	ESN	Urea
	kg ha^−1
Conrad-2011	56	34.6	29.4	30.3
	112	32.7	41.2	41.5
	168	49.7	47.6	37.3
	Prob > (trend)	0.05^‡	0.008^‡	0.045
Conrad-2013	56	89.5	94	95.2
	112	100.1	100.7	96.5
	168	104.8	93.9	94.5
	Prob > (trend)	0.022^‡	0.165	0.754
Kalispell-2011	112	64	74.1	68.7
	224	77.7	77.1	73.5
	336	81.5	80.2	71.5
	Prob > (trend)	0.007^‡	0.068^‡	0.171
	Topdress N, kg
Conrad-2013	0	94.9	93.1	99.1
	45	101.4	99.3	90.7

Across rows for each site-year, at-seeding N rate, or topdress N rate, LS means followed by different uppercase letters are significant at .
represents significant linear trend, for at-seeding N rate for each site-year.
Down a column for topdress N rates, LS means followed by different lowercase letters are significant at for each source.