Enhanced Efficiency Liquid Nitrogen Fertilizer Management for Corn Production

Table 4

Corn SPAD, plant population, and grain yield response to nitrogen sources/placements at 84 kg·N·ha⁻¹. Data were combined over factors or years in the absence of a significant interaction. Surface treatments were no-tillage with surface applied nitrogen and deep treatments were strip tillage with deep banded nitrogen application.

N source placement	Chlorophyll meter readings						Population		Grain yield
	2011		2012		2013				2011		2012		2013
	F	S	F	S	F	S	F	S	F	S	F	S	F	S
	SPAD units						No. ha^−1		Mg·ha^−1-
Surface UAN^†	48.2	44.6	47.9	48.8	39.2	39.3	70,000	67,800	6.91	5.98	2.14	2.30	6.53	7.23
Deep UAN	54.4	53.4	51.3	53.7	44.0	44.0	66,750	56,100	8.12	3.91	1.73	2.11	7.62	7.53
Surface NF	46.8	47.8	48.6	47.8	41.7	42.1	70,400	70,050	6.85	5.70	2.02	2.50	6.82	7.75
Deep NF	52.1	55.3	52.4	53.4	41.8	37.8	68,500	59,150	7.01	4.72	1.33	1.76	7.17	6.70
Deep AA	55.7	55.2	53.8	52.5	37.5	45.8	64,200	60,100	6.70	4.41	1.60	1.70	5.97	7.58
LSD ()^‡	4.7						8,700		0.95

^†Abbreviations: AA, anhydrous ammonia; F, fall; NF, Nitamin Nfusion; S, spring; UAN, 32% urea ammonium nitrate. ^‡Fisher’s protected least significant difference at .