Table 2. Shoot and grain dry weight (DW; g m⁻²) and total N, P and K contents (g m⁻²) of different maize varieties at silking in 2008 and at silking and maturity in 2009.

Years	Stage	Parameter	BMY	JHH	ZD2	TK5	ND108	ZD958
2008	Silking	Shoot DW	693b	-	865b	801b	-	1168a
		Total N	12.4 b	-	13.8b	13.1 b	-	22.2 a
		Total P	1.2 c	-	1.6 b	1.2 b	-	1.5 a
		Total K	5.6 c	-	8.9 b	7.8 b	-	10.8 a
2009	Silking	Shoot DW	707bc	652 c	760bc	800 b	932 a	946 a
		Total N	13.3bc	11.0c	13.1bc	14.6 ab	16.6 a	15.9 a
		Total P	1.5bc	1.4 c	1.5bc	1.8 ab	2.0 a	1.8 a
		Total K	8.4b	7.4b	9.0ab	10.8 a	10.7 a	10.7 a
	Maturity	Shoot DW	1295bc	1074c	1371 b	1763 a	2037 a	2006 a
		Grain DW	572bc	468 c	613 b	932 a	1013 a	1069 a
		Total N	16.3 b	13.4 b	15.8 b	20.5 a	22.7 a	20.9 a
		Total P	2.0 b	1.7 b	2.1 b	3.4 a	3.4 a	2.7 a
		Total K	6.9 c	6.4c	8.8 b	10.8 ab	11.2 a	12.5 a

BMY and JHH are early senescing varieties released in the 1950s; ZD2 and TK5 are two intermediate senescing hybrids released in the 1970s; ND108 and ZD958 are two currently popular stay-green hybrids. Values in rows followed by different letters represent significant differences between varieties (P<0.05) at a particular harvest. Values are means of three replications.