Potassium requirements of pastures on North Island east coast hill country in New Zealand

Figures & data

Table 1. The effect of K application rate on soil QT K levels for each site in each year.

Year/site	Soil QT K level					LSD (5%)
K rate (kg/ha/yr)	0	15	30	50	80
2004/2005
Waipawa-flat	4.0	4.5	4.7	4.0	5.0	0.91
Waipawa-easy	4.5	4.2	5.2	7.0	6.2	1.26
Puketapu-flat	2.7	2.2	3.0	2.7	3.0	NS
Wairoa-flat	2.7	3.0	3.2	3.2	4.0	0.46
Wairoa-easy	2.0	2.2	2.7	2.5	3.0	0.38
K rate (kg/ha/yr)	0	30	60	100	160
2005/2006
Waipawa-flat	3.8	4.3	4.0	4.5	6.0	1.03
Waipawa-easy	6.0	5.5	7.5	7.3	10.0	1.57
Puketapu-flat	2.6	2.8	2.8	2.8	3.8	0.38
Wairoa-flat	3.3	3.3	3.8	4.0	6.0	0.86
Wairoa-easy	2.5	2.5	3.3	3.3	4.5	NS
K rate (kg/ha/yr)	0	30	60	100	160
2006/2007
Waipawa-flat	3.8	3.5	5.3	4.5	6.0	1.02
Waipawa-easy	5.3	5.8	7.3	8.5	11.3	1.57
Puketapu-flat	2.3	2.0	2.5	3.3	3.5	0.52
Wairoa-flat	3.0	3.0	3.3	4.5	4.8	0.47
Wairoa-easy	2.0	2.5	3.0	4.5	6.0	0.69

Note: LSD is least significant difference in soil QT K between treatments (P < .05). NS denotes non-significant differences in soil QT K between treatments at the 5% level.

Table 2. The effect of K application rate on herbage K content in November of each year. LSD is least significant difference in herbage K content between treatments (P < .05).

Site	Herbage K content (%)					LSD (5%)
K rate (kg/ha/yr)	0	15	30	50	80
2004
Waipawa-flat	1.91	2.11	2.14	2.24	2.37	0.29
Waipawa-easy	1.77	1.67	1.71	1.80	2.03	NS
Puketapu-flat	1.78	1.58	1.78	1.78	2.13	0.21
Wairoa-flat	2.30	2.52	2.82	2.67	2.97	0.35
Wairoa-easy	1.84	1.90	1.91	2.24	2.30	0.19
K rate (kg/ha/yr)	0	30	60	100	160
2005
Waipawa-flat	2.00	2.38	2.42	2.72	2.79	0.27
Waipawa-easy	2.06	2.48	2.81	3.14	3.56	0.31
Puketapu-flat	2.56	2.59	3.21	3.25	3.97	0.45
Wairoa-flat	2.43	2.82	3.31	3.42	3.87	0.26
Wairoa-easy	1.77	1.81	2.35	2.75	3.27	0.18
K rate (kg/ha/yr)	0	30	60	100	160
2006
Waipawa-flat	1.56	1.72	2.17	2.34	2.58	0.30
Waipawa-easy	1.75	2.03	2.20	2.55	2.73	0.25
Puketapu-flat	1.69	1.59	1.83	2.03	2.89	0.25
Wairoa-flat	1.85	2.40	2.77	2.57	3.20	0.27
Wairoa-easy	1.45	1.76	2.09	2.68	3.24	0.29

Note: NS denotes non-significant differences in herbage K content at the 5% level.

Table 3. Clover cover on measurements dates where significant responses (P < .05) to K application rate were measured.

Site/measurement date	Clover cover (%)					LSD (5%)
K rate (kg/ha/yr)	0	15	30	50	80
2004/2005
Waipawa-flat 12/10/04	65	72	83	83	90	12.8
18/4/05	30	24	29	15	19	14.2
Puketapu-flat 30/9/04	48	66	50	66	60	17.2
1/11/04	68	70	68	75	83	13.8
Wairoa-flat 16/2/05	58	66	56	74	72	15.2
Wairoa-easy 1/12/04	13	30	20	48	38	16.7
K rate (kg/ha/yr)	0	30	60	100	160
2005/2006
Puketapu-flat 31/10/05	18	16	26	28	45	9.5
18/11/05	13	15	28	23	43	10.7
15/12/05	35	45	45	50	58	12.9
Wairoa-flat 15/9/05	16	60	48	40	62	16.9
1/11/05	22	59	35	45	51	13.2
25/11/05	28	59	50	70	66	15.5
Wairoa-easy 8/10/05	35	53	55	60	70	16.1
1/11/05	43	65	73	70	78	18.0
25/11/05	41	60	70	73	80	19.1
19/12/05	38	60	75	75	80	19.0
K rate (kg/ha/yr)	0	30	60	100	160
2006/2007
Waipawa-flat 18/9/06	70	77	75	79	81	6.4
27/11/06	63	65	67	79	76	11.8
Puketapu-flat 19/9/06	20	23	48	58	55	12.7
10/10/06	6	20	63	73	73	9.0
1/11/06	8	18	65	75	80	9.2
15/1/07	24	14	48	55	58	16.6
Wairoa-flat 28/9/06	7	25	53	28	36	10.9
31/10/06	11	37	60	50	50	12.5
23/11/06	19	57	73	65	52	18.2
Wairoa-easy 23/11/06	30	50	60	31	58	17.0

Note: LSD is the least significant difference in clover cover between treatments (P < .05).

Table 4. Annual pasture production at each rate of K application for each site. LSD is the least significant difference in annual pasture production between treatments (P < .05).

Site	Annual pasture production (kg DM/ha/yr)					Signif. (5%)
K rate (kg/ha/yr)	0	15	30	50	80
2004/2005
Waipawa-flat	7400	6920	7440	8100	7640	NS
Waipawa-easy	3090	3130	2920	3110	3420	NS
Puketapu-flat	3930	4170	4260	4710	4490	NS
Wairoa-flat	6980	6340	6360	6310	6200	NS
Wairoa-easy	3670	3610	2930	2620	3590	NS
K rate (kg/ha/yr)	0	30	60	100	160
2005/2006
Waipawa-flat	7300	7630	6810	7770	8140	NS
Waipawa-easy	3200	2925	3020	3470	3240	NS
Puketapu-flat	4600	4660	4820	5130	5080	NS
Wairoa-flat	9140	9470	9130	9320	9690	NS
Wairoa-easy	4650	4690	4750	4780	5490	NS
K rate (kg/ha/yr)	0	30	60	100	160
2006/2007
Waipawa-flat	5750	6030	5900	6440	7130	NS
Waipawa-easy	2420	2340	2350	2720	2450	NS
Puketapu-flat	2930	3160	4060	4630	5085	LSD = 538
Wairoa-flat	4440	4490	4670	4760	4700	NS
Wairoa-easy	1700	1940	1330	1420	2170	NS

Note: NS denotes non-significant differences in annual pasture production at the 5% level.