Effects of Vegetation-Free Strip Width and Irrigation on Newly Planted Peach

Figures & data

Table 1. Precipitation and irrigation data for Clayton and Jackson Springs, NC from 2006 to 2008.

	Clayton^a						Jackson Springs^b
	Precipitation			Irrigation^c			Precipitation			Irrigation^c
	2006	2007	2008	2006	2007	2008	2006	2007	2008	2006	2007	2008
Month	^___________________________________________________________ cm ^_________________________________________________________
March	3.2	8.1	8.02	0	0	0	4.97	7.49	8.76	0	0	0
April	9.67	8.4	14.42	0	0	0	8.48	9.14	11.96	0	0	0
May	11.17	2.31	7.34	0	5.08	0	8.28	3.47	5.33	0	5.08	0
June	21.92	6.5	6.78	0	5.08	7.62	29.38	8.53	4.08	2.54	10.16	10.16
July	5.38	10.38	12.44	5.08	2.54	5.08	3.3	6.37	13.23	8.89	7.62	5.08
August	8.35	1.8	4.95	7.62	12.7	2.54	14.75	1.04	22.27	7.62	7.62	2.54
September	11.02	8	4.26	0	0	0	9.98	4.24	14.98	0	0	0
October	9.09	7.79	3.98	0	0	0	7.79	12.92	4.14	0	0	0

^aPrecipitation data were obtained from the weather station located at Central Crops Research Station in 2006 and 2008 and State Climate Office of North Carolina ECOnet Database in 2007.

^bPrecipitation data were obtained from the weather station located at the Sandhills Research Station, Jackson Springs, NC.

^cIrrigation was applied to irrigated plots only and was 2.54 cm of water at each time.

Table 2. Regression analyses of total dry biomass (kg ha⁻¹) of herbaceous vegetation as influenced by vegetation-free strip width (VFSW) for various sampling dates combined over irrigation type.^a

Location	Sample Date	VFSW P Value	Equation	R^2
Clayton	21 May 2007	0.0002	Y = 402.0–121.7w	0.87
Clayton	13 Aug 2007	0.0008	Y = 873.4–222.1w	0.57
Clayton	22 April 2008	0.0002	Y = 760.5–215.8w	0.80
Clayton	08 Sept. 2008	< 0.0001	Y = 2927–789.6w	0.90
Jackson Springs	16 May 2007	< 0.0001	Y = 929.8–286.3w	0.95
Jackson Springs	10 Aug. 2007	0.0142	Y = 181.8–49.1w	0.57
Jackson Springs	22 May 2008	0.0003	Y = 1950.3–511.3w	0.61
Jackson Springs	15 Sept. 2008	< 0.0001	Y = 2159.5–658.2w	0.94

^aVFSWs of 3.6 m were not included in the analysis.

Figure 1. Effect of irrigation and VFSW on peach tree trunk cross-sectional area (TCSA), Clayton, NC, from 2006 to 2008. The value of VFSW at which the response plateau is represented by v.

Figure 2. Effect of irrigation and VFSW on peach tree trunk cross-sectional area (TCSA), Jackson Springs, NC, from 2006 to 2008. The value of VFSW at which the response plateau is represented by v.

Table 3. Parameter estimates and equivalent irrigated vegetation-free strip width (VFSW) to 3.0 m nonirrigated for peach tree winter pruning fresh biomass as influenced by VFSW and irrigation, at Clayton and Jackson Springs, NC, 2007 and 2008. (All pruning were cut and recorded in March of the year listed, therefore reflect previous growing season).

		Irrigated				Nonirrigated					Equivalent irrigated
Location	Year	a	b	c v (m)^a	R^2	a	b	c	v (m)	R^2	VFSW (m)^b
Clayton	2007	0.86	1.61	−0.30 2.72	0.75	1.11	0.62	-	-	0.88	2.17
	2008^c	-	-	-	-	-	-	-	-	-	-
Jackson	2007	0.12	0.73	−0.12 3.04	0.98	0.20	0.34	−0.03	5.98	0.98	1.53
Springs	2008	0.83	1.26	−0.10 6.27	0.95	0.63	0.81	−0.05	7.19	0.96	1.60

^aThe value of VFSW at which the response plateau is represented by v.

^bThe value of the irrigated VFSW for which pruning are equivalent to the 3.0 m VFSW, nonirrigated treatment.

^cClayton 2008 was not different by irrigation (P = 0.7980), and both levels followed liner the trend as Y = 0.73 + 0.76 VFSW; R² = 0.55.

Figure 3. Effect of irrigation and VFSW on SPAD value of peach, averaged across four sampling dates, Clayton, NC in 2008. The value of VFSW at which the response plateau is represented by v.

Figure 4. Effect of irrigation on SPAD value (a) 0 m VFSW, (b) averaged over 0.6 and 1.2 m VFSW, and (c) averaged over 2.4, 3.0, and 3.6 m VFSW at various sampling dates, Jackson Springs, NC in 2008.

Table 4. Parameter estimates for peach harvest as influenced by vegetation-free strip width (VFSW) and irrigation, Jackson Springs, NC, 2008.

		Irrigated				Nonirrigated				Equivalent irrigated
Parameter	Unit	a	b	c v (m)^a	R^2	a	b	c v (m)^a	R^2	VFSW (m)^b
Clayton
Yield	10^3 kg ha^−1	4.79	2.03	−	0.87	6.14	2.22	−	0.90	3.95
Fruit biomass	g fruit^−1	38.61	2.69	−	0.82	44.71	2.60	−	0.87	5.17
Jackson Springs
Yield	10^3 kg ha^−1	2.40	1.49	−0.15 5.12	0.83	1.44	1.07	−0.08 7.07	0.86	1.16
Fruit biomass	g fruit^−1	42.4	7.07	−1.25 2.83	0.96	35.6	8.12	−2.07 1.96	0.82	0.07

^aThe value of VFSW at which the response plateau is represented by v.

^bThe value of the irrigated VFSW for which prunings are equivalent to the 3.0 m VFSW, nonirrigated treatment.

Figure 5. Effect of irrigation and VFSW on total fruit yield (A) Clayton and (B) Jackson Springs, NC in 2008. The value of VFSW at which the response plateau is represented by v.