Yearly Crop Coefficient Plots

These are yearly crop coefficient plots for each year of the two peach plantings in the lysimeter. Both varieties were planted at a 6'x16' spacing and trained to a Kearney "V" system (Kearney Perpendicular "V" Training System - 1994). The O'Henry trees (1988-1997) were irrigated with a ring of 12 drip emitters around each tree. Irrigations were automatically called for after a weight loss equivalent to 1/4" (5-7 mm) of ET. Thus, irrigations occured daily with mature trees in the summer and every 2-3 days in the spring or when the trees were young. The Crimson Lady trees (1999-2006) were either irrigated by basin every 3 to 7 days or daily through a series of subsurface drip emitters at both 1' (30 cm) and 2' (60 cm) depth. The graphs also show harvest, summer pruning, water stress (accidental and intended) and rain events, as well as the proportion light interception measured at noon and the times when the lysimeter surface was covered to eliminate soil evaporation.

Shadow cast by the two peach trees in weighing lysimeter

	Crop coefficients (Kc) for mature peach trees derived from O'Henry and Crimson Lady trees planted in the Kearney weighing lysimeter. This graph is the average of all years when mature O'Henry (91-94) or Crimson Lady (02-05) peaches were growing in the lysimeter. Rainy days and periods of water stress have been removed.
	Kearney Peach Lysimeter Output - 1988, Year 1 of O'Henry Peach Planting This was the first year of the peach lysimeter operation so there were still some bugs to work out - data not too smooth. Trees grew OK, reaching a height of about 5' by the end of the season. Irrigation was stopped for about 3 weeks starting the end of August, which caused a substantial drop in wat...
	Kearney Peach Lysimeter Output - 1989, Year 2 of O'Henry Peach Planting Trees grew well in this second year, reaching a canopy cover of about 30% of the orchard floor by the end of the season. Lysimeter surface was covered on several dates showing a substantial contribution of soil evaportion to total ET. Irrigation cutoff in early September quickly reduced tree water u...
	Kearney Peach Lysimeter Output - 1990, Year 3 of O'Henry Peach Planting In their 3rd year of growth, the trees grew well, reaching a canopy cover of 50% of the orchard floor by the end of the season. Yield was equivalent to 14.1 tons/acre. During harvest, the irrigation pump failed for about a week, leading to substanial stress that took the trees a couple of months to ...
	Kearney Peach Lysimeter Output - 1991, Year 4 of O'Henry Peach Planting In their 4th year of growth, the trees were essentially full size, reaching 70% light interception by the end of the season. Yield was equivalent to 25.7 tons/acre. The crop coefficient (Kc) continued to increase throughout the season, reaching values of about 1.2 by September.
	Kearney Peach Lysimeter Output - 1992, Year 5 of O'Henry Peach Planting Trees grew well and were very productive, yielding the equivalent of 31.7 tons/acre. Automatic irrigations were called for daily during the middle of summer. Crop coefficient pattern was quite "smooth" this year and increased continually to values of about 1.2 by the end of September.
	Kearney Peach Lysimeter Output - 1993, Year 6 of O'Henry Peach Planting Trees were healthy and very productive this year, yielding the equivalent of 32.7 tons/acre. However, the lysimeter had a few problems. First, in the month of May there were some leaks and a mouse nest on the weigh beam. Data for this month are suspect. Second, there was a sudden, unexplained drop i...
	Kearney Peach Lysimeter Output - 1994, Year 7 of O'Henry Peach Planting Trees were healthy and grew well, but yield was down (22.6 tons/acre) due to heavy dormant pruning. Crop coefficients (Kc) were "smooth" and increased linearly until harvest and summer pruning in August. Values dropped from over 1.2 to about 1.0 for the rest of the season until irrigation cutoff in ...
	Kearney Peach Lysimeter Output - 1999, Year 1 of Crimson Lady Peach Planting This was the first year of the Crimson Lady planting. Trees were basin irrigated weekly and grew very well, reaching a height of 8.4' and canopy light interception of 30% by late September. At that time, crop coefficients were between 0.6 and 0.8.
	Kearney Peach Lysimeter Output - 2000, Year 2 of Crimson Lady Peach Planting For 2-yr-old trees, these peaches grew very well, reaching a height of 12.5' and a canopy light interception of 63%. Most of the fruit were thinned off to allow for maximum tree growth. Both basin and subsurface irrigation systems were used alternately throughout the season. Crop coefficients (Kc) i...
	Kearney Peach Lysimeter Output - 2001, Year 3 of Crimson Lady Peach Planting In their third season the trees grew well, reaching 75% canopy light interception by the end of September. The trees yielded 7.9 tons/acre, nearly a full crop for this early June harvested variety. Trees were accidently stressed in early July, but quickly recovered once the mistake was corrected. Cr...
	Kearney Peach Lysimeter Output - 2002, Year 4 of Crimson Lady Peach Planting The trees were healthy and productive this year, yielding the equivalent of 10.6 tons/acre. Irrigation was mostly by subsurface, but weekly basin irrigations were applied in May-June and again in July. Moderate water stress was measured at the end of each cycle. Canopy light interecption reached 86%...
	Kearney Peach Lysimeter Output - 2003, Year 5 of Crimson Lady Peach Planting Trees grew vigorouly this year, reaching a canopy light interception of 94%, which is the highest value ever measured in the lysimeter. Both subsurface and basin irrigation systems were used at different times, but were run frequently enough to prevent water stress. Crop yield was equivalent to 8.6 ...
	Kearney Peach Lysimeter Output - 2004, Year 6 of Crimson Lady Peach Planting Trees grew well and had a yield equivalent to 9.1 tons/acre. Mechanical topping occurred on June 1, which reduced light interception but didn't affect the crop coefficient. Irrigation was by subsurface and was triggered 2 to 4 times per day. Crop coefficients reached values of 1.0 to 1.2 during much...
	Kearney Peach Lysimeter Output - 2005, Year 7 of Crimson Lady Peach Planting Trees were healthy and productive as they yielded the equivalent of 9.8 tons/acre. Due to plugged emitters, the trees were stressed in May - problem corrected in early June. Trees were mechanically topped on June 1. Crop coefficient (Kc) values were between 1.0 and 1.2 for most of the summer until e...