Agriculture Reference
In-Depth Information
The difference between soil VWC at 6 and 12 inches was greatest in the −30/-
25 kPa and smallest in the −45/-10 kPa treatment (Table 2). Much of this difference
was due to an increase in the soil VWC at the 12-inch depth. Interestingly, for a given
threshold (-30 kPa or −45 kPa) in the paired tensiometer treatments, the pulsed treat-
ments had a larger difference in soil VWC between the 6 and 12-inch depths.
These results indicate that the automated irrigation management system used in
this trial provided the desired soil moisture regimes, similar to previously suggested
thresholds [20, 39]. In addition, the utility of using an automated system for conduct-
ing irrigation research in a fi eld setting has been demonstrated. Total marketable yields
were not affected by irrigation treatment in 2009, but were signifi cantly affected in
2010 (Table 3). However, these were not signifi cant year by treatment interactions for
yield parameters measured.
In 2009, total marketable fruit yields averaged 44,780 kg·ha -1 . Yields of medium
fruit averaged 16,750 kg·ha -1 , with large and extra large fruit contributing 12,970 and
15,050 kg·ha -1 , respectively. In 2009, the −35 kPa treatment had signifi cantly less
large fruit than the other treatments. However, this did not result in different total
marketable yields. Average fruit weight was 287 g/fruit in 2009 and was not affected
by irrigation treatment. Cull fruit averaged 27.6% in 2009 and were not signifi cantly
different among treatments.
In 2010 total marketable fruit yields were signifi cantly affected by irrigation
treatment. Yields of medium and large fruit were unaffected, averaging 9750 and
4280 kg·ha -1 , respectively. However, yields of extra large fruit were affected by irriga-
tion regime (Table 3).
Yields of extra large fruit were lowest in the −30/-25 kPa treatment and highest
in the −45/-10 and −30/-10 kPa treatments. When comparing the longer-duration ir-
rigation regimes (-30/-10 and −45/-10 kPa) to the pulsed (-30/-25 and −45/-40 kPa)
programs, the extended-duration regimes had higher yields of extra large fruit at a
given setpoint. The −30/-10 kPa program yielded signifi cantly more extra large fruit
than the −30/-25 kPa regime. Similarly, the −45/-10 treatment yielded signifi cantly
more extra large fruit than the −45/-40 treatment. The pulsed, −40-kPa treatment had
yields of extra large fruit that were signifi cantly different from the −45/-10 kPa treat-
ment, but no others. The −45/-40 kPa treatment used the least amount of water while
producing yields that were no different from the highest yielding treatments in both
years of the trial. Average fruit weight was 105 g/fruit and was not affected by irriga-
tion regime in 2010. The average percentage of cull fruit was unaffected by treatment
in 2010 and was 53.5%. In 2010, the cull rate was signifi cantly greater than in 2009.
The high percentage of cull fruit was the result of large numbers of small fruit in 2010.
Yields for all grades of fruit and total marketable fruit were signifi cantly
greater in 2009 than in 2010. Total marketable fruit yields ranged from 38,500 -
48,210 kg·ha -1 in 2009 and 15,460-19,730 kg·ha -1 in 2010. Yields were appropri-
ate for fresh market tomato grown in Kentucky in 2009, which typically average
45,500 kg·ha -1 , but were considered low in 2010 [41]. The growing season in 2010
was warmer than 2009, resulting in smaller plants with signifi cantly lower yields.
Yields of medium fruit, which were not signifi cantly affected by irrigation treatment
 
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