TX-53F Haby 07 Annual Rpt.pdf

TX-53
Table 16. Tifton 85 bermudagrass P conc. response to N and K rates and K, Cl, and S sources in 2007.
N rate Plant P concentration †
lb/ac/harv. Harvest 1 Harvest 2 Harvest 3 Harvest 4 Harvest 5 Season avg.
---------------------------------------------------%--------------------------------------------------
60 0.52 b 0.49 0.39 0.43 0.32 0.43
120 0.56 a 0.50 0.36 0.40 0.29 0.42
K rate
lb K 2 O/ac
0 0.67 a 0.59 a 0.55 a 0.50 a 0.36 a 0.54 a
134 0.57 b 0.53 b 0.37 b 0.44 b 0.30 b 0.44 b
268 0.50 c 0.47 c 0.37 b 0.40 c 0.31 b 0.41 c
402 0.52 c 0.45 c 0.34 b 0.37 d 0.29 b 0.39 c
K Source
KCl 0.54 0.50 a 0.38 a 0.43 a 0.37 a 0.44 a
KMag+KCl 0.50 0.48 b 0.36 b 0.40 b 0.27 b 0.40 b
ACT 62D+KCl 0.54 0.47 b 0.33 c 0.37 c 0.25 b 0.39 b
R 2 0.77 0.81 0.84 0.77 0.71 0.90
c.v. 9.72 6.46 9.76 9.04 17.30 5.01
† Values in a column/group followed by a dissimilar letter are significantly different statistically (α = 0.05).
Plant C concentration was unaffected by N rate and declined as yield increased in the first three harvests
and season average, but in the fourth and fifth harvests C content was unaffected by increased K
application rates. Even though statistically significant differences are indicated, there is little difference
in the C content of bermudagrass treated with KCl, KMag+KCl, or ACT 62D+KCl.
Table 17. Tifton 85 bermudagrass C conc. response to N and K rates and K, Cl, and S sources, 2007.
N rate Plant C concentration †
lb/ac/harv. Harvest 1 Harvest 2 Harvest 3 Harvest 4 Harvest 5 Season avg.
--------------------------------------------------%---------------------------------------------------
60 44.42 45.27 45.41 46.10 46.63 45.57
120 44.34 45.30 45.59 46.44 46.35 45.60
K rate
lb K 2 O/ac
0 45.19 a 45.84 a 46.15 a 46.75 46.41 46.07 a
134 44.38 b 45.44 b 45.70 b 46.41 46.72 45.73 b
268 44.33 b 45.19 c 45.43 c 46.03 46.36 45.47 c
402 44.17 b 45.05 c 45.16 d 46.21 46.43 45.40 c
K Source
KCl 44.42 a 45.33 a 45.50 a 46.14 46.19 b 45.52 ab
KMag+KCl 44.25 ab 45.30 a 45.53 a 46.37 46.78 a 45.65 a
ACT 62D+KCl 44.20 b 45.06 b 45.26 b 46.14 46.53 ab 45.44 b
R 2 0.67 0.79 0.76 0.43 0.61 0.70
c.v. 0.67 0.50 0.74 1.54 1.28 0.53
† Values in a column/group followed by a dissimilar letter are significantly different statistically (α = 0.05).
After the first year of treatment application and bermudagrass production, there were no statistically
significant treatment effects on pH, P, Ca, or Cl from N or K rates or K sources.. Increased yields at the
higher N rate lowered soil K and Mg. Increasing K rates significantly increased levels of Mehlich III
extractable soil K. The KCl and KMag+KCl treatments significantly increased extractable soil K
compared to ACT 62D+KCl. The KMag+KCl treatment significantly increased extractable Mg compared
to KCl or ACT 62D+KCl treatments. The ACT 62D+KCl treatment significantly raised the level of S in
the 0- to 6-inch depth compared to KCl alone or KMag+KCl. The Darco soil was not sampled deeper
than six inches in fall of 2007. Zinc levels in soil were not analyzed in these soil samples in 2007.
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