VARIETY AND IRRIGATION EFFECTS ON POTASSIUM RATES IN COTTON BEATRIX J. HAGGARD, PH.D.
Nutrient uptake rate lb K/acre/day POTASSIUM IN COTTON Potassium is needed for: Boll development and filling Fiber elongation Reduced diseases Peak uptake occurs between First bloom Peak bloom Mullins and Burmester, 1990
POTASSIUM UPTAKE Potassium deficiency symptoms Upper leaves Seen Recently Lower leaves Ideas for deficiency locations Potassium deficiencies should appear in lower leaves Potassium is mobile in the plant Newer varieties with increased boll load Seen mostly during boll development Increased occurrence of upper leaf deficiencies Potassium availability in the soil is directly tied to soil moisture
OBJECTIVES Variety by Potassium Rate Compare yields, leaf potassium content, gin turnout, and fiber quality of cotton under differing potassium rates Potassium Rate by Irrigation Evaluate the effect of irrigation on K deficiency and/or leaf spot incidence
TRIAL SETUP Location St. Joseph, Louisiana Commerce silt loam (Fine-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquepts) Variety by Potassium 5 current varieties were selected Stoneville 5288 B2F Deltapine 0912 B2RF Deltapine 1321 B2RF Phytogen 499 WRF Phytogen 339 WRF 3 potassium rates 0 lbs K2O/acre 60 lbs K2O/acre 120 lbs K2O/acre
Rainfall (Inches) PRECIPITATION DURING 2013 GROWING SEASON 30 Daily Rainfall Cumulative Rainfall 21.54 inches Cumulative Rainfall 20 Planted Tissue Sample Tissue Sample Tissue Sample Picked 10 0 Date
1-May 8-May 15-May 22-May 29-May 5-Jun 12-Jun 19-Jun 26-Jun 3-Jul 10-Jul 17-Jul 24-Jul 31-Jul 7-Aug 14-Aug 21-Aug 28-Aug 4-Sep 11-Sep 18-Sep 25-Sep 2-Oct 9-Oct Rainfall (inches) PRECIPITATION DURING 2014 GROWING SEASON 30 Daily Rainfall Cumulative Rainfall 28.08 inches Cumulative Rainfall 20 VxK 5/5 Irrigation Trial 5/23 Picked 10/8 10 0 Date
Visual Rating (0-5 scale) LEAF SPOT VS. COTTON VARIETY AT 3 K RATES 2013 5.0 4.5 0 60 120 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ST 5288 Phy 499 DP 1321 DP 0912 Phy 339 Cotton Varieties
Yield (Bales) RESULTS 2013 3.0 2.5 2.0 1.5 1.0 ST 5288 Phy 499 DP 1321 DP 0912 Phy 339 Cotton Variety
Visual Rating (0-5 scale) LEAF SPOT VS. COTTON VARIETY AT 3 K RATES 2014 5.0 4.5 0 60 120 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ST 5288 Phy 499 DP 1321 DP 0912 Phy 339 Cotton Varieties
Yield (Bales) RESULTS 2014 3.0 2.5 2.0 1.5 1.0 ST 5288 Phy 499 DP 1321 DP 0912 Phy 339 Cotton Variety
Yield (Bales) RESULTS 2013 3.0 2.5 2.0 1.5 1.0 0 60 120 Potassium Rate (lbs K/acre)
Yield (Bales) RESULTS 2014 3.0 2.5 AB B A 2.0 1.5 1.0 0 60 120 Potassium Rate (lbs K/acre)
Yield (Bales) 3.5 2012 POTASSIUM TRIAL - JOHN KRUSE 0 60 120 3.0 2.5 2.0 1.5 1.0 PHY 499 WRF ST 5458 B2RF DP 0912 B2RF Cotton Varieties
IRRIGATED VS. NON-IRRIGATED K is transported through soil water Even with K present, K deficiencies can exist if the plant is not able to access the K Due to the inconsistencies that had been seen with the previous data, it was decided to evaluate K with and without irrigation Non-Irrigated 120 lbs K/ac Irrigated 120 lbs K/ac
TRIAL SETUP Location St. Joseph, Louisiana Commerce silt loam(fine-silty, mixed, superactive, nonacid, thermic Fluvaquentic Endoaquepts) Irrigated vs Non-Irrigated Variety planted Deltapine 0912 B2RF 5 potassium rates 0, 30, 60, 90, and 120 lbs K 2 O/acre
Yield (Bales) IRRIGATED VS. NON-IRRIGATED 2.2 Irrigated Non-Irrigated 1.8 a [CELLRANGE] [CELLRANGE] [CELLRANGE] a [CELLRANGE] 1.4 b b 1.0 0 30 60 120 0 30 60 120 Potassium Rate (lbs K/acre)
OVERALL FINDINGS Water is the primary factor controlling K availability For the 5 varieties of cotton No significant yield differences were observed across K rates Very beneficial, so we do not have to recommend differing rates according to variety Yield inconsistencies were seen on a Commerce silt loam This is going to be evaluated in a greenhouse to determine if there are any nutrient ratios that could be causing this to occur Mg/K or Ca/K No differences were seen in 2013 for Mic values
OVERALL FINDINGS Water is the primary factor controlling K availability For the Irrigated vs Non-Irrigated Additional K that was applied to the plots did not influence the yield as much as the irrigation For a non-irrigated system, 120 lbs of K/acre was needed to achieve similar yields to that found in an irrigated system even under lower K rates
2014 SUMMER AGRONOMY/SOILS CREW