K Nutrition of Cotton

Potassium Nutritionof Cotton: 

Potassium Nutrition of Cotton

Outline – K Nutrition of Cotton: 

Outline – K Nutrition of Cotton U.S. cotton yields since 1975 Growth and development of the cotton plant Nutrient uptake General K nutrition and response K placement and timing considerations Foliar application Conclusions

U.S. Cotton Yield,1975 to Present . . . An Increasing Trend: 

U.S. Cotton Yield, 1975 to Present . . . An Increasing Trend Source: USDA-NASS

A Production Timeline for Irrigated Cotton in theTexas High Plains: 

A Production Timeline for Irrigated Cotton in the Texas High Plains Source: R. Boman

Early Season RootDevelopment of the Cotton Plant: 

Early Season Root Development of the Cotton Plant Source: Oosterhuis, 1990

Cotton Root Length asAffected by Days After Planting (Field Study): 

Cotton Root Length as Affected by Days After Planting (Field Study) Source: Schwab, Mullins & Burmester, 2000

Older K Uptake Patternvs. Newer Uptake Pattern: 

Older K Uptake Pattern vs. Newer Uptake Pattern A comparison of the percentages of maximum K and dry matter accumulated during the growing season by cotton grown in 1940 versus the mid-1980s Newer varieties accumulate K faster than older varieties

Cotton Nutrient Uptake Compared to Yield : 

Cotton Nutrient Uptake Compared to Yield * Irrigated tests

Cotton Peak NutrientUptake Rate 60 to 100 Days After Planting: 

Cotton Peak Nutrient Uptake Rate 60 to 100 Days After Planting Source: Mullins and Burmester, 1990; Schwab et al., 2000

Maximum Daily Uptakeof K, N, and P OccursNear Peak Blooming: 

Maximum Daily Uptake of K, N, and P Occurs Near Peak Blooming Source: Schwab et al., 2000 Lint yield 1,513 lb/A

Facts about K in Cotton Production: 

Facts about K in Cotton Production Affects quality (micronaire, length, and strength) Reduces the incidence and severity of wilt diseases Increases water use efficiency Functions in enzyme systems Bolls are major sinks for K, uptake may reach 3 lb/A/day during boll development About 70% of total uptake occurs after first bloom

K Uptake by Modern Cotton Varieties, Lint Yield 880 lb/A: 

K Uptake by Modern Cotton Varieties, Lint Yield 880 lb/A Source: Mullins & Burmester, 1990

K Compartmentation by Developing Cotton Bolls: 

K Compartmentation by Developing Cotton Bolls N-P-K compartmentation is 140-32-122 mg/boll 4.7 - 1 - 4 ratio Source: Leffler. 1986. Cotton Physiology

Reasons to BuildSoil Test K : 

Reasons to Build Soil Test K Stimulate photosynthetic efficiency Enhance efficient use of soil moisture Increase root growth for efficient uptake of other nutrients Capitalize on “good weather” years Minimize risk associated with “bad weather” years Raise soil productivity Increase yield potential of all crops in the rotation Improve grower profit potential Rules of thumb for raising soil test K 8 to 16 lb K2O needed above crop removal to build soil test K by 1 ppm on sandy loam to silt loam soils

Probability of a K Response: 

Probability of a K Response

Annual K FertilizationHas Advantages OverResidual K Fertility: 

Annual K Fertilization Has Advantages Over Residual K Fertility

Cotton Response to Timeand Rate of K Applicationin Alabama: 

Cotton Response to Time and Rate of K Application in Alabama Source: Mullins et al. 1999

Auburn University Research: 

Auburn University Research On low K soils, if a producer applies 90 lb K2O/A/year for 10 years, one might expect an average increase of 2.7 lb lint/lb K2O applied On medium K soils, if a producer applies 60 lb K2O for 6 years, one could expect 2.0 lb lint/lb K2O applied Lint yield peaked at a soil test of about 250 lb/A Mehlich 1 extractable K on a silt loam soil In some years, K fertilization increased lint yields by more than 450 lb/A

Relative Cotton Yield onTwo Silt Loam Soils asAffected by Soil Test K: 

Relative Cotton Yield on Two Silt Loam Soils as Affected by Soil Test K Source: D. Howard. 1997 soil test and 1998 yield in TN

Cotton Response to K2Oin Mississippi: 

Cotton Response to K2O in Mississippi

Adequate K Helps Sustain Yields in Seasons withLower Rainfall : 

Adequate K Helps Sustain Yields in Seasons with Lower Rainfall Source: Varco. 2000. Mississippi

Cotton K Response May Be Greater with No-Till Comparedto Disced or Plowed Systems: 

Cotton K Response May Be Greater with No-Till Compared to Disced or Plowed Systems Source: Varco. 2000. Mississippi

Soil K Stratification inNo-Till Cotton: 

Soil K Stratification in No-Till Cotton Test conducted from 1991 through 1996 on a Memphis silt loam soil in west Tennessee. Soil samples were collected after crop harvest in the fall of 1996. Cotton was planted within a few inches of the original rows each year. Source: Howard et al. 1999

Surface K Placement isEqual to or Superior to Subsurface Banding : 

Surface K Placement is Equal to or Superior to Subsurface Banding

Foliar K on Cotton: 

Foliar K on Cotton Under some conditions mid to late season foliar application of K on cotton can increase yield Foliar K response increased where soil K is low (low soil test level or fixation) root uptake is compromised petiole analysis indicates a pending shortage Foliar K begins to enter plant within 6 hours Maximum uptake occurs between 24 and 48 hours after application (60 to 65% of K) K is translocated to bolls with little delay once absorbed

Foliar K Research: 

Foliar K Research 3-year Beltwide test (Oosterhuis et al.,1994) showed variable response, with yield differences about 40% of the time California studies from 1992-1999 showed an average of about 100 lb lint/A response to foliar K on soils with high K fixation (vermiculite mineralogy) and high yield potential

Typical Cotton Response to Foliar K Fertilization inCalifornia: 

Typical Cotton Response to Foliar K Fertilization in California

Cotton Response to Soil and Foliar K Fertilization in No-tilland Disk-Till Systems (Tennessee): 

Cotton Response to Soil and Foliar K Fertilization in No-till and Disk-Till Systems (Tennessee)

Prevent Cotton K Deficiency: 

Prevent Cotton K Deficiency

Cotton K DeficiencySymptom in the Upper Canopy : 

Cotton K Deficiency Symptom in the Upper Canopy Rapid development of heavy boll load and boll maturation place big demand on plant K translocation

Conclusions: 

Conclusions Adequate K nutrition is critical in optimizing yield, quality, and profit in cotton production Placement of K fertilizer is not as important as the appropriate rates of K Soil application of K is the foundation of an effective program Increased soil test K levels may be required for reduced or no-till systems or under compacted soil conditions Soil test levels should be maintained in the medium to high range to assure consistent production, and that K does not limit cotton yield and quality

International Plant Nutrition Institute (IPNI)655 Engineering Drive, Suite 110Norcross, GA 30092-2604Phone: 770-447-0335; Fax: 770-448-0439Website: www.ipni.net: 

International Plant Nutrition Institute (IPNI) 655 Engineering Drive, Suite 110 Norcross, GA 30092-2604 Phone: 770-447-0335; Fax: 770-448-0439 Website: www.ipni.net Reference 06128