Charles H. Burmester Extension Agronomist Auburn University

Effect of Surface Application of Nitrogen Fertilizer Sources on

Cotton Yields and Quality inA Conservation Tillage

System

Charles H. Burmester

Extension Agronomist

Auburn University

Test Information

• Location: Tenn. Valley Research and Extension Center• Soil Type: Decatur Silt Loam• Variety : DP&L 454 Bt/RR• Tillage : No-Till Wheat Cover• Planting Date: April 24th

• Preplant N : 24lb/A• Plot Area: Irrigated

Fertilizers

• 34% Ammonium Nitrate

• 46% Urea

• 44.6% Urea + Calcium Thiosulfate 4.5%

• 42.3% Urea + Calcium Thiosulfate 7.0%

• 46% Urea + Agrotain(1 gal/Ton)

N RATES

60, 90 LB/A

Surface Applied June 5th

Rainfall 0.51 inch June 12th

Cotton 4-5 Leaf Stage

Fertilizers

Fertilizers

Fertilizers

Fertilizers

Cover Crop

TEST SITE

Data Collected

• Cotton leaf samples in mid July - cotton in 3rd week of bloom

• NAWF measurement in early August

• Cotton yields and quality

Pre-Harvest DataTreatment NAWF %N

60 Amm-Nit 4.3 abc 3.67 cd

60 Urea 3.8 bcd 3.41 e

60 U-Cats-4.5 3.7 bcd 3.43 e

60 U-Cats-7.0 3.6 cd 3.41 e

60 U-Agrotain 3.5 d 3.48 de

90 Amm-Nit 4.7 a 3.98 ab

90 Urea 3.9 bcd 3.85 abc

90 U-Cats-4.5 4.1 abcd 3.93 ab

90-U-Cats-7.0 4.0 abcd 3.81 bc

90-U-Agrotain 4.4 ab 4.04 aLSD (0.05 =.75 LSD (.05) = 0.23

Pre-Harvest Data

• Nutrient analysis of cotton leaves revealed no differences due to treatment in concentration of P, K, Ca or Mg.

• P levels averaged 0.27%

• K levels averaged 1.75%

• Mg levels averaged 0.34%

• Ca levels averaged 1.50%

Seed Cotton Yields

1500170019002100230025002700290031003300350037003900

Amm Nit Urea U-Cats-4.5 U-Cats-7.0 U-Agrotain

60

90

b

ac

c

bbc

a

bc

a

bc

a

LSD (0.05) =269CV = 5.4%

Cotton QualityTreatments Mic Len Str. Unif Lint%

60 Amm-N 4.67 1.09 28.6 82.8 0.46

60 Urea 4.40 1.10 28.8 83.3 0.46

60 U-Cats-4.5% 4.30 1.10 29.1 83.1 0.46

60 U-Cats-7.0% 4.30 1.10 28.7 83.1 0.47

60 U-Agrotain 4.37 1.11 28.9 83.0 0.46

90 Amm-N 4.50 1.10 28.7 82.7 0.46

90 Urea 4.50 1.10 28.6 83.2 0.46

90 U-Cats-4.5% 4.53 1.11 28.9 83.3 0.46

90 U-Cats-7.0% 4.60 1.09 29.1 83.0 0.46

90 U-Agrotain 4.57 1.10 27.9 82.5 0.45

Conclusions

• Increasing N fertilizer rates from 60 to 90 lb/A increased NAWF, Leaf N, and yields with all N sources.

• Cotton yields using Agrotain and Thiosulfate fertilizers were not significantly different than Ammonium Nitrate in this test.

Conclusions

• Cotton yields using urea fertilizer were significantly lower than yields produced using ammonium nitrate at both N fertilizer rates.

• Agrotain and thiosulfate fertilizers produced significantly higher cotton yields than urea fertilizer at the 90 lb/A rate of N fertilizer.

Conclusions

• Both Agrotain and the Thiosulfate fertilizers tested may be useful in reducing N loss from urea under a high residue conservation tillage cotton system.

Acknowledgement

• Thanks to Joe Duck with Agrotain International and John Clapp with Tessenderlo Kerley for their product support