Effect of Surface Application of Nitrogen Fertilizer Sources on Cotton Yields and Quality in A Conservation Tillage System

1
Effect of Surface Application of Nitrogen
Fertilizer Sources on Cotton Yields and Quality
inA Conservation TillageSystem

• Charles H. Burmester
• Extension Agronomist
• Auburn University

2
Test Information

• Location Tenn. Valley Research and
• Extension Center
• Soil Type Decatur Silt Loam
• Variety DPL 454 Bt/RR
• Tillage No-Till Wheat Cover
• Planting Date April 24th
• Preplant N 24lb/A
• Plot Area Irrigated

3
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)

4
N RATES

• 60, 90 LB/A
• Surface Applied June 5th
• Rainfall 0.51 inch June 12th
• Cotton 4-5 Leaf Stage

5
Fertilizers
6
Fertilizers
7
Fertilizers
8
Fertilizers
9
Cover Crop
10
TEST SITE
11
Data Collected

• Cotton leaf samples in mid July - cotton in 3rd
  week of bloom
• NAWF measurement in early August
• Cotton yields and quality

12
Pre-Harvest Data
Treatment 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 a
LSD (0.05 .75
LSD (.05) 0.23
13
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

14
Seed Cotton Yields
LSD (0.05) 269 CV 5.4
a
a
a
a
c
b
b
bc
bc
bc
c
15
Cotton Quality
Treatments 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
16
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.

17
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.

18
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.

19
Acknowledgement

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