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Uncovering the Facts and Fiction about Conservation Tillage Systems Wilson Faircloth and Diane Rowland USDA-ARS, National Peanut Research Laboratory, Dawson, GA. N. P. R. N. P. R. ational. eanut. esearch. ational. eanut. esearch. L. L. aboratory. aboratory. NPRL Mythbusters:.
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Uncovering the Facts and Fiction about Conservation Tillage Systems Wilson Faircloth and Diane Rowland USDA-ARS, National Peanut Research Laboratory, Dawson, GA N P R N P R ational eanut esearch ational eanut esearch L L aboratory aboratory
NPRL Mythbusters: Top 10 Myths About Conservation Tillage -OR- Why aren’t you using conservation tillage in your operation?
Conservation Tillage Absorbs rainfall impact Cooler soil temps Lower evaporative losses Greater soil water infiltration Increases plant available water
8” soil moisture in three tillage systems Cotton peak flowering and boll fill • Strip till maintains moisture: • Better infiltration -or- • Deeper rooting (no roots at this shallow depth to pull water)
16” soil moisture in three tillage systems Strip till remains moist
24” soil moisture in three tillage systems No till roots
Soil Moisture Deficits More irrigation required in Conventional Tillage Irrigation Required 24 Hour Difference in Soil Moisture Conventional Tillage Strip Tillage Excess Moisture
Soil Moisture Profile: Before Irrigation Low Water High Water Conventional till Strip till Conventional till Strip till Soil Depth (cm) 10% 20% 30% 40% = VWC
Daily Water Use Conventional Till Peanut Strip Till 24 Hour Water Flow Conventional Till Cotton Strip Till
Corn Water Use: Low Water ST Sap Flow (g/h) CT Day of Year
Corn Water Use: High Water ST Sap Flow (g/h) CT Day of Year
ST CT ST CT Water Use Strategies • High Water:Strip Tillage • Moisture stratification lessened • Higher water contents at 60 cm depth (high root mass) • Lower root signalling → water use higher or equal toCT • Low Water:Strip Tillage • Greater moisture stratification • Lower water contents at 60 cm depth (high root mass) • Greater root signalling → stomatal closure, lower water use
Corn Yield 2006 Strip Tillage Conventional Tillage Greater water-use efficiency High Water Low Water
MytH #2: nutrients are less available to the crop in conservation tillage
MytH #3: the cover crop interferes with root growth of the crop
Root Image Analysis • Root Length • Surface Area • Root Diameter • Volume • Number of Root Tips • Size Classification
Root Length - Peanuts May 11 Conventional Till Strip Till Total Root Length (cm) Cover Crop Rooting Pattern 4 inches 12 inches 20 inches 27 inches 33 inches Soil Depth (cm)
Root Length - Peanuts July 9 Large concentration of roots at 30-55 cm (12-22 in) depths in ST – follows cover crop pattern Conventional Till Strip Till Total Root Length (cm) 4 inches 12 inches 20 inches 27 inches 33 inches Soil Depth (cm)
Flowering Strip Tillage Conventional Tillage 2004 Cumulative # Flowers 2005 Date
Peg Formation Efficiency Tagged individual flowers in the field and monitored until development of peg Strip Tillage Conventional Tillage 2004
Pegging Strip Tillage Conventional Tillage 2005 # Pegs per Plant
Pod Number Strip Tillage, 2004 Conventional Tillage, 2004 Strip Tillage, 2005 Conventional Tillage, 2005 # Pods per Plant
Peanut Yield Strip Tillage Conventional Tillage Yield (lbs / Acre) 2003 2004 2005
2006 Flowers No Till Strip Tillage Conventional Tillage
2006 Pegs No Till Strip Tillage Conventional Tillage
2006 Pods No Till Strip Tillage Conventional Tillage
MytH #5: aflatoxin is increased in conservation tillage peanuts
Aflatoxin Contamination Strip Tillage No Till Conventional Tillage
Tillage Effect X Cultivar Strip Tillage Conventional Tillage • Percent STTSWV reduction: • GA-02C 41% • AP3 62% • GG 45% GA-02C AP3 GG GA-02C AP3 GG
Cultivar X Insecticide Control Temik Thimet+Proline Thimet Compared to control… GA-02C AP3 GG Cultivar
GA-02C Yield vs. Infection Control AP-3 Yield (lbs/Ac) Thimet Georgia Green Temik Percent TSWV Infection
Tillage X Insecticide Control Temik Thimet+Proline Thimet Conventional Tillage Strip Tillage • Percent STTSWV reduction: • Control60% • Proline64% • Temik25% • Thimet 48%
2005 peanut yield + grade Conservation systems: +583 lbs yield** +5.5% tsmk**
Average net return4-year summary • How we calculated this value: • Detailed records of all inputs • Budgets specific for every input • 4 years * 3 crops/year * 3 replications
MytH #8: Conservation tillage promotes digging losses in peanut
Peanut digging loss Dry soil Moist soil