Cover Crops and Nutrient Cycling TIM REINBOTT
#1 Reason For Cover Crops: Erosion Control April 1 2014-5 inch Rain
Soil Erosion-Even With No- Tillage
Wind Erosion: When The Soil Is Covered Little Loss of Soil, When Not.
Cover Crops Reduce Water Runoff or Increase Water Infiltration
Conventionally Tilled-Water Runoff 30 minutes
Water From Tilled (left), No-Till (middle) and No-Till With Cover Crop (right) Tilled No-Tilled No-Till Cover Crop
Run-Off Table
Reduce Erosion and Water Movement, Reduce Nutrient Loss Winter 1985 Winter 1988 Treatment No Cover Cover Crop No Cover Cover Crop Runoff (inches) 0.39 0.44 4.81 2.31 Soil Loss (lb/acre) 4,118 891 15,945 1,970 Soil P Concentration (ppm) 0.14 0.19 0.12 0.15 Total P (lb/acre) 1.2 0.42 5.25 0.82
Nutrient Cycling
Nitrogen-Legumes Cover Crops- Nitrogen From N 2 Fixation
How Much Nitrogen?-Depends On Species and Time of Termination 50 lbs N-1,250 lbs 150 lbs N-4,500 lbs
The N Effect From Legumes: Generally Can Replace Some Nitrogen
Corn Yield From Kentucky- 160 140 120 Hairy Vetch 187 lb N/acre 100 80 Crimson Clover 50 lb N/acre 60 40 Rye 36 lb N/acre 20 Control 0 0 50 100 From Ebelhar et al, 1986
Corn After Killing Cover Crop- MU Found Similar Response of About 40-70 lb N/acre Benefit
Cotton Yield-29 Years in Tennessee. Tillage Nitrogen Applied (lb N/acre) Cover Crop Method 0 90 lb lint/acre None Tillage 672 988 No-Till 610 819 Wheat Tillage 665 832 No-Till 621 838 Hairy Vetch Tillage 865 923 No-Till 870 906 Crimson Clover Tillage 829 870 No-Till 858 904 Zou et al, 2017 Agronomy Journal
What Determines How Fast the N is Released and How Much?
Cover Crop Nitrogen Production and Release-C/N Ratio Key Plant Dry Nitrogen Percent C/N Cover Crop Part Matter Accumulation Nitrogen ratio lb/acre lb/acre % Cereal Rye shoot 2165 35 1.61 22 Winter Pea shoot 2,768 106 3.85 15 Radish shoot 3,089 86 2.79 12 Root 2125 16 1.82 16 124 18 8.9 5.8
Cereal Crops Last Throughout the Season-Early August
Cover Crops Breakdown And Release Nitrogen Dependent Upon Tilled or No-tilled Buried 8 inches Your text here Surface Jananzad, et al., 2016
Soil N Changes After 3 years of Cover Crops In a Corn/Soybean Rotation Cover Crop 0-6 in 6-12 in 12-18 in lb/acre None -220 d -23 c -244 c Cereal Rye 20 c 22 bc 42 b Hairy Vetch 129 b 142 a 271 a HV+Rye 218 a 58 b 276 a Sainju and Sing, 2008
Do We Mix Cover Crops? If So, How Much?
Mixture of Hairy Vetch and Cereal Rye of Above Ground N Content 160 lb Nour text here 90 lb N
If Cover Crop Terminated Early April In Illinois Not Much Biomass. Applegate, et al, 2016
Less Than 20 lb N/acre Nitrogen When Cover Crop Terminated at Normal Corn Planting Time in Illinois Applegate et al, 2016
My Suggestion Is That Ahead of Corn-Plant Cereal Crops For Erosion Control Before Soybeans-Full Cover Crop Mix
Termination Timing When Planting Corn and Soybean Are Different Corn Soybean
The N Effect From Legumes: But There Is More To Cover Crops Than Just Nitrogen
Cover Crops Can Bring Nutrients Up From Deeper Depths
Percent Total Available P and K at Different Depths in the Soil Profile-30-55% in top 2 ft 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 36 to 48 29 to 36 24 to 29 18 to 24 12 to 18 9 to 12 3 to 9 0 to 3 0% P K Clark and Reinbott, 2012
lb K/acre Soil Potassium Levels After Three Years of Cover Crops 140 120 100 80 60 40 none Rye Crimson Clover Hairy Vetch 20 0 0 to 3 3 to 6 6 to 12 Hargrove et al, 1986
Forage or Diakon Radish Fall Spring
Increase in Soil Test P Around Tillage Radish Roots by 2X 1.25 inch 2 inches White and Weil, 2011
Corn Emerging Near Radish
Phosphorus Release Over Time From Cover Crop Your text here Days Varela et al, 2017
Scavenging Nutrients From the Grain Crop
Lbs/acre Nitrogen Capture By Radish 150 130 Soybean Soybean 110 90 70 50 30 10-10 CornCorn Shoot Root Dean and Weil, J Eniv. Quality 2009
Radish and Rye Capture Nitrate-N in the Soil Profile
Since Radish Do Not Survive Winter They Need A Companion Crop
Back To Soybean and Cover Crops
Planting Soybeans Into A Heavy Cover Crop Mix
Fall 2017 Soybeans
Corn Can Struggle Through The Residue And Can Reduce Stands
Soybeans Can Also Struggle But Patience Is Critical
In Drier Summers Better Results From Using Cover Crops Before Soybeans 7 more Bushels/acre- Seed Cost-$45/acre 7 bushel/acre @ $10/bushel=$70/acre Or about $25/acre profit Some years little yield difference-2014, 2015
Cover Yield and Soybean Yield Following Cover Crops, 2016 A Wet Year-2 nd year with cover crops Treatment Yield Dry Matter Bu/acre lb/acre Control 36 c - Hairy Vetch 45 ab 3094 c Crimson Clover 38 bc 523 d Austrian Winter Pea 39 bc 3436 bc Cereal Rye 42 b 3276 c HV+Rye 50 a 4258 b CC+Rye 47 ab 3649 bc AWP+Rye 47 ab 3404 bc Triticale 38 bc 3457 bc Rye+HV+CC+AWP 39 bc 5348 a *letters indicate significant differences at the 0.10 level
Corn Yield After Cover Crops In A Dry Year Corn Yield Cover Crops Overseeded into Soybean Previous September Corn Treatment Yield Bu/acre Control 175 b Hairy Vetch 199 a Crimson Clover 165 b Radish 174 b Cereal Rye 175 b Hairy Vetch+Rye 187 b Crimson Clv. +Rye 181 b Radish + Rye 173 b Rye+Radish+HV+CC 174 b Reinbott, 2013
Cover Crop and Corn Grain Yield Following 2 nd year of Cover Crops, 2016 Treatment Yield Dry Matter Bu/acre lb/acre Control 196 ab Hairy Vetch 210 a 2966 a Crimson Clover 197 ab 683 d Radish 202 ab 992 d Triticale 182 bc 1302 c Triticale+HV 207 a 3927 a Triticale+CC 176 bc 1654 b Triticale+Radish 194 ab 1702 b Cereal Rye 168 c 1088 cd Triticale+HV+CC+Ra 197 ab 1248 c *indicates significant difference at the 0.10 probability level
Soil Health AND NUTRIENTS
50 Micronutrients Phosphorus ph Chemical Potassium Electrical Conductivity Organic Matter Mineralizabl e Nitrogen Activ e C Microbial Biomass C Biological Glucosidase Physical Bulk Density Water- Filled Pore Space Aggregation
Ultimately Improve Soil Physical Properties Soil Structure-Physical arrangement of soil solids and voids aggregation is controlled by SOC, microorganisms, ionic bridging, clay http://ecomerge.blogspot.com/2010/05/what-soilaggregates-are-and-how-its.html http://vro.dpi.vic.gov.au/dpi/vro/vrosite.nsf/pages/soilhealth_soil_st ructure
Soil Physical Property: Calcium Influence on Soil Structure Aggregates Formation of Soil Structure Flocculation: Bringing the particles close together, enhanced by polyvalent cations (Al+++, Ca++, etc.). Mg is not as good as Ca in flocculation, by an order of over 2 times!
The Importance of Calcium on Aggregates (Flocculation)
Single Charge Cations Such as K and Na have little Flocculating Power Whereas Divalent Cations Much Greater Flocculating Power Your text here Al +3 > Sr+ 2 > Ca+ 2 >Mg+ 2, Cs+ 2, K + =NH4 + >Na + >Li +
Flocculated Particles-Opposite Charges Line Up: Negative On Clay Particle With Positive On The Divalent Cation
56
How Does Soil Calcium Affect Water Infiltration? High Ca Soil Infiltraton Total Runoff Total Rate Infiltration Rate Runoff in/h in in/h in 2.2 7.4 22.7 17.0 High Mg Soil 0.9 1.6 23.8 23.2
Example With Magnets
Aggregate Stability: Interaction of Soil Microbes, Clay, Ca, and Humus From Muneer and Oades, 1989
Aggregate Stability-How Quick Can it Change? Water Aggregate Stability After Two Years: Rotation Corn/Soybean Corn/rye/Soybean/rye Corn/rye/Soybean/hairy vetch Corn/rye/Soybean/hairy vetch+rye Water Aggregate Stability (mg/kg) 38 b 41 a 43 a 44 a Letters indicate significant difference at the0.10 probability level From Villamil, et al, 2006
Change In Aggregate Stability After 3 Years of Fertilizer Treatments Treatment percent N only 31.0 b NPKS+Ca 33.3 a NPKS only 30.4 b NPKS+Mg 25.1 c P and K only 28.7 bc Different Letters Indicate Significance at the 0.05 probability Level
% Water Stable Aggregates Sanborn Field Study-Higher Fertility and Wheat Has Greater Aggregate Stability: Why? Comparison of % Water Stable Aggregates Under Continuous Corn Versus Continuous Wheat at Sanborn Field 20 18 16 14 12 10 8 6 4 2 0 No Fertility Full Fertility 6 tons Manure Corn 3 6 14 Continuous Wheat 15 18 18
We Tilled Our Study and Tillage Destroys Aggregate Stability My son doing his favorite thing After a two inch rain
Influence of Structure on Water Movement Granular Prismatic Blocky Platey Flocculated by Ca Restricted Enhanced by OM Movement
The Slake Test Video
Questions? REINBOTTT@MISSOURI.EDU