1. KENT A MCVAY CROPPING SYSTEMS SPECIALIST SOUTHERN AG RESEARCH CENTER MONTANA STATE UNIVERSITY Crop Rotation Benefits

2. Harvested biomass production is a function of: Energy Input Energy capture Losses to competition Harvest loss

3. Energy Input All energy comes from the sun Efficiency of energy conversion to biomass is dependent on crop management C4 vs C3  Corn vs wheat Grass vs legume  Barley vs pea

4. So what is the optimum system for converting energy into biomass? Full canopied forests, like this Or Native rangeland These convert a large portion of the energy received into biomass

5. Cropland Captures a Fraction of Total Energy Although silage corn comes close ! So would sugarcane www.farmphoto.com

6. What about Montana? Rainfall limits production potential Average growing season limits most production to C3 metabolism: wheat, barley, peas, canola It will be hard to compete head to head against other less stressful environments.  Targeting markets is a good idea  e.g. high protein wheat  Specialty crops like camelina for special purpose industrial oils, or food grade oils, or pharmaceuticals  Crops that have multiple markets. Peas for human or animal consumption

7. Crop Rotation Benefits Usually a positive yield response Chance to use alternate herbicides  Cleans up some weed problems Disease pressure can be reduced Increases diversity  Spreads out planting and harvesting dates  More commodities to sell

8. Rotation Yield Benefits Tanaka et al. 1999. Agron J. 97:385-390 Mandan, ND 1999 Previous cropCanolaCrambe Dry beanDry peaFlax Saf- flowerSoy-bean Sun- flower Spring wheatBarley Canola Crambe Dry bean Dry pea Flax Safflower Soybean Sunflower Spring wheat Barley Year 1 Year 2

9. Rotation Yield Benefits Tanaka et al. 1999. Agron J. 97:385-390 Mandan, ND 1999 Previous cropCanolaCrambe Dry beanDry peaFlax Saf- flowerSoy-bean Sun- flower Spring wheatBarley ----------------------------------------------- lbs / acre ------------------------------------------------------------ Canola1413168812412335163910122032159735914680 Crambe12901769968214816058692039173832174981 Dry bean140015591175255015218882237160933084189 Dry pea1530236212162581143010422112176831144674 Flax1543179111312660690597199576936514617 Safflower12201518816253213874581735109630314579 Soybean123916491098230017528862501149834664363 Sunflower13631763989261016257601951130633884852 Spring wheat131218797583045157110261844149934284728 Barley1480202513322549164111062090175833854482

10. Rotation Yield Benefits Mandan, ND 1999 Previous cropCanolaCrambe Dry bean Dry peaFlax Saf- flower Soy- bean Sun- flower Spring wheatBarley Rot. Benefit Canola 1.000.951.060.902.382.210.811.221.051.041.26 Crambe 0.911.000.820.832.331.900.821.330.941.111.20 Dry bean 0.990.881.000.992.201.940.891.230.960.931.20 Dry pea 1.081.341.031.002.072.280.841.350.911.041.29 Flax 1.091.010.961.031.001.300.800.591.071.030.99 Safflower 0.86 0.690.982.011.000.690.840.881.020.98 Soybean 0.880.93 0.892.541.931.001.151.010.971.22 Sunflower 0.961.000.841.012.361.660.781.000.991.081.17 Spring wheat 0.931.060.651.182.282.240.741.151.001.051.23 Barley 1.051.141.130.992.382.410.841.350.991.001.33 Rot. Benefit0.981.020.910.982.151.890.821.120.981.031.19 Tanaka et al. 1999. Agron J. 97:385-390

11. Rotation Yield Benefits ------------------ Year --------------- Rotation Benefit Crop2003200419992000 Flax2.152.572.36 G. Sorghum2.35 Corn2.391.251.82 Chickpea0.972.581.77 Safflower1.891.331.61 Sunflower2.801.12 1.361.60 Lentil1.101.371.23 Proso millet1.301.061.18 Barley1.031.211.12 Buckwheat1.211.021.11 Dry Pea1.16 0.981.141.11 Canola1.060.920.981.291.06 Wheat1.030.840.981.161.00 Crambe1.020.991.00 Dry bean0.910.970.94 Soybean0.820.810.82 Tanaka et al. 1999. Agron J. 97:385-390

12. Alternate Herbicides Wheat-Wheat  What is the dominant weed?  Downy Brome  Wild oat Wheat –Pea: Downy Brome easily controlled with herbicides like Select, Assure, or Spartan during the Pea crop cycle Note: Research at Bozeman showed wheat/pea/fallow rotation compared to continuous wheat decreased downy brome density from 60 to 10 plants/ft 2

13. The Disease Triangle Environment Susceptible Host Organism Remember: All three must be present in order for the disease to be expressed

14. Increased Diversity Growing more crops spreads out the workload  Planting time  Spraying time  Harvest time More diversity requires greater management skills  Record keeping becomes even more critical  Time management  Rotation restrictions More commodities  greater flexibility in marketing

15. Crop Rotation Can Be Beneficial Yield increases Reduced need for herbicides Reduced disease pressure Diversified markets and crop management