Organic Soil Management Elsa Sanchez - PowerPoint Presentation

1. Organic Soil ManagementElsa SanchezBrian Caldwell

2. OutlineWhat are the farmers goals/needs for their soil? (Brian and Elsa) 5 minNutrient building (Elsa) 20 minSoil tests and recommendations (Brian and Elsa) 5 minNutrients and weeds (Brian) 10 minN from cover crops/green manures (Brian) 10 minCase studies (Brian and Elsa) 10 min

3. Farmer Goals/Needs for their SoilProductionSustainability (physical, biological, economic)Reduce off farm pollutionAlso--??

4. CompostDifficulty using conventional soil testsExcess nutrients – P, K, Mg, Ca – but many didn’t realize itCompost applied based on amount on hand vs. calculating Compost generally not analyzed prior to use

5. Case study of 11 organic farms:Those relying on compost, often had surplus nutrients, as much as about 160 – 182 lbs P & N/acre/yr excess. Drinkwater et al., 2005West Virginia organic research fields had begun to saturate soil nutrient holding capacity; decided to “restrict compost applications to crops with maximum yield response.” Kotcon, 2004Other SupportOver 2 years, Morris et al., (2004) sampled 30 farms, found on average: 42% had above optimum P levels, 20% below optimum.

6. Challenges Using CompostCompost, manures, other organic amendments & green manures slowly release nutrientsWhen & how much to apply challengingNutrient availability often unpredictable – especially nitrogenWhen & how much to apply challenging

7. MineralizationBreakdown of organic nutrient sources Conversion to inorganic, plant available formsRate and timing of mineralization depends on many variablesSoil temperatureSoil moistureIncorporation/depth of incorporation Soil microorganismsCarbon to nitrogen ratioParticle size10-50% a year

8. Who does the work of mineralization?Mineralization ProcessFungi, bacteria, yeasts, actinomycetes, some small critters (nematodes, rotoifers)Nitrogen temporarily tied up by microbes

9. C:N RatiosRatio of carbon to nitrogen in a materialC:N ratios decrease as organic material decomposes (CO2 given off, nitrogen incorporated into fungi & bacteria)C:N ratio & nitrogen availability> 30:1; nitrogen tied-up by microorganisms< 20:1; nitrogen release

10. Nutrient Build Up in SoilsBecause mineralization unpredictable & uncontrollable:Nutrients released at times when plant need is not high resulting in build up of nutrients & salts in soilOrganic nutrient sources are often over applied to insure nitrogen available for good crop yields

11. Nutrient Build UpAlso, organic nutrient sources often contain more than one nutrient, not in balance with crop needs resulting in surplusesCompost 1 – 0.7 – 1 Applied 12.5 tons/acre250 lbs nitrogen; 175 lbs P2O5; 250 lbs K2O

12. DeficientExceeds Crop NeedsPhosphatePotashMagnesiumCalcium

13. Compost Use for High Tunnel Bell Peppers10-wk-old ‘Paladin’ in 2000, ‘King Arthur’ in 2001 transplanted late May4 Raised beds per tunnel; 18” in row spacingDrip irrigationHarvest mid July – late Oct.Pests: weeds – hand weeded; aphids – lady-bird beetles

14. Compost TreatmentsCompost – dairy manure based 3 treatments compost applied at 1” or 2” depth, incorporated 12”; inorganic fertilizer at a rate of 75-150-75

15. Nutrient RecommendationsClay-loam soil, nutrients in optimum rangeNitrogen – 100 lb/acrePhosphate – 150 lb/acrePotash – 100 lb/acre

16. Beginning Soil AnalysisSoil Property lb/acreP2O5 174 ± 44 K2O 383 ± 66 CaO 3862 ± 565 MgO 356 ± 63 pH 6.7 ± 0.2Organic matter (%) 2.4 ± 0.3Soluble salts (mmhos/cm) 0.15 ± 0.03

17. Compost PropertiesSoil Property lb/ton FWN 33P2O5 15K2O 17Ca 117Mg 28pH 8C:N 12Soluble salts (mmhos/cm) 5.1

18. Available Nutrients Added lb/acre Fertilizer 1” 2”Nitrogen 75 441* 883*Phosphate 150 1345 2683 Potash 75 1559 3118Calcium 0 10570 21147Magnesium 0 2555 5110*using a 15% mineralization rate

19. Nutrient SummaryNitrogen1” compost = 4.5x more than 100 lbs/a2” compost = 9x more Phosphate1” compost + soil = 10x more than 150 lbs/a2” compost + soil = 19xPotash1” compost + soil = 13x more than 100 lbs/a2” compost + soil = 35x

20. Marketable Pepper Yield 2000 2001Treatment lb/ft2 Fertilizer 2.1 3.31” Compost 2.4 3.32” Compost 1.4 2.9

21. Soil Properties After Harvest Fertilizer 1” Compost 2” Compost 2000pH 6.4 7.3 7.4OM (%) 2.5 4.8 6.6Salts (mmhos/cm) 0.14 0.45 0.81 2001pH 6.8 7.3 7.3OM (%) 2.3 4.7 6.6Salts (mmhos/cm) 0.30 0.95 1.9

22. ConclusionsPossible salt injury led to lower yields0.40 or 1.5 mmho/cm threshold for peppersAbove threshold 16-50% yield reductionExclude precipitation and drip irrigationLeaching reduced; can lead to build up of salts

23. Using CompostNutrient content varies; recommend tested to determine amount of nutrientsApply nutrients based on plant needs vs. volumeLeaching in soil or compost - remove plastic, sprinkler irrigation

24. Problems with Over-ApplicationLoss profits due to cost of over-applied organic nutrient sourcesIndirect losses from decreased yields associated with high salt or nutrient levels in soil & weed competition Pollution of surface & groundwater

25. How to Avoid Over ApplicationSoil testingAnalyze compostCalculate how much to applyUse variety of nutrient sources Avoid continuous use of any single organic nutrient source with more than 1 nutrient

26. 3 CompostsSoil Property Compost 1 2 3Organic N (%) 1.1 1.2 0.7NH4+-N (lb/ton) 1.6 1.5 0.0Phosphate (%) 0.5 0.8 0.2Potash (%) 0.8 1.8 0.4pH 7.4 6.9 7.5C:N 12.1 13.2 14.7Soluble salts 5.5 14.1 0.8 (mmhos/cm)

27. 75 lb/acre NCompost 112.5 tons/acre (55 lbs organic N + 20 lbs ammonium-N)Compost 212 tons/acreCompost 327 tons/acre

28. For organic nutrient sources with more than 1 nutrientUse only when soil P, K levels not above optimum (exception, P in cold soils)If P, K levels high, use legume cover crops, nitrogen fertilizers with no or low levels of P & KAlways incorporate to minimize runoff & erosion lossesHow to Avoid Over Application

29. When Nutrient Levels are HighSoil testing to monitor levelsNitrogen supply – use N sources with no or minimal levels of other nutrientsLegume cover crops, other nutrient sourcesCalculate residual nitrogen to determine how much is neededPlant cover crop, reduce tillage, use grass waterways to minimize erosion, runoff losses

30. Soil tests and recommendationsVariety of tests and philosophiesEarly years—more intensive samplingAfter about 5 years—sampling to monitor the fertility program, every 2-3 years

31. Nutrients and WeedsRecent research results

32. Do organic nutrient amendments promote weed problems?Chuck MohlerCornell University

33. The problemMost livestock farms and organic farms use compost and manure as primary nutrient sourcesCorrect application rates are difficult to determineNutrients released slowly over timeConcentration variesFarmers often err on the high side to insure adequate nutrients for crop growthEnough to supply N needs usually applies excess P and K

34. Crop yield responses to compostRate giving full yieldYearCropSolubleHigh OM2004Corn0.5X0.67X2005SoybeanNo responseNo response2006Spelt0.8X2.0X2007CornNo response(to residual)No response(to residual)

35. Weed height did not reach a maximum as rate increasedGiant foxtailLambsquartersCommon ragweed

36. Cornell Organic Cropping Systems: Grain ExperimentInitiated 20053-year rotation: soybean  spelt/(red clover)  corn5 Systems“High” nutrientLow inputIntensive weed managementReduced tillageChemical

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38. Which nutrient is limiting for the weeds?The answer determines the management strategy.2010 ExperimentAlfalfa/clover plow down on low K, low P soil

39. Pigweed ControlPigweed with highest rate of compostPigweed with highest “N-P-K” treatmentPigweed biomass

40. Corn ControlCorn at highest compost rate

41. Error bars are standard error.0X 1X 2X 4X 8X

42. N from Cover Crops and Green Manures

43. Balancing Cover Crops and TillageTillage destroys soil organic matterHow to balance planting a cover crop which may require extra tillage?Get the most out of it

44. Spring Oats and PeasPlant as early as possibleTerminate in early July before fall-planted brassicasGood biomass production5000 lb/acre peas ~ 150 lb/acre NGood weed suppression

45. Summer Oats and PeasPlant before 8/15Allow to winter killModerate biomass production3000 lb/acre peas ~ 100 lb/acre NGood weed suppression

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47. Red CloverProduction of 1000-4000 lb/acre of dry biomass in the fallPlus 2500-5000 lb/acre by plowdown (mid May) the following springRoots are substantial as wellAdequate N for 160 bu/acre corn on a strong soil

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49. Hairy Vetch—Early FallPlanting date not critical if before 9/15Can plant with a grass companion crop5000 lb/acre biomass ~ 150+ lb/acre N

50. Hairy VetchTermination date makes a large differenceFair weed suppression

51. Rye can inhibit crop growthManaging for maximum biomass is good if residues are to be harvested (for mulch) or left on the surfaceIf tilled in, they can strongly inhibit crop growth Sucking all the moisture out of the soilTying up NAllelopathy (roots also?)To prevent this, till under in early May when the tissues are green and lushPlanting with hairy vetch will add more N

52. Vetch planted with low rate of rye

53. Cover cropPlanting windowTermination WindowCommentsHairy VetchBefore 9/15After 5/15Terminating in June is much betterAustrian Winter Peas9/1 to 9/15After 5/15Terminating in June is much betterField Peas and Oats --SpringAprilJulyThey should grow for at least 75 days; use forage varietiesField Peas and Oats—Later SummerBefore 8/15WinterkillA dramatic decrease in biomass after mid-August (50% in 10 days)RyeBefore 9/15Late MayBest with hairy vetch; if incorporated, terminate earlierRed CloverFrost seed into winter grainMay of following yearExcellent rotational strategyBuckwheat June and July40 days after plantingDo not wait to terminate; may produce seed

54. Making Legumes Work HarderLegumes get lazy and fix less N in a high N environment (it takes energy to feed the Rhizobium bacteria that fix the N)Planting with a grass companion can help If soil is already high in N, use lower grass seeding rateThis may also help slow down the release of legume N, making it better timed to crop needs

55. What do we know about root systems?Not muchRoots are woodier and decompose slower than plant topsSome researchers think that the main benefit from cover crops derives from their rootsRoot biomass is often in the range of 30% of aboveground for annualsPerennials like clover may have much larger relative root biomass

56. More sources of informationThomas Bjorkman at Cornell has created a clearinghouse of CC informationhttp://www.hort.cornell.edu/bjorkman/lab/covercrops/Managing Cover Crops Profitably, 3rd Ed.http://www.hort.cornell.edu/extension/organic/ocs/reports/Cover%20Crops%20Planting%20and%20Termination.pdfOthers?

57. Case StudiesNutrient budgetsBlue Heron Farm, Lodi, NYParadise Farm, Paradise, PA

58. Nutrient Budgets, 11 Farms58

59. Blue Heron Farm

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61. Blue Heron Farm Nutrient Budget

62. 62Table 2. Soil Test Results for Blue Heron Farm, 1993 and 1999, analyzed by Cornell University. Mean (with standard error) of 10 fields.1st Barn19931st Barn1999Vineyard1993Vineyard1999Phosphorus (lb/acre)6243629425Potassium (lb/acre)280935200715Magnesium (lb/acre)460875265425Calcium (lb/acre)4140836029804420pH7.47.57.17.4Percent Organic Matter4.44.92.72.7

63. Paradise Farm

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67. 67Figure 2. Cumulative nutrient balances for N,P, and K for five years of a typical rotation on Paradise Farm.