Drought Stress and Ontario Soybean Yields: Unravelling the Mystery. Hugh Earl, U of G Horst Bohner, OMAFRA

Transcription

1 Drought Stress and Ontario Soybean Yields: Unravelling the Mystery Hugh Earl, U of G Horst ohner, OMAFRA

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3 160.6 bu/ac Kip Cullers bu/ac Randy Dowdy bu/ac Robert and Jason Lakey Illinois

4 214.7 ushel Yields: Coming Soon to a Field Near You? soybeans can potentially produce hundreds of pods per plant. If every node on every branch produced multiple racemes and every raceme produced multiple flowers, a soybean plant can have a thousand potential pod sites.

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6 Rain makes grain!

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8 Where do High Yields Come From? asic principles of yield determination are more or less universal across grain crops. Agronomic decisions should be made with a clear understanding of how yield is determined from a crop physiology standpoint. There are many persistent misconceptions about how crops work.

9 Why Does Yield Vary So Much? True Causes of Large Yield Variations are Often Unknown The most limiting factor idea is not a very complete model of crop yield limitations! Factors may be co-limiting (interacting). The current most limiting factor will change over the season, and even over a single day. Crop yield determination is much more complicated than can be described with this model.

10 Water Stress in Ontario Soybean: Are we losing yield to water stress? If so, how much? Uncertainties How much of the in-season rainfall do we get to use? To what extent can soil water depletion delay the onset of stress during dry periods? Does dry soil at any point in the root profile constitute a water stress?

11 Quantifying Yield Lost to Drought Stress 1. Quantify yield reductions due to water stress under naturally-occurring (rainfed) conditions Compare to yield under water-replete (irrigated) conditions 2. Identify the specific aspects of crop growth and yield formation impacted by water stress Interception of solar radiation, biomass production, pods per unit area, seeds per pod, seed size

12 Past Studies: Yield more sensitive to stress during pod elongation and seed fill. Less sensitive to early season stress. Shaw and Lang, 1966; Doss et al., 1974; Andriani et al., 1991; Foroud et al., 1993 Pods per unit area most sensitive yield component, but late-season stresses can also reduce seed size. Sionit and Kramer, 1977; Korte et al.,1983; revedan and Egli, 2003 Late-season stress leads to early canopy senescence, shortening the seed fill period. Korte et al., 1983; Specht et al., 1986; Foroud et al., 1993

13 Methods: ~33 m 2009 Wet S Dry Solid set irrigation 4 replications 25 m Dry S Wet Dry 25 m uffered in-season dry matter harvests Final seed yield and yield components S Wet Wet 25 m Solid set sprinkler, 180 S Dry 12.5 m

14 Methods: buffer plots 10 buffer plots 2010 onward Hose-pull boom cart 4 replications

15 Precipitation (mm) Weekly temperature deviation from 10-yr average ( C) Year 1 (2009) Cumulative precipitation + irrigation Cumulative precipitation 10-year average cumulative precipitation Days after planting -5

16 Canopy interceptance of solar radiation Above-ground dry matter (g m -2 ) Year 1 (2009) Irrigated Rainfed Irrigated Rainfed Days after planting Days after planting yield yield pods m -2 seeds pod seed wt bu acre -1 kg ha -1 g Irrigated Rainfed P-value Irrigated / Rainfed = x x 1.047

17 Precipitation (mm) Weekly temperature deviation from 10-yr average ( C) Year 2 (2010) Cumulative precipitation + irrigation Cumulative precipitation 10-year average cumulative precipitation Days after planting -5

18 Canopy interceptance of solar radiation Above-ground dry matter (g m -2 ) Year 2 (2010) P < P < Irrigated 200 Irrigated 0.1 Rainfed 100 Rainfed Days after planting Days after planting yield yield pods m -2 seeds pod seed wt bu acre -1 kg ha -1 g Irrigated Rainfed P-value Irrigated / Rainfed = x x 1.066

19 Precipitation (mm) Weekly temperature deviation from 10-yr average ( C) Year 3 (2011) Cumulative precipitation + irrigation Cumulative precipitation 10-year average cumulative precipitation Days after planting -5

20 Canopy interceptance of solar radiation Above-ground dry matter (g m -2 ) Year 3 (2011) P < 0.05 P < P < 0.05 P < 0.05 P < P < P < Irrigated 200 Irrigated 0.1 Rainfed 100 Rainfed Days after planting Days after planting yield yield pods m -2 seeds pod seed wt bu acre -1 kg ha -1 g Irrigated Rainfed P-value Irrigated / Rainfed = x x 1.014

21 Canopy Senescence

22 Canopy Senescence 2009 Irrigated Rainfed NDRE Rep 1 Rep 2 Year Date Sep 8 Sep 1 Sep 12 DAP Irrigated Rainfed Rep 3 P-value <0.01 <0.01 <0.05 Rep 4

23 Cumulative Precipitation (mm) Weekly Temperature Anomaly ( C) Year 4 (2012) Days after Planting

24 Cumulative Precipitation (mm) Weekly Temperature Anomaly ( C) Year 5 (2013) Days after Planting

25 Years 4 and 5 ( ) 2012 yield yield pods m -2 seeds pod seed wt bu acre -1 kg ha -1 g Irrigated Rainfed P-value < < < Irrigated / Rainfed = x x Irrigated Rainfed P-value Irrigated / Rainfed = x x Mean responses across 15 varieties.

26 Summary 1. There was significant yield loss attributable to water stress in all five years. Yield loss ranged from 3% to 24%. These estimates are probably conservative. Yield loss occurred even when the in-season rainfall total exceeded the 10-yr average (2010, 2013), or when it equaled the 10-yr average and was very well distributed (2009)

27 Summary 2. When yield losses were small, it was sometimes difficult to parse the yield loss amongst the various yield components. pods m -2 was the component most consistently affected 3. Early canopy senescence was a consistent feature of water stress 4. There were never any obvious visual symptoms of stress, such as leaf wilting.

28 Water is not everything! Year Rainfed Yield Mg / ha Irrigated Yield Mg / ha Increase from irrigation % % % % % 24.9% Highest yields on this farm: 5.4 Mg / ha Highest yields in Ontario: 6.7 Mg / ha Average 12.2%

29 When during the season is yield determined? The Critical Developmental Stage is the one where the most Variable Yield Component is Determined. For soybean: Yield = pods per m 2 x seeds per pod x mass per seed

30 What determines pod number? Pod number (and therefore seed number) is determined by the plant growth rate during the critical period (R2 to R5). Pod number is NOT a direct function of plant size. It s now how big the crop is what matters is how fast it is growing. Maximizing pod numbers is mostly a matter of maximizing crop growth rate during the critical period. (Data of Vega, 2001)

31 Think at the Crop Scale The Plant Community ( Crop Canopy ) is more Relevant than Individual Plants. Think on a Ground Area asis. We measure yield per unit area, not on a single plant basis. Plant size is (almost) irrelevant. Many important processes that determine yield can only be properly understood at the crop canopy (plant community) scale. For maize and a few other crops, individual plant size can be important. For soybean it is very unimportant.

32 Plant size is unimportant in soybean Maize is prone to barrenness when there is insufficient assimilate flux prior to anthesis (i.e., plants are too small). Species with a larger number of fruiting structures, including soybean are much less sensitive to plant size. (Vega and Sadras, 2003)

33 Soybean is insensitive to seeding rate 120 Yield (percent of maximum) k = , early 2005, late 2006, early 2006, late Seeding rate (thousands per acre) Response of soybean yield to seeding rate.

34 Radiation Capture The Crop Growth Rate is Primarily Determined by Radiation Capture X X RUE =iomass

35 Radiation Capture time

36 Radiation Capture The crop growth rate during the critical period (R2 - R5) determines final pod numbers Maximizing the crop growth rate requires complete interception of sunlight.

37 Row Width still Matters

38 Closing the Yield Gap u/ac 1) 30 no-till ( ) ) 30 managed ( ) ) 30 managed ( ) ) 15 no-till ( ) ) 15 managed ( ) 69.9 Managed = 180 lbs/ac MESZ and (2X2), 3 gallons IF, spring strip tillage, foliar fungicide and feeding. Elora 2016, P = 10 ppm, K = 96 ppm

39 Closing the Yield Gap u/ac 1) 30 no-till ( ) ) 30 managed ( ) ) 30 managed ( ) ) 15 no-till ( ) ) 15 managed ( ) 67.0 Managed = 180 lbs/ac MESZ and (2X2), 3 gallons IF, spring strip tillage, foliar fungicide and feeding. Lucan 2016, P = 14 ppm, K = 109 ppm

40 Wide rows are not a good choice if rows do not fill by R3

41 Variety Selection is Key y = x

42 y = 1.125x

43 Good Variety Choice Equals Profit u/ac 1) 15 no-till (Variety A) ) 30 managed (Variety A) ) 15 no-till (Variety ) ) 30 managed (Variety ) ) 15 no-till (Variety C) ) 30 managed (Variety C) 81.5 Managed = 180 lbs/ac MESZ and (2X2), 3 gallons IF, spring strip tillage, foliar fungicide and feeding. Elora 2016, P = 10 ppm, K = 96 ppm

44 Good Soil Fertility is Essential bu/ac Randy Dowdy

45 Mega Fertilizer u/ac 1) Check 64 2) MESZ (375 lbs/ac) 72 3) MESZ (375 lbs/ac lbs/ac potash) ornholm 2016, P = 17, K = 98

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47 Mega Fertilizer u/ac 1) Check 64 2) MESZ (375 lbs/ac) 72 3) MESZ (375 lbs/ac lbs/ac potash) 4) Trt N (150 lbs/ac) 70 ornholm 2016, P = 17, K = 98

48 Yield (bu/ac) Yield Trends in Ontario of Corn, Soybean, Winter Wheat CORN WHEAT SOY

49 Yield (bu/ac) Yield Trends in Ontario of Corn, Soybean, Winter Wheat % yield increase 63 lbs P 2 O 5, 45 K 2 O 35 lbs P 2 O 5, 25 K 2 O CORN 65% yield increase 50 lbs P 2 O 5, 30 K 2 O 30 lbs P 2 O 5, 18 K 2 O WHEAT SOY 28 lbs P 2 O 5, 46 K 2 O 35% yield increase 37 lbs P 2 O 5, 61 K 2 O

50 P broadcast applied No P applied Soil test P = 7 ppm Soybean response to P and K fertilizer Hooker, UG 2013

51 Soybean yield response to background fertility and starter fertilizer Lucan ( ) Starter (per ac) No Fertilizer Approx. background soil test P and K (ppm) Low P Low K 56 b 3 gal (IF) 58 ab 100 lbs (2x2) 59 a 80 lbs (2x2) 58 ab 90 lbs (2x2) 59 a 180 lbs (2x2) 60 a Low P High K bu/ac NOTALE NOTE: n= lbs = 50 lbs of P 2 O 5 or K 2 O Mean separation within Current column rec statistically = 20 lbs/ac significant P 2 O 5, 30 at lbs/ac P=0.05 K 2 O High P High K ANOVA across #SWAC17

52 Soybean yield response to background fertility and starter fertilizer Lucan ( ) Starter (per ac) Approx. background soil test P and K (ppm) Low P Low K Low P High K bu/ac No Fertilizer 56 b 56 de 3 gal (IF) 58 ab 58 cd 100 lbs (2x2) 59 a 62 ab 80 lbs (2x2) 58 ab 55 e 90 lbs (2x2) 59 a 59 bc 180 lbs (2x2) 60 a 62 a High P High K ANOVA across background n=12 Mean separation within column statistically significant at #SWAC17

53 Soybean yield response to background fertility and starter fertilizer Lucan ( ) Starter (per ac) Approx. background soil test P and K (ppm) Low P Low K Low P High K bu/ac High P High K ANOVA across background No Fertilizer 56 b 56 de 63 a < gal (IF) 58 ab 58 cd 64 a < lbs (2x2) 59 a 62 ab 64 a < lbs (2x2) 58 ab 55 e 64 a < lbs (2x2) 59 a 59 bc 64 a < lbs (2x2) 60 a 62 a 63 a ns n=12, P = 10, K = 129 (low) and P = 27, K = 166 (high) Mean separation within column statistically significant at #SWAC17

54 Soybean yield response to background fertility and starter fertilizer Average across 17 site-years Starter (per ac) Low P Low K ackground treatment High P Low K bu/ac Low P High K High P High K No starter 53c 55b 55c 60a in-furrow 55b 56b 56b 61a 100 lbs (2x2) 55b 56b 58a 61a 80 lbs (2x2) 54b 58a 54c 60a lbs (2x2) 57a 59a 58a 61a Mean separation within column statistically significant at #SWAC17

55 Fertility Summary Fertility is KEY to high yields!!! Soil health includes good fertility ut it s not as simple as applying high rates of fertilizer uilding soil test values to a reasonable level provides more consistent and higher yields Low soil tests reduces yield by 4 7 bu/ac

56 214.7 ushel Yields: Coming Soon to a Field Near You? one important step was spoon feeding N, P and K through the drip irrigation based on growth stage. They applied 610 lbs. of nitrogen, 40 lbs. of phosphate and 200 lbs. of potash, and adequate micronutrients were added at planting.

57 2016 SMaRT Trial Locations KTS Starter Fertilizer roadcast Gypsum Planting Rate ILeVO Field Rolling Prescription Foliar Fertilizer White Mold Fungicide Comparison Intensive Management Radiate lackmax 22

58 2016 Prescription foliar fertilizer trial locations

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60 Prescription foliar fertilizer trial Field-specific prescription foliar fertilizer mixtures were compared to an unfertilized control at nine locations in Composite soil samples were collected from the trial area in the spring of 2016 and sent to Midwest Labs for testing. The field-specific prescription foliar fertilizer mixtures were developed by AgroLiquid and based on soil test nutrient levels. AgroLiquid also determined the application timing: V4 for row spacing of 15 or less and R1 where row spacing was greater that 15.

61 Soil test levels at the 2016 prescription foliar fertilizer trial locations Location O.M. P K Mg Ca ph CEC S Zn Mn meq/ % ppm :1 100g ppm Cass Ionia Gratiot St. Joseph Van uren Lenawee Monroe Lenawee Sanilac old figures indicate low or very low soil test levels.

62 Prescription foliar fertilizer products, application rates and costs for each location Location Foliar fertilizer products and application rates Fertilizer cost $/ac Cass 1.5 gal/ac of fertirain, and 1 qt/acre of Manganese $19.10 Ionia 1.5 gal/ac of fertirain, 2 qt/acre of Manganese, and 2 qt/ac of LiberateCa $28.70 Gratiot 1.5 gal/ac of fertirain, and 1 qt/acre of Manganese $19.10 St. Joseph 1.5 gal/ac of fertirain, and 1 qt/acre of Manganese $19.10 Van uren 1.5 gal/ac of fertirain, 1 qt/acre of Manganese, and 1 qt/ac of LiberateCa $19.50 Lenawee gal/ac of fertirain, 2 qt/acre of Manganese, and 2 qt/ac of LiberateCa $28.70 Monroe 1.5 gal/ac of fertirain, 2 qt/acre of Manganese, and 1 qt/ac of LiberateCa $20.80 Lenawee 1 1 gal/ac of fertirain, 1 gal/ac of Sure-K, and 2 qt/acre of Manganese $21.40 Sanilac 1.5 gal/ac of fertirain, and 1 qt/acre of Manganese $19.10 Analyses of the foliar fertilizer products are listed below: fertirain: plus 1.5% S, 0.10% Fe, 0.05% Mn, and 0.10% Zn LiberateCa: 3% calcium from calcium sulfate Manganese: 4% manganese from manganese sulfate Sure-K: 2-1-6

63 Yield difference (bu/ac) Yield difference produced by a single application of a prescription foliar fertilizer in 2016 *1.5 * Lowest breakeven yield increase for all sites (2.1 bu/ac) * The yield difference was statistically significant at these locations

64 Prescription foliar fertilizer trial The prescription foliar fertilizer treatment increased soybean yields at two of nine locations in However, the yield increases were not large enough to cover the cost of the foliar fertilizer ($19.10 to $28.70 per acre). The lack of a profitable response to foliar fertilization is most likely due to the medium to high soil test levels for many of the nutrients in the trials. However, soil test levels for sulfur were low at 3 sites and manganese was very low to low at 8 sites.

65 Production Practices That Often Have A Large (5 + u/a) Impact on Yield Planting Date Fertility Variety Selection and Placement Drainage and Compaction Management Insect, Disease, and Weed Management

66 Production Practices That Often Have A Moderate (2 to 5 u/a) Impact on Yield Foliar Fungicides Seed Treatments Residue Managment Crop Rotation Larger first year effect Row Spacing

67 Production Practices That Often Have A Small (<2 u/a) Impact on Yield Seeding Rate and Equipment Inoculants Micronutrients Can be large under the right circumstances More important as yield level increases

68 Thank you. Any QUESTIONS? Horst ohner