Maximum growth rate of sugar beet as a result of nutrient supply, ph and other environmental factors. Olof Hellgren

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1 Maximum growth rate of sugar beet as a result of nutrient supply, ph and other environmental factors Olof Hellgren

2 Nutrient addition and uptake traditional and static concept TRADITIONAL CONCEPT is based on concentration (static) Verification of concentration is required Concentration is a time dependent state variable When is it valid?

3 Nutrient addition and uptake dynamic concept DYNAMIC CONCEPT is based on rate of a process (dynamic) (increase/decrease rate per unit) as coupled to a state (dynamic) Verification of rate and state is required When is the rate valid? When is the state valid? For the whole period!

4 Nutrient addition and uptake Verification of a process rate dw 1 dn U 1 dn A 1 = = dt W dt NW dt N W

5 Nutrient addition and uptake Verification of the state dn 1 dw 1 = dt N dt W N d W dt = 0 a steady-state condition

6 Nutrient addition and uptake Change of state is time dependent and can only take place during a restrictive period of time dn 1 dw 1 < or > dt N dt W N d W dt < or > 0

7 Cultivation of sugar beet under controlled addition of nutrient elements Cultivation of plants with the roots in air Spraying of nutrient elements on the roots Addition of nutrient elements by titration Uptake controlled by the growth rate of the plants

8 Studies in 4 phases - controlled experiments - screening experiments - field like experiments - field observations

9 Growth rate from successive harvests of plants /85% NH /NO light µmol mm -2 s -2-1 s -1 ph dry weight per plant, g days

10 Growth rate from successive harvests of plants /85% NH 44+ /NO light light µmol m -2-2 s -1 s -1 ph ph dry weight per plant, g days

11 Growth capacity of sugar beet e 0 NH /85% NH/NO 4 4+ /NO light light µmol µmol m -2 sm -1-2 s -1 ph ph dry weight per plant, g e -1 e -2 e -3 e ± / g gg -1-1 day -1-1 r 2 r= 2 = double weight in 2 daysand and 3 hours 3 hrs days

12 Growth capacity of sugar beet e 1 e 0 NH /85% NH 4 /NO 4+ /NO light µmol m -2 ms -1-2 s -1 ph dry weight per plant, g e -1 e -2 e -3 e ± / g gg -1-1 day -1 r 2 r= 2 = double weight in 1 dayand and 9 hours 9 hrs days

13 Factors included in optimizing sugar beet growth relative growth rate, dwp, g g -1 day ph 5.4 ph 6.0 all ph relative growth rate, dwp, g g -1 day K/N 100% K/N 145% K/N 196% relative growth rate, dwp, g g -1 day dws/fws, g g -1 dws/fws, g g -1 nitrate 100% 90% 85% 80% 72% 67% 65% 44% Daylength light intensity temperature ph, nitrogen source nitrate/ammonium nutrient concentration nutrient elements relative growth rate, dwp, g g -1 day dws/fws, g g -1 all types of controlled experiments dwr/dwp, g g -1

14 Sugar beet and ph recommendations? Sugar beet cultivation is recommended in soils with ph not lower than why? Soil

15 Sugar beet, nitrogen source and ph We observed that sugar beet always and strongly decrease ph in both nitrate and ammonium Plant

16 Nitrogen source and ph in the process of nutrient uptake Normally, uptake of negatively charged nitrate ions are counterbalanced with the release of OH - and HCO 3 - resulting in an increasing ph Plant Normally, uptake of positively charged ammonium ions are counterbalanced with the release of H + resulting in a decreasing ph Plant

17 Sugar beet and ph We observed that Plant Sugar beet decreased ph to such an extent that growth was severely limited Therefore ph had to be continuously and carefully controlled Not only decreased ph was hazardous to the plants but also too large oscillations severely limited growth

18 How ph was controlled NaOH and Ca(OH) 2 could both be used to control ph and plant growth Soil Soil Ca(OH) 2 with low solubility had to be used as a saturated stock solution with inconvenient technical solutions as a consequence NaOH was used to control ph Soil

19 ph range and sugar beet growth 0.40 relative growth rate, dwp, g g -1 day /85% NH 4+ /NO 3-100% NO ph

20 Optimizing ph for sugar beet growth 0.6 relative growth rate, dwp, g g -1 day ph 5.4 ph 6.0 all ph dws/fws, g g -1 ph

21 Optimizing K for sugar beet growth 0.6 relative growth rate, dwp, g g -1 day K/N 100% K/N 145% K/N 196% 0.0 Potassium proportions dws/fws, g g -1

22 Optimizing nitrogen source sugar beet growth relative growth rate, dwp, g g -1 day Nitrogen source nitrate/ammonium 0.14 dws/fws, g g -1 nitrate 100% 90% 85% 80% 72% 67% 65% 44%

23 Daylength light intensity temperature 0.5 relative growth rate, dwp, g g -1 day Optimizing sugar beet growth all types of controlled experiments ph, nitrogen source nitrate/ammonium nutrient concentration nutrient elements dwr/dwp, g g -1

24 Optimizing sugar beet growth and uptake As could be seen from these diagrams, verifying the rate and the state lead to unambiguous, reproducible and comparable data

25 Proportions of nutrient elements for sugar beet at optimized growth N mg/g 40 mg g -1 Macro elements K/N 145% P/N 21% S/N 9% Mg/N 23% (9%) Ca/N 24% (7%) %

26 Proportions of nutrient elements for sugar beet at optimized growth Fe/N 0.7% Mn/N 0.4% Zn/N 0.09% B/N 0.065% Cu/N 0.03% Micro elements %

27 Growth of sugar beet and NaOH titration C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

28 Growth of sugar beet and NaOH titration C ph 6.0 NaOH titration/biomass increase 1 NaOH titration Biomass days

29 Growth of sugar beet and NaOH titration C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

30 Growth of sugar beet and NaOH titration C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

31 Growth of sugar beet and NaOH titration C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

32 Growth of sugar beet and NaOH titration C ph 6.0 NaOH titration/biomass increase 1 NaOH titration Biomass days

33 Growth of sugar beet and NaOH titration C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

34 Growth of sugar beet and NaOH titration C ph 6.0 NaOH titration/biomass increase 1 NaOH titration Biomass days

35 Growth of sugar beet and NaOH titration C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

36 Growth of sugar beet and NaOH titration C ph 6.0 NaOH titration/biomass increase 1 NaOH titration Biomass days

37 Growth of sugar beet and NaOH titration C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

38 Growth of sugar beet and NaOH titration C ph 6.0 NaOH titration/biomass increase 1 NaOH titration Biomass days

39 Growth of sugar beet and NaOH titration C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

40 Growth of sugar beet and NaOH titration C ph 6.0 NaOH titration/biomass increase 1 NaOH titration Biomass days

41 Growth of sugar beet and NaOH titration C changed to 18 C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

42 Growth of sugar beet and NaOH titration C changed to 18 C ph 6.0 NaOH titration/biomass increase 1 NaOH titration Biomass days

43 Growth of sugar beet and NaOH titration C changed to 18 C ph 5.4 NaOH titration/biomass increase 1 NaOH titration Biomass days

44 Growth of sugar beet and NaOH titration C changed to 18 C ph 6.0 NaOH titration/biomass increase 1 NaOH titration Biomass days

45 Growth of sugar beet and NaOH titration temperature change 2ºC 2 C =>18ºC 18 C =>2ºC 2 C =>18ºC 18 C log fresh weight, g 8 18 C 2 C 18 C day 0.26 g g -1 day -1-1 r = C days

46 Growth of sugar beet and NaOH titration 100 temperature change 2 C 18 C 2 C 18 C NaOH titration/biomass increase C 18 C 2 C 18 C NaOH titration Biomass days

47 Conclusion Soil To have a high uptake and growth rate the sugar beet plants require from the surrounding soil a high ph buffering capacity otherwise ph cannot be restored and kept high enough and stable

48 Question Do different soils with the same measured ph have different dynamic capacity to buffer a continuous decrease of ph caused by the plants? Soil Answer Soil Yes! But there is a flux and force identification problem

49 Question Can elements with low availability due to e.g. high ph in the soil be made available for uptake by plant acidification? Soil Answer Yes! Plant But by a spatial temporary lowering of ph induced by the plant roots?

50 Nutrient elements, ph and availability The poor mobility of inorganic P in soil makes it the number one limiting nutrient element Soil Soil solutions contain a marginal and insufficient amount of P ions for plant growth Plants are probably very effective in releasing P from soil mineral complexes by acidifying the rhizosphere Plant

51 Conclusions Plant Release of Pions and micro nutrient elements like Fe, Zn and Mn induced by root acidification of the rhizosphere must be treated as a release/uptake rate per biomass root Soil Concurrently the ph buffering capacity of the soil must be strong enough to continuously buffer hazardous root induced acidification

52 Conclusion The ph buffering capacity of the soil Soil should be treated as H + decrease rate capacity

53 Conclusion Sugar beet cultivation is recommended in soils with ph not lower than 6.5 This is certainly a very rough, imprecise and insufficient recommendation not reflecting the strategy and requirements of the plant and not reflecting the production capacity of the soil Plant Soil

54 Thank You

55 Growth Unit Control conductivity