Nitrogen, Potassium and Calcium in Potatoes. Barry Bull, Hydro Agri Specialities September 2003

Transcription

1 Nitrogen, Potassium and Calcium in Potatoes Barry Bull, Hydro Agri Specialities September 2003

2 Tuber Size Tuber Nu mber Tuber Quality Skin Finish Storage Quality N P K Ca Mg S Mn B Zn Role of nutrients in Potatoes

3 Nitrogen

4 Nitrogen ufor yield umore nitrogen uhigher yields ulower bulk density Nitrogen and tuber size 12 Hydro funded trials

5 Nitrogen ufor quality u high nitrogen usplit potatoes upoor cooking quality ubrown stains in crisps uslow skin-set

6 Sidedressing nitrogen usplit applications with one sidedress u 2/3 N applied at seeding u 1/3 N applied around tuber initiation Apply N when hilling up umore applications are better

7 Splitting Nitrogen Applications Total N Appl. Split t/ha Suecia 1988 CNTC

8 Effect of Nitrogen form & rate: Tuber yield in South Africa (cv. UTD) Relative Yield 1 0,95 0,9 0,85 0,8 0,75 0,7 0,65 0,6 80% NH4 / 20% NO3 50% NH4 / 50% NO3 20% NH4 / 80% NO3 Total N 120 kg/ha Total N 180 kg/ha Total N 240 kg/ha Ref: O. Achilea et al., 2000

9 Nitrogen - source u Ammonium nitrogen u Excess NH 4+ is toxic and reduces yield u NH 4+ Cannot be stored u NH 4+ must be detoxified u Nitrate nitrogen u not toxic u efficient u potatoes prefer nitrate

10 CN vs. AN

11 Potassium

12 Potassium uincreases tuber number udecreases tuber bruising udecreases enzymatic discolouration during cooking u Anti Stress Element

13 Field trials - results Bulgaria 1996 MT/ha KNO3 K2SO4 KCl

14 Effect of K on % damaged tubers % damaged tubers , , kg K per ha Source: Hunnius und Bachthaler - IPI

15 Mc Cains - Trial UK 97 Trial: Basedresser based on KCl just before planting Topdressing: with KNO3 217 kg/ha <-> AN Number of 170 tubers 160 bruised (SAC 150 damage 140 barrell) 130 No KNO3 +KNO3

16 Trial Mc Cains 97 - UK Number of peels, necessary to completely remove the bruise 1100 Number of Peels No KNO3 +KNO3

17 Potassium and Tuber Quality Effect of Potassium on discoloration Mondy & Munshi 1993

18 Potassium as Anti stress element: stomata regulation 1.5 Stomata H 2 O CO 2 TRANSPIRATION Water Transpiration g/g DM/day % K in DM STOMATA OPENING CONTENT OF K (mg/g) Source: Blanchet et Al., 1962

19 K effect on Low Temperature Tolerance K applied (lb/a) Yield (tons/a) Foliage Damaged by Frost (%) Grewal and Singh Plant Soil.

20 Calcium and heat stress

21 Potato is a cool season crop Hot dry weather is not beneficial Low levels of calcium in the leaf make the plant susceptible to foliar damage from heat stress. Calcium is important for the active transport of K for the regulation of stomatal openings. Low calcium levels in leaf means poor control of the stomata even with high K levels.

22 Calcium & heat stress Biotron studies from Wisconsin University show that: Plants with Ca produced 1.0 kg of tubers / plant Plants without calcium were heat stressed and produced 0.7 kg of tubers / plant A yield reduction of 30%

23 Calcium & crop stress The full study showed nitrogen during the stress helped but Ca & N was better. Fert applied Yield N only before stress 100 % N only during stress 117 % Ca & N during stress 167 % Calcium nitrate relieves heat stress in potatoes

24 Calcium and Potato Disease

25 Calcium & Erwinia uca improves tolerance to disease Peel Ca Surface area decayed 0,1 % 90 % 0.2% 50 % 0.3% 20 % 0,5 % nil

26 Calcium & Erwinia u Increasing calcium in cortex (red) & periderm (blue) u Deceases soft rot (yellow) % Ca Cortex (x 10-1) Periderm Soft Rot 50% 40% 30% 20% 10% %Wt. Loss From Soft Rot University of WI *Bacterial

27 Calcium & Internal Rust Spot u Ca improves tolerance to disease Ca IRS Peel Ca nil 60 % 0,11 % % 0,13 % % 0,15 %

28 Calcium & Internal Brown Spot (IBS) Ca in the inner part of tubers: Slight variations can make the difference % of IBS ,0050 0,0070 0,0090 0,0110 0,0130 0,0150 Ca in tuber flesh (% of DM) Tuber flesh, Site 1 Tuber flesh, site 2

29 Ca in tubers & Internal Brown Spot (IBS) % of IBS % of IBS Pulp R 2 = Ca (% of DM) Tuber flesh, Site 1 Tuber flesh, site 2 Tuber flesh Linear (Tuber flesh) Tuber skin, Site 1 Tuber skin, site 2 Linear (Tuber skin) % of IBS R 2 = Ca (% of DM) Skin

30 Calcium and Potato Skin Finish

31 Calcium Skin finish

32 Calcium and skin finish utubers need at least 0.15% Ca in peel u 0.2% is better for disease tolerance.

33 Ca & tuber storage Ca in the outer skin Confers resistance against pressure Calcium (% DM) 0,0700 0,0650 0,0600 0,0550 0,0500 0,0450 0, Resistance against pressure (g) 1 year trial, 2001 Germany Cooperation Hydro Agri / Uni. Goettingen / Bahlsen

34 Ca & tuber bruising All varieties increased in calcium All varieties had less bruising Tuber Calcium levels (ppm) 165 kg/ha Combination of CN & CaCl Amm Nit CN.CaCl Incidence of Bruising (%) 0 Atlantic Snowden Burbank Superior Norland Atlantic Snowden Burbank Superior Norland Amm Nit CN.CaCl Karlsson & Palta Uni. Of Wisconsin 2001

35 Does it work? u Example : In Australia - average peel analysis. u Ca ranged from 0.07 to 0.11% u Desired level at least 0.15% u CN rates used u 125 kg/ha solid when tubers 25mm u 25 kg/ha/week fertigated for 6 weeks u Total 275 kg/ha CN u Farmer increased his Ca levels to 0.15% u Skin blemishes decreased from 16% to 8% u Cost / Benefit u Cost Aus $192.5/ha u Benefit Aus $1088/ha

36 Calcium and Potato Yield

37 The importance of calcium in potato nutrition is demonstated in an experiment where seed potatoes were grown with and without calcium. Crops grown with these seed pieces showed substanial differences.

38 Calcium nitrate improves subsequent yield of seed potatoes.: Atlantic Norland Superior + Calcium Calcium Ca = Calcium nitrate - Ca = Ammonium nitrate

39 Minituber production using hydroponics Calcium nitrate removed Tuber skins cracked and peeled Internal breakdown.

40 Calcium uptake in tubers

41 Most Calcium absorption occurs from tuber initation and throughout tuber bulking Calcium Application Bulking Planting Stolon Growth Tuber Initiation Suberization Vine Kill Harvest

42 Calcium uptake is through stolon and tubers Ca applied ppm Ca % DM Stolon/tuber Main root Peel Tissue , , Field grown 100 0,27 0,08

43 Main Roots u (dyed water travels up to stem not into stolons and tuber)

44 Stolon - tuber connection Stolons pick up dyed water dyed water travels into tuber

45 Moving Ca into potatoes Foliar Ca remains in the leaf Stolon and tuber roots take in Ca for the tubers Soil Ca moves upwards into the leaves

46 Tuber initiation Varies with variety - digging is the best way to see

47 Applying CN Dry apply and incorporate Through watering system Both ways are effective in moving Ca over the tubers Apply in time for rapid cell division.

48 Calcium Analysis

49 Tissue analysis: Calcium levels in the leaf at start of flowering should be between 1 & 2 % If below these levels yield will be lower. Leaf analysis is not a good indicator of tuber Ca levels.

50 Tuber analysis: Tubers need higher levels of Calcium. Calcium levels are 3 to 5 times higher in peel than whole tuber. 0.15% Ca in peel will give better skin finish 0.2% Ca in peel gives good disease tolerance

51 Calcium in potatoes improves: Tolerance to heat and cold stress Tolerance to diseases Less internal tuber breakdown Better skin finish Yield: where soil Ca levels low where heat or cold stress results from low Ca levels Calcium is vital to potatoes

52 Tuber Size Tuber Nu mber Tuber Quality Skin Finish Storage Quality N P K Ca Mg S Mn B Zn Role of nutrients in Potatoes

53 Is it worth the effort? Australian example sandy soil Increased in program Nitrates Calcium Magnesium Yield: no difference Quality - Packout major improvement Cost: extra $A Return: extra $A Nutrition is vital to potatoes