Updated June 17, 2010 

Formal Recommendation by the 

National Organic Standards Board (NOSB) 

to the National Organic Program (NOP)

Date: April 29, 2011

Subject: Petition- Adding nickel to the list of micronutrients found on the 

National List, 205.601(j)(6)(ii)

Chair: Tracy Miedema

 

 

The NOSB hereby recommends to the NOP the following: 

Rulemaking Action X

Guidance Statement

Other

Statement of the Recommendation (Including Recount of Vote): 

Nickel to be added as a micronutrient to the list of micronutrients already included 

in §205.601(j)(6)(ii) was reviewed at NOSB at the April 2011 meeting following a 

petition for such use. The Crops Committee’s recommendation is attached. At the 

April 2011 meeting there was discussion of environmental and human health 

concerns related to the material as well as the merits of the material for growers. 

A motion was made and seconded to classify nickel as a synthetic substance. The 

NOSB voted unanimously to classify nickel as a synthetic substance.

Rationale Supporting Recommendation (including consistency with 

OFPA and NOP): 

See attached.

NOSB Vote: List nickel as a micronutrient on §205.601(j)(6)(ii)

Moved: John Foster Second: Tina Ellor

Yes: 5 No: 9 Abstain: 0 Absent: 2 Recusal: 0
Decision Sheets 

April 2010 

NOSB COMMITTEE PROPOSED RECOMMENDATION 

Form NOPLIST1. Committee Transmittal to NOSB 

For NOSB Meeting: Spring 2011—Seattle, WA Substance: Nickel as a micronutrient, added to 205.601(j)(6)(ii) 

Committee: Crops x Livestock  Handling  Petition is for: Adding nickel to the list of micronutrients found 

on the National List, 205.601(j)(6)(ii) 

A. Evaluation Criteria (Applicability noted for each category; Documentation attached) Criteria Satisfied? (see B below) 

1. Impact on Humans and Environment Yes  No x N/A 

2. Essential & Availability Criteria Yes  No x N/A 

3. Compatibility & Consistency Yes  No x N/A 

4. Commercial Supply is Fragile or Potentially Unavailable as Organic (only for 606) Yes  No  N/A x 

Substance Fails Criteria Category: 1, 2, 3 Comments: Fails categories.. Annotation in place for other micronutrients already on the list 

and--under which nickel would also be limited--is intended to mitigate effects of micronutrient use.

Proposed Annotation: 

§ 205.601 Synthetic substances allowed for use in organic crop production. 

(j) As plant or soil amendments. 

(6) Micronutrients—not to be used as a defoliant, herbicide, or desiccant. Those made from nitrates or chlorides are not allowed. Soil deficiency 

must be documented by testing. 

(i) Soluble boron products. 

(ii) Sulfates, carbonates, oxides, or silicates of zinc, copper, iron, manganese, molybdenum, nickel, selenium, and cobalt. 

Basis for annotation: 

To meet criteria above: 1, 2, 3. Criterion: Compatibility & consistency—to minimize the likelihood to overdependence on supplemental 

synthetic crop fertility practices in lieu of soil building practices as mandated in § 205.203. 

B. Recommended Committee Action & Vote, including classification recommendation (State Actual Motion): Classify nickel 

micronutrients as synthetic. 

C. Classification of the material: Synthetic 5 Non- synthetic 0 Absent 2 Abstain 0 

Motion by: John Foster Seconded Jay Feldman Yes: 5 No: 0 Absent 2 Abstain: 0 

Recommended Committee Action & Vote List nickel as micronutrient on § 205.601(j)(6)(ii) 

 

Motion by: John Foster Seconded: Tina Ellor Yes: 2 No: 3 Absent: 2 Abstain: 0 

 

1) Substance voted to be added as “allowed” on National List to § 205. with Annotation (if any) ____________________ 

2) Substance to be added as “prohibited” on National List to § 205. with Annotation (if any) _______________________ 

Describe why a prohibited substance:_______________________________________________________________________ 

 

3) Substance was rejected by vote for amending National List to § 205 601(j)(6)(ii) Describe why material was rejected: 

Concerns over toxicity, carcinogenicity, essentiality, and use pattern (spray into tall canopy) by those voting in the majority.. 

4) Substance was recommended to be deferred because _________________________________________________________ 

If follow-up needed, who will follow up _____________________________________________________________________ 

Crops x Agricultural Allowed1 

Livestock Non-Synthetic Prohibited2 

Handling Synthetic x Rejected3 x 

No restriction Commercially UnAvailable as Organic1

 Deferred4 

E. Approved by Committee Chair to transmit to NOSB: 

John Foster April 29, 2011 

Committee Chair Date
Decision Sheets 

April 2010 

EVALUATION CRITERIA FOR SUBSTANCES ADDED TO THE NATIONAL LIST 

Category 1. Adverse impacts on humans or the environment? 

Substance: Nickel (added to list of other micronutrients currently included on the National List) 

(RPet=Revised Petition; TR=Technical Review) 

 

Question Yes No N/A1 Documentation

(TAP; petition; regulatory agency; other)

1. Are there adverse effects on environment from 

manufacture, use, or disposal? [§205.600 b.2] 

 x 

2. Is there environmental contamination during 

manufacture, use, misuse, or disposal? 

[§6518 m.3] 

x The precise amount of nickel destined for 

agricultural use is unknown, but is known to be 

a fraction of 7% of nickel smelted and 

manufactured. ‘Agricultural use’ did not 

register as a subcategory within the use 

category “chemicals and chemical use”, 

suggesting that nickel for micronutrient use is 

an exceedingly small fraction of the total in 

play. RPet 9c. TR lines 459+, 671+ 

Surface mining involves large disturbance by 

earth-moving equipment. Nickel is no longer 

produced in US, so must be imported. Refining 

is very energy intensive. People around 

refineries are exposed to toxic nickel dust and 

sulfur dioxide.TR 422-457 

3. Is the substance harmful to the environment? 

[§6517c(1)(A)(i);6517(c)(2)(A)i] 

x When used as intended in this context, possibly 

but apparently not likely; the TR identifies 

certain harmful environmental effects outside 

of the use of nickel as a micronutrient in 

organic production systems. RPet 9c, 9e. TR 

lines 474, 484, 489+. 

Listed as a Hazardous Constituent of Waste 

(nickel, nickel compounds, nickel carbonyl, 

nickel cyanide) (305-306) 

On the other hand, these components, such as 

Cu, Zn, Ni, Co, Mo, Fe, and Mn, are also 

termed as “heavy metals”. The contamination 

of these heavy metals to the environment is 

well documented. It is a situation of case by 

case analysis, but the contamination problem 

such as the contamination of nickel in old 

orchard where fertilizers have been used 

extensively might be more general than the 

deficiency problem (e.g. U.S. EPA’s 

Background report on fertilizer use, 

contaminants and regulations; U.S. EPA’s 

Nutrient Management and Fertilizer; and 

USDA’s Heavy Metal Soil Contamination). 

(489-495) 

The toxicity effect of one component could be 

enhanced by another component. For example, 

scots pine (Pinus sylvestris L.) saplings did not 

survive when individually treated with 150 mg 

L-1 of copper or 150 mg L-1 of nickel. The 

lethal concentration substantially reduced to 15 

mg L-1 each when these two components were 

applied simultaneously (Nieminen, 1998). 

(521-524) 
Decision Sheets 

April 2010 

“Although Ni is a recognized essential mineral 

nutrient element for higher plants, its 

agricultural and biological significance is 

poorly understood. This is largely because of 

the low levels thought to be needed by plants 

(about 1–100 ng g-1 dry weight) in relation to 

the relative abundance of Ni in essentially all 

soils (> 5 kg ha-1),” (Bai et al., 2006 and 

additional references cited therein). (584-587) 

4. Does the substance contain List 1, 2, or 3 

inerts? [§6517 c (1 ) (B)(ii); 205.601(m)2] 

? Unknown 

Some micronutrients are chelated compounds 

such as chelates of citric acid, lignosulfonic 

acid, various amino acids, HEDTA 

(hydroxyethylenediaminetriaacetic acid), 

EDTA (ethylenediaminetetraacetic acid), and 

DTPA (diethylenetriaminepentaacetic acid). 

(97-99) Check to see if any are List 1,2, 3. 

Some are 4B, which likely will not be allowed 

in the future. 

5. Is there potential for detrimental chemical 

interaction with other materials used? 

 [§6518 m.1] 

x If misused, excessive nickel application could 

result in detrimental effects, particularly by 

causing imbalances with other micronutrients. 

RPet 9a. TR lines 513 

6. Are there adverse biological and chemical 

interactions in agro- ecosystem? [§6518 m.5] 

x If misused, levels above those required for plant 

growth and crop production can cause 

problems. Toxicity can occur when 

micronutrients are applied in excess. RPet 9. 

TR lines 534, 545+ 

When micronutrients are applied as chelates, 

some chelating agents such as ETDA are 

synthetic but do not naturally exist in soil. 

Potentially, these chelating agents may cause 

the loss of other components in soil by 

complexing those components and making 

those components soluble in water. (484-487) 

7. Are there detrimental physiological effects on 

soil organisms, crops, or livestock? [§6518 

m.5] 

x The TR does not note such effects when nickel 

is used appropriately as a micronutrient, though 

does suggests that possibility when misused, 

that is provided in excess of need. RPet 9. TR 

lines 560-651. 

The TR does not address impacts on the soil 

foodweb, but numerous studies show negative 

impacts on soil respiration and the growth of 

soil fungi, including mycorrhizal fungi. 

(Addendum) 

8. Is there a toxic or other adverse action of the 

material or its breakdown products? 

 [§6518 m.2] 

x See #7 above. Nickel is active in the Ni cation 

and does not break down further. TR lines 

661+. RPet 9, 10. 

Nickel is toxic and carcinogenic, it can be 

phytotoxic 

TR 489-495, 513-524, 545-555, 608-612 

9. Is there undesirable persistence or 

concentration of the material or breakdown 

products in environment?[§6518 m.2] 

x When used correctly, the TR notes no such 

effects. The TR does reference a line from 

ATSDR-Ni in line 705 stating that, “...it is 

impossible to predict nickel's environmental 

behavior on a general basis.” 

Nickel is a heavy metal. Contamination can be 

a problem, worse than deficiency, and interact 
Decision Sheets 

April 2010 

with other metals. TR 489-495, 513-524 

10. Is there any harmful effect on human health? 

[§6517 c (1)(A) (i) ; 6517 c(2)(A)I; §6518 

m.4] 

x Human health effects were addressed in the TR 

in general terms, but not in the context of nickel 

used as a micronutrient. Occupational hazards 

and exposures of the general public to nickel 

did not include mention of nickel as a 

micronutrient. For example, “The general 

population is exposed to low levels of nickel 

because it is widely present in air, water, food, 

and consumer products.” TR lines 816-817. 

RPet 9d, 10 

Nickel compounds are known to be human 

carcinogens (ATSDR-Ni, 2005; 11th Report on 

Carcinogens – Nickel Compounds and Metallic 

Nickel). (782-783) 

The effect of nickel on human health is 

extensively discussed in ATSDR-Ni (2005). 

Nickel compounds “can be grouped according 

to their solubility in water: soluble compounds 

include nickel chloride, nickel sulfate, and 

nickel nitrate, and less-soluble compounds 

include nickel oxide and nickel subsulfide. 

Both the soluble and less-soluble nickel 

compounds are important with regard to all 

relevant routes of exposure. Generally, the 

soluble compounds are considered more toxic 

than the less-soluble compounds, although the 

less-soluble compounds are more likely to be 

carcinogenic at the site of deposition.” (785-

791) 

11. Is there an adverse effect on human health as 

defined by applicable Federal regulations? 

[205.600 b.3] 

 x 

12. Is the substance GRAS when used according 

to FDA’s good manufacturing practices? 

[§205.600 b.5] 

 x 

13. Does the substance contain residues of heavy 

metals or other contaminants in excess of 

FDA tolerances? [§205.600 b.5] 

 x 

1

If the substance under review is for crops or livestock production, all of the questions from 205.600 (b) are N/A—not applicable. 
Decision Sheets 

April 2010 

Category 2. Is the Substance Essential for Organic Production? 

Substance: Nickel (added to list of other micronutrients currently included on the National List) 

Question Yes No N/A1 Documentation 

(TAP; petition; regulatory agency; other) 

1. Is there a natural source of the 

substance? 

 [§205.600 b.1] 

 x 

2. Is there an organic substitute? 

[§205.600 b.1] 

 x 

3. Is the substance essential for 

handling of organically produced 

agricultural products? [§205.600 

b.6] 

 x 

4. Is there a wholly natural 

substitute product? 

 [§6517 c (1)(A)(ii)] 

x None are available for rapid correction of 

micronutrient deficiencies or in soluble form. TR 867-

882 

Alyssum extracts are as efficacious as nickel sulfate in 

correcting or preventing Ni deficiency. 

Wood et al, 2006. 

5. Is the substance used in handling, 

not synthetic, but not organically 

produced? 

 [§6517 c (1)(B)(iii)] 

 x 

6. Is there any alternative 

substances? [§6518 m.6] 

x There are some plants that tend to accumulate nickel 

and other micronutrients when grown in appropriate 

conditions. TR 887-912 

pH adjustment might be more important than applying 

“required” micronutrients for correcting “deficiency” 

problems. “If the deficiency is due to pH imbalance, 

the approach is to modify the pH of the mix. In this 

case, adding micronutrients can make matters worse 

because the level of individual micronutrients may 

affect the level in the plant of other micronutrients 

through a process called antagonism. For example, too 

much iron may produce manganese and zinc 

deficiencies, while high levels of manganese may 

result in iron and zinc deficiencies. Copper and zinc 

are also antagonistic: too much of one may produce 

deficiency of the other,” (Ohio State University). 

Heavy metals such as Cu, Zn and Ni are strongly 

retained in soil. Excessively applied micronutrients 

remain in soil for a long time and may cause toxic 

effects to subsequent plants. (948-957 

7. Is there another practice that 

would make the substance 

unnecessary? [§6518 m.6] 

x Subject to the Law of the Minimum and in the some 

cases, yes. A healthy soil can provide sufficient 

micronutrients to some crops in some cases, although 

the dynamics of soil properties are such that 

micronutrient deficiencies can be found in crops even 

though soil micronutrient levels appear to be adequate. 

TR 584+, 594+. RPet 1, 4, 12. 

“Although Ni is a recognized essential mineral 

nutrient element for higher plants, its agricultural and 

biological significance is poorly understood. This is 

largely because of the low levels thought to be needed 

by plants (about 1–100 ng g-1 dry weight) in relation to 
Decision Sheets 

April 2010 

the relative abundance of Ni in essentially all soils (> 

5 kg ha-1),” (Bai et al., 2006 and additional references 

cited therein). (584-587) 

The nickel deficiency was especially evident in ureidetransporting woody perennials such as pecan tree 

(Wood et al., 2006; Bai et al., 2006). One cause of 

nickel deficiency is the suppressed nickel uptake by 

the excessive presence of zinc (University of Georgia). 

The metabolic consequence of nickel deficiency was 

the accumulation of urea, disrupted metabolism of 

amino acids, and reduced urease activity. The 

morphological symptoms of nickel deficiency in a 

woody perennial were dwarfing of leaves and leaflets 

with respect to healthy leaves, i.e. so called mouse ear 

in pecan (Wood et al., 2004; Bai et al., 2006; 

University of Georgia). (594-600) 1

If the substance under review is for crops or livestock production, all of the questions from 205.600 (b)are N/A—not 

applicable. 

 
Decision Sheets 

April 2010 

Category 3. Is the substance compatible with organic production practices? 

Substance: Nickel (added to list of other micronutrients currently included on the National List) 

 

Question Yes No N/A1 Documentation 

(TAP; petition; regulatory agency; other) 

1. Is the substance compatible with 

organic handling? [§205.600 b.2] 

 x 

2. Is the substance consistent with 

organic farming and handling? 

[§6517 c (1)(A)(iii); 6517 c 

(2)(A)(ii)] 

 X Applications of synthetic micronutrients have been 

consistent with organic farming practices for over 30 

years. Nickel is now recognized as an essential 

micronutrient. TR 54+, 101+, 184+, 228+, revised 

petition part 6, AAPFCO, professional knowledge, 

pre-NOP private standards, and 7 CFR 205. RPet 12 

Negative impact on soil organisms. (See citations in 

addendum.) 

3. Is the substance compatible with a 

system of sustainable agriculture? 

[§6518 m.7] 

 x See #2 above. In the long run (and that’s what 

“sustainable” means), it doesn’t work to mine metals 

and add them to soils to grow crops that could be 

grown in other places. 

4. Is the nutritional quality of the food 

maintained with the substance? 

[§205.600 b.3] 

 x 

5. Is the primary use as a preservative? 

[§205.600 b.4] 

 x 

6. Is the primary use to recreate or 

improve flavors, colors, textures, or 

nutritive values lost in processing 

(except when required by law, e.g., 

vitamin D in milk)? [205.600 b.4] 

 x 

7. Is the substance used in production, 

and does it contain an active 

synthetic ingredient in the following 

categories: 

a. copper and sulfur compounds; 

 

x In the nickel sulfate (most common) form. 

b. toxins derived from bacteria; x 

c. pheromones, soaps, horticultural 

oils, fish emulsions, treated seed, 

vitamins and minerals? 

x Minerals. 

d. livestock parasiticides and 

medicines? 

 

 x 

e. production aids including netting, 

tree wraps and seals, insect traps, 

sticky barriers, row covers, and 

equipment cleaners? 

 x 

1

If the substance under review is for crops or livestock production, all of the questions from 205.600 (b) are N/A—

not applicable. 
Decision Sheets 

April 2010 

Category 4. Is the commercial supply of an agricultural substance as organic, fragile or potentially 

unavailable? [§6610, 6518, 6519, 205.2, 205.105 (d), 205.600 (c) 205.2, 205.105 (d), 205.600 (c)] 

Substance: Nickel (added to list of other micronutrients currently included on the National List) 

 

Question Yes No N/A1 Documentation 

(TAP; petition; regulatory agency; other) 

1. Is the comparative description 

provided as to why the non-organic 

form of the material /substance is 

necessary for use in organic 

handling? 

 x 

2. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

appropriate form to fulfill an 

essential function in a system of 

organic handling? 

 x 

3. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

appropriate quality to fulfill an 

essential function in a system of 

organic handling? 

 x 

4. Does the current and historical 

industry information, research, or 

evidence provided explain how or 

why the material /substance cannot 

be obtained organically in the 

appropriate quantity to fulfill an 

essential function in a system of 

organic handling? 

 x 

5. Does the industry information 

provided on material / substance 

non-availability as organic, include ( 

but not limited to) the following: 

a. Regions of production (including 

factors such as climate and number 

of regions); 

 x 

b. Number of suppliers and amount 

produced; 

 x 

c. Current and historical supplies 

related to weather events such as 

hurricanes, floods, and droughts that 

may temporarily halt production or 

destroy crops or supplies; 

 x 

d. Trade-related issues such as 

evidence of hoarding, war, trade 

barriers, or civil unrest that may 

temporarily restrict supplies; or 

 x 

e. Are there other issues which may 

present a challenge to a consistent 

supply? 

 x 
Decision Sheets 

April 2010 

Addendum 

Some Studies of the Impacts of Nickel on Aspects of the Soil Food Web 

1. Inhibition of growth of nine ectomycorrhizal fungi by cadmium, lead, and nickel in vitro 

J.D. McCreight†, a

 and D.B. Schroedera

a

Department of Natural Resources Conservation University of Connecticut, Storrs, CT 06268, U.S.A. 

Received 18 February 1979; 

revised 7 January 1980; 

accepted 24 April 1980. 

Available online 26 June 2003. 

Abstract 

Growth of Amanita muscaria, Cenococcum graniforme, Laccaria laccata, Pisolithus tinctorius, 

Rhizopogon roseolus, Suillus brevipes, S. grevellei, S. luteus, and Thelephora terrestris on Hagem 

Nutrient Agar as modified by Modess at 20°C for 28 days was inhibited by cadmium, lead, and nickel. 

All fungi were arrested by 350 μg cadmium per ml (ppm) or less. Lead arrested five species at 200 ppm 

or less; Cenococcum graniforme, L. laccata, and S. luteus were arrested at 2,000 ppm lead. Nickel 

arrested growth of six fungi at 20 ppm or less. Amanita muscaria, S. luteus, and L. laccata were arrested 

at 40, 175 and 225 ppm nickel, respectively. Metal concentrations that did not arrest delayed growth for 

7–21 days after which the growth rate was comparable to the control. 

Scientific Contribution No. 791, Agricultural Experiment Station, University of Connecticut, Storrs, CT 

06268, U.S.A. 

†

 Present address: USDA, SEA-AR, U.S. Agricultural Research Station, P.O. Box 5098, Salinas, CA 

93915, U.S.A. 

Environmental and Experimental Botany

Volume 22, Issue 1, February 1982, Pages 1-7 

2. Nickel toxicity to fungi: Influence of environmental factors 

H. Babich and G. Stotzky 

Laboratory of Microbial Ecology, Department of Biology, New York University, 952 Brown Building, 

Washington Square, New York, New York 10003, USA 

Received 13 May 1982. 

Available online 16 December 2004. 

Abstract 

The toxicity of nickel (Ni) to the mycelial growth rates of filamentous fungi was influenced by 

environmental abiotic factors. Increasing the pH from acidic to alkaline levels completely eliminated the 

toxicity of Ni to Achyla sp. and Saprolegnia sp. Magnesium or zinc, but not potassium, sodium, calcium, 

or ferric, ions reduced the toxicity of Ni to Achyla sp. An antagonistic interaction between a combination 

of Ni + Pb was noted toward growth of Achyla sp. and Saprolegnia sp.; the interactions between 

combinations of Ni + Cd or Ni + Hg were less well defined. Chlorophyll, at 1%, reduced the toxicity of 

Ni toward Saprolegnia sp. and Cunninghamella blakesleeana, and increasing the chlorophyll 

concentration from 0.2 to 1% progressively reduced the toxicity of Ni to Aspergillus clavatus. The 

addition of 1% humic acid reduced the toxicity of Ni to Saprolegnia sp. and C. blakesleeana, and 

increasing the humic acid concentration from 0.2 to 1% progressively reduced the toxicity of Ni toward 

Aspergillus flavus. A. flavus was more resistant to Ni at 33 than at 23°C. 

3. Short-term and long-term effects of cadmium, chromium, copper, nickel, lead and zinc on soil microbial 

respiration in relation to abiotic soil factors 

P. Doelman and L. Haanstra

Abstract 
Decision Sheets 

April 2010 

The inhibition of the respiration rate by the heavy metals, Cd, Cr, Cu, Pb, Ni and Zn was investigated in 

five Dutch soil types in relation to the length of time these heavy metals were present in the soil. The 

amounts of heavy metal added as chloride salts to the soils were 0, 55, 150, 400, 1000, 3000 and 8000 

g·g–1, respectively. The measurements were carried out both immediately after the addition of the heavy 

metals and approximately 18 months later. The inhibition during the first two to eight weeks was not 

obscured by an extra nutrient flush to drying. During the 18 months, the toxicity decreased but was still 

significant. Inhibition was greatest in the sandy soil and least in the clay soil. In a loam soil and in a sandy 

peat soil, the inhibiting effects were intermediate, but distinct. The main abiotic factors responsible for 

these different degrees of inhibition were the clay fraction for Cd, the Fe content for Cu, Pb and Zn and 

the pH for Ni. Although clay, Fe, and Mn together with the organic matter fraction, determine the total 

cation exchange capacity of soil, their contribution to the toxicity of heavy metals may be antagonistic. 

The latter may increase the mobility due to chelation and therefore possibly increase the toxicity, while 

the other factors may bind the heavy metals and therefore decrease the toxicity. 

Key words Cd - CEC - Clay - Cr - Cu - Fe - Long-term - Mn - Ni - Organic matter - Pb - pH - Shortterm - Soil microbial respiration – Zn 

Use of Alyssum extracts to correct Nickel Deficiency 

B.W. Wood, R. Chaney, and M. Crawford, 2006. Correcting Micronutrient Deficiency Using Metal 

Hyperaccumulators:Alyssum Biomass as a Natural Product for Nickel Deficiency Correction. 

HORTSCIENCE 41(5):1231-1234. 2006. 

Abstract: 

The existence of nickel (Ni) deficiency in certain horticultural crops meritsdevelopment of fertilizer 

products suitable for specific niche uses and for correcting orpreventing deficiency problems before 

marketability, and yields are affected. The efficacyof satisfying plant nutritional needs for Ni using 

biomass of Ni hyperaccumulator specieswas assessed. Aqueous extraction of Alyssum murale 

(Waldst. & Kit.) biomass yieldeda Ni-enriched extract that, upon spray application, corrects and 

prevents Ni deficiency inpecan ICaiya illinoinensis (Wangenh.) K. Kochi. The Ni-Alyssum biomass 

extract was aseffective at correcting or preventing Ni deficiency as was a commercial Ni-sulfate 

salt.Foliar treatment of pecan with either source at -10 mg-L` Ni, regardless of source,prevented 

deficiency symptoms whereas treatment at less than 10 mg-L` Ni was onlypartially effective. 

Autumn application of Ni to foliage at 100 mg-L-' Ni during leafsenescence resulted in enough 

remobilized Ni to prevent expression of morphologicallybased Ni deficiency symptoms the following 

spring. The study demonstrates that micro-nutrient deficiencies are potentially correctable using 

extracts of metal-accumulatingplants.