J.G. Mexal

New Mexico State University

Las Cruces, NM

Soil Properties: Nutrients

Soils & Nutrients

Liebig’s Law of the Minimum

• Growth and Yield are limited by the nutrient in least supply

• Envision a barrel with staves of different heights.

Soils & NutrientsEssential Elements/macronutrients

Element Form % in plant

Function Symptoms Sources

N NO3-, NH4

+ 1.0-2.0 Amina acids, chlorophyll

Chlorosis Manure, symbiosis, urea

P H2PO4-, HPO4

= 0.2 ATP Purple leaves TSP, manure

K K+ 1.0 Catalyst, Ts Mottling, marginal necrosis

KCl, manure

Ca Ca++ 0.2-0.5 Cell growth Blossom end rot Limestone, gypsum

Mg Mg++ 0.2 Chlorophyll Chlorosis (interveinal)

Limestone, epsom salts

S SO4= 0.1-0.2 A.A.,

vitamins Chlorosis (NH4)2SO4

S, H2SO4

Soils & NutrientsEssential Elements/ micronutrients

Element Form ppm in plant

Function Symptoms Sources

Fe Fe++ 150-500 Chlorophyll synthesis

Chlorosis in new leaves

Chelates

Mn Mn++ 100 Chlorophyll synthesis

Chlorosis (intervenal)

Zn Zn++ 10-100 Chloroplast formation

Bronzing, rosetting

ZnSO4

Mo Mo++ <10 Protein synthesis

Leaf rolling or cupping

B B+ ~10 N metabolism, H2O relations

Bud necrosis, Manure, TSP

Cu Cu++ ~10 Growth Bud necrosis, chlorisis

CuSO4

Tree Nutrition

• Rules of Thumb– After water, N is the factor that most limits tree

growth.– N ~ 2% of foliage DW– Foliar fertilization works– Fall fertilization is not bad!

Tree Nutrition

• Nitrogen– mobile, resulting in general chlorosis, shorter

growth, fewer lateral breaks

– available as ammonium (NH4+) or nitrate (NO3

-)

– apply 1-2 kg N/100 m2 to soil surface– apply 1 kg N/100 L to foliage (wet to runoff)

Soils & Nutrients

Nitrogen Content vs Ps

Leaf N (mmol/g)

Net Ps rate (nmol CO2/g/s)

Death Valley annuals

Old field annuals

Deciduous chaparral shrubs

Evergreen shrubs & trees

Southern African shrubs

Soils & Nutrients

Nitrogen Fertilizer vs Corn Yield

yield = 2653Ln(x) - 6059

R2 = 0.97

0

2000

4000

6000

8000

10000

0 50 100 150 200 250 300

Nitrogen (kg/ha)

Yield (kg/ha)

1024kg

896kg896kg

832kg704kg

576kg 363kg128kg

64kg

Soils & Nutrients

Nitrogen Fertilizer vs Corn Yield

0

2000

4000

6000

8000

10000

12000

67 90 113 136 159 182 205 228

Yield (kg/ha)

Nitrogen Applied (kg/ha)

Added Return ($/ha)

100

80

60

40

20

0

Return

Yield

Soils and Fertilizers

Rules of Thumb

• Nitrogen = 2% of dry weight

• Phosphorus = 10% of N content» 0.2% of dry weight

Tree Nutrition

• Phosphorus– leaves turn purple– P ~ 10% of N content

– available as HPO4= or H2PO4

-

– incorporate 1-4 kg P/100 m2 into soil

Tree Nutrition/nutrient stress vs cold-hardiness

0

20

40

60

80

100

5 10 20 30

2.5/

.17

2.5/

.11

2.2/

.17

2.2/

.11

1.9/

.17

1.9/

.11

Winter Injury (%)

Pecan Yield (kg/tree)%

N /%P

Tree Nutrition

• Potassium– interveinal chlorosis and margin scorching– available as K+

– rarely limiting– incorporate 2-15 kg/100 m2 into soil

Tree Nutrition

• Iron– immobile in plants, new leaves become

chlorotic often with green veins– incorporating iron in calcareous soils is

ineffective– spray iron citrate or

Sequestrene 138 for alkaline soils or

Sequestrene 330 for acid soils (0.2 g/100L)

Soil Properties

Soil pH Estimate/ Lime use (1000 tons/yr)

• Complete fertilizer contains N:P:K

• Incomplete fertilizer is missing one of three

• Reading a fertilizer bag– 10:10:10 contains 10% N, 10% P, & 10% K– 46:0:0 contains 45% N alone

• Mixing 100# 45: 0: 0 +

100# 0:45: 0 +

100# 0: 0:60 =

300# 15:15:20

Fertilizer Content

Fertilizer N P K $/kg $/kg N

Manure ~1 ~1 ~1 Free?

Urea 46 -- -- 0.57 1.24

Ammonium sulfate 21 -- -- 0.37 1.76

Ammonium phosphate 16 20 0.48 3.02

Ammonium nitrate 33.3 -- -- 0.62 1.86

10-10-10 10 10 10 0.50 5.00

Osmocote® 17 6 10 3.42 20.13

Tree spikes 16 4 4 6.47 40.44

Fertilizer Content

Soils & NutrientsSources of Nitrogen

• Inorganic %N– Anhydrous NH3 82%

– Urea 46%

– NH4NO3 33%

– (NH4)2SO4 20%

– (NH4)2HPO4 20%

– KNO3 14%

• Organic %N– Dried blood 12%

– Bat guano 12%

– Fish meal 10%

– Cottonseed meal 7%

– Sludge 6%

– Cow manure 2%

Soils & NutrientsSources of Phosphorus & Potassium

• Phosphorus %P1

– (NH4)2HPO4 54%

– TSP 45%

– Cottonseed meal 3%

– 1 %P as P2O5

• Potassium %K2

– KCl 50-60%

– KNO3 46%

– Wood ashes 4-10%

– Seaweed4- 5%

– 2 %K as K2O

Fertilizer Rules!/ adapted from Vir.Tech

• DON’T GUESS -- TEST!

• Virginia pine: maintain soil pH between 5.0 and 6.0Eldarica pine: maintain soil pH between 6.5 and 7.5

• Don’t waste $ on expensive fertilizers unless soil or tissue analysis shows a need.

• Band fertilize in Years 1 and 2Broadcast fertilizer beginning Year 3

• Apply P in the spring Apply Ca in the fall

• Maintain soil test calcium at 50-60% saturation and Mg at 10-15% saturation. Use lime or gypsum.

• If more than 100 lb K/a is needed, apply muriate of potash in two applications or only in fall because of potential fertilizer burn.

Response toFertilizer

Nitrogen Phosphorus PotassiumClassific-ation

ppm ppm ppm

Very low High <3 <7 <10

Low High 3-10 8-14 11-30

Medium Moderate 11-30 15-22 31-60

High Not likely 31-50 23-30 61-80

VeryHigh

Not likely >50 >31 >80

Very High

Interpreting Soil Test Results--NM

Flynn 2002

Tree Nutrition/ Hartman et al.2000

Nitrogen(lb/1000 ft2/yr)

Turf growth Tree growth

0 Poor quality and growth Young = slow growthMature = moderate growth

2 Good quality and growth.Optimum growth w/oirrigation.

Young = stimulate growthMature = good growthDeclining = no effect

4 Lush, high maintenancegrowth.

Young = rapid growthMature = rapid, unneededgrowth.Declining = may help

6 Excessive shoot growth,poor root growth, diseaseproblems.

Too much for all trees

Put the Fertilizer where the Roots Are!

RoT: The radius of root extension ~ height of tree

Tree age Application Spring Fall

(years) Type -------oz/tree-------

1 Band 0.5 -

2 Band 0.5 -

3 Broadcast 0.5 0.5

4 Broadcast 0.5 0.5

http://www.agr.state.nc.us/agronomi/stnote5.htm

Nitrogen Rates for Virginia pine- NCSU

Tree age Application Spring Fall

(years) Type -------oz/tree-------

1 Band 0.5 -

2 Band 0.5 -

3 Broadcast 0.5 0.5

4 Broadcast 0.5 0.5

http://www.agr.state.nc.us/agronomi/stnote5.htm

Nitrogen rates for Virginia pine- NCSU

http://ohioline.osu.edu/b670/b670_31.html

Fertilizer Recommendations/ Vir.Tech

• Preplant or at planting: 1 oz/tree• Year 1: 0-46-0 @ 500 lb/ac• Year 2: 10-10-10 @ 2-3 oz/tree• Year 3: 10-10-10 @ 3-4 oz/tree• Year 4: 10-10-10 @ 4-5 oz/tree

http://www.agr.state.nc.us/agronomi/stnote5.htm

Fertilizer Recommendations/ Vir.Tech

• Preplant or at planting: 1 oz/tree• Year 1: 0-46-0 @ 500 lb/ac• Year 2: 10-10-10 @ 2-3 oz/tree• Year 3: 10-10-10 @ 3-4 oz/tree• Year 4: 10-10-10 @ 4-5 oz/tree

• NCSU and Virginia Tech recommend 2.2 to 2.5 oz N/tree over 4 years

• Is that enough?

Fertilizer Recommendations

Biomass Growth of Eldarica Pine /Sammis et al. 2002

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

4.500

0 250 500 750 1000 1250

Time (days)

Above Ground Biomass (kg)

Nitrogen Uptake of Eldarica Pine /Sammis et al. 2002

0.000

0.500

1.000

1.500

2.000

2.500

3.000

3.500

4.000

4.500

0 250 500 750 1000 1250

Time (days)

Above Ground Biomass (kg)

20 g N/tree

90 g N/tree

Year-1 Year-2 Year-3

4 g N/tree

• Yr-1– 2-3 applications (late)– Total N ~ 0.5 oz/tree (15 g)[uptake ~ 4 g/tree]

• Yr-2– 3-4 applications (Spring-Fall)– Total N ~ 2.0 oz/tree (60 g)[uptake ~ 20 g/tree]

• Yr-3&4– 3-4 applications (Spring-Fall)– Total N ~ 3.0 oz/tree (90 g)[uptake ~ 90 g/tree]

Nitrogen Fertilizer Recommendations/

96 g N

72 g N

48 g N

24 g N

Fertilizer Uptake Estimates- Eldarica pine-23 mo

Fertilizer Recommendations/-GroBag

• Root exploration is restricted

• Fertilize more like a container-grown tree

• You do not want much root development outside the bag

Where do you fertilize Gro-Bag trees?

Foliar Sampling

• Collect:– in September– 5-8 needles of current-

season growth– 15 locations on tree– 20-30 trees– analyze for N, P, K, Ca,

Fe, Mo, B, S

Samplecurrent-

year needles in

this area.

Bondi, et al. OSU CES 2000

Foliar Nutrient Content/ Hartman et al.2000

Nutrient Normal Deficient

Nitrogen 2.0-4.0 % 1.5 %Potassium 0.75-2.5 % 0.3-0. 6%

Calcium 0.7-2.5 % 0.2-0.5 %

Magnesium 0.2-0.6 % 0.05-0.2 %

Phosphorus 0.12-0.5 % 0.08-0.1 %

Sulfur 0.2-0.5 % 0.12-0.14 %

Iron 50-400 ppm 33 ppm

Zinc 15-100 ppm 8 ppm

Why is foliar testing important?

Bondi, et al. OSU CES 2000

Fertilizer RecommendationsElement Foliar Analysis Fertilizer CommentsP (%) < 0.08

0.08 – 0.15>0.15

180 lb P2O5/a 90 lb P2O5/a 0

Surface bandrather thanbroadcast

K (%) <0.40.4 – 0.8

>0.8

100 lb K2O/a 50 lb K2O/a 0

--

S (%) <0.080.08 – 0.12

>0.12

20-30 lb S/atrial application0

Test on smallplots or useAmSul

Mg (%) <0.070.07 – 0.12

>0.12

20-40 lb MgSO4/atrial application0

If pH < 5.0, use 1t dolomite

Ca (%) <0.25 100 lb gypsum/a If pH < 5.0, use 1t lime

B (ppm) < 6 2-3 lb B/a Broadcast only

Bondi, et al. OSU CES 2000