crop science 2 nutrients_etmo

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NUTRIENTNUTRIENTMANAGEMENTMANAGEMENT

Crop Science 2Crop Science 2

ExerciseExercise 77

FirstFirst SemSem 20112011--1212

ObjectivesObjectives

Name, distinguish and identify nutrientName, distinguish and identify nutrientsourcessources

Difference between organic and inorganicDifference between organic and inorganic

Various ways of compostingVarious ways of composting

Explain effects of different N levels on cropExplain effects of different N levels on cropgrowth and developmentgrowth and development

Compute fertilizer requirementsCompute fertilizer requirements

ActivitiesActivities Short LectureShort Lecture

Exhibit of different nutrient sourcesExhibit of different nutrient sources

CompostingComposting

Field fertilizer trial on lowland riceField fertilizer trial on lowland rice

Fertilizer calculationsFertilizer calculations



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OUTPUTSOUTPUTS

WorksheetWorksheet 7.17.1 Submit afterSubmit after class (Aug 10/11)class (Aug 10/11)

Worksheets 7.2/7.3Worksheets 7.2/7.3

SubmitSubmit after 1 week (August 17/18)after 1 week (August 17/18)

Assignment on Fertilizer CalculationsAssignment on Fertilizer Calculations

To beTo be emailed and submitted after 1 weekemailed and submitted after 1 week(August 17/18)(August 17/18)

Mineral Nutrition in plantsMineral Nutrition in plants

Plants are:

Capable of making all necessary

organic compounds from

inorganic compounds and

elements in the environment

( autotrophic)

Supplied with all the carbon,

hydrogen, and oxygen they could

ever need (CO2, H2O)

Required to obtain all other

elements from the soil so in a

sense plants act as soil miners.



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NutrientNutrient any substance that can be

metabolized by an organism to giveener and build tissue rowthand development

source of nourishment, especially a

nourishing ingredient in a food

providing nourishment

Plant NutrientsPlant Nutrients CategoriesCategories EssentialEssential BeneficialBeneficial

SourcesSources NaturalNaturalAtmosphere/ Air (O, N, C)Atmosphere/ Air (O, N, C)

Rhizosphere/ SoilRhizosphere/ SoilOrganic FertilizersOrganic Fertilizers

Synthetic/ Artificial/Synthetic/ Artificial/FertilizersFertilizersNutrient SaltsNutrient Salts

For a Nutrient To beFor a Nutrient To beConsidered Essential….Considered Essential…. If the nutrient is absentIf the nutrient is absent thethe

plant is unable to complete its lifeplant is unable to complete its lifec clec cle

The nutrient is a plant constituentThe nutrient is a plant constituentor metaboliteor metabolite

The nutrient must act directly inThe nutrient must act directly inthe metabolism of the plantthe metabolism of the plant



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The Essential NutrientsThe Essential Nutrients

Macronutrients:Macronutrients: Nitrogen, phosphorus, potassium,Nitrogen, phosphorus, potassium,

calcium, sulfur, magnesium,calcium, sulfur, magnesium, oxygen,oxygen,carbon h dro en carbon h dro en

Micronutrients:Micronutrients:

Iron, boron, copper, zinc,Iron, boron, copper, zinc,manganese, molybdenum, chloridemanganese, molybdenum, chloride(sodium, silicon, cobalt, selenium)(sodium, silicon, cobalt, selenium)

Plant nutrient Source

Air Water Soil

Carbon X

Oxygen X X

Hydrogen X

Macronutrients

Nitrogen X

Phosphorus X

Potassium X

Calcium X

Magnesium X

Sulfur X

Micronutrients

Boron X

Chlorine X

Copper X

Iron X

Manganese X

Molybdenum X

Nickel X

Zinc X

Nutrient cycleNutrient cycle describesdescribes howhow nutrientsnutrients move from themove from the

physical environment (SOURCE) intophysical environment (SOURCE) intoliving organisms (RECIPIENTS), andliving organisms (RECIPIENTS), andsubsequently are recycledsubsequently are recycled(DEGRADED/DECOMPOSED) from(DEGRADED/DECOMPOSED) fromorganisms (SOURCE) back to theorganisms (SOURCE) back to thephysical environment (now thephysical environment (now theRECIPIENT).RECIPIENT).



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The Sulfur Cycle

Animalmanures

i i

Mineralfertilizers

Cropharvest

Plantresidues

Atmosphericsulfur

Input to soilComponent Loss from soil

VolatilizationAtmospheric

deposition

and boso ds

Runoff anderosion

Leaching

Absorbed ormineral sulfur

Plantuptake

SulfateSulfur(SO4)

Elementalsulfur

Organicsulfur

Reduced sulfur

-

http://www.ipni.net/ppiweb/ppibase.nsf/$webindex/article=5203CB87852569B50057E346C0116272

Nutrients in the environmentNutrients in the environment

Can be stored in any of the ff componentsCan be stored in any of the ff components

Soil, microorganisms, animals, weeds,Soil, microorganisms, animals, weeds,vegetation, cropvegetation, crop

component to anothercomponent to another

Gained from an external sourceGained from an external source Lost via certain processesLost via certain processes

Guides in Nutrient ManagementGuides in Nutrient Management The amount of nutrient needed by a crop for optimal yieldThe amount of nutrient needed by a crop for optimal yield

can be ascertainedcan be ascertained

Preferred nutrient source will determine the most effectivePreferred nutrient source will determine the most effective

source and the most efficient manner in which the nutrientsource and the most efficient manner in which the nutrient

can be su lied to the crocan be su lied to the cro

Nutrient sources or fertilizers can be organic or inorganicNutrient sources or fertilizers can be organic or inorganic

EffectivityEffectivity, efficiency, safety, sustainability, efficiency, safety, sustainability

EffectivityEffectivity/efficiency can be enhanced by method of /efficiency can be enhanced by method of

application and timing of applicationapplication and timing of application

Sustainability of nutrient management should be assessed:Sustainability of nutrient management should be assessed:

Crop yield, longCrop yield, long--term ability to sustain yields, economy.term ability to sustain yields, economy.EnvironmentEnvironment--friendlyfriendly



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FERTILIZERSFERTILIZERS

Complete 14Complete 14--1414--1414

or 12or 12--1212--1212

MuriateMuriate of potash 0of potash 0--00--6060

Urea 46Urea 46--00--00

SolophosSolophos 00--1616--00

Ammonium sulfate 21Ammonium sulfate 21--00--00

Ammonium polyphosphate 10Ammonium polyphosphate 10--3434--00

What do the figures mean?What do the figures mean?

Complete fertilizerComplete fertilizer – – 1414--1414--1414

NN – – PP22OO55 – – KK2200

NN – – PP – – KK

Means that :Means that :

14% Nitrogen14% Nitrogen1414--% Phosphorus% Phosphorus

14% Potassium14% Potassium

Complete 14Complete 14--1414--1414

1212--1212--1212

Triple sourceTriple source

MuriateMuriate of potash 0of potash 0--00--6060

Single sourceSingle source

Urea 46Urea 46--00--00

SolophosSolophos 00--1616--00

Ammonium sulfate 21Ammonium sulfate 21--00--00

Ammonium polyphosphate 10-34-0



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Fertilizer RecommendationsFertilizer Recommendations

Recommended rate for a cropRecommended rate for a crop

Usually expressed on a per hectareUsually expressed on a per hectarebasisbasis

Example:Example:

120120 --6060--60 kg NPK per ha60 kg NPK per ha NN-- P2O5P2O5 – – K2OK2O

6060--3030--30 kg NPK per ha (ha30 kg NPK per ha (ha--11))

6060--3030--100 kg NPK ha100 kg NPK ha--11

CALCULATIONSCALCULATIONS

If fertilizer recommendation is for ONLY 1If fertilizer recommendation is for ONLY 1element:element:

Fertilizer recommendation: 60 kg NFertilizer recommendation: 60 kg N haha--11

How much urea is needed to satisfy thisHow much urea is needed to satisfy thisrequirement?requirement?

GetGet single source; e.g. Urea = 46single source; e.g. Urea = 46--00--00

CASE 1

o ca cu a e:o ca cu a e:

Weight nutrient = wt urea x % N in ureaWeight nutrient = wt urea x % N in urea

60 kg N60 kg N haha--11= wt urea x 46/100= wt urea x 46/100

(transpose!!)(transpose!!)

(60 * 100)/46 = 130.43 kg urea per ha(60 * 100)/46 = 130.43 kg urea per ha



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Fertilizer recommendation is for 3 elements that will comeFertilizer recommendation is for 3 elements that will comefrom 3 fertilizer sources that are single element sources:from 3 fertilizer sources that are single element sources:

Fertilizer recommendation: 50Fertilizer recommendation: 50--1818--2525

Sources:Sources:

Urea (46Urea (46-- 00 --0);0); SolophosSolophos (0(0--1818--0);0); MuriateMuriate of potash (0of potash (0--00--60)60)

To calculate:To calculate:

Wei ht nutrient = wt fertilizer re uired x % nutrient inWei ht nutrient = wt fertilizer re uired x % nutrient in

CASE 2

that fertilizerthat fertilizer

To get 50 kg N per ha:To get 50 kg N per ha: 50 = wt urea x 46/10050 = wt urea x 46/100

50/0.46 = 108.70 kg urea per ha50/0.46 = 108.70 kg urea per ha

To get 18 kg P per ha:To get 18 kg P per ha: 18 = wt18 = wt solophossolophos x 18/100x 18/100

18/0.18 = 100 kg18/0.18 = 100 kg solophossolophos per haper ha

To get 25 kg K per ha:To get 25 kg K per ha: 25=25= wtwt muriatemuriate of potash x 60/100of potash x 60/100

25/0.60 = 41.67 kg25/0.60 = 41.67 kg muriatemuriate per haper ha

Fertilizer recommendation is for 3 elements that will comeFertilizer recommendation is for 3 elements that will comefrom 3 fertilizer sources that can supply 2 or morefrom 3 fertilizer sources that can supply 2 or moreelements:elements:

Fertilizer recommendationFertilizer recommendation: 75: 75 --5555-- 3030 Sources:Sources:

Complete (12Complete (12--1212 --12)12)

CASE 3

Urea (46Urea (46--00--0)0)

ammonium phosphate (16ammonium phosphate (16--2020--0)0)

Calculate the amount of fertilizers needed for 3 hectaresCalculate the amount of fertilizers needed for 3 hectares

farm landfarm land

Weight nutrient = wt fertilizer required x % nutrient inWeight nutrient = wt fertilizer required x % nutrient in

that fertilizerthat fertilizer

• Step 1.

– Compute first for the fertilizer which contains the most number of nutrients

– Satisfy the requirement for the nutrient which is provided only by this fertilizer

• In this case use complete to get the requirement for K (30 kg N per ha)

Fertilizer recommendation: 75 ‐55‐ 30

Sources: Complete (12‐12 ‐12)

Urea (46‐0‐0) Ammonium phosphate (16‐20‐0)

• Recommended wt nutrient/ % nutrient = weight fertilizer

• (30 kg per ha *100)/12 = wt of complete

= 250 kg complete fertilizer per ha.

– This amount will also give 30 kg N and 30 kg P per ha.



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• Step 2.

– Considering that complete has met 30-30-30 kg NPK requirement, the

remaining requirement will only be 45-25-0

75-55-30 (original requirement)

- 30-30-30 (met by complete fertilizer)

45-25-0 remainin re uirement;



Urea (46‐0‐0)

Ammonium phosphate (16‐20‐0)

reqt for K has already been met!!

– Use ammonium phosphate to meet the requirement for P (20 kg perha, after 30 kg per ha was provided for by complete fertilizer)

• Recommended wt nutrient/ % nutrient = weight fertilizer

• (25 kg per ha *100)/20 = wt required of ammonium phosphate

= 125 kg ammonium phosphate per ha.

– This amount will also give 20 kg N per ha.

» 125 kg * 0.16 N / kg ammophos = 20 kg N

• Step 3.

– Considering that ammonium phosphate has met the additional 20

kg N requirement, then remaining requirement will only be 25‐0‐0

• 45‐25‐0

‐ 20‐25‐0 met by ammophos



Urea (46‐0‐0)

Ammonium phosphate (16‐20‐0)

25 – 0‐0 remaining requirement for N

– Use urea ( N source only) to meet the balance for N

• Recommended wt nutrient/ % nutrient = weight fertilizer• (25 kg per ha *100)/46 = wt required for urea

= 54.35 kg urea per ha.

– Multiply all computed values by 3 to get the total

requirement for a 3‐ hectare area

If fertilizer recommendation is same for allIf fertilizer recommendation is same for allthe 3 elements:the 3 elements:

6060--6060--60 kg NPK60 kg NPK

Choice would be complete fertilizerChoice would be complete fertilizer

REMEMBER!!REMEMBER!!

CASE 4

Recommended rate/percent nutrient = amount of sourceRecommended rate/percent nutrient = amount of source

60 kg NPK ha60 kg NPK ha--11/ 0.12 = kg complete fertilizer/ 0.12 = kg complete fertilizer

500 kg complete per ha500 kg complete per ha

how many bags if 25 kg/bag?how many bags if 25 kg/bag?

500/ 25500/ 25

20 bags of complete fertilizer for 1 hectare20 bags of complete fertilizer for 1 hectare



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Not the same requirement for eachNot the same requirement for each

elementelement FertilizerFertilizer reqtreqt: 200: 200--6060--6060

Get the lowest requirement, and that of theGet the lowest requirement, and that of the

Again!

fertilizer:fertilizer:

CALCULATE FROM 12CALCULATE FROM 12--1212--1212

Subtract the balance from the elementSubtract the balance from the elementwith the highest requirementwith the highest requirement

Add the lacking element using a singleAdd the lacking element using a singlesource fertilizersource fertilizer

crop science 2 nutrients_etmo

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