a) Nitrogenb) Magnesiumc) Sulphur

the stock solution supplies those elements required in large amounts for plant growth and development

Nitrogen, phosphorus, potassium, magnesium, calcium and sulphur are usually regarded as macronutrients

a) Nitrogen gas comprises about 78% of the earth's atmosphere

b) Also found in various forms. found in rocks, soils, sediment, oceans, and living matter.

- Organic form :• Amino acids• Protein• more resistant N compounds (ultimately,

humus)- Inorganic form :

• ammonium (NH4+)• ammonia (NH3)• nitrate (NO3-)• nitrite (NO2-)

Plant obtain N from the surrounding soil and water

Nitrogen considered as one of the most important plant nutrient

essential component of the proteins that build cell material and plant tissue

necessary for the function of other essential biochemical agents such as :a) Chlorophyll (an integral part of chlorophyll )b) many enzymesc) nucleic acids – DNA & RNA

Important in determining plant growth and crop yield

nitrogen

Promotes rapid growth increases leaf size and quality hastens crop maturity, and promotes fruit

and seed development

Too much or too little amount of nitrogen can cause problem

Problem caused can extend to plants, animals, human and environment

Too little: Show nitrogen deficiency

Too much: can produce weak stems in grain crops (lodging) reduce quality in fruit lower sugar content in sugar beets excessive vegetative growth delays maturity increases lodging fosters disease, poses an environmental threat to surface and ground

water

slow stunted growth yellowish leaves (pale green) Symptoms generally appear on the bottom leaves

first The older leaves, will first turn yellowish-green

and then possibly yellow, red or purple The newer growth, will show signs of being

deficient in nitrogen by turning slightly yellowish-green as well

In severe cases, leaves have a “fired” appearance on the tips, turn brown, usually disintegrate, and fall off

In leafy crops : ◦ low yield and quality◦ exhibit yellow leaf tips, stunted growth with

spindly stalks, and low yields of poor quality grain

How to fix the problem?◦ can be corrected with an application of nitrogen

fertilizer

Older leaves turn yellowish-green

Slow plant growth

New leaves turn yellowish green

Have 5 steps:1) Nitrogen fixation2) Nitrification3) Assimilation4) Ammonification5) Denitrification

3

4

5

2

1

N2 enters eco through 3 pathways:1) Atmospheric fixation2) Biological N2 fixation

N2 NH3

3) Industrial N2 fixation Atmospheric fixation and industrial fixation

fix N2 into nitrateN2 NO3-

Conversation of ammonia (NH3) or ammonium (NH4

+) to nitrites (NO2-) and nitrates (NO3-)

Involve the role of nitrifying bacteria Nitrosomonas & nitrobacter

Ammonia (NH3) or ammonium (NH4+)

Nitrites (NO2-)

Nitrates (NO3-)

nitrosomonas

nitrobacter

Absorption of ammonia, ammonium or nitrate by roots◦ Incorporate the N2 into protein, nucleic acids and

chlorophyll When animals consume plants tissues

◦ Assimilate N2 by taking in plant N2 compound and converting them into animal N2 compound

Conversation or organic N2 compound into ammonia (NH3) or ammonium (NH4

+) Begins when excretion (urea) and nitrogen

compound in dead organisms are decomposed

Releasing the N2 into the abiotic environment as ammonia or ammonium

The ammonia and ammonium produced are available for nitrification and assimilation

The reduction of nitrates (NO3-) to gaseous N2

Denitrifying bac (pseudomonas dinitrificans) reverse the action of nitrogen-fixing & nitrifying bac◦ Return N2 to atmosphere

Magnesium is essential for many plant functions. Some of them are:

•Photosynthesis: Mg is the central element of the chlorophyll molecule•Carrier of Phosphorus in the plant•Magnesium is both an enzyme activator and a constituent of many enzymes•Sugar synthesis•Starch translocation•Plant oil and fat formation•Nutrient uptake control•Increase Iron utilization

•Enzyme cofactor•Component of chlorophyll

Plant tissue culture

Magnesium

Component of chlorophyll

In photosynthetic organisms Mg2+ has the additional vital role of being thecoordinating ion in the chlorophyll molecule.

Enzyme cofactor

Magnesium is important in the production of ATP through its role as an enzyme cofactor,

Two major classes of the enzymes that interact with Mg2+ in the stroma during the light phase

1. enzymes in the glycolytic pathway most often interact with two atoms of Mg2+

( 1 ) first atom is as an allosteric modulator of the enzymes' activity ( 2 ) second atom is forms part of the active site and is directly involved in the catalytic reaction

2. enzymes include those where the Mg2+ is complexed to nucleotide di- and tri-phosphates (ADP and ATP) and the chemical change involves phosphoryl transfer.

Sulfur are required in smaller amount than the primary nutrients.

Primary nutrients are Nitrogen (N), Phosphorus(P), and Potassium (K)

Sulfur is available in fertilizers such as Potassium and Magnesium Sulfate, gypsum( calcium sulfate) and elemental sulfur.

Can be found from soil,lime and commercial fertilizers.

Added continually by rainfall and release from the soil organic matter

It is estimate that some 10 to 20 pounds of sulfur per acre may be deposited anually in precipitation.

Sulfur is an essential mineral nutrients, althought it is often overshadowed by nitrogen, phosphorus and potassium.

Because of its central role in soil condition, plant growth and nutrition, understanding how plants utilize sulfur is critical for optimizing crop yield and quality.

Moreover, sulfur incorporated into methionine and cysteine in plants directly impacts the nutrional value of human food and livestock feeds.

Sulfur involved in formation of nodules and chlorophyll synthesis, structural component of amino acids and enzymes.

Sulfur is a part of several amino acids and has an important function in protien structure.

It is supplied as the SO4- ion and generally with concentrations ranging from 1-3 mM

Sulfur is an essential component in the synthesis of amino acids required to manufacture proteins. Sulfur is also required for production of chlorophyll and utilization of phosphorus and other essential nutrients. Sulfur ranks equal to nitrogen for optimizing crop yield and quality. It increases the size and weight of grain crops and enhances the efficiency of nitrogen for protein manufacture.

SULFUR’S ROLE

Crops that have a high nitrogen requirement must have adequate sulfur to optimize nitrogen utilization.

Sulfur increases yield and protein quality of forage and grain crops along with production and quality of fiber crops.

Sulfur deficiency is characterized by stunted growth, delayed maturity, and general yellowing of plants. Then, the plants become small and spindly. There is retarded growth rate and delayed maturity.

Yellowed plants are also characteristic of nitrogen deficiency.

However, unlike nitrogen deficiency which begins in the older leaves and progresses up the plant, sulfur deficiency symptoms begin in the young, upper leaves first.

Sulfur deficiencies are often misdiagnosed as nitrogen problems, leaving growers to wonder why their nitrogen applications are ineffective.

In many crops, an acute sulfur deficiency causes the entire plant to turn yellow.In crops like corn and small grains, however, yellow stripes that run parallel to the leaf blade are common.Sulfur deficiency is most frequently observed on very sandy soils with a low organic matter content during seasons of excessive rainfall.Fertilizers that provide sulfur include potassium sulfate (18% S), potassium-magnesium sulfate (23% S),magnesium sulfate (14% S), gypsum (16.8% S), ammonium sulfate (23.7% S), and elemental sulfur (90% S).Under most soil and climatic conditions, 15 to 25 lbs of sulfur per acre should be adequate.

For crops that have a high nitrogen requirement (corn, small grains, tobacco, and cotton) and are grown on sandy soils, sulfur can be applied at planting or along with post-plant nitrogen applications.

Sulfur is a necessary constituent in several amino acids and proteins. Since these are building blocks in the plant, Sulfur becomes fixed into the plant's structure. Therefore, the classic symptom of deficiency is a paleness of the younger foliage. However, many times all of the foliage has a pale green color, and the difference in "paleness" between the older and younger foliage is not easily noticed. This can lead to a misdiagnosis of N deficiency for S deficiency (Nitrogen deficiency symptoms appear on the older leaves first.). In some cases, the leaf veins may be lighterin color than the surrounding tissue.

CORN

APPLES

Sulfur is essential for many plant functions. Some of them are

A structural component of protein and peptides Active in the conversion of inorganic N into protein A catalyst in chlorophyll production Promotes nodule formation in legumes A structural component of various enzymes A structural component of the compounds that give the characteristic odors and flavors to mustard, onion and garlic Also may acidity the soil which is lowering the pH