Hello everyone! So today's topic is about fertilizer. My name is Zohir Chowdhury.
let's get into it so fertilizers are essentially any materials of natural or synthetic origin
that is applied to soil or to plant tissues to supply plant with their needed nutrients
most of the fertilizers that are commonly used in agriculture they contain three uh
macronutrients we call them three basic nutrients that plant need that nitrogen
phosphorus and potassium beside these nutrients which are macronutrients um plants also need
micro nutrients and many of these micronutrients they are critical to plant functioning
such as production of enzymes and many other things and some of these are zinc two to name
one iron is another one molybdenum is another one for example in here you can see uh to your uh
right a chemical fertilizer fertilizer production industry and some chemical fertilizer pallets
um there are two main types of fertilizers one is uh synthetic or inorganic fertilizer
and then the other is organic fertilizer the inorganic fertilizer
can also be called as chemical fertilizers so this inorganic or synthetic fertilizers and
man-made fertilizers that can be formulated for various speeds of release and increase yield in
agriculture by providing the macronutrients which are nitrogen potassium and phosphorus
and this is a media for plant growth example of synthetic or inorganic fertilizers are urea
ammonium nit ammonium nitrate ammonium sulfate ammonium phosphate as well as ammonium chloride
on the other hand organic fertilizers are derived organically from animal or plant matters and
examples are manure slurry worm casting speed seaweed humic acid and guano to name a few
these are enriched with the macronutrient with both macronutrients and micronutrients
that plant need uh and as explained in the uh in the sliding here you can see the
difference between applying chemical fertilizers which predominantly targets plant nutrients
uh provides planted nutrients while on the other hand organic fertilizers not only
provides plants with the needed nutrients but also enriches the soil with critical organic matter
which is essential for soil health and if the soil is healthy there'll be microorganism and through
those microorganisms plant can also absorb the nutrients properly for for proper growth
so that's the difference between chemical and organic fertilizers in here you can see um
three my macronutrients and p k and so uh npk stands for n nitrogen p phosphorous k potassium
nitrogen n is the leaf maker it helps in the production of new cells enzymes and green pigments
it is also responsible for leave and stem growth and helps plants with rapid growth on the other
hand phosphorus p is the root maker and flour inducer it encourages root growth and blooming
it is it is an essential part of the process of photosynthesis and it is involved in the formation
of all oils sugars and starches it also helps with the transformation of solar energy into chemical
energy finally potassium k is the flower inducer and fruit maker it encourages uptake of water
it is essential in the development of flowers and fruits and increases plants resistance to diseases
it also helps plant uh plants make better use of light and air
so when you when you get a bag of fertilizer you see these three numbers what are those
three numbers um so in describing the contents of a bag of fertilizer each symbol will be replaced
by a number such as for example 10 10 10 or in this case in this bag 18 24 and 6 the first
number is the nitrogen number the second number is the phosphorous number and the last number
is the potassium number so n for nitrogen p for phosphorous k for potassium npk um and and that's
what this means so what this means in here is that 80 of the bags weight is made up of nitrogen 24
is of the weight is phosphorous and 6 of the weight is potassium in total if you add this up
i believe it is 48 so 48 of the bag's weight comes from these three main ingredients
which are known in this which we know just talked about that they are macronutrients the rest
which is 52 is essentially filler and other minor elements this filler they typically are not
uptaken by the plants and they don't affect plant in any manner on the other hand micronutrients are
consumed in smaller quantities and are required for enzymes essential to the plant's metabolism
so they helped with the build-up of the enzymes here you can see you can see some of the main
macronutrients beside nitrogen phosphorus and potassium there's also carbon hydrogen oxygen
calcium magnesium and sulfur on the other hand uh some of the critical micronutrients are chlorine
boron copper iron manganese molybdenum zinc nickel to name a few of them
so uh organic fertilizer one example would be composting and composting is essentially the
control decomposition of organic materials such as leaves grass food scraps by microorganisms
so microorgan organisms decompose uh leaves grass and food uh scraps into uh products
that can be recycled into the into the soil and be uptaken by the plants um so compost is a useful
material that resembles the resemble soils and can be used in gardening uh and in here you can see
uh organic fertilizers how it can enrich the soil by providing soil with soil nutrition
which in turn gives plant its nutrition five the best organic fertilizers are shown in gear so
humus um then molasses kelp sea minerals fish are some of the uh important organic fertilizers
so what are the environmental effects of fertilizers so according to the intergovernmental
panel on climate change or ipcc production of fertilizers and associated land use practices
are key drivers of global warming greenhouse gases are produced during the manufacture of nitrogen
fertilizer in addition nitrogen fertilizer once in the soil can be converted to nitrous oxide a
potent greenhouse gas by soil bacteria chemical fertilizer can degrade soil microbiome and lead
to accumulation of toxins in the ecosystems chemical fertilizers eventually deplete soil
of organic matter reducing their ability to hold water and making them subject to erosion um excess
fertilizer applied to crops and fields which haven't happened very often leads to soil erosion
well excess fertilizer on sub-rectangles and crops including soil erosion make agriculture
not the largest source of nitrogen and phosphorus pollution in the country once a fraction of the
nitrogen-based fertilizers is converted to plant matter so only a fraction i mean only a fraction
of the natural ingredients fertilizers are converted into plant matter the rest gets
through the runoff or goes into the soil absorbing the soil and eventually into the ground water
the remainder accumulates in the soil and is transformed into nitrate
which is highly water soluble and so when there's rainfall the water-soluble nitrates from
the fertilizer goes into the water runoff and eventually pollutes oceans rivers and lakes
and this leads to uh leaching of the fertilizer into the
into the nearby waterways leading to groundwater pollution beside pollution of other waterways
of excess fertilizer usage and runoff uh we see um uh that um dead zones as show as as shown in
this in the in these graphs so chemicals that are not uptaken by plants leech through the
soil and into our groundwater contaminating streams lakes and oceans as mentioned above
previously as well as our drinking water system by contaminating the groundwater nitrogen and
phosphorus based fertilizers cause eutrophication in water bodies which is essentially algae
growing and taking up the nutrients from the water because of this excess nutrients
and then and can lead to like growth of algae like in here or uh blooms of algae as shown in here
um so because uh this algae overtake the water they take up they take up um they take up the
oxygen from the water and as a result there's a lack of oxygen which leads to dead zones
in places where excess nutrients gets run off so those excess nutrients leads to the growth of
algae and they come over compete with the local fish for the needs of oxygen and other
organisms in the water and that's why you get uh dead zones in in in different parts of the globe
so thank you for listening um i hope you enjoyed uh this this lecture and i will see you next time