Loading

Alison's New App is now available on iOS and Android! Download Now

Module 1: Historical Perspectives of Agriculture

Study Reminders
Support
Text Version

Set your study reminders

We will email you at these times to remind you to study.
  • Monday

    -

    7am

    +

    Tuesday

    -

    7am

    +

    Wednesday

    -

    7am

    +

    Thursday

    -

    7am

    +

    Friday

    -

    7am

    +

    Saturday

    -

    7am

    +

    Sunday

    -

    7am

    +

Video 1: Natural Agriculture
Well resuming from where we had stopped in the last class, as I have already discussedwith you the way the course delivery will be progressing, so in the first week as wediscussed that we will be talking little about the historical perspective of agriculture. So if you back in the early civilization human beings were nomads, ways to move fromplace to place, gather food and once the resources at that particular location get consumed,move to another location.But in that whole process someone down the period learnt to grow plants, we as a racewere probably rearing animals much earlier than that, but after learning how to growplants, we kind of concentrated on few crops, few vegetable, few fruits and such variationshappened. So in terms of the grains, in terms of the food, in terms of the fruits, in termsof the vegetables happen across the world different places depending on the availability.We have different kinds of grains, different kind of vegetables, different kind of fruitsand of course different kind of rearing animals. But at the end of the day what happen is thatfrom a big pool of plant kingdom, from a big pool of animal kingdom we choose a few varietywhat makes us choose is the question, but we did choose and those choices includes riceas one of the major grains wheat, barley, mallets, Sargam, then you have poor malletssome of these.Similarly we selected potato, cassava, a source of sugar, we selected vegetables like youknow brinjal, cauliflower, ladies finger, beans. But if you look at the whole plantkingdom you will see only hand full of it got selected. So now while you are doing agriculturethe idea was you wanted to grow only handful of them and these handful plants have to competewith rest of the plant kingdom.Say in other word if you think of it this something like this, say for example theseare the different A, B, C, D, E likewise to Z. So if I choose say C, D, E, and say Z.Now I wanted to grow these for my staple food requirements, in fact to grow them and theseare the once which I am encircling in red, they will be competing with these ones.So what we can do once these one will be competing, so the first thing possibly what will happenin agriculture development is clearing up the land from all these and likewise. So nowyou have a piece of land out here I have shown with an arrow which is free from other plants.In another word you have the other form of biomass you are now getting rid of. Now exclusivelyI want to grow either C, E or Z.So first of all you have to ensure that competition between intercompetition is being reduced,that will be done physically by isolating or removing all the plants. But still therewill be some which will be more hard, more stronger which can compete with the ones thatare selected one, the chosen ones which can compete with your those other ones we cancompete with your selected ones this will always pose a threat in the production lineof your C, E and Z.These are weeds, they are also part of the plant kingdom, but they will compete withyour chosen crops and maybe they are much more stronger in terms of genetics, in termsof the physiology that they can outsmart your chosen crop. This is one example I am givingwhere slowly we will realise how we move towards modern agriculture.Now let us take the second situation, so here you have a finite land of a finite dimension.In this land you have top soil where things grow and which has a simple dimension whichyou can cross check in any soil science book. Now the thing is that, that finitevolume of soil has finite amount of different elements. In other words that finite soilwill have a fixed amount of carbon, nitrogen, hydrogen, sulphur, boron, zinc, molybdenum,manganese and this list can go on.And they will not be freely available, they will be in the form of complexes and the plantwhich are growing as their ability to derive those components from the soil. So you growa crop for a season, you grow a crop for second season, you grow a crop for a third season,you grow a cropper for a fourth season, eventually what will happen this particular piece ofland unless otherwise with supplement these different elements will be depleted of thoseelement to the level where plant cannot extract anymore.They may be there but plant would not be able to extract more, so what you have to do isyou have to supplement these, these things with those elements and the very moment wetalk about supplementing this we are talking about the word of chemicals, word of fertilizers.

Video 2: Modern Agriculture
So now after weeds let me introduce something called fertilizers. Now the third aspect thatI am going to introduce is you have chosen.Say for example you have C, E, Z and now that C, E, Z those are your chosen crops, you aregrowing them over acres, acres and hectares. Now think of it for a minute in a naturalsetting how that looks like, in a nature you have things going on like this.A, B, C, X, Y Z, E, Q, R, L, M, N, O, P, X, Z likewise. So this is a natural setting wherethings are growing, so there are insects, there are different forms of insects whichfeed on these vegetative kingdom or into the plant world. For insect say for example Idenote insect out here, insect say x or say I prime. For this insect most likely it hasmultiple possibilities, it may refer why and maybe a closer relative of Y maybe X or maybecloser relative of its Z.Similarly another insect I say you know I double dash, it may prefer say A and a closerrelative of A say B and may be a closer relative of C fine. Now I take up another example sayyou know I have insect I triple prime, so this may prefer O and a closer relative ofit say P may be closer relative of K. Now if I from here choose only handful of plantssay for example, say example let us take I chose C.I want to grow C as in a crop, I wanted to grow X as a crop and I wanted to grow sayO as a crop. So these are my crops, and now I increase the area of these cropsmany fold, many fold increase, acres after acres, hectors after hectors I am going onlynow your either C, X and O and the way I grow probably a lot of Cs like this, lot of X likethis, lot of Os like this. Now in the system insects are the same.Now for I insects think about yourself in this situation, for you here I come I sayI am the insect I prime, so I have to hunt down where is so my choices are X, Y, Z fine.Now I have to hunt up and come here, then I have to hope down here for you so, thathope down here and likewise (13:09) which is the lot of work for me similarly for Idouble prime I come here, I hope to here I from there hope here, my family and everything.And similarly for I three primes so come here then move here, now I see that I, I primethe insect, whose target is X, so which one I will prefer shall I go here or shall I comehere. Because if I come here I know all the plants are X X X X X X likewise. So for meto acquire resources will be much, much more easy out here, similarly for the O I tripleprime so we have lot of Os.So in other words what we are saying is the modern form of agriculture, what the wordthrough the ages since mankind learn how to grow crops has believed in a word called homogenousor homogeneity. Yet nature is a heterogeneous mixture, yet we know in a heterogeneous systemyou cannot really feed at a timid million. So your options are very clear, you will havethis strategy out here and you need to work around it.And you have to work around it, now in order to counter your pest in the form of insectsand by the way this could even microbes instead of say I, I can put it as M, M prime, M doubleprime, M triple prime. So these are the microbial infestation and they may have their own targets.Now in order to counter this, we started developing this set of chemicals which after I introduceweeds, fertilizers.Now I introduce the third thing which is called insecticide and pesticides, which will becountering our unfriendly never good which is, whereas I did not mention here regardingthe weeds.In order to counter the weeds we have different form of weedicides, herbicides, so these herbicides,weedicides are fairly specific to the weed plants as compared to the crop plants. So,they are also very specific chemicals which ensure that your weeds die out not the cropplants. So you see in this little course we are realizing as we, as a race mature to becomeextraordinarily advance agrarian society.We almost unconsciously become dependent on things which may be nature has seen but naturehas never seen them in such a huge quantity because now from nomads we became settledsocieties, the evolution from nomad to human society. A journey whose origin is learninghow to grow plants and which let to extraordinary dry divers with kind of development in thefield of agriculture.But that came because we kept on discovering, kept on developing different forms of compoundswhich either help us to replenish or depleting soil because see we are no more nomads, sothat whole strategy we do a cropping at a particular locations. So this kind of thingsalso use to happen at one point like you know.The tribes are moving out here, they grow, they stay there for a while, then grow cropsand then they change parts, they move to next place, there they consume the resources andthen they move for third place that is the burning, whereas the place what they haveleft behind over a period of time again by nature’s action regain its fertility andall other natural resources.But that means if this kind of theory goes then we are talking about something whichis unheard of is called moving cities, or moving civilization, yet we know when we talkabout cities across the world new york, san Francisco, Delhi, Madras, Bombay, they arecities, they cannot move on from place to place. They have to supply with there hasto food chain, they have to be continuously feed in and around.So you cannot add a particular distance, say for example you talk about Delhi or you talkabout Bombay, or talk about Madras, so you see the surrounding this cities you have theagrarian societies which are continues, there are the pipe lines which are continuouslyfeeding the cities. So it cannot happen that city will move along the part and how we doagriculture. So what are your options.So your this options is gone, you cannot move and this is what has happened, so in an aroundthe cities have developed and this land has and that land is finite, so this land hasto feed not only itself but the surrounding cities, surrounding urban civilization, whatare your options, your options are in the previous page, you have to depend on theseparameters, reduce the competition from your selected crops, weedicides, herbicide, fertilizers,insecticides, pesticides.