Lecture 53: Land Capability Classes

Hi ah. So, this is week 12 of the courseSoil and Water Conservation Engineering. So, in this coursewhat we are going to learn is the first the land capability classification . And thensedimentation, sediment transportationerosion, and thenI mean transportation mechanism. So, all these things and andhow to measure sedimentation and how to measure erosion ah, I mean the sample collection So, different ways of for collecting sediment samples ah, I mean, at different depths. So, all these things we are going to discuss in in the week number 12 . So, here the lecture number one specifically for land capability classification And the lecture number 2 will befocusing on improvinghow to improve the land I mean capability ah. Especially if you are talking about land capability so, that means, we are talking about how it can be used efficiently forcrop production So, then the lecture number 3 ah, we are going to talk about the sediment and it is transportation And lecture number 4 will be sediment sampling ah. 5measurement of suspendedsediment So, the first one is the land capability classification So, as I saidour intention of using the term capability. So,definitely that refers to the production of a crop production. So, how wellwe can use the land for for producing another crop ok . And then here ok so, here so, basically the what is land capability? So, it is a system of grouping soils so, basically it is a system of grouping soils ok. So, primarily on the basis of the capability to produce you know the common cultivated crops , and pasture plantswithout deteriorating the coverover a long period of time. So, this is basically the what the land capability classification means. So, so basically what we do? So, we are going to classify the the lands based onwhether we will be able to ah, you know,ah use the land for crop production or not or degree of wellness you can say So, and the suppose basically the common cultivated crops ok. And also the pasture landwhen we are talking about you knowthethe fodder crops and all other things . And the land capability classification is subdivided intoyou know capability class and capability subclasses So, we are going to see howwe can divide these classificationdivide these capabilities intoah main classes and subclasses ok. So, if you seebasically the overall you know land divisions if you see So, in 1950 and 51 so, the overall the the whole the lands available in theworld has been classified like, a forest about a 14 percent is the forest , and fallow 10 percent and the grass crops area is 42 percent . And and the land which is not available cultificfor cultivation is the 34 percent ok . So, the mostly here the the grass crop area the 42 percent, I will use for cultivation. And then in 2010 and 11 the scenario is much improved if you compare the not available for cultivation So, this is 34 percent where it is now it is 23 percent . So, it is reduced; that means, some not available for cultivation land is being used for, you know ,you know afforestation And then some fallow land also used for usedin case of forest as well as you know the crop areas that is 46 percent so, 42 to 46 percent ok ah. So, mostly the the croplandwe called arable land, and non-crop land is non arable lands ok. So, let us see the classification now ok So, land capability classification so, it is basicallyin 2 groups; so, that is arable

land and then non arable land So; that means, the land used for cultivation, and land used fornon cultivation crops like you know the perennial forage crops something like there is; arable classland class class 1, class 2, class 3 and class 4 . So, there are total 8 classes. So, these are 4 classes here right, and then 4 classes here . So, these non-arable land classes are classified as class 5 6 7 and 8 ok. So, 5 and 6 are used for perenial forage crops, that is a non-arable land buts ah. So, these classes of lands are being used for perennial forage cops And then so, let us discuss one by onethe land classification or lands So, the first one is arable land they or the broader you know classification, under that class 1 . So, the class 1 as I said this is a very good land. So, very fertile land, right and the slope is almost it is like a flat slope, 0 to 1 percent if you see here . So, this is theclass 1 here. So, so mostly this is the green color. So, dark green color so, that representsyou know the class 1 So, it is a I meanrelatively flat and has deep soil. So, deep root zone ah, it has and the good the internal and good surface drainages So, the amount of water you you just put on top. So, that drains very well ok so, and that will be useful for the crop production ok And then the land can be cropped every year withoutspecial practices to control erosion So, you do not need touse any engineering practices foryou know controlling erosion in in this kind of lands . And this is best suitable for all agricultural crops. So, since it is on a fertile land and flat land. So, a well-drained land. So, this can be used for most of the cropsto be grown ah. And also deep soil depth definitely there will helpin protecting the fertile land and and also you knowthe crops which are in deep rootthey will begetting the you know fertilegetting the nutrients from the deeper zones And the this is not affected by any appreciable erosion ah, wetness and salinity. So, so this isthis kind of lands are notyou knowaffected with salinity and drainage, I mean,water logging conditions . So, this is the class 1 is the good I mean very fertile land for crop production ok And then the next class class 2 is this is called a good land, that is very good land and now it is class 2 is a good land. So, and the slope of the land varies between 1 to 3 percent. So, the class 2 land you can see here ok , and that requires moderate attention toconservation practices So, since it has a slope so, there is a possibility thatthe soil may you knowrunoff from the field So, you needat leastsome attention to control erosion, and the generally the contour plowing and other easy to use practices will be usedto reduce or control the erosion . And it hasmoderate soil depth in the light or heavy texture ah, gentle slopemoderate soil fertility ok . And this is basically these lands are basically suitable for a permanent cultivation with some soil and water conservation practices Since it is a slope it has some slope . So, you need to I mean practice some conservation practices to control erosion in class 2, ok So, then class 3 under arable land ; so, this is moderately good land the slopewill go between 3 to 5 percent . If you see here so, the class 3 so, land is here ok. And it has 3 to 5 percentslope, and mostly it is found on gentle sloping hills right. So, the mostly this can be seen on it is not you knowsteep slope hills it is a gentle slope hills And the crops must be more careful beselected So, the plant cover should be maintained so, if you do not maintain the plant cover, because it is a sloppy. So, what happen there is a chance of you knowah soil erodefrom the fields So, an increased attention must be given to conservation practices because of the slope And mostly the terraces and strip cropping

, and contour bunding and graded bunding will be practiced to control erosion And it can be productivewith proper managementby a producer. So,it will be if the producer hasyou know properlyusing the conservation practices on these kind of lands, and even the I mean this could be a good arable land ok . And then the next class 4 of this is the last class of this arable land ; so, there is a class number 4 So, in this class so, the mostly this is a fairly a good land, and slope varies from 5 to 10 percent . So, hilly lands mostly these lands are located on hills , and lowest performancefor cultivatedcultivation . Andrequires special conservation management practices ; since it islying on on hills And frequently subjected to erosion; so, gullies can be formed or gullies can be seen in these lands very easily. Because so, if you see the class 4 the class 4 is here so, the mostly now this is a hilly areas ok . And this is suitable only for occasional or limited cultivation ok. So, sometimesI mean if you see the hilly areas. So, there you know oftenly you can see some cultivation be going on, because of the you know some moderate slopes or fairly good slopes. And definitely engineering measures are recommended here to control erosion ok And then so, the next is non arable land so, other classI mean other group you can show So, the class 5 so, the class 5 this is unsuitable suitable for cultivation. So, I said this is non arable land. So, definitely the slope will be you know wearing from 15 to 25 percent So, class 5 can be seenhere right. So, so theseclasses orthis is unsuitable for cultivation and used for pasture crops. The mostly for cattle grazing you know hay crops or you knowtree farmings all those thingsah will be done on these lands . And this is often used for wildlife and recreational areas So, since so, this is you know less important for cultivation. So, those lands are being used for grazing you know cattle or you can establish or recreational purposes like the wildliferecreation area. So, the soil typically has good tilth and fertility ah. The soil has good tilthand also the fertility , but the thing issince it is sloppy area. So, the cultivation cropsbecause requires lot of you know farming operations. So, that may lead tolosing the soils and definitelythat will increase the soil erosion. So, that is why and then have the potential to become class 1 ah, since it is a fertile and you know landit can be class 1, but due to particular problemlike hazard They cannot be fulfill the characteristics of class 1, because of the slope right. So, and and also the shallow depths ok so,shallowdepths So, definitely though the land top surface is fertile ah, this this is not suitable for growingyou know the regular cultivation crops So, then class 6 so, the class 6is definitely not suitable for row crops And slope can vary from 25 to 33 percent so, the class 6land is located here. So, mostly this is suitable for horticultural crops like mango coffee and guava cashew nut etcetera So, mostly the horticultural crops can be grown in thisthe grazingshould be regulatedpreserve the plant cover. So, plant cover needs to beah I I mean preserved ah. Otherwise if you allow you know free grazing , what happens the top surface will be open, and thatbecause of the high slopedefinitely that leads to erosion So, the soil may havefair productivity , if it has not been damaged by erosion. So, just like in class asyou know 5 . So, the class 6 also it is a very good fertile land, but because of the shallow depth. And so, and also the steep slopethe definitely aI mean it is not suitable foryou know regular crop cultivation. So, the gullies often quickly form if not carefully managed. So, the slopes here the steep slopes can definitely your resultin forming gullies very easily , ok

And then the next class is the class number7 so, here the class number 7 has slope between 33 to 50 percent . So, the class number 7 is located here, if you see, and highly unsuitable for cultivation ah, because the steep slope and best uses or permanent pasture or forestry and wildlife So, the most of the land is being used for you know forestry wild love wildlifeand recreational purposes. Andgenerally lands aredroughty and swampy having very deep slope ah, rough stony or very severely eroded or invested with gullies So, this is kind of this lands are rough, and you can see lot of undulations and lot of you know depressions lot of gullies ah, but can be used for you know pasture and forestry and wild lives. And also this isah generally seen in you know dry lands . So, the other category is class number 8 This is the last class of the landcapability classification. And the slopes are more than 50 percent So, this is definitely unsuitable forplant production. So, this is the class number 8 here . And the soil may bewet and high in sand or clay ah; often used for you know waterfowl habitat . So, the most waterfowl have habitats those are the birds. AndI meanin this so, I mean since it is wet and that the soil type is a clay soils . So, the water can be retained in you know small ponds and thenthe water fowl habit it can bemaintained there. So, very rough and not suitable for woodland or grazing. So, thesethis particular landsbecause the steep slope So, this cannot be use suitable forwoodland or grazing side. So, it is only like a like a rough landwith with some, you know, waterah I mean water storages and that can be used for waterfowl habitats , ok Land capability classification classes so, thesewe can also use some colors here. So, the deep green and the look at this the green color is beenchanging from deep to light and yellow. And then this isI mean yellow also and the red and then finally, you get the pink color . So, the arable lands here so, the mostly the green color . So, becauseyou can you know grow cultivation ah, you can start using it for cultivation purposes So, in the class 1 here have no significant limitations in using forcultivation. So, this is a good fertile land and I mean relatively flat slopes anddeep soil depths ah. So, definitely no significant limitations for crop course So, this is very good ah, and then and followed by so, the limitations will increaseif you go down from class 1 to you know class 8 ah These moderate limitationsrestrict the range of crops or require moderate conservation practices So, the conservation practices will will increase when you go down from class 1 toclass 7class 8. And this islike non arable land will start from class 5 to class 8 . And definitely class 8 is unsuitable for plant production. So,if you go from you know the top to bottom . So, the limitations will increase So, definitely in order to you know improvethe land for cultivation in especially in case of arable land. You may have to useengineering you know soil conservationmeasures ok And then so, the next is again the suitability of different land capability classes for land uses . So, if you see the land capability classes hereone to8, and very intense cultivation see this only class 1 is for very intense cultivation here , and other classes are not supporting for veryintense cultivation. And the second is intense cultivations only 1 and 2 classes are used for intense cultivation And moderate cultivation you can go you can alsothe third class also supports , and limited cultivation up to 4 classes and intensive grazing

So, up to you know 5 classes a moderate grazing So, grazing will start here from you know class number 5 to , because these are all you know non arable lands . And moderate grazingyou can go up to 6 class, limited grazing you know class 7 , and forestry class 8 and wildlife also supports almost all classes wildlife ok . So, this way you can interpret thistable And thenand then the next is ok Land classes is also based on soil texture So, soil classes textural classes like sandyloamy sand sandy loam. So, symbol generally for sandy you will use small s ah, loamy sand small ls, and sandy loam sl . And land capability class so, this is the you know 4th class, sandy soils of 4th class And then second classloamy sand , and first class look at this from here to here . So, the mostly the first class orfrom sandy loam to clay loam. So, these are allvery good for cultivation ok . And similarly sandy clay this is the second grade and silty clay second and clay third grade ok . So, this way based on the soil texture you can also put this different soil soilsah into land capability classification Similarly, in the nexttable if you see land classes based on the soil depth . So, see the soil depths here . So, this is this deepah you know deep soil depth or or deep depths you can say . So, d 5 will put the d 5, but class 1 supports d 5 because the soilthis this is the deeperdepths compared to the fifth class which has you know less than 7.5 centimeter So, that is that is the soil depth whichland capability classification of class 5 supports this . And we will use the these symbols So, thus definitely represents thedifferent soil depths So, the next is a land classification based onland slope. So, here the symbols we use A B C D E FG H I. These are all capital symbols And then land slopes 0 to 1 percent the class 1 , because you can see the the flatness will increaseor sorry the flatness or the slope will increase from class 1 to class class 8 , and the slopes are here the mention here. So, but different slopes we already mentioned in the previousyou know discussion ah, but only thing for different slopes we will givesymbol along with the class So, I A we will give class 1m and then land slope is 0 1 ok or 0 to 1 . So, similarly identification of classes based on erosion status. So, here erosion status e1 to e4 so, e1 represents a negligible erosion , where up to 25 percent is of a horizon lost ok Or it is a negligible erosion or 25 percent so, class 1 and class 2 can beI mean represented And then e4 which is very severe erosion about 25 percent to 75 percent of B horizon lost, may include narrow and deep gullies So, this is the you know the last class6th and7 classes are supporting this classification So, in addition to that you also have subclasses So, the subclasses basically the capability subclasses is the second category in the land capability classification system . And basically represent the soils physical chemical and atmospheric limitation due to whichthe land use is further restricted So, the previously we we are only looking for a restriction of cropgrowth. But here the soilyou know quality soil physical and chemical also the atmospheric limitations if you include, and you can also clearly there So, these things the limitations if you add that will be subclasses . So, cthis is the adverse climate so, denotes a significant adverse climate for crop production as median climate So, if you if you put c as subclass this is a median, and the d undesirable soilstructure or low permeability . E for erosion right, f for low fertility , i for inundationand m for moisture limitation. Similarly, so, we can go through the descriptionof individual you know sub classes

And then if you see I mean it will continue So, that like n for salinity and p for stoniness , r for consolidated bedrock, s root zone limitation, t for typography and w excess water , x for you know. So, this sub class is comprised of soil having limitation resulted from the cumulative effects of 2 or more of the adverse characteristics. So, come if you put like n and p salinity and stoniness and you may have to put x So, one or 2 I mean the combination of these 2 if you you can represent with x ok And then so, the mapping unit is very importantin order to or represent a land capability classification For example, this mapping unit the information is collected for land capability classification is recorded and map unit s. So, the mapping unit is represented as soil series minus texture of the soil , minus effective soil depth divided by landsslope minus erosion hazard . So, how to get this you know number? So, thatsub for example, here is example there is a parameter on column number one . For example, l for so, this is a small l alpha loam right and d 5 is equal soil depth So, that representgreater than 90 centimeter And capital A land slopes are 0 to 1 percent, and e1 erosion hazard and c climate limitation this is subclass ok . So, if this is the parameter right, and land capability class this is all you are talking about class 1 And mapping unit can be estimated like one as this is one , because land capability class So, soil series this is one , and the and then d 5 is the soil depth right. So, effective soil depth is a d 5 ok, and then a is land slope. So, this is a , and e this is erosion hazard e1 right. This is erosion hazard e1 ok. And then the land capability class with subclass lc . So, l is for loam and c is for climatelimitation ok So, with this so, definitely we can represent the mapping unit in this form and then the land capability you know class with subclass can be represented with lc. L is for loam and c is for climating limitations ok . So, this way we canrepresent the whole landclass I mean capability classification in using a mapping unit ok So, in this lecturewe started with you knowthe broad classification of lands. So, arable land and non-arable land, again arable land is being classified into 4 classes , and then non arable land is classified intoI mean continuously other 4 classes You know so, the class number 1 to 8 this is thethe whole class that represents the land capability, classification is the capability we are talking about whether the particular land is used for, you know, the cultivation or cultivating crops or not. And and and also there are other classes based on you know you know the erose I mean erosion, the slope and thenand then soil texture ok, and soil depth So, all different you knowah classes also we can get and thennot only that there is a sub classes. So, based on the limitations or restrictions we can say based on the restrictions if you have; restriction on, you know, climatic condition restriction on soil physical and chemical properties. So, definitely you need to addthatsubclass . So, and finally, the whole land capability classification is represented with a mapping unit. So, the mapping we have seen an example on how to presentah the land capability classification using a map unit Thank you