TYPES OF CROPPING SYSTEMS

Depending on the resources and technology availability, different types of cropping systems are
adopted on farms.

Intercropping Sequential cropping

Growing of two or more crops simultaneously Growing of two or more crops in sequence on the

on the same piece of land in a cropping season. same piece of land in a farming year (June–May)

(June–Sept. Kharif) Includes three seasons.

(Oct–Jan. Rabi)

Intercropping is intensive cropping mainly in Sequential cropping is intensive cropping mainly

space dimension. in time dimension.

Types Types

(i) Inter cropping (i) Mono cropping

(ii) Mixed cropping (ii) Multiple cropping

 CROPPING SYSTEM AND FARMING SYSTEM675

16.3.1 Intercropping

Intercropping refers to growing of two or more dissimilar crops simultaneously on the same piece of land.
The base crop, necessarily in distinct row arrangement and its recommended optimum plant population, is
suitably combined with the additional plant density of the associated crop. The objective is the
intensification of cropping both in time and space dimensions and to raise productivity per unit area by
increasing the pressure of plant population.

. On the basis of knowledge of the above some suitable combinations are:

Principal Crop Intercrop

Sugarcane Wheat, cowpea, soybean, moong, sunflower

Sorghum Cowpea, soybean, moong, urd, arhar

Maize Cowpea, soybean, urd, arhar, castor

Bajra Cowpea, soybean, urd, arhar, castor

Cotton Soybean, groundnut

Potato Wheat, radish

676 A TEXTBOOK OF AGRONOMY

16.3.1.1 Intercropping Vs Mixed Cropping

Intercropping: Growing two or more crops simultaneously on the same piece of land with a
definiterow arrangement.

For example, growing ground nut and red gram in 6:1 ratio.

Mixed cropping: Growing two or more crops simultaneously on the same piece of land in
aproportion without any row arrangement.

E.g., fodder sorghum + fodder cowpea or pillipesera.

I. Sole cropping Vs. Row intercropping

Sole cropping: One crop variety grown alone in pure stand at normal density. It is also called
solidplanting.

For example, Sorghum at 45 × 15 cm, groundnut at 30 × 10 cm.

Row intercropping: Growing two or more crops in the same piece land simultaneously
withdefinite proportion in rows.

E.g., Sorghum + cowpea : at 2:1 or 3:1

Sugarcane + soybean : at 1:2 or 1:1

II. Strip cropping Vs. Strip intercropping

Strip cropping: Growing soil conserving and soil depleting crops in alternate strips running
perpendicularto the slope of the land or to the direction of prevailing winds for the purpose of reducing
erosion.

Strip intercropping- Growing two or more crops simultaneously in different strips wide
enoughto permit independent cultivation but narrow enough for the crop to interact agronomically.
III. Row intercropping

Row intercropping is raised by way of additive and replacement series.

(a) Additive series: One crop (base crop) is raised in full population and in between the rows of
base crop, intercrops are raised at less population level by adjusting or changing crop geometry of the
base crop.

(b) Replacement series: By sacrificing certain proportion of population of one component crop,
another component crop is introduced.

For example, sorghum + cowpea at 2:1 ratio

IV. Relay intercropping

It is interplanting or inter sowing of the succeeding crop in the proceeding annual crops, succeeding
crop is sown after the proceeding crop has reached the maturity stage but before the harvest of
standing crop or it refers to planting of succeeding crop before the harvest of preceding crop. The
planting of succeeding crop may be done before or after flowering, before or after the attainment of
reproductive stage, completion of active life cycle, senescence of leaves or attainment of physiological
maturity of the crop. The common examples of relay cropping are maize-potato, maize-toria, maize-
turnip, ragi-horse gram.
 CROPPING SYSTEM AND FARMING SYSTEM 677

V. Multi tier or Multistoried intercropping

Growing of two or more crops having different growth habit differential rooting pattern and above
ground architecture, simultaneously in a piece of land.. Land used efficiency rises beyond 100 per
cent. The land use efficiency (LUE) can be expressed as:

LUE Number of days land used in a year 100

365
. Generally, three crops are taken as principal crop, primary companion and secondary companion,
other examples could be–coconut + pepper

For example,

• Coconut +bajra-napier grass + stylo in Western zone of Tamil Nadu;

• Sorghum + red gram + lab lab + pillipesara : Tamil Nadu;

• Ground nut + castor + red gram + lab lab. : Tamil Nadu;

VI. Alley cropping or Hedgerow intercropping

Raising two or more crops in alleys. For example, fodder crops in path way.
678 A TEXTBOOK OF AGRONOMY
16.3.1.2 Multiple Cropping

(a) Concept: It refers to intensification of cropping both in time and space dimensions. It includes
sequential cropping, inter-cropping and mixed cropping. In simplest form, multiple cropping is a one-
year cropping system in which two or more crops are grown within a year; if all the crops are cereals
it will resemble monoculture in its advantages and requirements. It may be pointed out that this pivotal
theme of intensive cropping may manifest itself in various forms such as relay, inter or just multiple
cropping. In a broader sense, it is continuous cropping. If all the post-harvest operations are taken into
consideration, then they are overlapping operations.

(c) Types:

1. Sequential cropping: It refers to growing two or more crops in sequence on the same field ina year.
The succeeding crop is planted after the preceding crop has been harvested. Actually, crop intensification is
only in the time dimension. There is no intercrop competition. One has to manage only one crop at a time
in the same field. Sequential cropping may be of many types as–(i) double cropping– growing of two crops
a year in sequence, (ii) triple cropping–growing of three crops a year in sequence, (iii) quadruple cropping–
growing of four crops a year in sequence and (iv) ratoon cropping – cultivation of crop regrowth after
harvest of plant crop, not necessarily for grain. Sequential cropping systems in irrigated conditions are
based on the availability of short duration, photo-insensitive and thermo-insensitivity high yielding
varieties while cropping systems of short duration, photo-insensitive and
 CROPPING SYSTEM AND FARMING SYSTEM 679

thermo-insensitivity high yielding varieties while cropping systems under rainfed conditions have
been developed depending on availability of cultivars with a short growing period that escape drought.

Ratoon cropping or ratooning refers to raising a crop with regrowth coming out of roots of
stalksafter the harvest of the crop.

For example, sugarcane–14 ratoons, Sorghum–Two or Three ratoons

Rice–‘Intan’ variety.

2. Mono cropping or monoculture: Growing only one crop (same crop) on a piece of land
yearafter year in the same field. Due to certain specific reasons, (e.g.), ground nut year after year
under rainfed condition of Tamil Nadu, and flue cured tobacco in Gunter region of Andhra Pradesh.

Fallowing

Fallowing means keeping the land vacant without raising any crop is called fallowing.

• Barren fallow–without ploughing and undisturbed land.

• Ploughed fallow–prepare the land and leaving without any crop.

Tillage
Tillage refers to the mechanical manipulation of the soil with tools and implements so as to
createfavourable soil conditions for better seed germination and subsequent growth of crops.

Tilth is a physical condition of the soil resulting from tillage. Tilth is a loose friable (mellow), airy,powdery,
granular and crumbly condition of the soil with optimum moisture content suitable for work-ing and
germination or sprouting of seeds and propagules i.e., tilth is the ideal seed bed

Jethrotull, who is considered as Father of tillage suggested that thorough ploughing is necessary so as
to make the soil into fine particles.

7.2 OBJECTIVES

Tillage is done:

• To prepare ideal seed bed favourable for seed germination, growth and establishment;

• To loosen the soil for easy root penetration and proliferation;

• To remove other sprouting materials in the soil;

• To control weeds;

• To certain extent to control pest and diseases which harbour in the soil;
 TILLAGE 287

• To improve soil physical conditions;

• To ensure adequate aeration in the root zone which in turn favour for microbial and
biochemical activities;

• To modify soil temperature;

• To break hard soil pans and to improve drainage facility;

• To incorporate crop residues and organic matter left over;

• To conserve soil by minimizing the soil erosion;

• To conserve the soil moisture;

• To harvest efficiently the effective rain water;

• To assure the through mixing of manures, fertilizers and pesticides in the soil;

• To facilitate water infiltration and thus increasing the water holding capacity of the soil, and

• To level the field for efficient water management

7.3 TYPES OF TILTH

Fine Tilth refers to the powdery condition of the soil.

Coarse Tilth refers to the rough cloddy condition of the soil.

Fine seedbed is required for small seeded crops like ragi, onion, berseem, tobacco.

Coarse seedbed is needed for bold seeded crops like sorghum, cotton, chickpea, lab-lab etc.

7.4 TYPES OF TILLAGE

1. On Season Tillage: It is done during the cropping season (June–July or Sept.–Oct.).

2. Off Season Tillage: It is done during fallow or non-cropped season (summer).

3. Special Types of Tillage: It is done at any time with some special objective/purpose.
7.4.1 On Season Tillage

Tillage operations done for raising the crops in the same season or at the onset of the crop season are
called as on season tillage. They are,

A. Preparatory Tillage

It refers to tillage operations that are done to prepare the field for raising crops. It is divided into three
types viz., (i) primary tillage, (ii) secondary tillage, and (iii) seed bed preparation.

(i) Primary tillage - The first cutting and inverting of the soil that is done after the harvest of the
crop or untilled fallow, is known as primary tillage. It is normally the deepest operation
performed during the period between two crops. Depth may range from 10–30 cm. It includes
ploughing to cut and invert the soil for further operation. It consists of deep opening and
loosening the soil to bring out the desirable tilth. The main objective is to control weeds to
incorporate crop stubbles and to restore soil structure.

(ii) Secondary tillage - It refers to shallow tillage operation that is done after primary tillage to
bring a good soil tilth. In this operation the soil is stirred and conditioned by breaking the clods
and crust, closing of cracks and crevices that form on drying. Incorporation of manures and
fertilizers, leveling, mulching, forming ridges and furrows are the main objectives. It includes
cultivating, harrowing, pulverizing, raking, leveling and ridging operations.

(iii) Seed bed preparation - It refers to a very shallow operation intended to prepare a seed bed or
make the soil to suit for planting. Weed control and structural development of the soil are the
objectives.
288 A TEXTBOOK OF AGRONOMY

B. Inter Tillage/Inter Cultivation

It refers to shallow tillage operation done in the filed after sowing or planting or prior to harvest of
crop plants i.e., tillage during the crop stand in the field. It includes inter cultivating, harrowing,
hoeing, weeding, earthing up, forming ridges and furrows etc. Inter tillage helps to incorporate top
dressed manures and fertilizers, to earth up and to prune roots.

7.4.2 Off Season Tillage

Tillage operation is done for conditioning the soil during uncropped season with the main objective of
water conservation, leveling to the desirable grade, leaching to remove salts for soil reclamation
reduc-ing the population of pest and diseases in the soils. etc. They are:

(a) Stubble or Post harvest tillage - Tillage operation carried out immediately after harvest of crop
to clear off the weeds and crop residues and to restore the soil structure. Removing of stiff
stubbles of sugarcane crop by turning and incorporating the trashes and weeds thus making the
soil ready to store rain water etc., are the major objectives of such tillage operations.

(b) Summer tillage - Operation being done during summer season in tropics to destroy weeds and
soil borne pest and diseases, checking the soil erosion and retaining the rain water through
summer showers. It affects the soil aggregates, soil organic matter and sometimes favour wind
erosion. It is called as Kodai uzavu in Tamil Nadu state.

(c) Winter tillage - It is practiced in temperate regions where the winter is severe that makes the
field unfit for raising crops. Ploughing or harrowing is done in places where soil condition is
optimum to destroy weeds and to improve the physical condition of the soil and also to incor-
porate plant residues.

(d) Fallow tillage - It refers to the leaving of arable land uncropped for a season or seasons for
various reasons. Tilled fallow represent an extreme condition of soil disturbance to eliminate
all weeds and control soil borne pest etc. Fallow tilled soil is prone to erosion by wind and
water and subsequently they become degraded and depleted.

7.4.3 Special Types

Special type tillage includes

 (i) Subsoil tillage (sub soiling) is done to cut open/break the subsoil hard pan or plough pan using
sub soil plough/chisel plough. Here the soil is not inverted. Sub soiling is done once in 4–5
years, where heavy machinery is used for field operations and where there is a colossal loss of
topsoil due to carelessness. To avoid closing of sub soil furrow vertical mulching is adopted.

(ii) Levelling by tillage - Arable fields require a uniform distribution of water and plant nutrition
for uniform crop growth. This is achieved when fields are kept fairly leveled. Levellers and
scrapers are used for levelling operations. In leveled field soil erosion is restricted and other
management practices become easy and uniform.

(iii) Wet tillage - This refers to tillage done when the soil is in a saturated (anaerobic) condition. For
example puddling for rice cultivation.

(iv) Strip tillage - Ploughing is done as a narrow strip by mixing and tilling the soil leaving the
remaining soil surface undisturbed.

(v) Clean tillage - Refers to the working of the soil of the entire field in such a way no living plant
is left undisturbed. It is practiced to control weeds, soil borne pathogen and pests.

(vi) Ridge tillage - It refers to forming ridges by ridge former or ridge plough for the purpose of
planting.
 (vii) Conservation tillage - It means any tillage system that reduces loss of soil or water relative to
conventional tillage. It is often a form of non-inversion tillage that retains protective amounts of crop
residue mulch on the surface. The important criteria of a conservation tillage system are: (i) presence of
crop residue mulch, (ii) effective conservation of soil and water, (iii) improve-ment of soil structure and
organic matter content, and (iv) maintenance of high and economic level of production (refer section 7.10
of this chapter).

(viii) Contour tillage - It refers to tilling of the land along contours (contour means lines of uniform
elevation) in order to reduce soil erosion and run off.

(ix) Blind tillage - It refers to tillage done after seeding or planting the crop (in a sterile soils) either
at the pre-emergence stage of the crop plants or while they are in the early stages of growth so
that crop plants (cereals, tuber crops etc.) do not get damaged, but extra plants and broad
leaved weeds are uprooted.

7.5 FACTORS AFFECTING (INTENSITY AND DEPTH OF) THE

TILLAGE OPERATIONS

Several factors are responsible for deciding intensity and depth of tillage operations. They are soil
type, crop and variety, type of farming, moisture status of the soil, climate and season, extent of weed
infestation, irrigation methods, special needs and economic condition, and knowledge and experience
of the farmer.

(i) Crop- It decides the type, intensity and depth of tillage operations with small sized seeds like
finger millet, tobacco etc. Require a fine seedbed which can provide intimate soil-seed contact
as against coarser seed bed required for larger size seeds such as sorghum, maize, pulses, etc.
Root or tuber crops require deep tillage whereas rice requires shallow puddling.

(ii) Soil type - It dictates the time of ploughing. Light soils require early and rapid land preparation
due to free drainage and low retentive capacity as against heavy soils.

(iii) Climate - It influences soil moisture content, draught required tilling and the type of cultivation.
Low rainfall and poor water retentive capacity of shallow soil do not permit deep ploughing at
the start of the season. Heavy soils developing cracks during summer (self tilled) need only
harrowing. Light soils of arid regions need coarse tilth to minimize wind erosion.

(iv) Type of farming- It influences the intensity of land preparation. In dry lands, deep ploughing is
necessary to eradicate perennial weeds and to conserve soil moisture. Repeated shallow tilling
is adequate under such intensive cropping.

(v) Cropping system - In involves different crops, which need different types of tillage. Crop
following rice needs repeated preparatory tillage for obtaining an ideal seedbed. Crops follow-
 ing tuber crops like potato require minimum tillage. Similarly crops following pulses need
lesser tillage than that of following sorghum, maize or sugarcane.

7.6 DEPTH OF PLOUGHING

Desirable ploughing depth is 12.5–20 cm. Ploughing depth varies with effective root zone depth of the
crops. Ploughing depth is 10–20 cm to shallow rooted crops and 15–30 cm to deep-rooted crops. Deep
ploughing is done to control perennial weeds like Cyanodon dactylon and to break soil hard pans.
Since deep ploughing increases the cost, most farers resort to shallow ploughing only.

7.7 NUMBER OF PLOUGHING

It depends on soil conditions, time available for cultivation between two crops, (turn over period) type
290 A TEXTBOOK OF AGRONOMY

of cropping systems etc. Small or fine seeded crop requires fine tilth, which may require more
ploughings. Zero tillage is practiced in rice fallow pulse crops or relay cropping system. Three
numbers of puddling is sufficient for rice cultivation. Minimum numbers of ploughing are taken up at
optimum moisture level to bring favourable tilth depending on the need of the crop and financial
resources of the farmer. In fact, this brought the concept of minimal tillage or zero tillage systems.

7.8 TIME OF PLOUGHING

The time of ploughing is decided based on moisture status and type of soil. The optimum moisture
content for tillage is 60% of field capacity. Ploughing at right moisture content is very important.
Summer ploughing (March–May) can be practiced utilizing summer showers to control weeds and
conserve soil moisture. Light soils can be worked under wide range of moisture. Loamy soils can be
easily brought to good tilth. Pulverization of clay soils is difficult as they dry into hard clods.

7.9 METHOD OF PLOUGHING

Ploughing aims at stirring and disturbing the top layer of soil uniformly without leaving any
unploughed strips of land. Straight and uniformly wide furrows give a neat appearance to the
ploughed field. When the furrows are not straight or when the adjacent furrows are not uniformly
spaced, narrow strips of land are left unploughed. The correct inter furrow space is little over the
width of the furrow slice. After the harvest of a crop the land is first ploughed along the length of the
field. This reduces the number of turns at the headlands for opening fresh furrows. The next ploughing
is done across the field for breaking furrows of the previous ploughing. This must increase the turns at
the headlands and the empty turns along the headlands, but is unavoidable. New turns are taken 6 m
wide each time, till the entire field is covered.

7.10 MODERN CONCEPTS OF TILLAGE

In conventional tillage combined primary and secondary tillage operations are performed in preparing
seed bed by using animal or tractor, which cause hard pan in sub soils resulting in poor infiltration of
rain water, thus it is more susceptible to run off and soil erosion. Farmers usually prepare fine seed
bed by repeated ploughing, when the animal of the farm is having less work. Research has shown that
frequent tillage is rarely beneficial and often detrimental. Repeated use of heavy machinery destroys
structures, causes soil pans and leads to soil erosion. Moreover energy is often wasted during tillage
processes. All these reasons led to the development of modern concepts namely the practices like
minimum tillage, zero tillage, stubble mulch farming and conservation tillage, etc.
7.10.1 Minimum Tillage

Minimum tillage is aimed at reducing tillage to the minimum necessary for ensuring a good seedbed,
rapid germination, a satisfactory stand and favourable growing conditions. Tillage can be reduced in
two ways by omitting operations, which do not give much benefit when compared to the cost, and by
combining agricultural operations like seeding and fertilizer application.

7.10.2 Zero Tillage/No Tillage/Chemical Tillage

Zero tillage is an extreme form of minimum tillage. Primary tillage is completely avoided and secondary
tillage is restricted to seedbed preparation in the row zone only. It is also known as no-tillage and is
resorted to places where soils are subjected to wind and water erosion, timing of tillage operation is too
difficult and requirements of energy and labour for tillage are also too high. Weeds are controlled using
herbicides. Hence, it is also referred as chemical tillage. There are two types of zero tillage.

(a) Till Planting is one method of practicing zero tillage. A wide sweep and trash bars clear a strip
over the previous crop row and planter–opens a narrow strip into which seeds are planted and
covered. In zero tillage, herbicide functions are extended. Before sowing, the vegetation
present has to be destroyed for which broad spectrum non-selective herbicides with relatively
short residual effect (Paraquat, Glyphosate etc.) are used and subsequently selective and
persistent herbicides are needed (Atrazine, Alachlor etc.).

(b) Sod planting or sod culture: Sod refers to top few centimeters of soil permeated by and held
together with grass roots or grass-legume roots. Planting of seeds in sods without any tillage
operation is known as sod culture or sod seeding. Usually legumes or small grains are
mechanically placed directly into a sod.

• .

7.10.3 Stubble Mulch Tillage or Stubble Mulch Farming

In this tillage, soil is protected at all times either by growing a crop or by leaving the crop residues on
the surface during fallow periods. Sweeps or blades are generally used to cut the soil up to 12 to 15 cm
depth in the first operation after harvest and the depth of cut is reduced during subsequent operations.
When unusually large amount of residues are present, a disc type implement is used for the first
operation to incorporate some of the residues into the soil.

Two methods are adopted for sowing crops in stubble mulch farming.
 • Similar to zero tillage, a wide sweep and trash-bars are used to clear a strip and a narrow
planter-shoe opens a narrow furrow into which seeds are placed.

• A narrow chisel of 5–10 cm width is worked through the soil at a depth of 15–30 cm leaving
all plant residues on the surface. The chisel shatters tillage pans and surface crusts. Planting is
done through residues with special planters.

Disadvantages

• The residues left on the surface interfere with seedbed preparation and sowing operations.

• The traditional tillage and sowing implements or equipments are not suitable under these conditions.

7.10.4 Conservation Tillage

Though it is similar to that of stubble mulch tillage, it is done to conserve soil and water by reducing
their losses.

Modern tillage methods are practiced in western countries especially in USA. In India, it is not
suitable due to several reasons. In USA, straw and stubbles are left over in the field but in India, it is a
valuable fodder for the cattle and fuel for the home. Use of heavy machinery in India is limited and
therefore, problem of soil compaction is rare. The type of minimum tillage that can be practiced in
India is to reduce the number of ploughings to the minimum necessary i.e., unnecessary repeated
ploughings/harrowing can be avoided.

7.11.1 Primary Tillage Implements

Primary tillage is the deepest operations/performed during the period between two crops. The
following are the implements used for primary tillage.

1. Country/wooden/Desi plough - The indigenous plough consists of a wooden body to which

ahandle and a shaft pole are attached. The body is made of a bent piece of hard wood with two arms
making an angle of about 135°. It is given a wedge shape with an isosceles triangular section. A
small piece of flat iron (shares) serves as the piercing point of the plough and is fixed
 over the plough body with clamps. The shaft
pole is secured with the yoke during working.
The working of plough results in the opening
of ‘V’ shaped furrow. The width of furrow de-
pends on the size of the plough bottom. The
depth of penetration of a country plough can
be altered a little by pulling the implement
behind or pushing forward, which results in
deeper or shallow ploughings respectively. It
covers 0.15 to 0.20 hectare in 8 hours.
Fig. 7.1 Ploughing with country plough

2. Improved iron plough - The bullock drawn

improved iron plough is made of mild steel

except the pole shaft and hence it has longer
life. As and when the share wears off, it can be
pushed forward. Pole shaft angle and height of
the handle can be adjusted according to field
requirements. The plough is provided with a
mould board as optional attachment for soil
inversion. This plough is suitable for dry
ploughing in all types of soil with a pair of
bullocks. It covers 0.5 ha per day and costs Rs.
750-1000/-.

3. Bose plough - It is wooden plough with a

mouldboard can share instead of the usual small
iron
share. It is used for the primary tillage opera-
Fig. 7.2 Rotavator
tions in wetlands. Nowadays this plough is made

up of iron angles instead of woods to make it

sturdy. It is also called as Melur plough in
Tamil Nadu.
Fig. 7.2a Tractor operated rotavator

4. Mould board plough - It is a modern

tillageimplement used to plough deeply and
pulverize the soil. It is more durable, easy to pull
and can be adjusted properly. The main parts of
the mould board plough are the frog or body,
han-dle, beam, share, mould board, wheel and
coul-ter. This type of plough leaves no
unploughed
 land as the furrow slices are cut clean and in-
verted to one side resulting in better pulveriza-
tion. The animal drawn mould board plough is

small, ploughs to a depth of 15 cm. Big size tractor drawn mould board ploughs can plough up
to a depth of 30 cm. Mould board ploughs are used when soil inversion is necessary. Victory
plough is an animal drawn mould board plough with a short shaft.

5. Turn wrest plough - This is also called reversible plough. The mould board with share is
hingedeither left or right side of the central body with a hook. When the mould board is needed to
shift to another side, the hook is released and the mould board is easily swing to the opposite side.
By this when the plough reaches to one end of the land instead the mould board can be shifted
294 A TEXTBOOK OF AGRONOMY

to other side and the ploughing can be continued, so that furrow slices will uniformly fall and
same direction.

6. Disc plough - In the disc plough, the share, the mould board and coulter of the mould
boardplough are replaced by an inclined concave steel disc of 60-90 cm diameter, set at an
angle to the direction of travel. Each disc revolves on an axle and the angel of the disc to the
vertical position and to the furrow wall is adjustable. Lever arrangements are provided to lift
the discs clear off the ground and for changing the angle of molding and adjusting the depth of
penetra-tion of the discs into the soil. While working, the discs rotate, scoop out furrows, invert
the furrow slice and pulverize them thoroughly. Disc plough is especially useful under the
following soil conditions: Soil with hard pan and sticky soil, Dry hard ground,Rough and stony
ground, Ploughing weedy lands and lands with stubbles, Deep ploughing.

Fig. 7.3 Mould board plough Fig. 7.3a Disc plough

7. Reversible disc plough - It is constructed in such a way that the disc can be reversed and
thesoil is thrown on one side. The land and furrow wheel adjust themselves properly when the
plough is reversed. Reversible disc plough saves time taken up by ordinary disc plough. The
furrow slice cut at each trip by the reversible disc plough is laid over the previous furrow thus
resulting in a leveled field after ploughing.

8. Chisel plough or subsoil plough - It is bullock drawn implement used to break hardpan
thatexists in the soil due to continuous same type of operation. It consists of a curved chisel
 “C” like tyne with 37 cm radius of curvature and 3 cm thickness. It is rigidly held in a frame,
which is provided with a handle and a shaft pole. The operation of this plough is the same as
that of an ordinary plough. It makes a simple vertical cut in the sub soil up to a depth of 45 cm
and facilitates the downward movement of water and sub soil drainage. Chiseling becomes
necessary in soil with hard impermeable plough pan. Both animal drawn (coverage 2 ha/day)
costs Rs. 1200/- and tractor drawn (coverage 5 ha/day) costs Rs. 6000/- are available for usage.

7.11.2 Secondary Tillage Implements

Secondary tillage is the shallow operation performed after the primary tillage. Secondary tillage
imple-ments are used for breaking clods and producing a loose, friable, smooth state. These
implements are used with the following objectives.

• Breaking the furrow slice and working the soil to get the required tilth

• Destruction of weeds

• Stirring the soil and forming mulch

 TILLAGE 295

• Mixing the manures and fertilizers with soil

• Covering the seeds

1. Cultivators - These implements have number of tines for piercing the soil and breaking
clods.Tines of 23–30 cm long are fixed to a heavy and sturdy, frame, mounted on wheels.
These tines penetrate up to a depth of 20 cm in heavy models. Cultivators are used when the
soil is ploughed deep with heavy mould board ploughs to break the big clods that are formed.

Fig. 7.4 Cultivator Fig. 7.4a Disc harrow

2. Harrows - They are smaller implements with many tines like cultivators. Used for
breakingsmaller clods left unbroken by cultivators and for producing a powdery seedbed. Tines
are set closer (5-8 cm) and are smaller in size. They penetrate up to about 10 cm depth. There
are different types of harrows in use.

A. Spike tooth harrow - Peg like steel tines of round, oval, square, triangular or rhomboid
sectionare fixed on a rigid or flexible frames for use under different soil conditions. Rhomboid
section offers straight cutting edge and it enters the soil properly and is better than others. In
undulating lands the flexible types adjust themselves to the uneven surface. When the frame is
of a zigzag type it called zigzag harrow.

B. Spring tine harrow - Instead of rigid tines strong steel springs shaped like the letter “C”
areattached to the frame. Depth of penetration is adjusted with lever arrangements. Tines ride
 over rocky and other obstructions in the field and are not damaged since the spring tines recoil
on obstruction. Due to vibration they pulverize clods better than rigid types.

C. Chain harrow - Number of stout steel links is connected together to spread over the soil like
amat. Links may have spike like projections. Since, they are flexible they adjust unevenness of
the surface. These harrows are used for breaking clods and making the surface smooth and
even. It can also be used for covering seeds after broadcasting.

D. Disc harrow - These harrows are made up of number of concave discs of 46–56 cm in
diameter,fitted 15 cm apart on square axles. Two sets of discs are mounted on different axles.
Discs cut through the soil and effectively pulverize clods. Small animal drawn harrows have
six discs and power driven harrows have larger number.

E. Intercultivating harrow - Different types of harrows are used for intercultivation. Tines
passthrough the inter row spaces and effectively remove the weeds. The typical example of the
intercultivating harrow is junior hoe.

Different attachments can be made in the tines of the junior hoe to make use of same harrow for
different purposes.
296 A TEXTBOOK OF AGRONOMY

Sweeps are blades that move horizontally under the soil and cut the shallow rooted weeds.
Thereare two kinds of sweeps. The Central sweep attached to the central tines has horizontal
wings extending on both the sides. The One side sweep has the wing on the right or left side.
On the side tines, one-sided sweeps are fixed on the side away from the crop rows.

Hiller is a rhomboidal curved steel plate, shaped like the mould board, which is used for earth-
ing up crop rows.

Furrows have a double mould board one on either side, which splits the furrow slice and laysit
on both sides equally. It is used with a central tine to open the furrow for sowing or to clean the
furrow for irrigation.

Cultivator steel is a steel plate with sharp edge, which penetrates into the soil.

F. Blade Harrows - Different from conventional harrows in that there are no tines but they are
fixedwith horizontal blades, which enter into the soil and travel below the surface at a constant
depth. These blades severe (cut) the surface layer from the soil below and leaves it in its
original position with slight disturbance to the surface soil. These harrows cut the weeds,
eradicate all weeds except those, which have under ground bulbs.

The Guntaka is the blade harrow used for primary tillage in ceded districts of Andhra
Pradesh.It has a horizontal wooden beam of 15 cm diameter with a fixed handle, shaft pole and
blade. The blade is fixed to the beam near the ends by two standards at 25 cm distance from
beam. The blade is 1.0 m long, 7.5 cm broad and 1.25 cm thick, with a cutting edge in front.
Big sized guntakas are called as bara guntakas (1.8 m long blade). Small guntakas with 15 to
33 cm long blades are called as danties that are used for inter cultivation in crops, spaced at
28–46 cm apart. Since they are small, five or six danties are attached to a common yoke and
guided by three or four people. It covers 0.4 ha/day of eight hours.

7.11.3 Inter Cultural Implements

(i) Japanese rotary weeder - It consists of two small-toothed rollers or drums mounted on a frame
provided with handle. Each roller consists of about 5-toothed blades. This implement, while
working is pushed and pulled alternatively by the operator in between rows of rice crop. The
float provided will guide the implements smoothly while working and prevent the implement
sinking into the puddle. The weeder is used to bury the weeds into the mud so as to decompose
them add organic matter to the soil, sufficient for working this implement.

(ii) Conoweeder - It is also similar to rotary weeder in which instead of two toothed rollers or
drums two toothed cones are mounted on a frame provided with handle. This implement while
working is pushed and pulled alternatively by the operation in between rows of rice crop. The
 float provided will guide the implement smoothly while working and prevent the implement
from sinking.

(iii) Long-handled weeders - Long handled weeders are used for weeding in row crops for remov-
ing shallow rooted weeds. Useful in dry land and garden land crops when the soil moisture
content is 8–10 percent. They are manually operated. One-man labour covers 0.05 ha/day. It
costs Rs. 350/-.

(a) Peg tooth type- It is a long handled tool consists of two numbers of 2.5 cm diameter, 120
cm long pipes over which 52 cm long handled is fitted. To the bottom of the vertical pipe
frames, two arms made of 25 × 2.5 × 0.3 cm MS plates are fitted. At the extreme end of the
arm, peg wheel is placed. The blade can be adjusted to the desired angle and depth. The
peg teeth permit the movement of the roller in clay soil without getting clogged.
 TILLAGE 297

(b) Star wheel type- It is similar to the peg type weeder excepting that the star type roller
facilitates easier operation of the weeders in loamy and sandy soils.

7.11.4 Special Purpose Implements

Implements that are used for a specific purpose other than primary or secondary and intercultural
tillage are called as special purpose implements. The following are some of them.

7.11.4.1 Multipurpose tool bar/carrier

The multipurpose tool carrier is used for primary, secondary and intercultural operations, forming
bunds, ridges and furrows and for sowing crops in rows. It is suitable for all soils. A multipurpose tool
carrier is made up to G.I. tube, which has the provision to attach cultivators (4 Nos.), ploughs (3 Nos.),
ridger (2 Nos.), seed drill (4 Nos.) and bund formers (2 Nos.). The spacing between rows is adjustable.
The field capacity of plough is 1.2 ha/day, while for cultivator and ridger, it is about 0.74 ha/day.

7.11.4.2 Land leveling implements

(a) Buck scraper - It is a bullock-drawn implement made up of steel sheets like an open box with a
bottom and three sides; the fourth side is left open. Two flat steel runners are provided at the
bottom to protect the base and prevent the steel plate from being worn-out while leveling. Two
handles are fixed at the sides for assisting in filling the box with earth and for emptying the
contents. The drawbar is attached to the sides with hinge arrangement. It is a bullock drawn
implement very useful to carry the soil to a long distance while levelling.

(b) Levelling board - It is a channel like or trapezoidal shaped wooden board with 2-2.75 m length
and 20 cm diameter. It is attached to the shaft pole with a hinged hook. It is used for levelling
rice fields after the final ploughing to facilitate uniform seed germination. When the operator
stands over the board; it sinks lightly into the loose mud and when it moves, the soil in front of
it is also moved, but is released when he gets down.

(c) Wooden float- It is a bullock drawn implement with a long sledge-like drag used for land
smothering. By working the field with wooden float three or four times lengthwise, crosswise
and diagonally the field is smoothen in a better way.

7.11.4.3 Land shaping implements

(a) Ridge plough- It is a bullock or tractor drawn implement. It is a double mould board plough
with mould boards on both the sides, which meet along a central line. The mould boards are
either fixed or adjustable so that the width of the furrow can be adjusted. The ridge plough lays
the earth on both the sides equally, leaving an open furrow in the middle. It forms furrows and
not ridges. However, when the furrows are close to one another; the inter furrow spaces take
the form of ridges but when furrows are formed apart for planting sugarcane, cotton, etc., the
inter furrow spaces take the form of ridges but when furrows are formed apart for planting
sugarcane, cotton, etc., the inter-furrow spaces take the form of raised flat beds.

(b) Bund former - This consists of a pair of opposing wings, which are wide apart in front and
converge towards the rear with a gap at the end. The wings gather loose soil from the surface
and leave it in the form of bund with approximately 18-20 cm in height. To form reduced size
bunds, the wings are lightly raised at the fore end and pulled a little backward. When the
implement is hitched near the yoke, a small quantity of earth alone is gathered. The gaps
formed at the intersection of long and cross bunds while working with the implement are
closed with manual labour. Ridges for sowing cotton and similar crops are also formed with
bund former, with the bunds close to one another as when irrigation channels are formed.
298 A TEXTBOOK OF AGRONOMY

(c) Bed-furrow former- It is a tractor-drawn iron implement, which is capable of forming alternate beds
and channels. It will form two beds and three furrows in one pass of unit. Using this implement a
well defined, raised beds 30 cm wide at top and ‘V’ shaped channels 45 cm wide and 15 cm deep
are formed on the well-ploughed and harrowed field. It covers an area of 3–3.5 ha/day.

(d) Rollers - The rollers are used for breaking clods and compacting the soil. There are different
types of rollers in use.

(i) In Iron rollers cast iron rings of 0.6 m in diameter are fixed to an axle and provided with a
hoped frame for hitching with power unit. Surface of the roller may be plain or fluted or
ribbed. The fluted and ribbed rollers are more efficient in breaking clods. The plain rollers
are used for compacting the soil surface.

(ii) Stone rollers are commonly used for threshing grains. They are made up of cylindrical
stone with 0.75 m length and 0.4 m diameter.

(iii) Sheep foot roller is the latest implement developed by TNAU, to create partial compaction
in rice fields in light soils. It has a cylindrical drum with projections on the surface like
sheep foot.

7.11.4.4 Sowing implements

(a) Country seed drill/‘Gorru’- It consists of a horizontal beam on which a number of tines are fixed at
suitable distances. The tine is like the body of the common wooden plough, but is much smaller. It
has a vertical hole, a little above the point of penetration into the soil. Seeds are released from the
above placed seed hoppers steadily few seeds at a time. The base of the hopper has as many holes as
there are tines in the gorru and narrow bamboo or metal tubes connect the hopper and the tines. This
enables the seeds released in the hopper being dropped in the furrows opened by the tines. The
hopper and the seed tubes are held in position with thin ropes.

(b) Mechanical seed drills- It is of both bullock and tractor drawn.

(i) Bullock drawn seed drill/TNAU improved planter - A medium size five tined cup feed seed
drill suitable for heavy size bullocks, a small three tined cup feed seed drill called as
Kovaiseed drill are suitable for small pair of bullocks. These drills are suitable for sowing
seedsof groundnut, maize, sorghum, cotton, Bengal gram and pulses. It covers on ha per
day and costs Rs. 3,500/-.

(ii) Tractor drawn seed drill - Both simultaneous formation of 1.5 m wide beds and sowing in
the bed is possible using this drill. The implement consists of a pair of furrowers made of
 sheet metal with suitable hitching arrangements to the three-point linkage of the tractor.
Over the framework of these furrowers 7 numbers of hoppers with metering mechanisms
have been mounted. This implement simultaneously sows in seven rows in the broad bed.
It covers an area of 4 ha/day and saves 25% of sowing cost.

(iii) Rice drum seeder for wetland (Drum seeder for direct sowing of rice) - A manually pulled,
rice seeder has been developed at TNAU for sowing pregerminated rice seeds in rows
directly in well puddled and leveled soil. It requires 2 labourers and covers 0.4 ha/day.
Using this seeder green manures (Sesbania sp.) can also be sown as intercrop in between
rice rows. Cost of this seeder is Rs. 3000/-.

5 Implements for wetlands

Under wetland system the land is prepared by puddling for planting wet rice. Puddling means mechanical
manipulation of saturated soils with standing water in the field. Actually the structure of the

TILLAGE 299

soil is destroyed under puddling. The optimum depth of puddling is about 10 cm in the clay and clay-
loam types of soils. Good puddling or neatly ploughed means the soil should be soft, uniformly
leveled without weeds or stubbles and with minimum percolation.

A. Why puddling?

Puddling is done

• To obtain a soft seedbed for the seedling to establish faster,

• To minimize percolation of water so that water can stagnate in the field,

• To minimize leaching loss of nutrients and thereby increase the availability of plant nutrients,

• To facilitate better availability of nutrient by achieving reduced soil condition,

• To incorporate the weeds and stubbles into the soils, and

• To minimize the weed problems

The implements used for puddling the wet soils are as follows:

(i) Country plough, (ii) Bose plough, (iii) Wetland puddler, (iv) Cage wheel, (v) Sheep foot roller,
and (vi) Helical bladed puddler.
 (i), (ii) and (v) were discussed already in this chapter.

(iii) Wetland puddler- It consists of three angular bladed cast iron hoods rigidly fixed to a hallow
horizontal pipe and is rotated when dragged by a pair of bullocks. This implement is proved to
be an economic, labour saving and an effective dual-purpose implement useful for puddling
and trampling green leaf manure in the puddle field. When used for trampling the vegetative
matter is cut and buried in the soil. It covers an area of 0.8 ha/day.

(iv) Cage wheel - It is used for puddling in medium and heavy clayey soils in wetlands for rice
cultivation. The cage wheels are attached in place of pneumatic wheels in power tiller and
tractor. The cage wheels perform well in all the fields except in fields with clay and silt content
of the soil was more than 56%. It saves cost, time and brings more uniformity and
thoroughness in the puddle than country ploughing. Cage wheel attached to power tiller covers
an area of 0.44 ha/day. The average depth of puddle is 23 cm.

(vi) Helical bladed puddler - It is used to puddle the wetland soil after initial ploughing with
country plough or melur plough. It is a bullock-drawn implement. Five numbers of helical
blades made of mild steel are fixed in a skewed shape and

mounted on a wooden frame having wooden

bearing such that the blades can rotate freely. A
handle and pole shaft are provided. Due to the
helical shape of the blade, there will be
continuous contact between the blades and the
soil, which gives uniform load on the neck of
the bullocks. After ploughing the land with
country plough, the implement can be used to
puddle the soil up to a depth of 10 cm. The
helical geometry facilitates better churning and
slicing of the soil required for puddling. It
covers 0.6 ha/day.