Paddy field soil conservation: Indian historical practices

doi:10.4236/as.2011.23045

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Vol.2, No.3, 341-346 (2011) Agricultural Sciences

doi:10.4236/as.2011.23045

Paddy field soil conservation: Indian historical practices

Deepak Bhattacharya

Head-Oddisi Research Laboratory, C/O Sri Radha Krishna, Bhubaneswar, India; Corresponding Author: [email protected]

Received 28 January 2011; revised 5 July 2011; accepted 29 July 2011.

ABSTRACT

India is an ancient land having high seasonal

rain fall (4 months rain & 8 months dry), has

paddy cultivation. Becauses silt-sand separa-

tion; buoyant sand gets carried; silt aggluti-

nates. Rill fluid dissolves agglutinated soil;

vectors as silt → degradation. Indian farmer has

unique agricultural field conservation; soil cum

fertility maintenance/regeneration heritage; also

use the stubble and cow dung (cellulose) as

binder cum multi purpose in-field uses. Eco-

nomic; ecologically safe; and not discussed

earlier. Good tool for altruistic administrations.

Keywords: Stubble; Cow Dung; Paddy;

Multi-Crops; Heavy Monsoon Rains; Soil

Conservation

Abbreviation: Soil Moisture—SM; Rain Fall—RF;

Outgoing Long Waves Radiation—OLR

1. INTRODUCTION

India an ancient nation having a continuous settled

agriculture type of civilization for last few millennia is

intently agricultural even to this day. During the same

period numerous civilizations have risen and fallen. The

Indian civilization continues. India is also known as

Orient and rice (paddy: Oryza Sativa Linn) is the gift of

the Orient. Paddy cultivation requires inundation which

in turn requires copious rain. Much of India is also high

land and has good gradient [1]. Has an annual average

rain fall of the order ranging between 300 mm and 1500

mm [2]. The annual gross rain fall and surface run off to

the sea being of the order 400 billion m3 [3]. But copious

rain is also associated with soil degradation and erosion.

Indian (Hindus specially) are also world wide known for

their ancient scientific knowledge base [4]. India’s

population has been leaping forward, and stress on land

forms is mounting. Indian administration is often seen

giving more priority to welfare of its Govt. employees

than to the common man. Therefore, discussing time

vetted, economically and ecologically safe practices is

called for urgently. In this communication we examine

how the native Indians have been conserving soil-bio

mass. We report few unique practices and discuss the

underlying scientific reasons.

2. SOIL MOISTURE ASPECTS

SM loss arises out of heat wave. India has 8 months of

no rain period of which 4 months is noted for dry winds

from the north-west (middle-east). In the rural, the na-

tives of India do not use any term that can directly be

associated with SM, which arises out of narrow agro-

nomic consideration. They use the term murtika sanrak-

shana (soil conservation), which socio-culturally is a

holistic usage. We again note Sri Balabhadra/Baldev/

Baldeo is the jaistha (senior most)—incarnation of Lord

Siva Mahadeva (the supreme Hindu God) in his (former)

farmer format, holding a ploughshare. Alike a farmer, his

is a well built personage of impeccable character. So, the

supreme Hindu God head in India is a farmer, indeed. In

relation to our caption, we may aver that ancient India

had given much importance to farming and to the farm-

ers. In this segment we consider as to how the native

Indian farmer has been coping with the principal under-

lying cause of ‘SM loss’ and how we have been inspired

i.e. we discuss few tangible cum intangible heritage as-

pects. We then raise the question, what then has been the

historical practice to retain soil moisture and to arrest

soil erosion/field degradation? We note that, historically,

the Indian and specially the east coast farmer (case of

excess RF + prolonged dry + acute heat) has devised

time tested methods to arrest soil erosion and top soil

recharge. Herein the term ‘farmer’ denotes settlement

based life (which in India is at the least 2 millennia old,

recorded) and not podu (burn) nor jhum (shifting culti-

vation).

3. OUT-DOOR OBSERVATION - RECORD

Figure 1 is that of a small segment of a plot on dt.01-

D. Bhattacharya / Agricultural Science 2 (2011) 341-346

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Figure 1. Stubble on field; post harvest period.

Figure 2. Stubble less field; post harvest period (nearby loca-

tion of Figure 1).

03, 2007, well post removal of crop to khala (stock yard),

location district Angul (central Odisa; onset of heat wave

period). The field has good clay soil (chikita mati). Mono

crop, rice cultivation has been practiced in this field for

last few centuries (as far back as memory of the local

native can go). The field has been left fallow, because of

rain fed, subsistence type, and mono cropping practice (to

be cultivated in next year rainy season). We can see the

fresh off shoots from around the stubble. The soil looks

moist, a fresh crack has evolved; the green shoots looks

healthy. The cracks seem to avoid the location of the

stubbles. Our Figure 2 is that of another plot in the

neighbourhood (within a range of 500 mts) that has no

stubble and has reddish type soil texture. Photographs

are taken at the same period (01-03, 2007). We see that

in the stubble less field even the low regions have more

cracks (caking) than the upper regions. Our Figure 3 is

that of the stubble filed (F-1 region) re-exposed during

the Rajo festival period (mid June) i.e. pre next cultiva-

tion cycle [5], which is a non baroclinic period, whence

invariably the coastal regions receive premonsoon show-

ers. We can see that the stubble in the field is virtually

Figure 3. Stubble field as in Figure 1, re-exposed post field

preparatory seasonal rains.

indiscernible (decomposed into soil). Instead a green

carpet is noted with no sign of soil moisture stress or soil

denudation or even surface erosion. During the same

period the red soil, stubble less field (F-2) wore a deso-

late look with heightened caking, rills all over our erst-

while designate place (photo not included). Pre monsoon

showers had inflicted remarkable surface level changes.

We think that the contrast between Figures 2 and 3

could primarily be caused by the stubbles and the

pre-monsoon showers have rejuvenated the green carpet

although the soil had caked limitedly. K. G. Vernekar,

et.al. [6] have indicated that SM and vegetation effect

atmospheric boundary layer and land surface processes.

We relate with evolution of refractile ecology and

socio-economic stress. In other words this results in tur-

bulence and becauses rain.

We raise the question, why should the soil crack? And

cake (disassociate from the ground)? Surface soil mois-

ture is the water that is in the upper 10 cm of the soil,

whereas root zone soil moisture is the water that is

available to plants, which is generally considered to be

200 cm downwards from the top surface of the soil. SM

is expressed in ‘%’, wherein 75% - 100% means ‘wet -

muddy’ and forms ball when clasped by (bare) palm. We

also found that as evapotranspiration proceeds from the

surface due to top heating from astronomical source, the

soil looses mass, shrinks in volume. Loss of fluid makes

the soil less elastic. Yet, no work has been done on the

surface. However there has been loss of volume in terms

of fluid loss via the top surface which is (also) work

done—beneath the surface (due capillary motion). Dry-

ing, i.e. loss of volume proceeds from the top. Physical

property between the surface (hard) and the inner soil

(soft) take a paradigm shift. The dried surface area has to

remain constant (or else it is not hard). Moisture stratifi-

cation happens. Soil is permeable, due osmosis moisture

must flow out. The contrast of physical property (vol-

D. Bhattacharya / Agricultural Science 2 (2011) 341-346

343343

ume: mass) between the outer and the inner layers of the

soil leads to infractions (internal fractions). In fact the

infractions are ‘shear cracks’ due to opposing longitudi-

nal forces. The point of least resistance is the point of

shearing. But, soil is homogenous. Therefore, internal

binders act as resistors. In order to retain surface archi-

tecture (which was formed when soil had higher plastic-

ity) the (dry) surface has to crack and readjust to the new

volume: mass conditions of the underlying strata. Sub-

sequently, it is through these cracks moisture from inner

layers start escaping into the atmosphere (which has a

lower relative humidity). Soil masses around which fine

cracks have developed experiences heightened SM loss

from enhancing depths. Differential contraction and

variable shrinking from all sides (which) also assists in

irregular cracking, widening, gets isolated as a ‘cake’.

The cake undergoes moisture loss from all around its

edges and along the inner line of disassociation as com-

pared to the top-exposed mid regions; this creates the

(unique) pan shaped cake. Decrease in surface area

(concave architecture) occurs to reduce the area that is

incident to astronomical heating. It is a preferred (natural)

thermodynamic architecture. This in turn acts as a ‘ob-

ject for frying’ and finally disassociates from the lower

strata with SM loss > 80%. Powderisation process and

wind’s erosive action then start registering. Sand silt

separation sets in. Process desertification has been initi-

ated.

In contrast to such mechanics, wherever available, the

stubble roots hold soil in clumps, acts as capillary path-

ways for soil moisture translocation. Therefore, superfi-

cial roots act as ‘resistors, while the stubble acts as ae-

rial(s) for evapo-transpiration and also provide limited

shade to the soil. The stubble being porous weatherized

hay acts as an insulator of heat, with a hollowed centre

made of long fiber cellulose. It acts as antennas (pro-

jecting into the air mass) and traps ground skimming

cum escaping moisture from the vicinity, and re-trans-

locates back into the soil by reverse capillary mechanism

towards the parched soil, post dawn every day → few

hours into the pre-noon. Further, during dusk to dawn

period, nocturnally condensation occurs on the aerial

stubble. Such moisture is also reverse translocated back

into the root base soil. Overtime, the entire blocks of the

stubble cum roots turn into soil, pre next field prepara-

tion. When admixed in soil, the stubble also act as

‘moisture retainers’, apart from its initial ‘binder’ role.

Therefore, stubble less plain surface (although it offers

least surface area) leads to more cracking, caking, rill

formation even during pre-monsoon showers and exten-

sive top soil loss. We also note that feet trampled (pug

marked) semi-dried undulated surface (Figure 3) offer

variable angles to the radiant Sun, create micro shadow

areas and also down regulate OLR. Therefore wet land,

moist land and standing crop fields respectively give out

less OLR, create scope for lot much work done in the

land-atmosphere couple; impede process barocilinic.

4. INDOOR EXPERIMENTS

Two experiments were done of which one was to ver-

ify the heritage practices of the Indian farmer. An seg-

mented tray was taken. Two sample of identical volume

of soil was collected from the field as in Figure 3. Sam-

ples of neat soil were made wet and poured into the seg-

ment marked ‘A’ of the tray. Into another neat soil of

identical volume was admixed 5% hay and 5% dry cow

dung by volume and stirred to uniformity with identical

amount of water and poured into the segment marked

‘C’ of the tray ( to viewer’s right Figure 4). The tray was

left to dry in hot summer of May (Bhubaneswar: +20.5°/

+85.82°). After 7 days, the photograph was exposed. We

can see that segment ‘C’ which contains 5% hay and 5%

dry cow dung (as alike the usage by the Indian farmer)

has developed less cracks, although both the samples are

dried to a moisture content of less than 5%. Therefore,

the historical practice of adding cow dung, burnt plant

matter (variously treated cellulose) and retaining the

stubble is deemed applied science.

5. CO-RELATIONING OF ON-FIELD

OBSERVATIONS

On field study, it is noted that the agriculture fields

seem to retain loam and finer silt comes to the top when

Figure 4. In-lab demonstration of soil binding effect of dried

stubble & cow dung (cellulose).

D. Bhattacharya / Agricultural Science 2 (2011) 341-346

344

wet. The sand seem to flow away towards the peripher-

ies. We raise a question why? An experiment was con-

ducted in the field. A block of soil was dug out from the

field as in Figure 3 and deposited on the surface (Figure

5). It was allowed to get exposed to natural weathering

process for only 2 weeks. We can see in Figure 5 that

sand has come to the top. Figure 6 is that of post 6

months (spring and pre-monsoon shower exposed). We

can see sand has virtually been washed/removed. Loam

has formed as a pack and has yet not experienced any

denudation/scouring/rill formation. Figure 7 is post 14

months, we can see that loam is appearing as very sticky

and has experienced extensive scouring and rill forma-

tion. Hence we may say that sand (silica particulates)

being more buoyant due to less specific gravity than silt

particulates (which are finer), get to top when fluid is

added to solid (soil). Loam adsorbs water and then de-

velops a binding property, while silica does not. So, fluid

action is the cause. Moreover, fluid thrust on larger sur-

faces (herein sand particles) is more linear (Pascal effect)

while on smaller surfaces (herein loam) it is more non

linear (non Newtonian effect). However, sand is very

important as a constituent as it also (limitedly) acts as a

binder and thermal regulator (silica property). In the

stubble field however, the sand that is expressed to the

surface during inter-crop periods eventually fall and sink

into the cracks/crevasse and get re-assimilated into the

soil matrix. There is a no loss. It is a loop. Hence allow-

ing a inter-crop period is good for soil conservation!

This is history of soil conservation applied science.

6. DISCUSSION

Addition of water (RF) makes soil buoyant (gain vol-

ume). Constituent sand (silica) has lower specific gravity;

greater surface area becomes relatively more buoyant

and is pneumatically raised to the upper regions (quench-

ing stage dependant). Whereas, constituent silt (the ma-

Figure 5. Sand particulates come to the surface and silt clumps

and sinks in exposed soil (non rain).

Figure 6. Sand particulates are washed away and silt clumps

(as in Figure 5) and sinks in soil exposed to initial rainy sea-

son.

Figure 7. Silt clumps (as in Figure 5); appearing very sticky,

has experienced extensive scouring and rill formation post

expouser to full rainy season (Indian monsoon).

jor component by weight & also greater bulk density)

sinks deeper. This is mechanical. Separation is potenti-

ated and occurs if there be alternating wet-dry spells.

Buoyant sand gets carried easily and earlier (than silt)

D. Bhattacharya / Agricultural Science 2 (2011) 341-346

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during initial rain. Thereafter, the kinetic energy com-

ponent of a rain drop (on ground hit) gets fractionated

efficiently (due greater cross section of the sand particu-

late that populates the upper regions) and dissipates into

the crystalline structure(s); radiating upwards (towards

lower bulk density). Whereas, the cohesive mass of the

silt segment develops a shock wave type behavior, radi-

ating downwards (towards higher density) leading to

compaction. All this are due to the imparted energy.

Tropo-Equatorial RF is marked by large droplets; free-

falling from higher altitudes (convective clouds). Again,

in cultivable soils, acids have affinity for the silt com-

ponent, and alkalis have for the silica (inert). Injection of

adequate neutral fluid (viz. RF) generates a surfactant

effect. Water washes additionally. All this happen pre rill

formation.

Silt also agglutinates and tends to clump. Rain water

being Newtonian fluid when energized, exhibits cen-

trifugal property until dissipation of the kinetic compo-

nent. This additionally assists separation, mechanically.

Post rain, low energy surface flow only dissolves and

carries silt. In agitated state the carrying capacity of

Newtonian fluids rises exponentially. Rill forms due to

significant amount of unhindered flowing fluid (period

& volume of surface flow). Rill fluid is in hyper agitated

state. It is stream flow having significant velocity (high

energy/Reynolds). Scours and dissolves the agglutinated

material and vectors the (silt). This results in land form

degradation. Stubble robustly down-regulates all the

stages, even rill formation. Stubble is a formidable bar-

rier. Stubble field is the secret behind the historically

well conserved soils.

The eastern coastal district of Ganjam in Odisa, India

has a decadal annual average RF of only 800 mm and

yet is the granary of that province. It is relevant to relate

that paddy requires on an average 750 mm of RF. Al-

though much of Ganjam’s domain is precipice and high-

land (with bare sustenance amount of RF) such bounty

production (granary aspect) is possible only because the

farmer also puts leafs and whole hay, burnt organic mat-

ter as well. Carbon from burnt organic matter we know

traps nitrogen, while wood carbon has a surface area of

the order 1000 - 2000 mt2/gm, also adsorbs moisture and

helps in retaining SM that assists soil binding. Hence,

soil cracking and moisture loss is down-regulated due

the ‘binder effect’ of the stubble’s roots cum cow dung

& ash (which is loaded with digested cellulose). This is

an example of such soil conservation sciences in applied

form.

Therefore, organic long fiber binders can thwart SM

loss and consequent top soil loss, etc. Excessive cracking

of stubble field is a conclusive early (warning) sign of

‘heat wave’ and impending ‘Sun stroke conditions’. The

occidental farmer is not known to have such practice

(wherever such practices are not noted desertification

mechanics have evolved). Our inspiration for this ex-

periment came by observing the field preparation inputs

by the Indian farmer in general and via personal com-

munication from farmer’s guilds collected ranging over

a decade.

7. ACKNOWLEDGEMENTS

Heavy RF and even alternating wet-dry spells, inflicts

sand-silt separation leading to soil & surface degradation,

if the top soil be bare. The mechanics proceeds as poly

modal (not as a cascade). Adding cow dung, burnt plant

matter (variously treated cellulose; carbon particulates)

and retaining the stubble acts as anti-dote. The admini-

stration can do precious enough by monitoring soil

cracking i.e., SM loss over extensive region (earliest

signature). India has a good data bank in agro-met do-

mains. The data should be opened to the public (IMD

and GOI data are not available to the common man, be-

cause the administration considers the common man as

suspect and treats alike alien citizen. Moreover, almost

every thing in India is by the Govt., of the Govt. and for

the Govt.). The nation can then pre-calculate with near

precision about likely period, and intensity of any im-

pending ‘Heat wave’ conditions in relation to time and

place, and its impact on flora, fauna and anthropomorphs

(homeotherms). Heat wave effect on homeotherms is

preceded by noticeable effect on poikilotherms such as

lizards; snakes and other non climber reptiles often

coming on-ground or trying to climb trees; absence of

butterflies; juvenile sized leafs falling off from trees (off

season patjhar), wide spread viral attacks on domesti-

cated animals and pets, many similar signs (again a se-

ries, pre human fatality).

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(1950-1980). Vth Edition, Government of India, New

Delhi.

[3] Planning Commission (2002) Report of the committee on

India vision 2020. Planning Commission, Government of

India, New Delhi.

[4] Bhattacharya, D. (2010) Indian ancient sciences. Lap

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[5] Rajo festival is celebrated in Odisa very intently. It is a 3

day deemed (cultural) menstruation period for mother

Earth. No earth related activity are done. Farm imple-

ments are put on worship. Ladies do not cook, take to the

D. Bhattacharya / Agricultural Science 2 (2011) 341-346

346

swing. Outside it is cloudy, sultry and breezeless. Swing

helps in evapotranspiration → cooling →feel comfort

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doi:10.1023/A:1021283503661