Mulching: A Soil and Water Conservation Practice

Abstract

India being an agriculture country should have a good respect towards conservation strategies especially of water. Already we are suffering from a great stress of water scarcity. Each and every drop of water is important for us but unfortunately because of carelessness, we often waste huge amount of water. One of such practices is over and excessive irrigation. Mulching is a soil and water conserving and weed management practice through soil solarisation also in which any suitable material is used to spread over the ground between rows of crops or around the tree trunks. This practice helps to retain soil moisture, prevents weed growth and enhances soil structure. There are various types of mulching such as surface mulching, vertical mulching, polythene mulching, pebble mulching, dust mulching live vegetative barriers, straw mulching etc. Mulching proves to be beneficiary though increment in soil moisture, reduction in soil erosion, maintenance of soil temperature etc. It helps in improvise in soil structure, soil fertility and soil biological regime. Though also mulching is having many advantages it shows some limitations as it may harbour some pests and diseases. It is not so appreciable in wet conditions. It is little bit difficult to get even mulching on steep lands. Some grass species used as mulch can root and become a weed problem. The present review deals with the discussion of every aspect of mulching and how it has beneficiary effect.

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Research Journal of Agriculture and Forestry Sciences __________________________________ ISSN 2320-6063
Vol. 1(3), 26-29, April (2013) Res. J. Agriculture and Forestry Sci.
International Science Congress Association 26
Review Paper
Mulching: A Soil and Water Conservation Practice
Patil Shirish S., Kelkar Tushar S. and Bhalerao Satish A.
Environmental Sciences Research Laboratory, Department of Botany, Wilson College, Mumbai, INDIA
Available online at: www.isca.in
Received 9
th
November 2012, revised 29
th
December 2012, accepted 30
th
January 2013
Abstract
India being an agriculture country should have a good respect towards conservation strategies especially of water. Already we are
suffering from a great stress of water scarcity. Each and every drop of water is important for us but unfortunately because of
carelessness, we often waste huge amount of water. One of such practices is over and excessive irrigation. Mulching is a soil and
water conserving and weed management practice through soil solarisation also in which any suitable material is used to spread
over the ground between rows of crops or around the tree trunks. This practice helps to retain soil moisture, prevents weed growth
and enhances soil structure. There are various types of mulching such as surface mulching, vertical mulching, polythene mulching,
pebble mulching, dust mulching live vegetative barriers, straw mulching etc. Mulching proves to be beneficiary though increment
in soil moisture, reduction in soil erosion, maintenance of soil temperature etc. It helps in improvise in soil structure, soil fertility
and soil biological regime. Though also mulching is having many advantages it shows some limitations as it may harbour some
pests and diseases. It is not so appreciable in wet conditions. It is little bit difficult to get even mulching on steep lands. Some grass
species used as mulch can root and become a weed problem. The present review deals with the discussion of every aspect of
mulching and how it has beneficiary effect.
Keywords: Mulching, conservation, weeds, improvement of soil structure
Introduction
Over 50 years since its independence, India has made immense
progress in Agriculture and food security. Prior to the mid-
1960s India relied on imports and food aid to meet domestic
requirements. However, two years of severe drought in 1965
and 1966 convinced India to reform its agricultural policy, and
that India could not rely on foreign aid and foreign imports for
food security. India adopted significant policy reforms focused
on the goal of foodgrain self-sufficiency. This ushered in India's
Green Revolution. It began with the decision to adopt superior
yielding, disease resistant wheat varieties in combination with
better farming knowledge to improve productivity.
Development of irrigation schemes, copious use of fertilizers
and pesticides, use of high yielding varieties made the green
revolution possible.
But the population of India continues to rise, and we have
realized that this one green revolution will not help. We have to
adopt to other means of sustaining our agricultural growth and
how can we do that?
We can do it through conservation farming. Organic farming is
the answer. We have realized that the green revolution saved us
once but now its dependence on heavy use of fertilizer and
pesticides are polluting our environment and degrading our
soils. Excessive irrigation is bringing problems of soil erosion
and salinity of soils. Though a lot of irrigation schemes have
been developed we still have only 1/3
rd
of our agriculture under
irrigation.
So what is the way out? What do we do to restore the health of
our soils? What do we do to add nutrients to our soils? What do
we do to maintain a good micro-flora and a fine balance of
micro-organisms in the soil? What do we do to conserve the
moisture in the soil? What do we do to control the weeds in our
fields?
The answer is simple, to adopt the age old practice of Mulching
in our agricultural fields. So what is a Mulch? It is a protective
covering, usually of organic matter such as leaves, straw, or
peat, placed around plants to prevent the evaporation of
moisture, and the growth of weeds.
The word mulch has probably derived from the German word
“molsch” means soft todecay, which apparently referred to the
gardener’s use of straw and leaves as a spread overthe ground as
mulch
1
.
Mulching reduces the deterioration of soil by way of preventing
the runoff and soilloss, minimizes the weed infestation and
checks the water evaporation. Thus, it facilitates formore
retention of soil moisture and helps in control of temperature
fluctuations, improvesphysical, chemical and biological
properties of soil, as it adds nutrients to the soil andultimately
enhances the growth and yield of crops. Further, reported that
mulching boosts theyield by 50-60 per cent over no mulching
under rainfed situations
2
.

Research Journal of Agriculture and Forestry Sciences _______________________________________________ ISSN 2320-6063
Vol. 1(3), 26-29, April (2013) Res. J. Agriculture and Forestry Sci.
International Science Congress Association 27
Organic Mulch
An organic mulch is made up of natural substance such as bark,
wood chips, pine needles, dry grasses, paddy straw, dry leaves,
saw dust, grass clipping, etc. But organic mulch attracts insects,
slugs and the cutworms that eat them. They get decomposed
easily and need frequent replacements.
Grass Clipping: This is one of the most abundantly and easily
available mulch materials across the country. It provides
nitrogen to the soil, if incorporated fresh. However, application
of green grass in rainy season may result into the development
of its own root system which will be detrimental to plant
growth. Therefore, use of dry grass as mulch material is
suggested.
Straw: Paddy and wheat straw are the commonest mulching
materials used for fruit and vegetable production. Though straw
is poor in nutrient value but after decomposition, it makes soil
more fertile. Among organic mulching materials, straw has a
long life in comparison to other mulches (grasses, leaves and
leaf mould).
Newspaper: Newspaper mulching helps to control weeds. One
to two cm thick sheet of newspaper should be used and edges
should be fastened with materials like pebbles, gravels, etc. The
application of newspaper mulch should be avoided on a windy
day.
Dry leaves: Leaves, an easily available material, are good for
mulching. Though leaves are good for protecting dormant plants
during winter by keeping them warm and dry but due to
lightweight they may be blown away even by light wind. To
counter this problem, it requires anchoring which can be done
with stones, chipped bark and covering with net or some form of
sheet.
Bark clippings: These are good mulch materials as they are
long lasting and allow proper aeration to the soil underneath.
Hardwood bark clippings contain more nutrients than softwood
but bark clippings are not easily and abundantly available, and
some bark products may cause phytotoxicity.
Saw dust: Saw dust, obtained during finishing operation of
wood, is very poor in nutritive value as it contains only half the
nutrients of straw. It decomposes slowly. Being acidic in nature,
it should not be used in acidic soils.
Compost: The compost is one of the best mulch materials. It
increases microbial population, improves the soil structure and
provides nutrients. It is the excellent material for improving the
health of soil.
Benefits of Organic Mulching: Mulch reflects a lot of the sun
that otherwise heats the soil. This keeps the soil cooler and helps
prevent evaporation. This is especially important in hot, dry
climates. When the soil is covered in mulch, weeds do not grow
under it as they do not get the light they need to grow. Mulches
prevent soil erosion, as the wind or running water does not
directly come in its contact and does not blow or wash it away.
Mulches spread over soil, slow down rainwater run-off, and
increase the amount of water that soaks into the soil. And more
water in the soil means more water for the crops. Organic
mulches also improve the condition of the soil. As these
mulches slowly decompose, they provide organic matter which
helps keep the soil loose. This organic matter becomes food for
the beneficial earthworms and other soil micro-organisms in the
soil and create a very good porous soil. This improves root
growth, increases the infiltration of water, and also improves the
water-holding capacity of the soil. Decaying organic matter also
becomes a source of plant nutrients. Maintains a more even soil
temperature. Keeps feet clean, allowing access to field even
when damp
Limitation of Organic Mulching: Mulches can keep the soil
too moist, restricting oxygen in the root zone on poorly drained
soils. If mulch is applied close to or in contactwith the stem,
trapped moisture creates anenvironment conducive to
development ofdiseases and pests. Many organic type
ofmulches also encourage and providerefuge or breeding
locations for snails,slugs, mice, etc. that may attack the plants.
Certain types of mulches such as hay andstraw contain seeds
that may becomeweeds
Inorganic Mulch Material
Gravel, Pebbles and Crushed stones: These materials are used
for perennial crops. Small rock Layer of 3-4 cm provides good
weed control. But they reflect solar radiation and can create a
very hot soil environment during summer.
Plastic mulch
Both, black and transparent films are generally used for
mulching. Advancement in plastic chemistry has resulted in
development of films with optical properties that are ideal for a
specific crop in a given location. Horticulturists need to
understand the optimum above and below ground environment
of a particular crop before the use of plastic mulch. These are
two types.
Photo-degradable plastic mulch: This type of plastic mulch
film gets destroyed by sun light in a shorter period.
Bio-degradable plastic mulch: This typeof plastic mulch film
is easily degraded inthe soil over a period of time.
Colour of film: Soil environment can be managedprecisely by a
proper selection of plastic mulchcomposition, colour and
thickness. Films areavailable in variety of colours including
black,transparent, white, silver, blue red, etc. But theselection of
the colour of plastic mulch filmdepends on specific targets.
Generally, thefollowing types of plastic mulch films are usedin
horticultural crops.

Research Journal of Agriculture and Forestry Sciences _______________________________________________ ISSN 2320-6063
Vol. 1(3), 26-29, April (2013) Res. J. Agriculture and Forestry Sci.
International Science Congress Association 28
Black plastic film: It helps in conserving moisture, controlling
weed and reducing outgoing radiation.
Reflective silver film: It generally maintains the root-zone
temperature cooler.
Transparent film: It increases the soil temperature and
preferably used for solarization.
Advantages of Inorganic Mulching: Moisture conservation,
Soil Conservation, Soil Temperature, Soil Solarization (With
Transparent Plastic Mulch Controls disease pest), Weed Control
Apart from the above classification there is another way of
classifying Methods in Mulching
3
Surface Mulching: Mulches are spread on surface to reduce
evaporation and increase soil moisture.
Vertical Mulching: It involves opening of trenches of 30 cm.
depth and 15 cm. width across the slope at vertical interval of 30
cm.
Polythene Mulching: Sheets of plastic are spread on the soil
surface between the crop rows or around tree trunks.
Pebble Mulching: Soil is covered with pebbles to prevent
transfer of heat from atmosphere.
Dust Mulching: Interculture operation that creates dust that
breaks continuous capillaries, and deep and wide cracks thus
reducing evaporation from the exposed soil areas.
Live Vegetative Barriers: Subabul and Glyricidia when used
as live vegetative barriers on contour key lines not only serve as
effective mulch when cut and spread on ground surface but also
supply nitrogen to the extent of 25 to 30 kg per ha, besides
improving soil moisture status.
The benefits of Organic Mulching have been documented in
various studies: Straw mulch conserved higher soil moisture to
an extent of 55 per cent morecompared to control
4
. Average
available soil moisture stored up to1.5 m depth of soil increased
significantly by mulching of wheat residue @ 6730
kg/hacompared to bare soil
5
.
Okra production was significantly higher under straw mulch
followed by dust mulchover control
6
. Similar beneficial
effectsof mulching through improvement of soil environment
resulting in better plant growth andtuber yield of potato were
observed
7
. Application of straw mulch @ 6 t/ ha increased yield
of tomato and okra by 100 and 200 per cent, respectively over
control
8
.
The yield of potato was the highest under paddy straw mulch
(27.9%) and also starch content was highest in paddy straw
mulch (18.18%) than unmulched plot
9
.
Organic mulches induced earliness in flowering, less days
tofruit set and days to harvest, also increased number of flowers
and per cent fruit set in tomatocrop over control
10
.
Table – 1
Increase in Yield of Fruit Crops through Plastic Mulching
Crop Yield (T/Ha.) Increase in
Yield (%)
Unmulched Mulched
Guava 18.36 23.12 25.93
Mango 4.93 7.16 45.23
Papaya 73.24 120.29 64.24
Ber 7.02 8.92 27.06
Pineapple 10.25 11.75 14.63
Banana 53.99 73.32 33.95
Litchi 111.0 125.0 12.61
Source: NCPAH, New Delhi (National Committee on
Plasticulture Applications in Horticulture)
Table- 2
Increase in Yield of Vegetable Crops through Plastic
Mulching
Crop Yield (T/Ha.) Increase in
Yield (%)
Unmulched Mulched
Broccoli 15.64 25.14 60.74
Cauliflower 18.58 25.02 34.66
Brinjal 36.73 47.06 28.12
Tomato 69.10 94.85 37.26
Okra 6.91 8.56 23.88
Bitter Gourd 20.12 25.63 27.39
Chilli 16.79 19.71 17.39
Cabbage 14.3 19.9 39.16
Source: NCPAH, New Delhi (National Committee on
Plasticulture Applications in Horticulture)
Conclusion
In the present scenario of globalization and health consciousness
demand for horticultural crops has increased world over.
Excessive competition has not only compelled us to produce
more but also to produce quality fruits for sustaining in the
international market. Apart from using high yielding varieties
and good agricultural practices, there is a need to utilize
environmental/biological energy for higher production.
Mulching is one such process that can help us in producing
quality food in quantities. In the days to come, farmers will
make use of this innovative technique that helps them conserve
moisture, avoid weeds and improve soil health tremendously
while producing more. This will also go a long way in the
world achieving food security sustainably.
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Research Journal of Agriculture and Forestry Sciences _______________________________________________ ISSN 2320-6063
Vol. 1(3), 26-29, April (2013) Res. J. Agriculture and Forestry Sci.
International Science Congress Association 29
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