soil health issues and strategies

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Welcome

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Soil Health – An Overview Dr. M. Dhakshinamoorthy Professor of Soil Science Tamil Nadu Rice Research Institute, Aduthurai

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Soil is one of the most important earth materials we encounter each day, but the definition of soil is difficult. Soil Scientists (and most ordinary people): fine-grained, well-weathered earth material that is able to support plant growth focus on the physical and chemical properties Engineers: any earth material that can be removed without blasting focus on particle size and the amount of organic material engineering applications What is meant by the word “Soils”?

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Soil defined as “Soil is a natural dynamic body differentiated into horizons of variable depth which differ among themselves and from the parent material below in morphology, physical properties and constitution, chemical properties and composition and biological characteristics” (Joffee)

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The soil is teeming with life. It is a world of darkness, of caverns, tunnels and crevices,inhabited by a bizaree assortment of living creatures J. A. Wallswork

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Some Facts about soil Soil is not dirt Soil is not inert Soil is dynamic Soil is a three dimensional body Soil is a three/four phase system

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Soil Profile VERTICLE SECTION OF THE SOIL BODY

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D Humus gives the topsoil a rich brown color Leaching takes minerals carried by water to the subsoil Topsoil Subsoil Weathered Bedrock Bedrock

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In the A horizon, water percolates downward and carries minerals as it goes. This is called “leaching.” Leaching carries minerals down into the lower soil horizons.

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The B-Horizon is called the subsoil. This horizon is where the leached minerals from horizon A end up. These leached minerals may color the subsoil. For example, the presence of iron my color the subsoil red. Horizon B-Zone of Accumulation of leached minerals

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The C-horizon is called the zone of weathered bedrock. When you have a residual soil, one formed over the original bedrock, the C-horizon resembles the bedrock, but it is weathered. In a residual soil, the bedrock is below the C-horizon. Remember that the Coastal Plain does not have bedrock under the soil profile, but it has layers of sand, clay and gravel. That is because of the sea level changes over time and the rivers that flowed over it.

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Red Soil Black Soil Alkali Soil Sandy soil S O I L S O F I N D I A

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Soil Taxonomy Entisols - soils with little or no morphological development Vertisols - clayey soils with high shrink/swell capacity Inceptisols - soils with weakly developed subsurface horizons Aridisols - CaCO3-containing soils of arid environments with moderate to strong development Mollisols - grassland soils with high base status Andisols - soils formed in volcanic ash Spodosols - acid soils with a subsurface accumulation of metal-humus complexes Alfisols - soils with a subsurface zone of silicate clay accumulation and >35% base saturation Ultisols - soils with a subsurface zone of silicate clay accumulation and <35% base saturation Oxisols - intensely weathered soils, tropical and subtropical Histosols - organic soils (peak, bog, muck) Gelisols - soils with permafrost within 2 m of the surface

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Soil health, provides an overall picture of the condition of many properties and processes; the terms soil health and soil quality can be used interchangeably. Soil health or quality is the soil's fitness to support crop growth without resulting in soil degradation or otherwise harming the environment. Soil quality changes slowly because of natural processes, such as weathering, and more rapidly under human activity; land use and farming practices may change soil quality for the better or for the worse Soil health deteriorates mainly through erosion by wind and water, loss of organic matter, breakdown of soil structure, salinization, and chemical contamination. Soil Health

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Assessing Soil Quality Human Health – Physical functions, Mental capacity, Emotional well – being Soil Quality – Physical, Chemical and Biological properties of the soil – Soil Texture, Structure, Water holding capacity, pH, EC, CEC, etc.

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Elements of soil quality Support Plant Growth – Soil Fertility vs Productivity Water storage and supply – Minimum surface runoff Environmental buffering – reduce toxicity of some elements

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Plant growth A good-quality soil is both tillable and fertile. provides a suitable medium for seed germination and root growth supplies a balance of nutrients to plants receives, stores, and releases moisture for plant use supports a community of microorganisms that recycle nutrients through decomposition and help plants to resist disease.

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Water regulation and partitioning Percolation – Entry Infiltration – Downward movement Seepage – Lateral movement Runoff – Overflow A good quality soil must reduce surface runoff, deep percolation and infiltration into groundwater and stores enough water to promote optimal crop growth.

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Environmental buffering Accept and hold nutrients and release them as required by plants Break down harmful compounds into substances that are nontoxic to plants and animals and do not pollute surface water and groundwater.

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Processes affecting soil health

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“Towards a Thematic strategy for Soil Protection” Main Threats to Soil Erosion Decline in organic matter Soil contamination Soil compaction Decline in soil biodiversity Salinization Floods and landslides

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SOIL EROSION Detachment Transportation Deposition (Foster, 1982)

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THE SOIL WATER EROSION PROCESS

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Soil Surface just before rain drop impact Soil Surface after Rain drop impact SPLASH EROSION

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WIND EROSION WIND CREEP SUSPENSION SALTATION SALTATION DETACHES PARTICLES SMALLER PARTICLES SUSPENDED LARGER PARTICLES CREEP SANDY AND SILTY SOILS MOST SUSCEPTIBLE SOIL ACCUMULATION IN DITCHES AND FENCE ROWS

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SOIL CONSERVATION STRATEGIES Cultivated land Agronomic measures Soil management Mechanical methods Mulching Crop management Conservation tillage Natural Synthetic Ridging Minimum tillage Terracing Structures High density planting Multiple cropping Cover cropping Morgan, 1986

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LOSS OF SOIL ORGANIC MATTER Soil Erosion Microbial Oxidation Intensive Cultivation Arid and Semi Arid Climate Lack of organic manure addition Removal of stocks and/or burning

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Deterioration of Soil Structure Soil Erosion – Break down of Soil Aggregates Physical Degradation – use of heavy implements Chemical Degradation - Irrigation with Poor Quality Waters Intensive Mono – crop Cultivation

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SOIL CONTAMINATION Indiscriminate use of Pesticides and Inorganic Fertilizers Accumulation of solid waste, is a major problem in developing countries like India where the garbage and refuse products are not degraded Radioactive substances from nuclear plants which are released into the soil and Indiscriminate discharge of industrial effluents on land And water bodies

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Consumption of pesticides in important states of India (Agnihotri,2000)

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Persistence of pesticides in soil

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Pesticide Residues

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Buyanovsky et al. (1990) Metal content of some rock phosphates (mg kg-1)

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Content of some heavy metals in imported rock phosphates (mg kg-1) FAO, 1975

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Cd concentrations in phosphate fertilizers (mg kg-1) Tiller, 1983

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Heavy metal contents (average) in fertilizers

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Industrial Effluents The Hindu, 1997

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Industrial units

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Industrial units

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Content of Toxic heavy metals (mg kg-1) in Punjab Source : Khurana et al. (2003)

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Heavy metal characterization in various industrial effluents S1- Sewage water ; S2 - Electroplating ; S3 - Textiles ; S4 - Dying ; S5 – Foundry Sewage EP Textiles Dye

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Range and mean values of the total heavy metal content of the soil collected from Erode

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Heavy metal content (mg kg-1) of soils treated with sewage and solid waste around Hyderabad Jeevan Rao and Shanta Ram(1999)

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TANNERY INDUSTRY WASTE India is the major exporter of processed leathers. Animal skins and hides are converted into non-biodegradable, stable and quality leathers through a process known as tanning. This process includes dehairing, removal of flesh and fat, and treatment with either plant extracts (vegetable tanning) or chemicals (chrome tanning). Several chemicals, including salts and heavy metals, are used in chemical tanning. Such process results in large quantities of solid waste (sludge). It is estimated that annually more than 1,24,400 tonnes (dry weight basis)of tannery sludge are produced from 1008 small and 75 large tanneries in India.

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STATUS OF TANNING INDUSTRIES IN INDIA It is estimated that tanning industry wastes have already contaminated over 50,000 ha of productive agricultural land. In chrome tanning, 276 chemicals and 14 heavy metals are used. It is estimated that approximately 32,000 t of basic chromium (cr) sulfate salts are used annually in Indian tanneries. This amounts to an annual loss of nearly 2000-3200 t of Cr (on an elemental basis). The concentration of Cr in the effluents from the chrome tanning yard is in the range 2000-5000 mg L-1. International regulations stipulate that the Cr concentration in industrial waste shall not exceed 2 mg L-1.

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Salt and heavy metal content of tannery sludge

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Accumulation of Cr in parts of sunflower grown on soil treated with tannery sludge bdl = below detectable limit *at harvest

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Heavy metal content (ppm) of the soil treated with different dilutions of tannery effluent Treatment Zn Cu Fe Mn Cr 100% effluent 2.2 1.2 5.4 6.2 0.17 50:50 effluent:water 2.3 1.3 5.8 0.6 0.15 33:67 effluent:water 2.2 1.3 5.6 7.2 0.12 25:75 effluent:water 2.2 1.3 5.6 6.6 0.99 20:80 effluent:water 2.4 1.4 5.4 8.8 0.12 10:90 effluent:water 2.5 1.4 6.8 8.8 0.10 Control(water alone) 2.6 1.6 7.2 10.0 0.02 (Singaram, 1995)

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DISTILLERY SPENT WASH More number of sugar factories in the country, more and more factories producing alcohol are being established. Molasses, containing 8 per cent of sugar, serves as a cheap source of raw material for the production of alcohol. Every Lit of alcohol, nearly 12 to 14 Lit of effluent is discharged. Each unit is discharging 5 to 10 lakh Lit of raw effluent every day. Sakthi Sugars Distillery Unit discharged 10 lakh Lit of effluent/ day. The primary treatment plant the BOD has been reduced from 45,000 to 4,500 ppm and COD from 1,00,000 to 35,000 ppm. These values are found to exceed the limits prescribed by PCB norms.

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SAGO FACTORY EFFLUENT Most of the sago factories in India are concentrated in Tamil Nadu. Out of 800 sago factories in Tamil Nadu, 650 are located in Salem district. A Sago factory with a capacity to produce 3,500 kg starch per day, uses 110 m3 to 115 m3 water per day. Of this, 95-100 m3 (nearly 87%) water comes out as waste water after processing. Because of the starch content in the waste water, the microbial activity is more in the stagnated waste water resulting in unpleasant odour (Balagobal et al., 1977).

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Sago factory effluent contains appreciable quantities of TSS and is acidic in nature with high EC. High amounts of P and K and moderate level of N with very low quantities of trace elements. Sago factory waste water irrigated soils have lower apparent and absolute specific gravity and water holding capacity and has slightly higher porosity than the corresponding control soil. Balagobal et al., 1977 SAGO FACTORY EFFLUENT (Continued)

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TEXTILE INDUSTRY EFFLUENT Processing such as boiling, bleaching, dyeing, sizing desiring mercerizing, printing and finishing which can let out copious quantities of waste waters and sludges which are usually dumped on river beds as well as on public areas. Accumulation of such waste material slowly create environmental degradation on soil ecosystem, ground water status and crop stand and its yield potentials. For Colouring the textile materials several dyes and colouring agents were used Textile mills require large quantity of high degree pure water and also they discharge high volume of wastewater. The land and water and the ecosystem located on the Cauvery river area and its tributaries Bhavani, Noyyal are adversely affected.

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Causes of Acid Rain The principal cause of acid rain is from human sources Industrial factories, power-generating plants and vehicles Sulphur dioxide and oxides of nitrogen are released during the fuel burning process (i.e. combustion) MSN Encarta

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Formation of Acid Rain

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05/15/10 Acid Deposition

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NITRATE POLLUTION OF GROUNDWATER Pollution of groundwater from fertilizer N is caused by leaching. The magnitude of loss depends upon soil conditions, agricultural practices, agro-climatic conditions, and type of fertilizers and methods of application. The time taken by nitrate to move from the root zone to the water table, therefore, varies considerably. In sandy soils with high water table and high rate of fertilizer application, it may reach the water table in matter of days whereas in heavy soils, low rainfall and low rate of application with deep water table, it may take years. Two main alleged health hazards are blue baby disease of young babies and cancer due to nitrate ingestion in food and water. World Health Organization (WHO) recommends that drinking water should not contain more than 50 mg NO3 – L-1.

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ENVIRONMENTAL PROBLEMS RELATED TO FERTILIZER USE, THEIR MITIGATION STRATEGIES AND IMPLICATIONS IN INDIA

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What we know about GW CO2 content of the air has increased from 280 to ~360 PPM since the industrial revolution. Average world temperatures have risen by around 0.5 centigrade in the last 100 years. The levels of CFCs, nitrous oxide and methane have also increased in the upper atmosphere. The ozone layer above the poles continues to thin. The world’s forested area has shrunk by more than 50% in 100 years. The last 20 years has been dominated by a series of record climatic highs. Sea levels have risen 1 foot in the last 100 years and alpine glaciers are shrinking/retreating rapidly.

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Anthropogenic greenhouse gases in the atmosphere. (Source: Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory.)

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Nutrient Mining in India (Fert. News, April 2001)

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Extent of Nutrient Deficiency (%)

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Nutrient Use Efficiency in India

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Soil Health care – Issues and Strategies

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Integrated Nutrient Management What is INM? Integrated use of all available resources – Fertilizers, Organic and Green Manures, Biofertilizers, Crop Residues, Agricultural and Industrial Wastes Why INM? To effectively utilize all the available resources and bridge the gap between the requirement and availability of fertilizers and thereby reduce the cost of cultivation

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Estimates of the availability of some crop residues in India and their plant nutrient potential

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Nutrient potential of harvest residues in Tamil Nadu

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Nutrient potential of urban and Agro-industrial wastes in Tamil Nadu

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Animal manure and its nutrient potential in Tamil Nadu

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Composting technologies available and developed at TNAU 1. Preparation of coirwaste compost using yeast sludge 2. Rapid composting technology for sugarcane trash using yeast sludge 3. Alternate method of sugarcane trash composting 4. Vermicomposting technique 5. Farm waste composting 6. Urban solid waste composting 7. Bio-compost from bagasse based pulp and paper mill

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UPON THIS SOIL OUR SUVIVAL DEPENDS HUSBAND IT AND DO NOT ABUSE IT WARNING PL……..