1. Soil health Physical indicators.pptx

Soil

1. SAC 202 Problematic Soils and their Management (2+0)

2. Soil health - Definition - Soil Quality Indices – Physical indicators Soil Quality Indices - Chemical and biological indicators Distribution of waste lands and problem soils in India and Tamil Nadu Categorization of waste lands based on properties Soil physical constraints – slow permeable, excessively permeable soils and fluffy paddy soils - Characteristics and management Soil crusting, soil compaction, sub soil hard pan, sand dunes and shallow soils – characteristics and management Eroded soil – Genesis, types and characteristics: water- sheet, rill, gully, ravines, wind – Aeolian, loess, saltation , suspension , soil creep, Universal soil loss equation and erosion control measures Flooded soils – Formation, characteristics and management Acid soil and acid sulphate soil – Genesis and characteristics. Lime requirement of acid soil, liming materials, reclamation and management of acid soil Formation and classification of Saline, Sodic and saline sodic soils Effects of Salts on soils- Physical: Clay swelling and Dispersion, permeability, Infiltration, Crust, Water transmission. Chemical: pH and EC. Biological : Microbial activity. Effects of Salts on plants – Plants response to saline and sodic conditions, Factors affecting salt tolerance, crop response to salinity, ratings of crop salt tolerance. Salts and plant mineral nutrition- Salinity and nutritional effects: Salinity and N, P, K, Ca, Mg, S, and Micronutrients. Alkalinity and nutritional effects. Saline, Sodic , saline sodic , and degraded alkali soils- characteristics and their management Saline soil-reclamation – Leaching requirement. Sodic soil – reclamation -gypsum requirement – calculations.

3. 17. Mid semester examination 18. Polluted soils- industrial effluent s- Characteristics, reclamation and management 19. Polluted soils- mine spoils- Characteristics, reclamation and management 20. Irrigation water – quality and standards - EC, SAR, RSC, RSBC SSP, PSI and PS 21. Irrigation water – quality and standards -USDA system and specific ion toxicity-USSL system 22. Factors affecting suitability of irrigation water and Management of poor quality water in agriculture 23. Remote sensing and GIS in assessment of wastelands and problem soils 24. Remote sensing and GIS in monitoring and management of wastelands and problem soils 25. Multipurpose tree species for waste lands and problem soils 26. Bio remediation through MPTs of soils 27. MPTs - Nutrient cycling under waste lands and problem soils 28. Land capability and classification 29. Land suitability classification 30. Problematic soils under different Agro ecosystems- coastal salinity, inland salinity 31. Problematic soils under different Agro ecosystems- marshy, swampy soils, red sand dunes ( Theri soils) Tsunami affected soils 32. Agricultural Ecosystem services- Soil fertility improvement in problem soils 33. Potential of agro forestry systems in management of problem soils 34. Carbon sequestration and its role in problem soil management

4. References Sehgal , J. 2005. Pedology concepts and applications, Kalyani Publishers, New Delhi Gupta, S.K. and I.C. Gupta 2014. Salt affected soils: Reclamation and Management. Scientific Publishers. Richards, L.A. 2012. Diagnosis and improvement of saline and alkali soils. Scientific Publishers. Soil Survey Staff. 2006 . Keys to Soil Taxonomy. United States Department of Agriculture, Natural Resources Conservation Service. Maliwal , G.L. and L.L. Somani . 2010. Nature, Properties and Management of saline and alkali soils. Agrotech publishing academy, Udaipur.

5. E-references ftp://ftp-fc.sc.egov.usda.gov/NSSC/NCSS/Conferences/scanned/ ftp://ftp-fc.sc.egov.usda.gov/NSSC/Lab References/SSIR 51.pdf ftp://ftp-fc.sc.egov.usda.gov/NSSC/Lab_References/SSIR 51 . pdf www.iuss.org/Bulletins/00000096.pdf www.oosa.unvienna.org/pdf/sap/centres/rscurrE.pdf- www.csre.iitb.ac.in/~dd/detail.html www.dvsinstitute.org/forms/pg/M.Sc.%20-%20RS%20&%20GIS-350.pdf inkinghub.elsevier.com/retrieve/ pii /S0166248197800335 www.scribd.com/doc/40246764/Description-Pedon-Copy- www.angrau.net/BSc(Aq)CourseCurriculum.htm www.euroiournals.com/ejsr 42 2 10.pdf www.springerlink.com/index/R177R744722222UN.pdf-Similar content.alterra.wur.nl/ lnternet / webdoc $/ ilri - publicaties /.../Bib10.pdf www-wds.worldbank.org/ external /.../INDEX/ multi_ .. page.txt-Cached openaccess.icrisat.org/.../Proceedings-integrated-watershed-management-for-land-Asia.pdf

6. Soil health Soil Quality Indices

7. 1.Physical indicators

8. The multiple roles of soils go often unnoticed Soils dont have a voice , & few people speak out for them They are our silent ally in food production Jose Graziano da Silva , FAO Director-General

9. Soil health , or quality , is the soils fitness to support crop growth without resulting in soil degradation or harming environment Ecological definition of soil quality

10. What is soil quality ? Soil quality is defined as the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant & animal productivity, maintain or enhance water , air quality, and support human health & habitation ( Karlen et al ., 1997 )

11. Inherent and Dynamic Qualities of Soil Soil has both inherent & dynamic qualities 1. Inherent soil quality is a soils natural ability to function Eg .,. Sandy soil drains faster than clayey soil . Deep soil has more room for roots than soils with bedrock near surface These characteristics do not change easily 2. Dynamic soil quality is how soil changes depending on how it is managed Management choices affect the amount of soil organic matter, soil structure , soil depth, and water and nutrient holding capacity Goal of soil quality research is to learn how to manage soil that improves soil function Soils respond differently to management depending on inherent properties of soil

12. Soil Health The soil health refers to self-regulation, stability, resilience, and lack of stress symptoms in a soil as a ecosystem Soil health describes the biological integrity of soil community - balance among organisms within a soil and between soil organisms and their environment

13. The terms soil quality & soil health are often used interchangeably Producers prefer soil health , which portrays soil as a living, dynamic organism that functions holistically rather than an inanimate mixture of sand, silt & clay , characterized on the basis of descriptive & qualitative properties Soil scientists prefer soil quality, which describes quantifiable soil physical, chemical & biological characteristics (Harris and Bezdicek , 1994)

14. Difference in simplest form Soil health is the status of soil , while soil quality is the service that a soil is providing towards plant growth

15. Soil health

16. Components of soil health Soil health is determined by several physical, chemical & biological i ndicators, as well as strong interaction among these components (i.e. bio-physical, bio-chemical & physico -chemical ), several soil health indicators can be used to evaluate soil health

17. Soil Quality Indicators Measures the functional state of soil Scientists use soil quality indicators to evaluate how soil functions, since soil function often cannot be directly measured Measuring soil quality is an exercise in identifying soil properties that are responsive to management, affect or correlate with environment and are capable of being precisely measured within certain technical and economic constraints

18. What are soil health indicators? Soil health indicators are key parameters that are specific to three distinct soil components ( physical, chemical & biological ) that together provide clues about how a soil is functioning These indicators should be easily measured, reproducible & sensitive enough to detect changes in soil function as a result of anthropogenic degradation Soil health indicators may be quantitative (e.g., infiltration rate is 25 mm/hr ) or qualitative/descriptive (e.g., drainage is fast )

19. Qualities of soil health indicators Correlate well with ecosystem processes Integrate soil physical, chemical, & biological properties & processes Be accessible to many users Be sensitive to management & climate Be a components of existing databases Be interpretable Applicable to field conditions Doran & Parkin (1996)

20. Components of soil quality Soil quality is a composite of individual capacity of a soil to perform three functions viz., Crop and animal productivity Environmental protection and safety Contribution to human and animal health Indicators of soil quality can be categorized into four general groups: v isual p hysical c hemical b iological  Soil quality attempts to integrate all the four indicators

21. 1. Visual indicators This may be from physical observation Exposure of subsoil , change in soil color , ephemeral gullies , ponding , runoff , plant response , weed species are few examples of potential visual indicators Visual evidence can be a clear indication that soil quality is threatened   2. Physical indicators It is related to arrangement of solid particles and soil pores Examples include topsoil depth, bulk density, porosity, aggregate stability, texture, crusting, and compaction Physical indicators primarily reflect limitations to root growth, seedling emergence, infiltration, or movement of water within soil

22. 3. Chemical indicators It include soil pH, salinity, organic matter, phosphorus concentrations, cation -exchange capacity, nutrient cycling, and concentrations of elements that may be potential contaminants (heavy metals, radioactive compounds, etc.) The soils chemical condition affects soil-plant relations , water quality, buffering capacities, availability of nutrients and water to plants and other organisms, mobility of contaminants 4. Biological indicators It includes measurements of micro and macro-organisms , their activity, or byproducts Earthworm, nematode, or termite populations have been suggested in some parts of country Respiration rate can be used to detect microbial activity, specifically microbial decomposition of organic matter in soil Ergosterol , a fungal byproduct, has been used to measure the activity of organisms that play an important role in the formation and stability of soil aggregates

23. Why to assess soil health ? Soils vary naturally in their capacity to function ; therefore, soil health is specific to each soil type Soil health is primarily evaluated to measure the effects of management practices on soil function with objective to improve or maintain soil health The maintenance of good soil health is vital for environmental & economic sustainability of agricultural activities A decline in soil health has a marked impact on plant growth, yield, grain quality, production costs etc.,

24. Physical indicators provide information about soil hydrological characteristics , such as water entry & retention , that influences water availability to plants Some indicators are related to nutrient availability by their influence on rooting volume & aeration status 1 . Physical indicators of soil quality

25. Physical indicators of soil quality Aggregate stability Available water capacity Bulk density Infiltration Slaking Soil crusts Soil structure & macro pores

26. Measures the ability of soil aggregates to resist disintegration, when immersed & shaken in water Aggregate stability is an indicator of how well water can infiltrate into soil during rainfall or irrigation & how easily soil is washed off or blown away due to erosion 1. Aggregate Stability

27. Soil aggregates are groups of soil particles that bind to each other more strongly Wet aggregate stability suggests how well a soil can resist impact of raindrop & water erosion, while dry aggregates can be used to predict resistance to abrasion & wind erosion

28. Why it is important ? Changes in aggregate stability may serve as early indicators of recovery or degradation of soils Aggregate stability is an indicator of organic matter content, biological activity, & nutrient cycling in soil Microbial decomposition of fresh organic matter releases products that bind small aggregates into large aggregates (> 2-5 mm ) These large aggregates are more sensitive to management, serving as a better indicator of changes in soil quality Greater amounts of stable aggregates suggest better soil quality, when the proportion of large to small aggregates increases , soil quality increases

29. 2. Available Water Capacity Available water capacity is the maximum amount of plant available water a soil can provide/ hold It is an indicator of a soils ability to retain water & make it available for plant use Available water capacity is the water held in soil between its field capacity & permanent wilting point Field capacity is the water remaining in a soil after it has been thoroughly saturated & allowed to drain freely , usually for one to two days Permanent wilting point is the moisture content of a soil at which plants wilt & fail to recover when supplied with sufficient moisture

30. Why it is important? Water availability is an important indicator , because plant growth & soil biological activity depend on water for hydration & delivery of nutrients in solution Runoff & leaching volumes are determined by storage capacity & pore size distribution

31. Conservation practices Crop rotation Cover crop Prescribed grazing Residue & tillage management Salinity & Sodicity Soil management

32. 3.Bulk Density Bulk density is an indicator of soil compaction It is calculated as the dry weight of soil divided by its volume Bulk density is typically expressed in g/cm 3 Bulk density is an indicator how well seedlings can emerge & how well air can circulate through soil Why it is important? Bulk density reflects the soils ability to function for structural support, water & solute movement, soil aeration

33. General relationship of soil bulk density to root growth based on soil texture Soil Texture Ideal bulk densities for plant growth ( g/cm 3 ) Bulk densities that restrict root growth ( g/cm 3 ) 1. Sandy < 1.60 > 1.80 2. Silty < 1.40 > 1.65 2. Clayey < 1.10 > 1.47

34. The practices which lead to poor soil bulk density Consistently plowing or disking to same soil depth Allowing equipment traffic , especially on wet soil Adopting limited crop rotation without variability in root structure or rooting depth Burning, or removing crop residues Overgrazing forage plants, & allowing development of livestock lie around Using heavy equipments

35. 4. Infiltration Infiltration is the downward entry of water into soil The velocity at which water enters the soil is infiltration rate Infiltration rate is typically expressed in inches per hour Water from rainfall or irrigation must enter the soil

36. Why it is important? Infiltration is an indicator of soils ability to allow water movement into & through soil profile Soil temporarily stores water , making it available for root uptake, plant growth & soil organisms When water is supplied at a rate that exceeds soils infiltration capacity, it moves downslope as runoff on sloping land When runoff occurs on bare or poorly vegetated soil, erosion takes place Runoff carries nutrients, chemicals, & soil with it, resulting in decreased soil productivity, off-site sedimentation & diminished water quality Sedimentation decreases storage capacity of reservoirs

37. Conservation practices Crop Rotation Cover Crop Prescribed Grazing Residue & Tillage Management Waste Utilization

38. 5. Slaking Slaking is the breakdown of large soil aggregates (>2-5 mm ) into smaller microaggregates (<0.25 mm ), when they are immersed in water Slaking occurs when aggregates are not strong enough to withstand internal stresses caused by rapid water intake Both poor aggregate stability & slaking result in detached soil particles that settle into pores, & cause surface sealing, reduced infiltration & plant available water, & increased runoff & erosion

39. Why it is important? Slaking indicates stability of soil aggregates, resistance to erosion & suggests how well soil can maintain its structure to provide water & air for plants & soil biota

40. Conservation practices Crop rotation Cover crops Prescribed grazing Residue & tillage management

41. 6. Soil Crusts Structural soil crusts are relatively thin, dense, somewhat continuous layers of non-aggregated soil particles on tilled & exposed soils Structural crusts develop, when a s ealed-over soil surface dries out after rainfall or irrigation Water droplets striking soil aggregates & water flowing across soil breaks aggregates into individual soil particles Fine soil particles wash, settle into & block surface pores causing soil surface to seal over & preventing water entry into soil Structural crusts range from a few mm thick to two inches A surface crust is much more compact, hard & brittle when dry

42. Why it is important? A surface crust indicates poor infiltration, a problematic seedbed, & reduced air exchange between soil & atmosphere It can also indicate that a soil has a high sodium content that increases soil dispersion when it is wetted As they are hard & relatively difficult to break, crusts restrict seedling emergence Crusts can also reduce oxygen diffusion into soil profile Crust development soon after a crop is planted can result in such poor emergence Surface sealing & crusts greatly reduce infiltration, & increase runoff & erosion

43. Conservation practices Crop Rotation Cover Crop Residue and Tillage Management Salinity & Sodic Soil Management

44. 7. Soil Structure & Macro pores Sand, silt & clay particles are primary mineral building blocks of soil Soil structure is the combination or arrangement of primary soil particles into aggregates Soil structure affects water & air movement through soil Soil pores exist between & within aggregates & are occupied by water & air Macropores are large soil pores, usually between aggregates, that are generally > 0.08 mm in diameter Macropores drain freely by gravity & allow easy movement of water & air They provide habitat for soil organisms & plant roots can grow into them With diameters <0.08 mm , micropores are small soil pores usually found within structural aggregates Suction is required to remove water from micropores

45. Why it is important? Important soil functions related to soil structure are, sustaining biological productivity, regulating & partitioning water & solute flow, cycling & storing nutrients Soil structure & macropores are vital that influence water & air exchange , plant root exploration & habitat for soil organisms Granular structure is typically associated with surface soils, particularly those with high organic matter Granular structure is characterized by loosely packed, crumbly soil aggregates & an interconnected network of macropores that allow rapid infiltration & promote biological productivity Platy structure is often indicative of compaction Crumbly structure of surface soil is associated with adequate organic matter

46. Practices that lead to poor soil structure Disturbance that exposes soil to adverse effects ie ., drying, raindrop and rill erosion, & wind erosion Conventional tillage & soil disturbance that accelerates organic matter decomposition Residue harvest, burning or other removal methods that prevent accumulation of soil organic matter Overgrazing that weakens range & forage plants & leads to declining root systems, poor growth & bare soil Equipment or livestock traffic on wet soils Production & irrigation methods that lead to salt or sodium accumulation in surface soil s

47. What you can do? Practices that provide soil cover, protect or result in accumulation of organic matter, maintain healthy plants, & avoid compaction improve soil structure & increase macro pores Practices for greater occurrence of macro pores Cover Crop Crop Rotation Irrigation Water Management Prescribed Grazing Residue & Tillage Management Salinity & Sodic Soil Management

48. thanks