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1. UNIVERSITY OF HORTICULTURAL SCIENCE, BAG A LKOTE COLLEGE OF HORTICULTURE MUNIRABAD (KOPPAL) TOPIC : SOIL AND WATER QUALITY IN GREENHOUSE CULTIVATION Presentend by, Tathagath (5992) Monappa (5956) Nagraj.c (5958) Submitted to, LINGAMURTHY.K.R sir..

2. SOIL QUALITY Soil quality is The capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant productivity, maintain or enhance water and air quality. Soil quality refers to the condition of  soil  based on its capacity to perform  ecosystem services  that meet the needs of human   Soil quality is primarily measured by chemical, physical, and biological indicators because soil function cannot easily be measured directly. Each of these categories comprises several indicators that provide insight into overall soil quality .

3. Physical indicators include… Soil structure : Depth of soil Infiltration INDICATORS/ PARAMETERS : Physical indicators provide information about soil hydrologic characteristics, such as water entry and retention, that influences availability to plants. 1.PHYSICAL INDICATORS Soil with good structure has approximately 40-60% of its volume in pore space, or empty space between soil particles It is usually measured by the depth (in mm) of the water layer that can enter the soil in one hour

4. Bulk density Bulk density is an indicator of soil compaction. It is calculated as the dry weight of soil divided by its volume. Water holding capacity the volume of water retained by a saturated growing medium after it is allowed to drain . common recommendation has been that the substrate should have a water-holding capacity of 50% to 65%.

5. Chemical indicators can give you information about soil water and nutrients clay particles, organic matter, the nutritional requirements of plant and soil animal communities; and levels of soil contaminants and their availability for uptake by animals and plants. Indicators include Electrical Conductivity Soil Nitrate Soil Reaction (pH) 2. CHEMICAL INDICATORS

6. ELECTRICAL CONDUCTIVITY Soil electrical conductivity (EC) is a measure of the amount of salts in soil (salinity of soil). It is an important indicator of soil health. # EC is expressed in milliSiemens per meter ( mS /m) or in deciSiemens per meter ( dS /m) SOIL NITRATE measures the amount of available nitrogen in the soil that can be absorbed immediately by plants. The amount required in the soil for specific crops varies from crop to crop, but in general the levels should not fall below 10 mg/kg and should not exceed 50 mg/kg.

7. Electrical conductivity Ranges

8. # SOIL PH Soil pH is a measure of the acidity or alkalinity of the soil. The pH scale ranges from 0 to 14 ; a pH of 7 is considered neutral . If pH values are greater than 7, the solution is considered basic or alkaline; if they are below 7, the solution is acidic Many crops grow best if pH is close to neutral (pH 6 to 7.5)

9. Biological indicators can tell us about the organisms that form the soil food web that are responsible for decomposition of organic matter and nutrient cycling. Information about the numbers of organisms. Indicators include Particulate Organic Matter Potentially Mineralizable Nitrogen Respiration Soil Enzymes Total Organic Carbon & more... 3.BIOLOGICAL INDICATORS

10. PARTICULATE ORGANIC MATTER It is a source of food/energy for microorganisms and soil animals as well as nutrients for plant growth. Particulate organic matter enhances aggregate stability, water infiltration and soil aeration; it increases cation exchange capacity and buffering pH. Particulate organic matter (POM) fraction referred to in this document comprises all soil organic matter (SOM) particles less than 2 mm and greater than 0.053 mm in size  POM is biologically and chemically active and is part of the labile (easily decomposable) pool of soil organic matter (SOM

11. RESPIRATION Carbon dioxide (CO2) release from the soil surface is referred to as soil respiration. This CO2 results from several sources, including aerobic microbial decomposition of soil organic matter (SOM) to obtain energy for their growth and functioning (microbial respiration), plant root and faunal respiration, and eventually from the dissolution of carbonates in soil solution. Soil respiration reflects the capacity of soil to support soil life including crops, soil animals, and microorganisms. It describes the level of microbial activity, SOM content and its decomposition. 

12. SOIL ENZYMES Soil enzymes increase the reaction rate at which plant residues decompose and release plant available nutrients. The substance acted upon by a soil enzyme is called the substrate. Sources of soil enzymes include living and dead microbes, plant roots and residues, and soil animals. Enzymes stabilized in the soil matrix accumulate or form complexes with organic matter (humus), clay, and humus-clay Soil enzymes play an important role in organic matter decomposition and nutrient cycling.

13. Total organic carbon (TOC) is the carbon (C) stored in soil organic matter (SOM). Organic carbon (OC) enters the soil through the decomposition of plant and animal residues, root exudates, living and dead microorganisms Soil Organic Carbon (SOC) is the main source of energy for soil microorganisms.  # SOM contains approximately 58% C , There is more inorganic C than TOC in calcareous soils. TOC is expressed as percent C per 100 g of soil . TOTAL ORGANIC CARBON

14. WATER QUALITY There are many factors, which determine water quality. Among the most important are alkalinity, pH and soluble salts. But there are several other factors to consider, such as whether hard water salts such as calcium and magnesium or heavy metals that can clog irrigation systems High soluble salts can directly injure roots, interfering with water and nutrient uptake. Salts can accumulate in plant leaf margins Water with high alkalinity can adversely affect the pH of the growing medium Water quality plays a critical role in determining successful production of nursery and greenhouse crops , and should be considered in fertilization management and disease control

15. Irrigation Water Quality Indices: The parameters characterizing irrigation water quality can be divided into three categories: Physical : temperature, suspended solids (soil particles, impurities etc.) Chemical : gaseous substances, pH, soluble salts, hardness, sodium and chloride concentration etc. Biological : algae, bacteria, various micro-organisms

16. Chemical Quality Indices of irrigation water Water pH The total concentration of soluble salts The relative proportion of sodium to the other cations The carbonate and bicarbonate concentration The concentrations of specific elements and compounds

17. 1.Irrigation Water pH Potentiometric method- Using pH meter PH Class/category Interpretation <6 . 5 Acidic Can be used after treatment 6.5-7.5 Neutral Can be used safely The pH expresses the concentration of hydrogen ions in an aqueous solution. The pH regulates all biological functions and, if unsuitable, can inhibit certain vital processes. The minimum acceptable limit is 5.0 and at lower pH levels, the presence of free acids can cause direct damage to the root system of the crops. At high pH levels presence of salts increases soil pH and have detrimental effect on crop.

18. Irrigation Water Salinity Salinity indicates the total soluble salt present in water. Salinity is determined by measuring the ability of water to conduct an electrical current. The most common salts in irrigation water are: sodium (Na+) calcium (Ca++) magnesium (Mg++) iron (Fe++ or Fe+++) bicarbonate (HCO3-) carbonate (CO3-) sulphate (S04-) chloride (CI-)

19. Salinity class Electrical conductivity Total dissolved Low 0.25 <150 Medium 0.25-0.75 150-300 High 0.75-2.25 500-1500 Very high >2.25. >1500 Potential injury and necessary management for use as irrigation water Low salinity hazard: generally not a problem additional management is not needed. Damage to salt sensitive plants may occur. Occasional flushing with low salinity water may be necessary. Damage to plants with low tolerance to salinity will likely occur. Plant growth and quality will be improved with excess irrigation Damage to plants with high tolerance to salinity may occur. Successful use as an irrigation source requires Salts (ppm) ( dS /m)

20. 3.Irrigation Water Sodium Hazard Sodium Adsorption Ratio (SAR) The sodium adsorption ratio relates the concentration of Na to the concentration of Ca and Mg. The higher the Na in relation to Ca and Mg, the higher the SAR Problems with high SAR Destruction of soil structure- defloculation Poor infiltration of water. Poor aeration. High pH- poor nutrient availability Poor microbial activity Accumulation of dissolved carbon

21. Classification of irrigation water based on SAR SAR Sodicity classes Remarks <10 Low (S1) Little or no hazard 10-18 Medium(S2) Amendments (such as gypsum) and leaching needed 18-26 High(S3) Unsatisfactory for most of the crops >26 Very High(S4) Unsatisfactory for most of the crops High water SAR enhances ESP in soil ESP = Exchangeable sodium ( meq /100 grams). x 100 Cation exchange capacity ( meq /100 grams) An ESP>15% or a soil SAR>13 indicates that Na hazard on soil health

22. Carbonates in Irrigation Water Bicarbonate (HCO3) and to a lesser extent carbonate (CO3) are found in high pH water and are collectively referred to as carbonates. When water containing carbonates dries at the soil surface, Ca and Mg carbonates (lime) are formed. Since Ca and Mg are no longer dissolved, they do not counteract the negative effects of Na, and problems related to high Na may occur. Carbonates( meq /1) 1. 1.5 2. 1.5-8.5 3. >8.5 Potential Limitation Generally safe for irrigation Increasing problem Severe problem

23. Residual sodium carbonate (RSC) Assessment for poor water infiltration due to high carbonates and low Ca and Mg as determined by the RSC equation If water high in RSC is repeatedly used, the soil becomes alkaline and is likely to become sodic over time if the water also contains appreciable quantities of Na If irrigation RSC values are high but SAR values are low, insufficient Na is present to cause water infiltration problems. Classification of irrigation water based on RSC RSC Sodicity classes Remarks <1.25 Low (RSCI) Water can be used safely 1.25-2.5 Medium(RSC2) Water can be used with mangmt . >2.5 High(RSC3) Unsatisfactory for most of the crops

24. Management practices for irrigating with saline or sodic water Provide adequate internal drainage Leaching Excess Salts Maintain high water availability in the soil. Monitor salt and sodium with saline-alkaline soil tests Add soluble calcium such as gypsum (calcium sulphate ) to reduce the SAR to a safe value

25. Physical Quality Parameters of irrigation water Suspended Solids Very fine dispersion of clay, silicate and carbonate materials as a result of erosion. Different types of suspended matter disposed of in watercourses by various industries. Particulates contained in unpurified or partially purified municipal wastewater

26. Removal of suspended solids The particles many times smaller than the size of the water pathways in the emitter should be removed by the filtration system as in the process of time many particles can group together to block the water pathways. In general following five types of the filters are used in combination or standalone depending on the need. Screen filter Dise filter Media filter Hydrocyclone filter Settling ponds

27. Correcting water quality problems Desalination Water evaporation Freezing (direct freezing process) Use of salt-permeable membranes ( electrodialysis ) Use of ion exchange resins (ionic exchange) Use of semipermeable membranes (reverse osmosis) pH correction: Acidification Q=[HA] EW/(10x DX AC) where: Q is the quantity of acid (ml/ litre or litre /m³) necessary to obtain the desired pH EW the equivalent weight of the acid D the density (kg/ litre ) of the acid AC its concentration (% w/w) HA Concentration of acid required to neutralize carbonate

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