CHAPTER V DEVELOPMENT OF LAND SUITABILITY MODEL FOR IRRIGATION MANAGEMENT

Transcription

1 97 CHAPTER V DEVELOPMENT OF LAND SUITABILITY MODEL FOR IRRIGATION MANAGEMENT 5.1 GENERAL Soil is a component of the lithosphere and biosphere system. It is a vital natural resource on whose proper use depends on the supporting life systems and socio economic development. The constraint increasing crisis of land degradation was mainly related to increasing population pressure. The per capita cultivable land has been declined from 0.32 ha through 0.14 to less than 0.1 ha (by 2020). The challenge is thus being faced not only of increasing productivity on sustainable basis, but also of the preserving and maintaining of soil resource basis for the posterity. The ability of the land to produce is limited and the limits to produce are set by soils, climate and landforms conditions. However, the capacity of soil to produce is limited and the limits to production are set by intrinsic characteristics, agro ecological settings, use and management, despite the significant growth in production The sustainability of some cropping systems have been showing signs of failure over a period of time Therefore comprehensive account of our land resource ascertaining its potential and problems towards optimizing land use on Sustainable basis is necessary and in the present context, it is one of fundamental pathway for sustainable land use. Soil characterization determines the soils individual inherent potentials and constraints for crop production besides giving detailed

2 98 information about the different soil properties. Characterization and systematic classification of dominant soil groups, is an essential tool and a pre requisite for soil fertility evaluation and efficient soilfertilizer-water management practices and, thus, crop management. Soil site suitability studies provide information on the choice of crops to be grown on best suited soil unit for maximizing crop production per unit of land, labour and inputs. For planning and effective utilization of soil resources, the information relating to soil site and characteristic for cultivation of crops is necessary. Each plant species require specific soil-site condition for its optimum growth. For rationalizing land use, the soil site suitability for different crops needs to be determined. These suitability models provide guidelines to decide the policy of growing most suitable crops depending on the capacities of each soil unit (Sehgal, 1986). It has become imperative that the land resources need to be intensified in terms of their suitability for different agricultural uses with a view to maximize production of food, fuel and fiber. The soil and land resource inventory at regional and state level are providing a basis for blanket recommendation of various package of practice including fertilizer as other inputs. The inherent diversity in soils and the adopted practices with intensive apply, the soils are evidently expressing numerous, complex problems, which are identified at different stages. Further, it is becoming difficult to provide solution at later stages. The multi pronged problems of intensive cropping are very diversified in nature and manifesting

3 99 physically, chemically, biologically and ultimately nutritionally, the blanket recommendations are not providing a suite of solutions. Essential soil and land resources of Nagargunasagar command area of prakasam district are diversified in nature and characteristics in supplying nutrients and providing necessary anchorage for the crop growth and development. There are number of variations in growth and disparities in the packages adopted by farmers. Vary little attention was paid to study of the soils of this area of Prakasam district. Most of the studies conducted earlier were only broad based and were conducted as a part of their study of soils of country or state. So, it is essential to understand the land suitability for irrigation of Nagargunasagar command area of prakasam district. This land suitability model is developed by the fallowing step-by-step procedure. Collection of water and soil samples Analysis of collected samples Generation of spatial distribution maps Physical, chemical analysis Correlation between soil parameters and water parameters. Development of land capability classification Development of Soil-site characteristics for land evaluation

4 ENVIRONMENTAL PARAMETERS The water samples were analyzed following the procedures of standard methods of water analysis. The following parameters were studied for water quality. Soil and Water Quality Parameters Studied: General - ph, EC, TDS, THS, Cations - Ca, Mg, Na, K Anions HCO3, Cl Ratios - SAR, RSC, Mg/Ca and Na/Cl 5.3 FIELD DATA COLLECTION At the pre-fieldwork stage a sampling design was formulated to cover all categories of various physical units like landuse activities, soil units, geomorphoic units etc., within each section, a stratified random plan was adopted based on patterns on satellite image. To study the environmental parameters of the study area field survey was carried out during Febuary 2007, apart from ground truth checking for the thematic maps. Soil and Groundwater samples were collected as per the strategy planned. The location information was collected using Garmin GPS (Global Positioning Sytem) Distribution of Soil and Water Samples The Detail of soil sampling sites are shown in table 5.1, The soil sample data was shown in table 5.2. The water sample data are shown in table 5.3.

5 101 Table 5.1: Details of soil sampling sites. Sl. Mandal Area Village Name of the farmer No (Sq.Kms.) 1 N.G.Padu 62,755 Kanaparthi U. Narasa Reddy» V.R.Palem V. Pitchi Reddy» N.G.Padu M. Ramanjaneyulu 2 Addanki 63,650 Gopalapuram D. Peddanna» Addanki S. Veera Reddy " Chakraya Palem P. Anjaiah» Uppalapadu B. Ratna Reddy 3 Korisapadu 36,976 Korisapadu K. Viswanatha Reddy» Pamidipadu B. Vijaya Bhaskar 4 J.Panguluru 41,616 Panguluru K. Samba Reddy Muppavaram T. Krishna Murthy 5 Ballikurava 54,900 Kopparapalem P. Venkateswarlu Namalapalfi 6 Santamaguluru 51,599 Santamaguluru V. David M. Koteswara Rao n Putta Vari Palem B. Deva Raju 7 Martur 44,860 Nagaraju Palli K. Lakshmaiah Dronadala P. Venkateswarlu " Kolala Pudi K. Swarneswara Rao» Martur K. Venkaiah 8 Yeddanapudi 26,119 Jagarlamudi R. Potu Raju " Yeddanapudi K. Chennakesava Rao 9 Chirala 24,762 Chirala J. Srinu» Epurupalem G. Subba Rao 10 Vetapalem 22,030 Papaipalem D. Yelamanda» Vetapalem P. Pitchaiah» Vadarevu K. Yesebu 11 Chinaganjam 42,472 Chinaganjam G. Lakshmi Narayana» Kadavakuduru R. Veera Swamy " Pedaganjam T. Venkat Rao 12 Parchuru 55,136 Nuthalapadu U. Venkateswarlu " Parchuru K. Abraham 13 Inkollu 35,550 Inkollu M. Potu Raju» Nagandla L. Brahmaiah» Pusapadu K. Subbaiah 14 Karamchedu 40,071 Karamchedu P. Raghavayya» Swarna K. Anjaneyulu

6 102 Table 5.2: Showing with Soil Sample Location (SSL) with Long-Lat collected using GPS. S. SAMPLE MANDAL NAME S VILLAGE NAME S LONGITUDE LATITUDE NO CODE S 01 SSL1 N.G Padu Kotha kota E N SSL2 Ammanabrolu E N SSL3 Matticunta E N 02 SSL4 Addanki Kotikalapadu E N SSL5 Kasyapuram E N SSL6 Uppalapadu E N SSL7 Klavakuru E N 03 SSL8 Korisapadu Bodduvari Palem E N SSL9 Ravinuthala E N 04 SSL10 J.Panguluru J.panguluru E N SSL11 Kondamanjulur E N 05 SSL12 Ballikaruva Vaidana E N SSL13 Konidena E N 06 SSL14 S.Manguluru Koppera Palem E N SSL15 Kamepalli E N 07 SSL16 Martur Kolalpudi E N SSL17 Konanki E N SSL18 Nagarajapalli E N SSL19 Bobbepalli E N 08 SSL20 Yeddanapudi Jagarlamadi E N SSL21 Yeddanapudi E N 09 SSL22 Chirala Chirala (Rural) E N SSL23 Egavinivaripalem E N 10 SSL24 Vetapalem Kathapeta E N SSL25 Nayanipalle E N SSL26 Pullari Palem E N 11 SSL27 Chinnaganjam Chinnaganjam E N SSL28 Pedaganjam E N SSL29 Kadavakuduru E N 12 SSL30 Parchur Inagallu E N SSL31 Bodawadamandagutta E N 13 SSL32 Inkollu Inkollu E N SSL33 Pusapadu E N SSL34 Duddukur E N 14 SSL35 Karamchedu Karamchedu E N SSL36 Daggubadu E N

7 103 Table 5.3: Showing with Water Sample Location (WSL) with Long-Lat collected using GPS. S.NO SAMPLE MANDAL VILLAGE NAME LONGITUDE LATITUDE CODE S NAME 01 WSL1 N.G Padu Naguluppalpadu E N WSL2 Kothakota E N WSL3 H.Nidamanur E N WSL4 Pothavaram E N WSL5 Chadalavada E N WSL6 Uppugundur E N WSL7 Machavaram E N WSL8 Raparla E N WSL9 Kanuparthi E N WSL10 Ammanabrolu E N WSL11 Cheervanuppalapadu E N WSL12 Chekurapadu E N 02 WSL13 Addanki Addanki E N WSL14 Uppalapadu E N WSL15 Vemparala E N WSL16 Chinakothapalli E N WSL17 Dharmavaram E N WSL18 Kalvakuru E N WSL19 Manikeshwaram E N WSL20 Dheruvakonda E N WSL21 Kotikalapudi E N WSL22 Ramayapalem E N 03 WSL23 Korisapadu Bodduvaripalem E N WSL24 Kasripodu E N WSL25 Ravinuthala E N WSL26 Pamidipadu E N WSL27 Rachapudi E N WSL28 Prasangulapadu E N WSL29 Dyvalaravuru E N 04 WSL30 J.panguluru Janakavampanguluru E N WSL31 Ramkur E N WSL32 Kondamanjulur E N WSL33 Budavada E N WSL34 Chandalur E N WSL35 Alavalapadu E N WSL36 Kondamur E N 05 WSL37 Ballikurava Ballikurava E N

8 104 WSL38 Uppamangalur E N WSL39 Konidena E N WSL40 Mukteshwaram E N WSL41 Vaidana E N WSL42 Gorrepadu E N WSL43 Sankaralingam gudipadu E N 06 WSL44 Santamangaluru Santamangaluru E N WSL45 Komepalli E N WSL46 Gopapura E N WSL47 Elchur E N WSL48 Tangedumalli E N WSL49 Kopparam E N WSL50 Kunduru(East) E N WSL51 Kunduru(West) E N 07 WSL52 Martur Martur E N WSL53 Rajupalem E N WSL54 Nagarajupally E N WSL55 Bobbepally E N WSL56 Dronadula E N WSL57 Kolalapudi E N WSL58 Konanki E N WSL59 Valaparla E N 08 WSL60 Yeddanapudi Yeddanapudi E N WSL61 Ananthavaram E N WSL62 Yanamadala E N WSL63 Poluru E N WSL64 Jagarlamudi E N WSL65 Punuru E N WSL66 Gannavaram E N 09 WSL67 Chirala Chirala(Rural) E N WSL68 Chirala(M) E N WSL69 Wada E N WSL70 Epurupalem E N WSL71 Egavinivaripalem E N 10 WSL72 Vetapalem Vetapalem E N WSL73 Kothapet E N WSL74 Nayanipalle E N WSL75 Pullaripalem E N WSL76 Padillapalli E N 11 WSL77 Chinaganjam Chinaganjam E N WSL78 Kadavakuduru E N WSL79 Pedaganjam E N

9 105 WSL80 Santharavur E N 12 WSL81 Parchur Inagallu E N WSL82 Garnepudi E N WSL83 Ramayanapalem E N WSL84 Cherukuru E N WSL85 Veerannapalem E N WSL86 Upputur E N WSL87 Bodawadamandagunta E N WSL89 Parchur E N WSL90 Nuthalapadu E N 13 WSL91 Inkollu Inkollu E N WSL92 Pusapadu E N WSL93 Idupulupadu E N WSL94 Nagandla E N WSL95 Pavullur E N WSL96 Koniki E N WSL97 Duddukur E N 14 WSL98 Karamchedu Karamchedu E n WSL99 Daggubadu E N WSL100 Kodavalivaripalem E N WSL101 Swarna E N WSL102 Audipudi E N WSL103 Kunkalamarru E N

10 106 Fig 5.1: showing soil sample location of study area Fig 5.2: showing water sample location of study area Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

11 107 The soil and water analysis results obtained from the present investigation for part of Nagarjunasagar command area of prakasam district have been discussed under the following headings and sub-headings. Physical, chemical and physico-chemical characteristics of the soil samples. Quality of ground waters of Ongole division Correlation between soil parameters and water parameters. 5.4 PHYSICAL, CHEMICAL AND PHYSICO - CHEMICAL HARACTERISTICS OF THE SOIL SAMPLES Soil Reaction (ph) The degree of acidity or alkalinity in soils, also known as soil reaction, is determined by the hydrogen ion (H+) concentration in the soil solution.an acid soil has more H+ than OH- ions,where as a basic or alkaline soil contains more OH- than H+ ions. To characterize these conditions, the term soil ph is used. And is defined as ph= -log (H+) Out of 36 surface soils tested, about fourteen percent of samples were neutral, thirty percent of samples were mildly alkaline and fourty six percent samples were moderately alkaline in their soil reaction as per the prescribed ratings. On the whole, the soils of part of Nagarjunasagar command area are moderately alkaline (mean 8.43) in soil reaction. Mildly or moderately alkaline soil reaction

12 ph 108 could be maintained despite the heavy use of acid producing nitrogenous fertilizers particularly urea, because of presence of free calcium carbonate in these soils which could be neutralising. In the sub-surface samples out of 36 samples, about 56 per cent of samples were moderately alkaline, 20 per cent samples were mildly alkaline. Overall the ph of sub-surface samples was more compared the surface samples. Fig 5.3 graph showing ph or surface and subsurface soils, Table 5.4 shows ph content of soils. Ranges of ph: ph less than 4 strongly acid 4 to 5 Moderately acid 5 to 6 Slightly acid 6 to 8 Neutral 8 to 9 Slightly alkaline 9 to 10 Moderately alkaline Greater than 10 Strongly alkaline Fig 5.3: Graph showing ph of Surface & Subsurface soils 8.6 SURFACE SUBSURFACE N.G.Padu Addanki Korisapadu J.Panguluru BallikuravaSantamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu -- Mandals

13 109 Table 5.4: ph content of soils of study area No. of S.No Mandal samples SURFACE SUB-SURFACE ph Slightly Normal Mildly Moderately Strongly ph Normal Mildly Moderatel Strongly acidic alkaline alkaline alkaline alkaline y alkaline alkaline Range Mean No. No. No. No. No. Range Mean No. No. No. No. 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu Average

14 110 Plate: 5.1 spatial distribution maps for ph for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

15 EC Electrical Conductivity (ds/m) Electrical conductivity cell should be kept in distilled H 2 O and adjust the reading to 1000 in press mode by adjusting the calibrate mode. By using 0.01N kcl solution adjust the reading to 1413 micro siemens in release mode. Sample conductivity was read by at 250 c in release mode. Electrical conductivity of surface soils ranged from 0.26 to 1.02 ds/m with a mean value of 0.64 ds/m. All the soil samples tested were normal in their soluble salt content i.e., < 2 µmhos ds/m 1 as per the ratings for clay loam soils. The electrical conductivity of the soils indicated that the soils in the study area were found to be well drained and / or water used for irrigation might be free from soluble salts. In sub-surface samples the range of electrical conductivity was 0.21 to 0.94 ds/m with a mean of 0.56 ds/m. It indicates that subsurface soils are less in soluble salt content compared to surface soils. Fig 5.4 and Table 5.5 shows EC of soils Fig 5.4: Graph showing EC of Surface & Subsurface soils SURFACE SUBSURFACE N.G.Padu Addanki Korisapadu J.Panguluru BailikuravaSantamaguiurL Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu -- Mandals

16 112 Table 5.5: EC (ds/m) content of soils of study area S. No. MANDAL No. of samples EC SURFACE Low Medium saline saline High saline Very high saline Range Mean No. No. No. No. Range Mean No. No. No. No. EC Low saline Medium saline SUB-SURFACE High saline Very high saline 1 N.G.Padu N.G.Padu ,85 0, Addanki , Korisapadu J.Panguluru Bailikurava Addanki , , Santamaguluru Korisapadu , Martur J.Panguluru Yaddanapudi Bailikurava , Chirala SantamaguiurL , _ Martur 10 Vetapalem Yeddanapudi 11 Chinaganjam _ Chirala 12 Parchur _ Vetapalem 13 Inkollu Chinaganjam 14 Karamchedu _ Parchur Average Inkollu

17 113 Plate: 5.2 spatial distribution maps of Electrical Conductivity for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

18 caco Calcium Carbonate (%) Soils in desert climates may be high in Ca, often containing Ca as CaCO3 nodules. Calcium carbonate is insoluble in water, but will dissolve in water containing Co2, a process called carbonation,which is a weathering process.in surface soils the calcium carbonate content ranges from 4.9 to 8.9 percent with a mean of 6.53 percent. In subsurface soils the calcium carbonate content ranges from 5.3 to 8.89 with a mean of 6.64 percent, sub-surface soils were more calcareous than surface soils. 52 percent of surface and 56 percent of sub-surface soils were strongly calcareous and 48 percent of surface, 44 percent of sub-surface soils were weakly calcareous. High calcium carbonate content of these soils may exert a profound influence on the fixation, retention and adsorption of plant nutrients by these soils. Fig 5.5 and 5.6 shows calcium carbonate of soils in study area Fig 5.5: Graph showing Calcium Carbonate of Surface & Subsurface soils % SURFACE % SUBSURFACE N.G.Padu Addanki Korisapadu J.Panguturu BallikuravaSantamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu -- Mandals

19 115 Table 5.6: Calcium carbonate content (%) of soils S. No. Mandal No. of samples SURFACE SUB-SURFACE Calcium carbonate Weakly calcareousss Strongly calcareous Calcium carbonate Weakly calcareous Strongly calcareous Range Mean No. No. Range Mean No. No. 1 N.G.Padu Addanki Korisapadu J.Panguturu Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu Average

20 116 Plate: 5.3 spatial distribution maps of Calcium Carbonate for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

21 organiccarbon Organic Carbon {%) Air drying will not affect total carbon analysis, but oven drying may cause some Carbon to be lost due to oxidation of organic matter. In microbial studies, drying at elevated temperatures may also cause destruction of a number of micro organisms. Organic carbon content of the surface soil samples ranged from 0.26 to 0.62 percent with a mean value of 0.44 percent. For sub-surface soils the organic carbon ranges from 0.21 to 0.47 percent with a mean of 0.34 percent. Chimakurthy mandal recorded the highest (mean 0.7 7%) and Tangutur mandal recorded lowest (0.21%) organic carbon contents in the surface samples. Among subsurface samples, highest and lowest organic carbon content was found in Karamchedu mandal (0.71%) and Vetapalem mandal (0.09%) respectively. The low organic carbon content of these soils could be due to compost in lesser quantities. Fig 5.6 and Table 5.7 shows the organic carbon content of soils in study area 0.8 SURFACE SUBSURFACE N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu -- Mandals Fig 5.6: Graph showing Organic Carbon of Surface & subsurface soils

22 118 Table 5.7: Organic carbon content (%) of soils S. No. Mandal No. of samples SURFACE SUB-SURFACE Organic Carbon Low Medium High Organic Carbon Low Medium High Range Mean No. No. No. Range Mean No. No. No. 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu Average

23 119 Plate: 5.4 spatial distribution maps of Calcium Carbonate for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

24 Available potassium As is the case with phosphorus the total K content does not reflect its availability to plants, and much efforts have been spent for developing the so- called K-availability indices. Potassium ions are normally very stable ions, and very difficult to precipitate. Therefore when they are not used by plants, they tend to be leached rapidly from the soil. Only by complex formation or cation exchange can they be retained or immobilized in soils Seventy two percent of surface and sixty per cent of sub-surface soils under study recorded high potassium status, 20% surface and 26% subsurface soils recorded medium potassium status, while remaining 8% of surface and 14% of subsurface soils recorded low. The high available potassium in these soils could be due to greater potassium retention on the exchange complex by the high CEC clays on organic colloids. The higher potassium content of loamy or clayey soils might be attributed to the presence of potassium bearing minerals in heavy textured soils. The present investigation was in accordance with earlier reports. The low and medium available potassium content was due to light coarse texture (sandy, loamy sand and sandy loam) of these soils, which can retain less potassium in external position and also because of low CEC. Fig 5.7 and Table 5.8 shows the available potassium of soils of study area.

25 Potassium 121 Fig 5.7: Graph showing Available potassium of Surface & subsurface soils 1400 SURFACE SUBSURFACE N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parch ur Inkollu Karamchedu -- Mandals

26 122 Table 5.8: Available Potassium content (Kg K20 ha -1 ) of soils S. No. Mandal No. of samples SURFACE SUB-SURFACE Potassium Low Medium High Potassium Low Medium High Range Mean No. No. No. Range Mean No. No. No. 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi _ 2 9 Chirala Vetapalem Chinaganjam Parch ur Inkollu Karamchedu Average

27 123 Plate: 5.5 spatial distribution maps of Available Potassium for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

28 Cations Cation Exchange Capacity and Exchangeable cations The cation exchange capacity of soils under study ranged from to 49.6 with a mean value of c mol (p + ) kg- 1 soil. The highest value of cation exchange capacity was recorded in the soils of Parchur mandal (mean 74 c mol (p + ) kg- 1 soil), while the least value of the same was observed in sols of Kothapatnam mandal (mean 17.9 c mol (p + ) kg- 1 soil). High CEC of soils of Ongole division might be due to the montmorillonite type of clays, which are having high cation exchange capacity. The results further revealed that Ca- 1 was the most dominant cation on the exchange complex, ranging from 37.2 to 54.8 c, mol (p + ) kg- 1 soil with a mean value of c mol (p + ) kg- 1 soil followed by Mg, Na and K. High values of exchangeable calcium and low values of Mg 2+, Na + and K + might be due to high calcium carbonate content in these soils and lesser leaching losses of calcium salts on account of lesser solubility of calcium salts than those of magnesium, sodium and potassium salts. Fig 5.8 and Table 5.9 shows cation exchange of soils of study area. 80 Ca Mg Na k CEC ESp N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu -- Mandals Fig 5.8: Graph showing cation exchange capacity and exchangeable cations in study area

29 125 S. No. Mandal No. of samples Exchangeable CEC ESP Exchangeable Exchangeable Exchangeable Mg Ca Na K Range Mean Range Mean Range Mean Range Mean Range Mean Range Mean 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala " , , Vetapalem , Chinaganjam Parchur Inkollu Karamchedu Average , Table 5.9: Cation Exchangeable of soils

30 126

31 127 Plate: 5.6 spatial distribution maps of Cation Exchange Capacity and Exchangeable cations in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

32 128 Table 5.10: Mechanical composition of soils S. No. Mandal No. of samples % Sand % Silt % Clay Range Mean Range Mean Range Mean Texturare class 1 N.G.Padu SCL 2 Addanki CL 3 Korisapadu CL 4 J.Panguluru CL 5 Ballikurava SCL 6 Santamaguluru SCL 7 Martur SC 8 Yeddanapudi CL 9 Chirala LS 10 Vetapalem S 11 Chinaganjam SCL 12 Parchur CL 13 Inkollu CL 14 Karamchedu CL Average

33 Mechanical Composition The soil is a mixture of mineral matter, organic matter, water and air. The mineral matter is composed of inorganic particles varying in size from stone and gravel to powder, the inorganic particles, separated according to size, are referred to as soil separates. The percentage of sand, silt and clay content varied from , and respectively. They come under the textural classes loamy sand, sandy clay loam, sandy and clay loam. Table 5.10 shows the mechanical composition of soils of study area.

34 130 Plate: 5.7 spatial distribution maps of sand, silt and clay in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

35 Available nitrogen Nitrogen is an essential nutrient for plant growth, chlorophyll and protein formation.it is taken up by plants in large amounts, where as its concentration in soils is frequently very small.plants satisfy their nitrogen requirement from the inorganic fraction. The organic fraction serves as a reserve of nitrogen in plant nutrition, and will be released only after decomposition and mineralization of organic matter. Available nitrogen content of surface soils ranged from 158 to 211 kg ha-1 with a mean value of 184 kg ha-1 and for sub-surface soils it ranged from 145 to 189 kg ha-1 with a mean value of 168 kg ha-1. The minimum available nitrogen content (mean 122 kg ha-1) was recorded in Tangutur Mandal in surface samples while in subsurface samples it was found in Vetapalem mandal (mean 121 kgha-1) soils, while maximum content in surface and sub-surface soils was recorded in the soils of J. Panguluru (mean 228 kg ha 1 ) and Chirala (mean 213 kg ha- 1 ) soils respectively. 100 per cent of the both surface and sub-surface soils are low in available nitrogen content. Low available nitrogen in these soils was due to low organic carbon content as revealed by significant positive correlation (r=0.5631) between the two. Available nitrogen decreases with the depth in case of the soils of Ongole division. Fig 5.9 and Table 5.11 shows the Available Nitrogen of soils of study area.

36 %Nitrogen 132 SURFACE SUBSURFACE N.G.Padu Addanki Korisapadu J.Panguluru BallikuravaSantamaguluru Martur Yeddanapudi Chirala VetapalemChinaganjam Parchur Inkollu Karamchedu -- Mandals Fig 5.9: Graph showing Available Nitrogen of Surface & subsurface soils

37 133 Table 5.11: Available Nitrogen content (Kg ha-1) of soils s. No. Mandal No. of samples SURFACE SUB-SURFACE Nitrogen Low Nitrogen Low Range Mean No. % Range Mean No. % 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu Average

38 134 Plate: 5.8 spatial distribution maps of Nitrogen for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

39 phosphours Available phosphorus On the whole 80% of surface and 66% of sub-surface soils are high in available phosphorus and 20% of surface and 34% of sub-surface soils were medium in available phosphorus content. Medium and high available phosphorus content could be ascribed to heavy application of phosphatic fertilizers and organic matter, which favored the solubilisation of fixed phosphorus releasing more quantity to the available pool. Fig 5.10 and Table 5.12 shows available phosphorus of soils in study area SURFACE SUBSURFACE N.G.Padu Addanki KorisapaduJ.PanguluruBallikurava SantamaguluruMartur Yeddanapudi Chiraia VetapalemChinaganjamParch ur Inkollu Karamchedu -- Mandals Fig 5.10: Graph showing Available phosphorus of Surface & subsurface soils

40 136 Table 5.12: Available Phosphorus content (Kg P2O5 ha -1 ) of soils S. NO. MANDAL No. of samples SURFACE SUB-SURFACE Phosphorus Low Medium High Phosphorus Medium High Range Mean, No. No. No. Range Mean No. No. 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chiraia Vetapalem Chinaganjam Parch ur Inkollu ' Karamchedu AVERAGE

41 137 Plate: 5.9 spatial distribution maps of phosphorus for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

42 Iron Available iron Iron is another important element in soils. It is the third most abundant element in rocks and minerals. The central core of the earth is made up mostly of iron, In the study area Sixty four percent of surface and sub-surface samples were above critical limit, while remaining thirty six percent of both the samples were below critical limit. The soils of Prakasam district had sufficient iron in available form. Fig 5.11 and Table 5.13 shows available iron content of soils of study area. Below critical limit (<2.5mg/l), Above critical limit (>4.5 mg/l), (Soil sampling preparation and analysis / Kim H.Tan 2 nd ed-2005) SURFACE SUBSURFACE N.G.Padu Addanki Korisapadu J.Panquluru Ballikurava Santamaquluru Martur Yeddanapudi Chtrala Vetapalem Chinaqanjam Parchur Inkollu Karamchedu -- Mandels Fig 5.11: Graph showing Available iron of Surface & subsurface soils

43 139 Table 5.13: Available Iron content (ppm) of soils S. No. Mandal No. of samples Iron SURFACE Below critical limit <2.5 mg/l Above critical limit >4.5 mg/l Iron SUB-SURFACE Below critical limit Above critical limit Range Mean No. No. Range Mean No. No. 1 N.G.Padu Addanki Korisapadu J.Panquluru Ballikurava Santamaquluru Martur Yeddanapudi Chtrala Vetapalem Chinaqanjam Parchur _ Inkollu Karamchedu Average

44 140 Plate: 5.10 spatial distribution maps of iron for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

45 Available Manganese Magnesium is another microelement that are present in soils mostly in inorganic forms, through all organic matter contains Mg. The organic forms of Mg are of minor concern to most people as a source of Mg in soils, Drying of soils increases the exchangeable Mn content, fresh collected samples are needed for determining of exchangeable Mn and the drying effect is related to a reduced biological activity and this results in more manganese remaining in the ionic form, which can be adsorbed by the clay complex, All the soil samples in the study area were found to be above critical limit. Table 5.14 shows available manganese content of soils of the study area. (Soil sampling preparation and analysis / Kim H.Tan 2 nd ed-2005)

46 142 Table 5.14 Available Manganese content (ppm) of soils S. No. Mandal No. of samples Manganese SURFACE Below critical Limit 0-20ug/g Above critical limit 20-50ug/g Manganese SUB-SURFACE Below critical limit Above critical limit Range Mean No. No. Range Mean No. No. 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu , Karamchedu AVERAGE

47 143 Plate: 5.11 spatial distribution maps of manganese for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

48 Available zinc Zinc is a micronutrient to plants, and is therefore needed only in very small amount. The nutrient element functions as a catalyst. It is present in several plant enzymes and it is also essential for seed and grain production, and development of growth hormones. Plants Zn has been noted to be also deficient in auxins. In the study area eighty two percent of surface and ninety six percent of sub-surface samples were below critical limit while remaining 18% of surface and 4% of sub-surface were above critical limit. Zinc deficiency in Prakasam district was observed in the earlier investigations. The low available zinc content in these soils might be due to the fact that the farmers do not apply zinc as a fertilizer. Table 5.15 shows available zinc content of soils of study area. (Soil sampling preparation and analysis / Kim H.Tan 2 nd ed-2005)

49 145 Table 5.15: Available Zinc content (ppm) of soils S. No. Mandal No. of samples Zinc SURFACE Below critical limit <15 ug/g Above critical limit ug/g Zinc SUB-SURFACE Below critical limit Above critical limit Range Mean No. No. Range Mean No. No. 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu AVERAGE

50 146 Plate: 5.12 spatial distribution maps of Zinc for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

51 Copper Available copper Hundred per cent of both the surface and sub-surface samples are above critical limit. The available copper content was above critical limit in vertisols of Andhra Pradesh. The present investigation was in accordance with the reports of above workers. Fig 5.12 and Table 5.16 shows the available copper content of soils of study area. (Soil sampling preparation and analysis / Kim H.Tan 2 nd ed-2005) 3.5 SURFACE SUBSURFACE N.G.Padu Addanki Korisapadu J.Panquluru BallikuravaSantamagulur Martur Yeddanapudi Chirala Vetapalem Chinaqanjam Parchur Inkollu Karamchedu -- Mandals Fig 5.12: Graph showing Available copper of Surf subsurface soils

52 148 Table 5.16: Available Copper content (ppm) of soils S. No. Mandal No. of samples Copper SURFACE Below critical limit <3 ug/g Above critical limit 4-30 ug/g Copper SUB-SURFACE Below critical limit Above critical limit Range Mean No. No. Range Mean No. No. 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu AVERAGE

53 149 Plate: 5.13 spatial distribution maps of copper for surface & subsurface soils in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

54 QUALITY OF GROUND WATER OF STUDY AREA Electrical Conductivity (µmhos/cm) The electrical conductivity of all the water samples ranged from 1.02 to 7.06 µmhos/cm with a mean value of 3.42 µmhos/cm. Highest value of EC was found in case of Chinaganjam mandal (mean 3.96 µmhos/cm) waters because of the dominance of sodium ions, while lowest EC was found in Chimakurthy mandal (mean 1.39 µmhos/cm) waters. Around 25.6 percent of ground water samples of this division have the EC<1.5 µmhos/cm and can be used without any possible risk of soil Stalinization. Further 46 percent of water samples have EC between µmhos/cm and thus can be rated as marginal with regard to their suitability for irrigation and 19.6 percent of waters have EC between µmhos/cm and 8.8 percent of water have EC between 5-10 µmhos/cm and are usually considered unfit for irrigation, (Soil sampling preparation and analysis / Kim H.Tan 2 nd ed-2005 and Encylopaedia of Environmental Sciences / 1992 revised vol 15) Water reaction (ph) The ph of all the water samples ranged from 7.28 to 8.40 with a mean value of The highest mean value was found in Ballikurava (8.45) and the lowest mean value in Chinaganjam (7.31). According to classification of water based on ph, 65.6 per cent of samples were categorized under alkaline range having

55 151 ph>7.5 and 34.4 per cent of samples under neutral range having ph between Sodium Absorption Ratio (SAR) The overall SAR of water samples ranged from 2.16 to with a mean value of The highest SAR was found in N.G.Padu mandal (mean 9.57) and lowest was in Chimakurthy mandal (mean 3.71) waters. The main reason for high SAR in ground waters is their sodium dominating character. On an average 92 per cent of samples were under S1 class (SAR<10), 7.6 per cent samples under S2 class (SAR10-18) and only 0.4 percent of samples were under S3 class (SAR18-26) respectively Residual Sodium Carbonate (RSC) The range of RSC for all the waters of Ongole division are from nil to 6.17 me l- 1 with a mean value of 1.39 me l- 1. The highest RSC value was found in Ballikurava mandal (mean 12.2 me l- 1 ) waters. In higher salinity range the sodium is associated mainly with chloride and sulphate, where as in low to medium salinity waters it is associated with carbonates and bicarbonates. This causes problem of high RSC in these waters. However, irrigation with this water for a long time leads to slight to moderate sodicity in soil. Fig 5.13 and Table 5.17 shown the chemical composition of ground water of study area

56 Chemical composition of under ground water EC PH SAR RAC N.G.Padu Addanki Korisapadu J.Panguluru BallikuravaSantamaguiuru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parch ur Inkollu Karamchedu -- Mandals Fig 5.13: Graph showing EC, ph, SAR, RSC of water samples.

57 153 Table 5.17: Chemical composition of under ground water s. No. of EC (ds/m) ph SAR RSC (me/i) No Mandal sample Range Mean Range Mean Range Mean Range Mean 1 N.G.Padu Nil Addanki Nil Korisapadu Nil J.Panguluru Nil Ballikurava Nil Santamaguiuru Nil Martur Nil Yeddanapudi Nil Chirala Nil Vetapalem Nil Chinaganjam Nil-0.00 Nil 12 Parch ur Nil Inkollu Nil Karamchedu Nil-Nil Nil AVERAGE Nil

58 Plate: 5.14 spatial distribution maps of EC, ph, SAR, RSC of water samples in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH 154

59 Classification of Ground Waters On an average out of 110 samples, 57 samples were good for irrigation (34.8%), 90 samples were marginally saline (36%), 33 samples were saline (13.2%), 2 samples were high SAR saline (0.80%), 7 samples were marginally alkali (2.80%), 12 samples (4.8%) were alkali and 19 samples (7.6%) were high alkali waters. These are rated as per the guide lines given by the All India Coordinated Research Project on use of saline water in agriculture. The waters falling under "good" category can be used safely for groundnut and leguminous crops whereas water which is marginally saline can be used for pearl millet and mustard crops in areas having coarse textured soil. Also the ground water rated as marginally alkali can be used effectively with gypsum application for mustard and pearl millet crops. The water rated as saline, high-sar saline, alkali and highly alkali are unfit for irrigation and their indiscriminate use will cause secondary salinization and sodication Different Cationic Compositions Among the cations the dominant cation was sodium. The highest Na + content was found in N.G.Padu mandal (25.1 mg/l- 1 mean) and lowest in Chimakurthy mandal (mean 6.83 mg/l- 1 ) waters. The order of the cations in the Ongole division with descending order are Na + > Ca 2+ > Mg 2+ > K +. Table 5.18 & Fig 5.14 shows cationic composition.

60 Different anions compositions in ground water Different cationic compositions in ground waters Different Anionic Compositions Among the anions the dominant anion was chloride with highest mean value of me l -1 in N.G.Padu mandal and lowest in Chimakurthy (mean 7.83 me I" 1 ) mandal waters. The dominance order of anions in the ground water of Ongole division are as follows CI" > HCO3" > SO4 = > CO3 =. Fig 5.15 & Table 5.18 shows anionic - composition 25 Ca2+ Mg2+ Na+ K N.G.Padu Addanki Korisapadu J.Panguiuru BallikuravaSantamaguluru Martur Yeddanapudi Chirala VetapalemChinaganjam Parchur Inkollu Karamchedu -- Mandals Fig 5.14: Graph showing Different cationic compositions in ground water CARBONATES BICARBONATES CHLORIDES SULPHATES N.G.Padu Addanki Korisapadu J.Panguluru BallikuravaSantamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu -- Mandals Fig5.15: Graph showing Different anions compositions in ground water

61 157 Table 5.18: Different cationic compositions in ground waters S. No Mandal No. of samples Ca 2+ (me/i) Mg 2+ (me/i) Na + (me/l) K + (me/i) Range Mean Range Mean Range Mean Range Mean 1 N.G.Padu Addanki Korisapadu J.Panguiuru Ballikurava , Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu AVERAGE

62 158 Table 5.19: Different anions compositions in ground water S. No Mandal No. of samples Carbonates (me/i) Bicarbonates (me/i) Chlorides (me/i) Sulphates (me/i) Range Mean Range Mean Range Mean Range Mean 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santhamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu ,83 AVERAGE

63 Plate: 5.15 spatial distribution maps of Different cationic compositions in ground waters in study area. (Source: Prepared using ArcGIS Software) 159

64 160 Plate: 5.16 spatial distribution maps of Different anions compositions in ground waters in study area. (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH

65 Fluorides Under acidic conditions fluoride(hcl) react with zirconium (sulphophenyl azo dihydroxy naphthalene disulphuric acid) SPADNS solution and gets bleached, due to formation of zirconium chloride(zrx6).since bleaching is a function of fluoride ions it is directly proportional to the concentration to the fluoride and obeys beers law in a reverse manner The overall range of F in ground water of study area ranges from 0.39 to 1.58 mg l- 1 with a mean value of 0.89 mg l- 1. The highest F was found in Chimakurthy mandal (mean mg l- 1 ) and lowest was in Karamchedu (mean 0.36 mg l- 1 ) mandal waters. The data from table 29 show that 70 percent of samples were safe in fluoride content i.e., <1mg l and 30 percent of samples ranges between 1-5 mg I" 1 and these are moderately safe for irrigation. Fluorides are more commonly found in ground waters than in surface water, the main source of fluoride in water are different fluoride bearing minerals like apatite and mica. The maximum permissible limit of fluoride in ground water is 1.5 mg/g (WHO), (Methods in Environmental Analysis water, soil and air / P.K.Gupta 2004).

66 Nitrates Nitrates are the most oxidizing form of nitrogen compounds present in the natural water because it is the product of organic nitrogenous matter. Significant source of nitrogen (or) chemical fertilizers degrade vegetables of chemical matter, domestic effluent industrial discharges.depending on the significance the source can contaminate rivers, lakes of ground water. Nitrate is a beneficial element which may be considered important in irrigation water, although for drinking purpose it is considered as a pollutant above specified limit of 10 mg l- 1.From irrigation point of view the effect of nitrate ion has been found more spectacular than all the other nutrients because irrigated soils are generally deficit in nitrogen. The nitrate-nitrogen range of these water samples ranged from 2.34 to mg l- 1 with a mean value of 7.19 mg l- 1. The highest and lowest values of means were found in Ongole (mean 9.95 mg I" 1 ) and Karamchedu (mean 3.03 mg l- 1 ) mandals respectively. The data from table 29 show that 80.8 per cent of water samples shows that the nitrate-nitrogen ranges between 5-30 mg I" 1 and 19.2 per cent of samples shows <5 mg l- 1, on an average the nitrate-nitrogen levels of these waters are moderately safe in nitrate-nitrogen content.

67 Fluorides, Nitrates and Micro nutrient composition of ground water Micronutrients Trace element analysis is usually considered the determination of elements present in soils in trace amounts it is generally not interpreted as analysis of nutritients required by plants in small (trace) amounts several of the latter, customarily known as micro nutrients The mean values of the four micronutrients were 0.08, 0.042, 0.03 and ppm for iron, manganese, zinc and copper respectively in Ongole division. 10 F NO3 Fe Mn Zn Cu N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapafem Chinaganjam Parchur Inkollu Karamchedu -- mandals Fig 5.16: Graph showing Fluorides, Nitrates & Micronutrients in ground water

68 164 Table 5.20: Fluorides, Nitrates and Micro nutrient composition of ground water s. No. Mandal No. of samples F (mg I" 1 ) NO3-N (mg I" 1 ) Fe (ppm) Mn (ppm) Zn (ppm) Cu (ppm) Range Mean Range Mean Range Mean Range Mean Range Mean Range Mean 1 N.G.Padu Addanki Korisapadu ' J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapafem Chinaganjam Parchur Inkollu Karamchedu AVERAGE

69 165 Plate: 5.17 Spatial distribution maps of Fluorides, Nitrates & Micronutrients in ground water (Source: Prepared using ArcGIS Software) Prepared Ionic by: K.Santosh Ratios Kumar, Centre for Environment, IST, JNTUH

70 Mean values of different Ionic ratios of ground water Mean values of different Ionic ratios of ground water Ionic Ratios Ground waters are classified as good quality water and presence of seawater based on the ionic ratios mentioned in table 5. Based on the Ca/Mg ratio 91.2 percent of samples were having traces of seawater and remaining 8.8 percent were good quality water. Based on Ca/Na ratio 61.2 percent of samples were having seawater intrusion and remaining 38.8 percent are good quality water. It is clearly observed that most of the ground water is affected by the intrusion of seawater based on the ionic ratios. Fig 5.17 and Table 5.21 shows ionic ratios of ground water in study area 10 Ca/Mg Ca/Na Mg/Na Ca/SO4 Mg/HCO N.G.Padu Addanki Korisapadu J.Panquluru BallikuravaSantamaquluru Martur Yeddanapudi Chirala Vetapalem Chinaqanjam Parchur Inkollu Karamchedu -- Mandals CI/HCO3 SCVHCOa HCO3/SO4 HCO3/CI CI/SO N.G.Padu Addanki Korisapadu J.Panguluru BallikuravaSantamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur Inkollu Karamchedu -- Mandels Fig 5.17: Graph showing Mean values of different Ionic ratios of ground water

71 167 Table 5.21: Mean values of different Ionic ratios of ground water s. No. of Ca/Mg Ca/Na Mg/Na Ca/SO4 Mg/HCO3 No. Mandal sample Range Mean Range Mean Range Mean Range Mean Range Mean 1 N.G.Padu Addanki , , Korisapadu , J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem , Chinaganjam ,65 12 Parchur Inkollu Karamchedu AVERAGE Table Contd..

72 168 S. No. Mandal No. of sample Mean values of different Ionic ratios of ground water CI/HCO3 SCVHCOa HCO3/SO4 HCO3/CI CI/SO4 Range Mean Range Mean Range Mean Range Mean Range Mean 1 N.G.Padu Addanki Korisapadu J.Panguluru Ballikurava Santamaguluru Martur Yeddanapudi Chirala Vetapalem Chinaganjam Parchur , Inkollu , , , Karamchedu AVERAGE

73 169 Maps Contd..

74 170 Plate: 5.18 spatial distribution maps of different Ionic ratios of ground water (Source: Prepared using ArcGIS Software) Prepared by: K.Santosh Kumar, Centre for Environment, IST, JNTUH 5.6 CORRELATION STUDIES