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Open Access
Spatial variability of soil nutrients and carbon pools under different land uses in hilly zone of Doda district of J&K
(Sher-e-Kashmir, University of Agricultural Sciences & Technology-Jammu, Jammu, 2018-08) Manoj Kumar; Dr. M.P. Sharma
The area under study located at longitude 32°17° to 32°40°E North and latitude 74°35° to 75°10° East from mean sea level. The 236 composite soil samples from different depth viz., 0-20, 20-40, 40-60, 60-100 covering agriculture, horticulture, forest, grassland, eroded and barren land use systems by using global positioning system to assess the “spatial variability of soil nutrients, carbon pools and to establish their relationship between soil properties and nutrients /carbon pools”. The mean values of pH, EC, CEC,BD WHC, sand, silt, clay, exch. Ca, Mg, Na and CaCO3 were 6.34, 6.28, 5.30, 6.33,6.62, 6.36;0.23, 0.37,0.21, 0.19, 0.22, 0.10;18.06, 18.95, 23.30, 21.35,9.05, 13.50, 1.45, 1.41,1.36, 1.49, 1.55, 1.53; 30.88, 35.61, 36.45, 36.34,24.88, 32.83, 51.25, 62.56, 50.07, 56.64, 66.74, 64.25;15.28, 17.83, 18.32, 17.58,22.48, 19.99; 21.39, 25.77,30.16, 28.57, 10.77, 14.77;17.38, 40.63, 41.46, 39.18,44.78, 38.65; 44.84, 9.98,11.79, 9.87, 12.72, 8.97; 15.18, 0.93, 0.95, 1.27,0.19, 0.87; 0.88, 1.29; 1.30, 1.07, 1.46;1.40: 1.69 for corresponding of agriculture, horticulture, forest, grass, eroded, and barren land use systems. The pH of the soils were slightly acidic to neutral in nature and dominant textural classes were sandy loam followed by sandy clay loam in all land use systems. The mean values of available macronutrients viz NPKS in surface soils were 266.60, 276.02, 301.40, 284.78, 195.20, 216.00 ; 13.50, 13.30 ; 16.85, 14.25, 9.00, 10.60 ; 259.6, 226.80, 273.90, 270.90, 199.25, 209.95 ; 3.95, 3.71 ; 5.85 : 4.65, 2.60, 3.25 in agriculture, horticulture forest, grass, barren and eroded land use systems respectively. The available N was medium to low, available P was high to medium and available S was medium to low in surface soil under all land use systems and decreased with increasing depth. The mean values of available micronutrient viz., iron, copper, zinc and manganese in surface soil under agriculture, horticulture, forest, grass, eroded, and barren land use systems were 37.55, 41.71, 51.76, 47.27,21.14, 27.36, 2.85, 3.19,3.59, 3.26, 1.55, 2.82; 1.09, 0.92, 1.01, 0.85, 0.77; 0.87, 18.64, 20.75, 25.88, 21.68, 11.32, 12.81. The available Fe and Cu were high to medium in range and available Zn and Mn were sufficient and moderate in all land use system. The mean values of the organic carbon pools comprises of SOC, WSC, LC, MBC and TC were 6.20,7.53, 11.75, 9.67, 4.90, 5.41, 44.12, 47.6,59.10, 52.75, 38.40,42.60;2.90, 3.44, 3.69,3.57,1.27,1.37; 83.86,104.05, 117.75, 112.01, 64.25,68.20; 25.05, 27.30, 33.56,32.54,20.95, 24.55 in agriculture, horticulture forest, grass, barren and eroded land use systems respectively. The soil organic pools were higher in forest land, grassland and horticulture land and agriculture land use systems and lower in eroded and barren land use systems respectively. The available macro nutrient N, P, K, S holds a positive relationship with pH, EC, CaCO3, silt, clay and exch. Mg at surface as well as subsurface depth. The available micronutrients including Fe, Cu, Zn and Mn were positively correlated with pH, EC, silt, clay, CEC, exchangeable Ca and Na. There was a positive co-relationship between carbon pools (SOC, WSC, LC, MBC and TC) with soil properties (pH, EC, CaCO3). The results indicated that available macro and micro nutrients (N, P, K, S, Fe Cu, Zinc and Mn), carbon pools (SOC, WSC, LC, MBC and TC) and clay, CEC, WHC, CaCO3, exch. Ca, exch. Mg and Na contents were highest in forest land use system and lowest in eroded land use system followed the trend : forest land use system, grass land use system, horticulture land use system, agriculture land use system, barren land use system and eroded land use system.
Open Access
EFFECT OF ADDED PHOSPHORUS, ORGANIC MATTER AND MOISTURE REGIMES ON PHOSPHORUS ADSORPTION IN SOILS OF VARIOUS AGRO-CLIMATIC ZONES OF JAMMU REGION
(Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, 2007) Arya, Vivak Manohar; Jalali, V.K.
Four hundred soil samples (0-22.5cm) collected from cultivable areas representing three agroclimatic zones viz. subtropical, intermediate and temperate zones of Jammu region were studied for P adorption/desorption behavior of these soils. Further relationship between adsorbed P and various soil properties were studied. Besides incubation study was conducted to ascertain the effect of various levels of P, organic matter and moisture regimes on P adsorption. Langmuir and Freundlich isotherms were tested for adsorption/desorption studies and from these isotherms adsorption maxima (b), bonding energy (K) and maximum buffering capacity (MBC) were calculated. The soils varied in their physical and chemical properties. P adsorption by soils of three agro climatic region of Jammu region, irrespective of the treatments increased with rise in the concentration of added P, the magnitude of its increase, however, varied between soil and concentration. The mean P adsorption by the temperate soil was 523.1 mg kg^-1 as compared to 296.6 mg kg^-1 in the intermediate zone soils, subtropical zone soils recorded lowest P adsorption of 126.1 mg kg^-1. The adsorption isotherm indicated, although the adsorption of P increased with increasing concentration of P, yet the percentage of adsorbed P decreased from 65.3 to 57.0 percent, 83.1 to 21.4 percent and 85.2 to 39.7 percent for different soil in subtropical, intermediate and temperate zone soils respectively. Langmuir adsorption maxima (b), bonding energy (K) and maximum buffering capacity (MBC) of these soils ranged from 101 to 1000 mg kg^-1, 12.0 to 56.01 L, kg^-1 and 2.62 to'20.0 L kg^-1 respectively. P adsorption maxima was positively and significantly correlated with organic carbon, CEC and clay, the coefficient of correlations being 0.892**, 0.900** and 0.935** respectively. Bonding energy was positively correlated with clay, CEC, while maximum buffering capacity had a significant negative corelationship with pH (r = -0.743**) but a significant positive corelationship with clay (r =0.849**). Multiple regression analysis indicated significant influence of clay and organic matter on P adsorption in these soils. The percentage of desorbed P was higher at higher level of added P, while percentage of adsorbed P decreased with the increase in the P level. Highest P desorption was noticed in Smailpur (37.9 mg kg^-1) and lowest in Thein (24.8 mg kg^-1) both in subtropical zone. The range of desorption in the intermediate zone soils was from 26.1 mg kg^-1 to 21.4 mg kg^-1. Lowest P desorption was in temperate zone soils. The percentage of desorbed to adsorbed P varied from 16.9 to 11.5 percent, 14.0 to 9.5 percent and 12.9 to 7.9 percent in subtropical. Intermediate and temperate zone soils respectively. In all the soils the bonding energy (K) and adsorption maxima (b) decrease with the addition of farm yard manure but the decrease was more at saturation than at field capacity. The bonding energy decreased from 23.6 to 20.2 L kg^-1 with 0 level of FYM at field capacity. At saturation point bonding energy decreased from 16.8 to 14.0 L kg^-1 and with addition of FYM (5 t ha^-1) decrease was from 23.2 to 19.6 L kg^-1 at field capacity and from 16.4 to 13.7 L kg^-1 at saturation. The decrease was more at saturation as compared to field capacity. Similar decreasing trend were found with the addition of 50 and 100 ppm P in all the three agro climatic zones of Jammu region. Incubation of soils at saturation and field capacity and addition of FYM @ 5 tonne ha^-1 invariably resulted in significantly higher P extraction with 0.5 M NaHCO₃ through out the incubation period .The increase at saturation point was from 12.5 to 20.9 kg ha^-1 while at field capacity it was from 11.2 to 18.6 kg ha^-1.
Open Access
CHARACTERIZATION OF SOILS OF KATHUA DISTRICT IN JAMMU REGION OF JAMMU AND KASHMIR STATE
(Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, 2000) Upadhayaya, Vijay Kumar; Gupta, R.D.
Twenty one soil profiles from different locations representing three biosequences viz., cultivated, forest and grasslands of Kathua district in Jammu region of Jammu and Kashmir state, were collected for studying their morphological, physical, physico-chemical and fertility status. Morphologically, hue of soil matrix colour ranged from 5YR to 10YR, value from 4 / to 6/ and chroma from / 1 to / 6 . Texturally, the soils were clayey to coarse loamy with gravels and pebbles in many profiles. Soil structure varied widely in type, size, grade and soil consistence in dry, moist and wet soil condtions too, varied largely. Among "Physical parameters", the mechanical components viz. coarse sand, fine sand, silt and clay ranged from 0.00 to 50.30, 2.00 to 82.40,4.00 to 80.00 and 8.00 to 68.00 per cent, the mean weight diameter (MWD) and percentage of aggregates >0.25 mm ranged from 0.26 to 5.30 mm and 25.7 to 96.25 per cent. The moisture retention at suctions 0, 33 and 1500 kpa showed a range of 28.4 to 95.1, 6.0 to 33.6 and 2.2 to 17.9 per cent, respectively. In respect of "Chemical characteristics" pH varied between 4.4 to 7.1 (strongly acidic to neutral), EC between 0.10 to 0.97 dSm^-1 (normal), OC between 0.07 to 2.47 per cent (low to high), total N between 0.01 to 0.23. C:N ratio between 3.6 to 20, base saturation between 10.2 to 97.4 per cent and CEC between 5.02 to 19.0 Cmol (P⁺) kg^-1 soil. Exchangeable, Ca⁺⁺, Mg⁺⁺, K⁺⁺ and Na⁺⁺ values fluctuated between 0.8 to 6.4, 0.00 to 4.7, 0.07 to 0.28 and 0.04 to 0.17 Cmol (P⁺) kg ^-1 soil, respectively. Available macronutrients viz. N, P and K ranged in the vicinity of 13.0 to 817.2 (low to high), 4.7 to 101.1 (low to high) and 61.2 to 199.2 kg ha^-1 (low to medium), exchangeable Ca and Mg showed a range of 0.8 to 6.40 (deficient to sufficient) and 0.00 to 4.7 Cmol (P⁺) kg^-1 soil (deficient to sufficient). Sulphur content ranged between 4.9 to 12.4 ppm (deficient). Of the total macronutrients content determined in concentrated HCl extract N, P, K were in the range of 0.01 to 0.23, trace to 0.22 and 0.15 to 0.45 per cent, while total Ca and Mg varied between 25.00 to 62.5 and 12.50 to 50.00 Cmol (P⁺) kg^-1 soil. The values of DTPA extractable micronutrients viz. Fe, Zn, Mn and Cu ranged from 12.0 to 320.4 (high), 0.29 to 3.14 (low to high), 3.00 to 150.00 (low to high) and 0.04 to 5.20 ppm (low to high), respectively. Correlation studies indicated positive and significant relationships between MWD and OC (r = 0.70^**), clay content and available moisture (r = 0.44*), OC and available moisture (r = 0.48*), OC and CEC (r = 0.55**), OC and Total N (r = 0.58**) etc. Taxonomically, the soil profiles were classified into three orders viz., Entisol, Inceptisols, Alfisols. Within these three orders eight subgroups Typic Ustpsamments, Typic Ustorthents, Typic Udifluvents, Typic Haplumbrepts, Typic Hapludalf, Typic Ustochrepts, Ultic Haplustalf, Typic Fragiudalf were recognised. Depending upon soil constraints and limitations, the soils were classified into six land capability classes (II,III, IV, V, VI and VII) and eleven subclasses (II_s, III_w, III_es, III_e, III_s, IV_es , IV_e, V_s, VI_es, VI_e andVII_es ).
Open Access
SULPHUR RETENTION AND RELEASE AS INFLUENCED BY SOIL TYPE AND MANAGEMENT PRACTICES IN THE AGROCLIMATIC ZONES OF JAMMU REGION
(Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, 2006) Kour, Sarabdeep; Jalali, V.K.
Soil samples from thirty profiles (depth wise) from cultivable areas representing three agroclimatic zones viz. sub-tropical, intermediate and temperate zones were studied for sulphate retention and release. Besides, a field experiment was conducted at Research Farm, Faculty of Agriculture, Chatha to study the response of sulphur on oilseed crop and its residual effect on the succeeding rice crop. In the current study, it was found that the amount of total sulphur content in soils varied between 65 to 882 mg kg^-1 and it decreased with increasing depth. Mean contents of total S in temperate, intermediate and sub-tropical zone was 848, 601 and 371 mg kg^-1 in surface layers and 671, 439 and 272 mg kg^-1 in sub-surface layers. Organic S was the dominant fraction constituting 65, 50 and 41 per cent of total S in temperate, intermediate and sub-tropical zones, respectively with a range of 31 to 592 mg kg^-1 in the soils of different agro-climatic zones and followed distribution pattern as that of organic carbon. Sulphate S constituted the lowest component of in-organic S. the amount being 2.4 to 51.1 mg kg^-1 constituting on an average 5.3, 5.2 and 2.8 per cent of total S in subtropical, intermediate and temperate zone soils, respectively. Non-sulphate S ranged from 28 to 361 mg kg^-1 in all the profiles studied and was second largest fraction of total S after the organic S. Water soluble S varied from 9.2 to 66.5 mg kg^-1 and this fraction on an average constituted 6.5 per cent of total sulphur. Adsorbed S in all the soils varied between 23.0 and 98.0 mg kg^-1 showing an increasing trend down the profile. Consequently, order of abundance of S content in soils studied was : Total S >Organic S > Non-sulphate > Adsorbed S > Water soluble S > Sulphate S. Total S had a significant and positive association with organic carbon content and soil pH in all the three agro-climatic zones, whereas, it exhibited a positive relationship with silt and clay content in intermediate and sub-tropical zones. Multiple regression analysis indicated significant influence of organic carbon on total S. Organic, sulphate and water soluble S fractions were significantly and positively correlated with organic carbon in all the three zones. Non-sulphate S had a significant and positive association with pH and organic carbon but negatively correlated with exchangeable aluminium. All the forms of S were positively and significantly correlated with each other except adsorbed S and from these studies it is evident that different forms of S are dependent upon soil characteristics and a relationship exists among themselves. Sulphate adsorption by soils of three agro-climatic zones of Jammu region, irrespective of the treatments increased with rise in concentration of added sulphate solution, the magnitude of its increase however varied between soils and concentrations. In sub-tropical zone maximum adsorption of sulphate was noticed in Samba soils (296.2 mg kg^-1) while lowest adsorption was noticed in Lakhanpur soils (100 mg kg^-1) at 300 mg L^-1 of sulphate added. In intermediate zone soils, maximum sulphate was adsorbed in Rakhsansu soils. Temperate zone soils recorded sulphate adsorption of 87.5 to 437.5 mg kg^-1 at different concentrations of sulphate added. Adsorption isotherms indicated that adsorption of sulphate increased with increasing concentration and the percentage of adsorbed sulphate decreased from 70.0 to 6.6, 77.0 to 13.4 and 70.0 to 25.8 per cent in subtropical, intermediate and temperate zone soils, respectively. Langmuir adsorption maxima (b), bonding energy (k) and maximum buffering capacity of these soils varied from 111.1 to 556.0 mg kg^-1,0.009 to 0.058 L mg^-1 and 2.36 to 19.34 L kg^-1, respectively. Sulphate adsorption maxima and maximum buffering capacity had significant negative relationship with pH and significant positive relationship with exchangeable aluminium and free iron oxides. Bonding energy was positively associated with clay content. Freundlich K value varied from 11.26 to 61.10 mg kg^-1 in all the three zones and showed a positive and significant relationship with clay content. However. Freundlich l/n varied from 0.256 to 0.596 for soils of three zones. The amounts of sulphate extracted by KH₂PO₄ varied considerably with the levels of sulphur and increased with increasing amounts of sulphate sorbed. Amount of S desorbed varied from 62.4 to 84.4 per cent of the sorbed sulphur. Field studies conducted to find out the direct and residual response of sulphur indicated that up to 30 kg S ha^-1 applied through gypsum, increased yield of mustard (variety Varuna) by only 21.3 per cent over control. Although the residual effect of S on rice yield was non-significant, the grain yield of rice increased by 5.32 per cent.
Open Access
BORON ADSORPTION-DESORPTION CHARACTERISTICS AND ITS AVAILABILITY IN SOILS REPRESENTING DIFFERENT AGROCLIMATIC ZONES OF JAMMU REGION
(Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, 2008) Sharma, Neeraj; Sharma, R.K.
Sixty one soil samples depthwise collected from cultivable areas representing three agroclimatic zones viz. sub-tropical, intermediate and temperate zone were studied for different forms of B, out of these only 12 surface soil samples were selected for adsorption-desorption studies. Besides a pot experiment was conducted at Faculty of Agriculture, Chatha to estimate critical limit of available boron for berseem (Trifolium alexandrinum) crop. The current investigation demonstrated that there was a wide variation in different forms of B in three agro-climatic zones of Jammu region. Mean WS-B in the surface soils was 0.26, 0.32 and 0.38 mg kg^-1 while in sub-surface soils it was 0.20, 0.22 and 0.31 mg kg^-1 in sub-tropical, intermediate and temperate zone soils, respectively. HWS-B varied from 0.22 to 0.60, 0.31 to 0.76 and 0.34 to 1.20 mg kg^-1 and considering 0.5 mg kg^-1 hot water soluble B as the critical limit, 47, 43 and 25 per cent soils were deficient in HWS-B in sub-tropical, intermediate and temperate zone soils, respectively. CaCl₂-B was higher than HWS-B and WS-B and it varied from 0.26 to 0.64, 0.37 to 0.77 and 0.36 to 1.25 mg kg^-1 in sub-tropical, intermediate and temperate zone soils, respectively. CaCl₂-B was highest in temperate zone soils followed by intermediate and sub-tropical zone. AS-B was the dominant fraction of available boron in all the three agro-climatic zones of Jammu region and in surface soils the mean content of this form of B was 0.48, 0.55 and 0.67 mg kg^-1 in sub-tropical, intermediate and temperate zone, respectively while in sub-surface layers the mean content were 0.45, 0.50 and 0.60 mg B kg^-1 soil. Total boron content in soils varied from 15.30 to 31.14, 16.35 to 41.90 and 16.85 to 33.20 mg kg^-1 and it decreased with depth. Mean content of this form in sub-tropical, intermediate and temperate zone was 22.28, 22.96 and 25.14 mg kg^-1 in surface soils and 18.94, 20.76 and 22.15 mg kg^-1 in sub-surface soils, respectively. Consequently their order of abundance was Total B>AS-B> CaCl₂-B> HWS-B>WS-B. WS-B, HWS-B, CaCl₂-B and AS-B were positively and significantly correlated with EC, Organic Carbon. CEC and clay but negatively and significantly correlated with pH and sand content. Multiple regression analysis indicated 60.9 62.3, 61.7 and 60.0 per cent of variation in WS-B. HWS-B. CaCl₂-B and AS-B were due to EC, OC, CEC, Clay, pH & Sand. All these available forms of boron were positively and significantly correlated with each other. Boron adsorption by soils of three agro-climates zones of Jammu region, irrespective of the treatments increased with rise is concentration of added boron. The adsorption isotherms indicated adsorption of boron increased with its increasing concentration in the equilibrium solution. Adsorption data were fitted both in Langmuir and Freundtich equations. The Langmuir adsorption maxima (b) and bonding energy (K) of these soils varied from 17,66 to 28.24 μg g^-1 and 0.022 to 0.041 ml B μg^-1, respectively. The Freundlich l/n and K varied from 0.68 to 0.76 and 1.21 to 2.31, respectively. Langmuir adsorption (b) were positively and significantly correlated with organic carbon, CEC and clay content and negatively but significantly correlated with pH and sand content. Bonding energy (K) was non-significantly correlated with all these soil properties. Freundlich (k) was significantly correlated with organic carbon, CEC and clay content. Boron desorption in soils was less than the boron adsorbed. The amount of boron desorbed increase with the increase in amount of adsorbed boron. The per cent desorbed to the adsorbed boron varied from 14.43 to 50.18, 14.00 to 44.84 and 10.71 to 37.63 per cent at 2 to 100 μg g^-1 B added for sub-tropical, intermediate and temperate zone soils, respectively. Pot culture studies indicated, dry matter yield of berseem increased with application of 0.5 and 1.5 mg kg^-1 and yield increased from 5.08 g pot^-1 to 6.17 g pot^-1 with application of these levels of B, further uptake of B increased with B applications. Critical limit by Cate and Nelson procedure was 0.51 mg kg^-1 for soil and 23.03 μg B g^-1 for berseem plant.
Open Access
STUDIES ON INDICES OF AVAILABILITY AND CRITICAL LEVELS OF POTASSIUM FOR WHEAT IN SOILS OF SUBTROPICAL ZONE OF JAMMU REGION
(Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, 2000) Verma, Mahesh Kumar; Bedi, A.S.
The investigation entitled, "Studies on indices of availability and critical levels of potassium for wheat in soils of subtropical zone of Jammu region" was undertaken on the soils of sub-tropical zone of Jammu region. The investigation comprised of both green house, as well as laboratory studies on soils collected from wheat growing areas of the subtropical zone of Jammu region. In the laboratory, the results of various studies showed that the soils were widely differing in their physico-chemical characters. The soils also exhibited differently in availability of K with different extractants. Neutral normal ammonium acetate (pH 7.0) was observed the most suitable extractant and it also showed a highly significant relationship (r=0.695) for prediction of K availability in these soils. Incubation of these soils in the laboratory without test crop but with graded levels of K, also showed that these soils differed in their capacity of fixation and release of available K. A pot experiment was conducted in green house at R.A.R.S., R. S. Pura with graded levels of K (0, 6, 12, 18 mg K kg^-1) with wheat as the test crop. The results showed that dry matter production and K uptake increased with K application especially, in soils testing low to medium in K status. The rate of accumulation of dry matter was low in early stages of crop growth upto 46 days (1.03 mg pot^-1 day^-1) and it increased gradually after 46 days upto 60 days (10.10 mg pot^-1day^-1). The K content of wheat plant increased with increase in K application in all the soils under test. The critical concentration of K in plant at 46 and 60 day stages was 1.25 and 1.80 per cent, respectively. Among the six extractants studied, maximum K was found (1566 mg kg^-1 soil) in Reasi soil with boiling 1N nitric acid and the lowest available K was found with 0.01 M CaCl₂ in soils of R.S.Pura (9 mg kg^-1 soil). The neutral normal ammonium acetate extractable K correlated highly significantly with all the other five methods. The critical limits of soil K, below which the crop may respond to K application, with 1N neutral ammonium acetate, boiling 1N HNO₃, 1.38N H₂SO₄, Morgan's reagent. Distilled water and 0.01M CaCl₂ were 82.0, 870.0, 82.5, 41, 44 and 19 mg K kg^-1 soil, respectively.
Open Access
INFLUENCE OF IRRIGATION SCHEDULING, PHOSPHORUS LEVELS ON YIELD AND PHOSPHORUS UPTAKE IN WHEAT (TRITICUM AESTIVUM L.)
(Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, 2000) Kotwal, Ashwani Kumar; Sharma, R.K.
The investigation was undertaken at Water Management Research Centre Ponichak (Jammu) during Rabi 1998-99, to study the influence of irrigation scheduling, Phosprous levels on yield and uptake of Phosphorus in Wheat crop. A field experiment was conducted in split plot design with three levels of irrigation (IW/ CPE ratio 1.0, 0.8 and 0.6) in the main plot and four levels of phosphorus (0.0, 25.0, 50.0 and 75.0 kg P₂O₅ ha^-1) in the sub plots. The treatments were replicated thrice and wheat crop (variety PWB-154) was used as a test crop. Uniform dose of N and K was applied as per package of practices (l00.0Kg N and 25.0 Kg K_{2-1). The irrigation was applied as per treatments based on pan evaporation readings. Different levels of irrigation increased the grain yield of wheat significantly, the percentage ranged from 22.0 to 26.0. Out of various IW / CPE ratios, 1.0 recorded the highest grain yield (44.22 qha^-1). The consumptive use of water was computed for different IW/ CPE ratio and water use efficiency was calculated. IW/CPE ratio of 0.6 recorded the highest water use efficiency. Similarly, with increase in phosphorus levels from 0.0 to 75.0 kg P₂O₅ ha^-1 yield increased significantly, the increase varied from 2.75 to 19.0 percent. The second-degree simple non-linear regression equation (Y= a + bx + cx²) was fitted and dose of 72.5 Kg P₂O₅ ha^-1 was found as optimum. Positive interaction was recorded between irrigation and phosphorus treatments and maximum yield of 48.75 qha^-1 was recorded with IW/ CPE ratio of 1.0 and 75.0 Kg P₂O₅ ha^-1 . The phosphorus uptake and irrigation levels were positively correlated and maximum uptake of 19.4 kg P ha^-1 was recorded with IW/CPE ratio of 1.0 and 75 kg P₂O₅ ha^-1.
The results thus suggest that the existing dose (P₂O₅ @ 50 kg ha^-1) for irrigated wheat can be increased upto 72.5 kg ha^-1 especially for the soils having low and medium available P status for the sub tropical zone of Jammu region.}
Open Access
POTASSIUM FIXATION AND RELEASE IN SOILS OF DIFFERENT AGRO-CLIMATIC ZONES OF JAMMU REGION
(Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, 2006) Sharma, Anil; Jalali, V.K.
Soil samples from thirty profiles (depth wise) from cultivable areas representing three agro-climatic zones viz. sub-tropical, intermediate and temperate zone were studied for fixation and release of potassium. Besides a pot culture experiment was conducted at Faculty of Agriculture, Chatha to evaluate non-exchangeable K in relation to crop availability for these agro-climatic zones. The current investigation demonstrated that there was a wide variation in different forms of K in three agro-climatic zones of Jammu region. Mineral K was the dominant form of total K constituting about 92.36 and 92.47 per cent in surface and sub-surface soils, where as, non-exchangeable K (NEK) constituted 6.92 and 6.97 and IN HNO₃ K constituted 7.64 and 7.53 per cent to total K in surface and subsurface soils respectively and the contribution of rest of the forms of K i.e. available (Av. K), exchangeable (Ex. K) and water-soluble K (WSK) was negligible to total K in these soils. The forms of K (mg kg^-1) in terms of their distribution could be expressed as under: Soil depth Total K Mineral K NEK IN HNO3 K Av. K Ex. K WSK Surface 10037-17693 9221-16462 741-1556 816-1743 47-187 37-142 8-45 Sub-surface 10343-18831 9523-17673 761-1679 820-1791 32-155 23-130 7-37 Consequently, their order of abundance was total K>mineral K>IN HNO₃ K> non-exchanfeable higher than both sub-tropical and intermediate zone soils. Water-soluble K had a significant and positive association with organic carbon, CEC where as exchangeable K did so with clay, silt, CEC and organic carbon. Generally IN HNO₃ K, NEK, mineral K and total K did so with clay and silt. Multiple regression studies demonstrated the effect of organic carbon and clay on various forms of K in the soils of three agro-climatic zones. A positive correlation amongst various forms of K indicated a thermodynamic equilibrium in these pools.

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