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Effect of organic amendments on boron availability in calcareous soils under raya (Brassica juncea L.) and soybean (Glycine max.L.)
(Punjab Agricultural University, Ludhiana, 2019) Sukhvir Kaur; Sharma, Sandeep
A pot experiment was conducted during rabi (2016-2017) and kharif (2017) season to study the response of raya (Brassica juncea L.) (cv. PBR 357) and soybean (Glycine max L.) (cv. SL 958) to different levels of boron (B) and different organic manures in boron deficient calcareous soils of Punjab. Three different soils with varying calcium carbonate content viz. 0.65 (soil I), 4.1 (soil II) and 5.4 per cent (soil III) were collected from Ludhiana, Sudhar (Ludhiana) and Bathinda Districts for experimental study. The treatments comprised six levels of boron for soil application viz. 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mg B kg-1 and two levels of farmyard manure viz. control and FYM @10 t ha-1. The experiment was laid out in CRD factorial design with three replications. Yield and yield attributing characters at different crop growth stages (grand growth and maturity stage) increased significantly at 1.5 mg B kg-1 with FYM irrespective of the soils. The boron content and its uptake was higher in leaves followed by stem, grains and root, respectively both in raya and soybean crop. Among calcareous soils, soil I with lowest calcium carbonate was the best soil in respect of yield, yield components, boron content and its uptake in comparison to soil with medium and high calcium carbonate content. Boron transformation in soil after the harvesting of raya and soybean crop revealed that readily soluble was higher in soil I compared with soil II and soil III. Specifically adsorbed, oxide bound, residual and total boron were more in soil III however, oxide and organically bound fractions were higher in soil II. The coefficient of determinations (R2) for Langmuir adsorption isotherm were lower compared with Freundlich adsorption isotherm which proved that Freundlich adsorption isotherm to be more valid for adsorption studies. It indicated that B adsorption data fits excellent to Freundlich adsorption isotherm. The highest value of adsorption maxima (b) (45.0 mg kg-1) was recorded in silty clay. However, the highest bonding energy constant (k) (0.111 L kg-1) value was recorded in sandy soil whereas; the (k) lowest value 0.047 mg L-1 was recorded in silty clay. The Freundlich bonding energy constant increased with increase in soil clay content having minimum value in sandy soil 1.405 mg kg-1 and maximum (2.29 mg kg-1) in silty clay soil. In incubation study, the availability of boron in soil was studied with six varying levels of boron (0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mg B kg-1), five organic amendments (control, farmyard manure, press mud, poultry manure and rice straw compost) with three levels of calcium carbonate content (0.64, 4.1 and 5.4 per cent) at 15, 30 and 60 days of intervals. The soil was incubated in a temperature controlled room at 25oC. Boron availability increased as a function of time and treatment for different soils. The mean boron content was highest in soil application of 2.5 mg B kg-1 with farmyard manure followed by press mud, poultry manure, rice straw and control (no-amendment) in different types of soils. Availability of boron was highest in soil with low calcium carbonate content and decreased with increasing levels of calcium carbonate content over time period.
Open Access
Nitrogen, phosphorus and potassium management for wheat in poplar based agroforestry system
(Punjab Agricultural University, Ludhiana, 2019) Janpriya Kaur; Baljit Singh
The present studies were conducted to evaluate the influence of different levels of N, P and K on wheat productivity in poplar plantations. Litterfall addition, return and release of nutrients through decomposition of litterfall were also evaluated. Wheat intercropped with different aged (2, 3, 5 and 6 year) poplar plantation and sole wheat was treated with different levels of N (0, 60, 90, 120, 150, 180 kg N/ha and LCC based-115 kg N/ha) and also different levels of nutrients (P and K) i.e. 0:0, 60:0. 60:30, 60:90, 90:0, 90:30 and 90:60 kg P2O5:K2O kg/ha in another experiment. Results indicated that growth, yield parameters, yield and nutrient (N, P and K) uptake by wheat grains and straw decreased significantly with increasing tree age but increased significantly with N fertilization. The best N level for wheat growth, yield, nutrient use efficiency and nutrient uptake under trees was LCC based application followed by 180 kg N/ha. Highest grain yield (44.2 q/ha), nutrient uptake by grains (kg/ha) i.e. N (86.1), P (14.27) and K (33.8) were obtained on fertilization with 180 kg N/ha while agronomic efficiency was maximum (18.4 kg grains/kg N applied) in LCC based treatment. Nutrient content and soil properties (OC, available N, P and K) showed a significant increase with tree age and N fertilization to maximum with 180 kg N/ha. Results of experiment with variable P, K levels indicated that wheat growth, yield, nutrients content, uptake and soil properties (OC, available N, P and K) under trees increased on fertilization with nutrients to maximum in T7 (90:60 kg P2O5:K2O/ha). In another experiment litterfall addition and return of nutrients showed significant increase with advancing tree age (2 to 6 years) and months of litterfall (October to December). The highest litterfall (5.51 t/ha) and among macronutrients maximum return of Ca (104.8 kg/ha) and in micronutrients highest return of Fe (7529 g/ha) was observed in 6 year plantation. Macronutrient return followed trend Ca>N>Mg>K>S>P and micronutrients Fe>Mn>Zn>Cu. Release of nutrients from litter under 2 and 5 year poplar with 120 and 180 kg N/ha increased with increasing N levels and time of decomposition to maximum with 180 kg N/ha 2 year plantation. Order of nutrient release was K>P>N. In incubation study, available N, P and K increased to maximum in soil amended with 0.3 % leaf litter levels treated with 75 mg N/kg soil at 90 days of incubation.
Open Access
Dynamics of soil phosphorus in relation to carbon under different cropping systems
(Punjab Agricultural University, Ludhiana, 2016) Dhram Prakash; Benbi, D.K.
Dynamics of phosphorus in soils were studied in relation to nutrient management and land-use practices. The nutrient management practices evaluated included source (rock phosphate and single superphosphate) and rates of P application in rice-wheat system; and integrated nutrient management (INM) and organic farming practices in basmati-wheat system in field experiments conducted at the research farm of Punjab Agricultural University, Ludhiana. The land-uses studied included ricewheat, maize-wheat, cotton-wheat and poplar based agroforestry systems at farmers’ fields in different districts of Punjab. After seven cycles of rice-wheat cropping, farmyard manure (FYM) and rock phosphate (RP) application increased available P and soil organic carbon (SOC) by 72% and 98%, respectively over control. Inorganic P constituted the largest proportion (88-92%) of total P in soil and relative abundance of different inorganic P fractions in soils followed the order Ca-Al associated > Fe associated > humic bound > water soluble P. In basmati-wheat system, application of recommended rates of NPK and adoption of INM improved available P in soil over unamended control by 75 and 100%, respectively. The comparison of three organic sources revealed that available P was the highest in soil receiving 400 kg N ha-1 through FYM followed by rice straw compost and the lowest in vermicompost-amended plots. Application of FYM significantly increased inorganic, organic and total P, SOC and labile C pools compared to INM treatments. The INM increased inorganic, organic and total P by 77, 82 and 78%, respectively over NPK. Humic-bound organic P constituted major proportion (39.5-49.5%) and water soluble organic P comprised the smallest proportion (0.83-2.5%) of organic P in soils under basmati-wheat system. Beneficial effects of different treatments on soil properties were higher in surface soil (0-7.5 cm), which decreased with soil depth. Generally, soil P fractions were positively correlated with soil C pools. Cumulative P released in 96 hours of equilibration increased with manure and fertilizer application either alone or in combination. Phosphorus release kinetics were best described by Elovich and power function equations (R2≥0.98). Results of land-use studies showed that agroforestry systems had relatively higher proportion of organic P (27%) compared to sole cropping (6-7.7%). Soil organic C was the highest (0.58%) under agroforestry and was significantly correlated with soil P fractions under sole cropping systems. Soil properties viz. clay, organic C, CaCO3 and available P content significantly influenced soil P sorption and release kinetics. Phosphorus release decreased with increase in clay and CaCO3 content. On the contrary, P release increased with increase in available P and organic C. The results suggested that P availability will be higher in coarse-textured, non-calcareous soils having higher levels of organic C and available P. Therefore, for efficient P management it is important to take into account soil texture, the existing soil P level, organic C content and calcareousness of soil. Practices that increase SOC content and ameliorate CaCO3 could lead to improved P use efficiency.
Open Access
Contribution of different chemical pools of potassium towards wheat nutrition
(Punjab Agricultural University, Ludhiana, 2019) Harpreet Kaur; Gill, Roopinder Singh
The field and pot experiments were conducted to study the effect of potassium (K) application on availability of K to wheat and contribution of exchangeable and non exchangeable K towards wheat nutrition. In pot experiment, twenty bulk soil samples having a range in available K were used and K was applied @ 0, 15, 20, 25 and 30 kg K ha-1soil. Wheat (cv PBW 725) was grown as a test crop. The different potassium fractions i.e. water soluble, exchangeable, available and non exchangeable K were determined. The amount of corresponding forms ranged between 8.86 to 23.7, 66.1 to 379.8, 75.1 to 403.1 and 898.4 to 1861.3 mg kg-1 soil in these soils. The mean grain yield varied from 8.43 to 20.58 g pot-1. All the forms of K showed positive and significant correlation with grain & straw yield, K content and K uptake. The highest positive and significant correlation of wheat grain yield was found to be with water soluble K (r = 0.905*) followed by available K (r = 0.836*), exchangeable K (r = 0.831*) and non exchangeable K (0.815*). In K deficient oils, grain yield of wheat increased significantly with graded levels of applied K. However, in K sufficient soils, grain yield increased significantly up to application of 25 kg K ha-1. In both K deficient and sufficient soils, K concentration and uptake by grain and straw of wheat increased significantly with incremental levels of applied K. About 83.6 per cent variation in grain yield of wheat was due to the combined influence of water soluble and exchangeable potassium while available and non exchangeable form of potassium explained only 2.3 per cent variation in grain yield of wheat. However, in K deficient soils, contribution of non exchangeable K towards grain yield was higher as compared to K sufficient soils. The critical limit of available and non exchangeable potassium for wheat as determined by graphical method was 168 and 1338 kg K ha-1, respectively. The field experiment was conducted at two sites, at the Research Farm of Department of Soil Science, Punjab Agricultural University (PAU), Ludhiana (medium in available potassium i.e. 228.9 kg ha-1) and at Regional Research Station, Gurdaspur (low in available potassium i.e. 125.6 kg ha-1). The K was applied @ 0, 10, 15, 20, 25, 30, 35 and 40 kg K ha-1 soil and wheat (cv PBW 725) was grown as test crop. The mean grain yield in PAU, Ludhiana and RRS, Gurdaspur soil was found 47.5 and 42.5 q ha-1, respectively. In PAU, Ludhiana soil, the significant response of wheat to applied potassium was recorded up to 25 kg K ha-1 soil, however, in RRS, Gurdaspur soil response was recorded up to 40 kg K ha-1. The water soluble, exchangeable, available and non exchangeable K were found to be 13.8, 75.9, 84.5 and 1053.6 mg kg-1 soil, respectively in PAU, Ludhiana soil and 10.1, 61.1, 70.5 and 969.7 mg kg-1 soil, respectively, in RRS, Gurdaspur soil. The kinetics of non-exchangeable K release from ten bulk soil samples having a range in available K was investigated using 0.01 M oxalic acid. The cumulative amount of K released in 200 h ranged between 86 and 253 cmol kg-1 x 10-2. The highest amount of non exchangeable K release (253 cmol kg-1 x 10-2) was found in Mansa soil (sufficient in K) and lowest amount (86 cmol kg-1 x 10-2) was recorded in Gurdaspur soil (deficient in K). Kinetics of non exchangeable K release from soils were adequately described by Elovich, first order, power function and parabolic diffusion models while zero order model was not suitable to describe K release.
Open Access
Effect of residue management tillage and irrigation on water balance of direct seeded rice and wheat
(Punjab Agricultural University, Ludhiana, 2019) Gurpreet Singh; Singh, K. B.
Adoption of proper tillage and residue management practices are must for sustaining soil and crop productivity. Residue retention or incorporation with proper irrigation scheduling improves soil water storage, soil physical characteristics and crop productivity. However, the tillage and residue management practices are very site specific. Therefore, field experimets were conducted during rabi 2015-16 and 2016- 17 and kharif 2016 and 2017. Wheat was sown with three residue management tillage systems (residue incorporation, residue standing and residue removal) under flood and drip irrigation. Rice seeds were directly sown in previously established main plots of residue management tillage (same as in wheat) and further wheat residue incorporation and removal in sub-plots along with flood and drip irrigation. The data indicated that during 2015-16 and 2016-17, all growth attributes of wheat i.e., plant height, leaf area index (LAI) and dry matter accumulation (DMA) were highest in reisdue incorporation with drip iriigation. The yield attributes i.e., grain yield and biological yield were also highest in residue incorporation with drip irrigation (RI+D) and lowest in residue removal with flood irrigation (RR+F). During 2015-16 and 2016- 17, maximum amount of irrigation water was received by RR+F (29.76 and 29.07 cm) and lowest amount of irrigation water was received by RI+D (20.51 and 19.66 cm). Maximum soil water contribution to wheat crop was also observed from RI+D. Irrespective of irrigation treatments, residue incorporation also resulted in 2.65% lower bulk density and 11.67% higher saturated hydraulic conductivity at 0-7.5 cm soil depth and 28.57% higher final infiltration rate, 41.46% higher mean weight diameter and 29.03% higher organic carbon as compared residue removal treatment after 2 years. Crop water productivity was significantly more under drip irrigation as compared to flood irrigation during 2016-17. However, apparent water productivity was significantly higher under residue incorporation as compared to residue standing and residue removal. In direct seeded rice, during 2016 and 2017, all growth attributes i.e., plant height, LAI and DMA of DSR was highest in the treatment which received double incorporation (incorporation of paddy straw and wheat straw). Combination of residue incorporation with drip irrigation resulted in highest values of crop growth attributes. The yield attributes i.e., grain yield and biological yield was 20.31 and 17.59% higher in residue incorporation as compared to residue removal during 2017. All flood irrigated plots received same amount of irrigation 109.53 and 116.95 cm during 2016 and 2017, respectively. The lowest amount of irrigation 98.12 and 103.61 cm during 2016 and 2017 was received by RI-RI+D. Residue incorporation also resulted in lowest drainage and more soil moisture storage at harvesting of direct seeded rice during both years. Residue incorporation resulted in significant reduction in soil bulk density of surface soil (0-15 cm) after harvesting of rice during both years. Saturated hydraulic conductivity and soil infiltration rate also improved under residue incorporation. The study finally concluded that residue incorporation along with drip irrigation saves irrigation water and improves soil moisture storage and crop performance.
Open Access
Effect of tillage, green manuring, rice establishment methods and crop residue management practices on micronutrient uptake and transformation under rice-wheat cropping system
(Punjab Agricultural University, Ludhiana, 2018) Mandeep Kaur; Dhaliwal, S.S.
The present study was carried out under two on-going field experiments at research farm, Department of Soil Science, Punjab Agricultural University, Ludhiana in split plot design with three replications. The soil of both experimental fields was loamy sand in texture, taxonomically classified as Typic Ustrochrept. The first experiment comprised of twelve treatment combinations among which the main plots consisted of four rice establishment methods viz. direct seeded rice under zero tillage (DSR-ZT), conventional tillage (DSR-CT), reduced tillage (DSR-RT) and puddled transplanted rice (PTR) and three subplots in wheat viz. conventional tillage (CTW-R), zero tillage without rice straw (ZTW-R) and zero till with rice straw (ZTW+R). In this study, soil samples were analyzed for basic chemical indices of soil quality. The DTPA-extractable micronutrient cations (Zn, Fe, Mn and Cu) and their different chemical fractions were analyzed using atomic absorption spectrophotometer (Varion AAS-FS Model). The ZTW+R showed marked increase in concentration of DTPA-extractable Zn, Fe, Mn and Cu and their transformation from occluded fractions towards bio-available forms. Residual fraction of all the micronutrient cations was found to be the most dominant fraction and water soluble + exchangeable fraction was found to be least dominant in soil. Organically bound fraction of all the micronutrient cations studied was found to be most important fraction contributing towards micronutrient uptake by both rice and wheat crops. The ZTW+R produced significantly higher wheat grain yield than ZTW-R. Moreover, rice grain yield under PTR and DSR-RT was comparable but significantly higher than DSR-CT and DSR-ZT. The second experiment consisted of twelve treatment combinations among which the four main plots comprised of puddled transplanted rice with no wheat straw retained (PTRW0), puddled transplanted rice with 25% anchored wheat straw retained (PTRW25), PTRW0 + GM and PTRW25 + GM. Similarly, three subplot treatments included conventional tillage wheat without rice residue (CTWR0) zero tillage wheat without rice residue (ZTWR0) and ZTW with 100% rice residue retained as mulch (ZTWR100) in subsequent wheat crop. The results of the study revealed that soil pH decreased however, SOC and availability of DTPA-extractable micronutrients increased with crop residue retention and GM incorporation in soil. The DTPA-extractable Zn, Cu, Fe and Mn showed sharp decrease from 0-7.5 cm to 7.5-15 cm soil depth and afterwards the decrease was gradual with further increase in soil depth. The transformation of Zn, Cu, Fe and Mn was found higher under PTRW25 + GM treatment from occluded (AFeOx and CFeOx) fractions to mobile (WSEX) ones. Highest productivity and Zn, Cu, Fe and Mn uptake by grain and straw of rice and wheat were also recorded under PTRW25 + GM treatment. In nutshell, green manure incorporation and crop residue retention over the soil surface substantially increased the crop productivity and availability of Zn, Fe, Mn and Cu in soil.
Open Access
Behaviour and availability of boron in soils under cotton-wheat rotation
(Punjab Agricultural University, Ludhiana, 2017) Boparai, Arpandeep Kaur; Manchanda, J.S.
Surface (0-15 cm, n=155) and profile (0-15, 15-30, 30-60, 60-90 cm, n=8) soil samples, cotton leaves at pre flowering stage (n=75), wheat flag leaves (n=80) and tube well water (n=75) samples were collected from Bathinda, Mansa and Mukatsar districts of Punjab. About 5, 18 and 20 per cent of soil, cotton and wheat samples were deficient in B, respectively. Hot water soluble B in soil was significantly positively correlated with pH (r= 0.230*), ESP (0.680**), B concentration in leaves of cotton (r=0.259*) and wheat (r=0.531**) but negatively with CaCO3 in soil (r= -0.210*). About 40 per cent of tubewell waters had >2.0 mg B l-1. On an average, one cm ha of tube well water may add up to 93g B ha-1 to soil. Boron concentration in tubewell water was significantly positively correlated with HWS-B (r=0.286**) and cotton leaf B (r=0.286*). Available B in soil decreased with soil depth (0-90 cm). Two field experiments were conducted to study the response of cotton (Bt cv. RCH 650 BGII; non Bt cv. F 2228; desi cv. FDK 124) and wheat cultivars (T. aestivum cv. PBW 62; T. durum cv. PDW 314; Triticale cv. TL 2908) to B application (0, 0.5, 1.0 and 2.0 kg B ha-1 as borax) using a Typic Ustrochrept, loamy sand (pH 7.2, EC 0.36 dS m-1, HWS-B 0.36 mg kg-1 soil) soil. A significant response of 2.18 and 1.52 q ha-1 in seed cotton and grain yield of wheat was recorded with an application of 1.0 and 0.5 kg B ha-1, respectively. Boron concentration in different plant parts of cotton followed the order: leaves>boll squares>petioles>sticks. On the basis of agronomic and B uptake efficiency, cultivars of cotton (RCH 650 BG II > FDK 124 > F 2228) and wheat (PDW 314>TL 2908>PBW 621) responded differentially to B application thus indicating that yield of Bt cotton and durum wheat will be reduced more than the other cultivars under B deficiency. Two pot studies were conducted, using the same soil as was used for field experiments, to study the effect of boron (0, 0.12, 0.25, 0.50, 0.75, 1.0, 2.0 3.0, 4.0, 5.0 and 10 mg B kg-1 soil as borax) and commercial grade calcium carbonate (0, 1.25, 2.5 and 5.0% w/w as) on growth and yield of cotton (cv. RCH 650 BG II) and wheat (cv. PBW 621). In the absence of applied CaCO3, growth of cotton and wheat was reduced when B was applied in excess of 2.0 mg kg-1 soil. Necrosis of leaves from tip to margin in cotton and purple coloration of plumule in wheat was observed with application of 10.0 mg B kg-1 soil. Application of CaCO3 (1.25, 2.5 and 5.0% w/w) significantly improved the growth of both the crops. Irrespective of the levels of CaCO3, a value of 0.57 and 7.67 mg HWS-B kg-1 soil, a concentration of 62 and 940 mg B kg-1 dry matter of leaves, 45 and 210 mg B kg-1 dry matter of petioles and 20 and 51 mg B kg-1 dry matter of sticks, produced 90 and 50% of the maximum dry matter yield of cotton, respectively. The corresponding values for wheat were 0.66 and 6.71 mg HWS-B kg-1 soil, 7.94 and 27.0 mg B kg-1 grain and 15.3 and 170 mg B kg-1 straw, respectively. Twenty one surface (0-15 cm) soil samples selected from those collected from different districts were analyzed to estimate chemical pools of B and available B by using different extractants (NH4OAc, AB-DTPA, hot and cold calcium chloride, tartaric acid, HCl, mannitol and hot water soluble). The amount of B in readily soluble, specifically adsorbed, oxide bound, organically bound and residual mineral fraction varied from 0.17 to 2.71, 0.14 to 1.77, 0.31 to 5.88, 0.56 to 7.42 and 0.17 to 2.71 per cent of total B in soils, respectively. Of the several extractants, NH4OAc extracted the minimum (0.39 to 3.53 mg B kg-1 soil) and HCl extracted the maximum (1.16 to 14.74 mg B kg-1 soil) amount of available B in the soils. HWS-B was significantly and positively correlated with B extracted by other reagents (r=0.772** to 0.905**) thus indicating that these extractants may also be used to delineate the available B status in soils of arid region.
Open Access
CARBON AND PHOSPHORUS DYNAMICS IN SOIL IN RELATION TO NUTRIENT MANAGEMENT IN RICE-WHEAT SYSTEM
(PAU Ludhiana, 2012) Seema Sharma; G. S., Saroa
The study comprised of two field and two laboratory experiments. In field experiment on organic and integrated nutrient management of basmati-wheat sequence, the effect of inorganic, organic and integrated nutrient management was studied on crop yield and soil properties. Water infiltration rate was highest and soil bulk density was lowest in recommended fertilizer + FYM (INM2) treatement. Total water stable aggregates (WSA) in the 0-15 cm soil depth ranged from 58.5 to 82.4 per cent; minimum WSA were observed in control and maximum in INM2 treatment. Among the aggregates 0.11-0.25 mm fraction constituted the greatest proportion and > 2 mm fraction constituted the least proportion. Maximum pH and EC were recorded in control plots and minimum in plots receiving 400 kg N ha-1 through FYM. Soil organic carbon (SOC), aggregate associated C, labile C and hot water soluble C was highest in FYM 400N treatment. Ammonical-N, nitrate-N, Olsen P, Bray I P, ammonium acetate extractable K, soil P fractions and total P in soil were highest in INM2 treatment and lowest in control. Grain yield, straw yield, NPK content and their uptake by basmati and wheat were maximum in INM2 treatment and minimum in control. Basmati and wheat grain yield were significantly correlated with soil P fractions and the highest correlation was observed with saloid-P. In the second experiment, effect of rock phosphate on crop yield and P fractions in soil under rice-wheat sequence was studied. Highest SOC, Olsen P, soil P fractions, ammonium extractable K and non-exchangeable K were recorded in rock phosphate (RP) and FYM treatment and lowest content of all these parameters was observed in control. Highest pH was observed in control P treatment and lowest in treatment where FYM was applied along with RP. Grain yield, straw yield, NPK content and uptake in grain and straw were also highest in plots recieving P from RP along with FYM. Grain and straw yield of both the crops were significantly correlated with all the soil P fractions (Sa-P, Al-P, Fe-P and Ca-P). Highest correlation of paddy grain yield was observed with Sa-P whereas wheat grain yield gave highest correlation with Al-P fraction and lowest with Ca-P. Rock phosphate gave almost similar crop yield and P availability in soil as that with SSP. In laboratory study I, P was extracted by different methods and the lowest amount of P was extracted with AB-DTPA and the highest with Bray-I method. Phosphorus extracted by Olsen, Bray-I, Morgan and AB-DTPA methods gave significant positive correlations with grain yield and nutrient uptake of paddy and wheat. In the soils from long-term experiments with different fertilization history, maximum P adsorption was observed in unammended soil and minimum in soils where FYM was applied alongwith chemical fertilizer. Contrarily, desorption was minimum in control plots and maximum in plots where organic sources along with inorganic fertilizers were applied. Adsorption data fitted well to both Freunlich and Lagmuir models. .
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Studies On Moisture Regime And Nitrogen Fertilizer Interaction In Winter Sunflower
(Punjab Agricultural University ;Ludhiana, 2002) Satwinderjit Kaur; Hira, G S

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