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Open Access
Assessment and development of microbial biofilms for efficient degradation of paddy straw
(Punjab Agricultural University, Ludhiana, 2020) Gurshinderdeep Singh; Neemisha
An experiment was conducted to assess the potential of lignocellulolytic microorganisms and their biofilms for paddy straw degradation. Fifty four fungal and 10 bacterial cultures were screened qualitatively on the basis of zone formation for cellulolytic (31 cultures,0.2-5.1cm), hemi-cellulolytic (13 cultures,0.3-1.8cm) and lignolytic activities (15 cultures,0.2-1.8cm). Quantitatively, during submerged and solid state fermentation, highest cellulase and laccase activities were obtained by culture17 (0.709IC/ml and 0.666IU/ml), and Lignin7 (0.821CU/ml and 3.919CU/ml), whereas, highest xylanase activity was observed in culture F2C5 (0.840IU/ml) and L1C8 (1.555IU/ml), respectively. On the basis of functional properties and growth characteristics, 11 lignolytic, 10 cellulolytic and 9 xylanolytic cultures were used for interaction studies. After testing for compatibility, cellulolytic (Culture17&Compost fungus), xylanolytic (F2C5&L1C8) and lignolytic fungi (Lignin7&White4) were selected for biofilm formation. Under laboratory conditions, the biofilms were used for paddy straw degradation and treatment T14(Bacillus subtilis+CF1+CF2+XF1+XF2+LF1+LF2) showed best results after 30&60 days for reducing cellulose (28.9&24.1%), hemicellulose (16.6&13.4%) and lignin (6.8&5.8%) content of paddy straw. The effect of sequential addition of cellulolytic, hemi-cellulolytic and lignolytic cultures on paddy straw degradation was tested for 21 days in which treatment B14 resulted in highest decrease in cellulose (32.8%), hemicellulose (24.3%) and lignin (7.3%). The best biofilm was further evaluated using different N and C sources and treatment T7 supplemented with ammonium sulphate@0.5% and jaggery@1% was found to be most effective in degrading the paddy straw. A significant reduction was observed in cellulose (26.0%), hemicellulose (31.2%) and lignin (44.4%) content as compared to 9.4%, 6.8% and 22.6% in control, respectively.
Open Access
Bioavailability of heavy metals to maize grown in sewage sludge amended soil
(Punjab Agricultural University, Ludhiana, 2020) Gupta, Soura Shuvra; Dhanwinder Singh
Sludge generated from the sewage treatment plants (STPs) has a potential for its use in agriculture, as it contains a good amount of organic carbon as well as macro and micro nutrients. However, due to the presence of heavy metals, its use in agriculture is restricted. If used judiciously, it can become one of the alternates to the organic manures. A field experiment was conducted at the research farm of Department of Soil science, PAU, Ludhiana to evaluate the different rates (0, 2.5, 5, 7.5 and 10 t/ha) of sewage sludge along with three different levels of nitrogen (0, 90, 120 kg N/ha) on dry matter yield of maize (Zea mays var PMH 1) and to study the bioavailability and transformations of heavy metals in post-harvest soil. Application of sewage sludge up to 5 t/ha along with 120 kg N ha-1increased the maize grain and stover yield significantly. The maize grain yield increased from 30 q/ha in absolute control to52.6 q/ha and maize stover yield increased from 67 q/ha to 109.6 q/ha with the application of sludge @5 t/ha along with 120 kg N/ha. Heavy metals (cadmium, chromium, lead and nickel) content in maize grain and stover and their uptake also increased significantly with the increasing rate of sludge application. The mean cadmium, chromium, lead and nickel content in maize grains increased from 0.015 to 0.032 mg/kg, 0.629 to 0.698 mg/kg, 0.157 to 0.195 mg/kg and 0.93 to 1.61 mg/kg, respectively with the highest rate of sludge application. These concentrations were within the respective permissible limit given by FAO/WHO. Sequential fractionation of post-harvest soil samples suggested that proportion of Cd and Pb to their total content significantly increased in the labile fraction of soil pool and percentage of Ni and Cr to total significantly increased in the residual fraction with application of 10 t/ha sludge over control. Application of 5 t/ha could be more sustainable approach for a longer period.
Open Access
Assessment of water quality of river Beas, Punjab
(Punjab Agricultural University, Ludhiana, 2020) Kundel, Aman; Kuldip Singh
A systematic study was carried out assess temporal and spatial variation of physico-chemical parameters and heavy metals in Beas river water. Sixty water samples were collected from five different locations (Mukaian, Bhet, Tanda, Dhilwan and Goindwal) in four different sesaons (pre-monsoon, monsoon, post-monsoon and winter). The water quality assessment is made by estimating pH, electrical conductivity (EC), major ions (Ca2+, Mg2+, K+, Na+, Cl-, HCO3-), biological oxygen demand (BOD) and chemical oxygen demand (COD). Water quality index (WQI), heavy metal pollution index (HPI), hazard quotient (HQ), hazard index (HI) and cancer risk (CR), was estimated to assess river water pollution. The water quality parameters like pH, EC, Ca2+, Mg2+,K+, Na+, Cl-, HCO3- and COD were within acceptable limits except BOD in some of the samples as per Bureau of Indian standards (2012). All the heavy metals (HM) were also within acceptable limits except arsenic in 10% of samples postmonsoon season. On the basis of physico-chemical parameters such as pH, EC, Ca2+, Mg2+,K+, Na+, Cl-, HCO3- , BOD, COD and heavy metals, river water quality was found fit for drinking purpose after filtration and chlorination. Irrigation water quality parameters such as RSC, SAR, %Na, MR and KAR was found in excellent class. Water quality index (WQI) falls under the medium class (0.50-0.70) where as heavy metal pollution index (HPI) falls under excellent (Ni>Cd>Cr indicating least cancer risk due to HM. The study revealed that children were more sensitive (0.455) than adults (0.437) to CR. Since some of the heavy metals exceed the critical limits, therefore long term monitoring is required to assess the water quality of Beas River for its use in agricultural and drinking purpose.
Open Access
Temporal biochemical changes under tillage and rice residue management in rice-wheat system
(Punjab Agricultural University, Ludhiana-, 2020) Pankaj; Sharma, Sandeep
To maintain agricultural productivity and environmental integrity, it is crucial that soil quality to be improved or maintained. Crop residues are the non-utilized sources of renewable biomass generated in large quantities in agriculture and excess residues are disposed by means of burning. Fourteen treatment combinations of fertilizer dose, tillage and residue management included two main plots treatments of nitrogen (N) application in wheat (1) N75, 75% recommended dose of nitrogen and (2) N100, 100% recommended dose of nitrogen and seven subplot treatments (1) CT-R, 100% rice residue removed- Conventional Tillage (2) RS-R, 100% rice residue removed and sowing with Rotoseeder (3) HS+R50, loose rice residue removed and sowing with happy seeder (4) HS+R100, 100% rice residue retained and sowing with Happy seeder (5) RS+R50, loose removal of rice residue and sowing with Rotoseeder (6) RS+R100, 100% rice residue retained and sowing with Rotoseeder (7) CT+R100, 100% incorporation of rice residue and sowing with drill in wheat. The present study evaluated the effects of N application, tillage and rice residue management practices in wheat on changes in soil enzyme (dehydrongenase, fluorescein diacetate, alkaline phosphatase, β-glucosidase, xylanase, cellulase, polyphenol oxidase, peroxidase) activities, microbial biomass carbon, soil respiration, microbial count (bacteria, fungi, actinomycetes, Agrobacterium, Rhizobium and Azotobactor), quotients (microbial quotient, metabolic quotient and metabolic potential), chemical properties (soil organic carbon and water soluble organic carbon) at different growth stages of wheat during 5th cycle of continuous rice-wheat system. The results showed that integrated use of fertilizer N and residue management practices increased wheat yield, water soluble carbon and soil enzyme activities except polyphenol oxidase and peroxidase as compared to conventional practices (CT – R and RS – R). The majority of enzyme activities were higher at vigorous vegetative growth stage as compared to reproductive growth stage. Soil enzyme activities were significantly and positively correlated with each other, microbial biomass carbon and water soluble carbon except polyphenol oxidase activity, peroxidase activity and metabolic quotient. Principle component analysis (PCA) identified dehydrogenase, soil organic carbon, metabolic potential as the most sensitive indicators for assessing soil quality for conservation agriculture based rice-wheat system in surface soil layer. The present study provided reliable biochemical indicators to monitor the changes in soil biological quality response to conservation agriculture practices in rice-wheat system.
Open Access
Effect of irrigation in combination with farmyard manure, biochar and nitrogen levels on growth and water productivity of spring maize
(Punjab Agricultural University, Ludhiana, 2020) Goyal, Ruchi; Kahlon, M.S.
The use of biochar and other organic amendments not only reduce the dosage of fertilizers but also helps in improving soil physical health, crop growth and water productivity. Thus, a field experiment was conducted on spring maize in split plot design with three replications having six organic and inorganic treatment combinations i.e. BN1 (biochar @ 7.5 t ha-1 + N @ 75 kg ha-1), BN2 (biochar @ 7.5 t ha-1 + N @ 150 kg ha-1), FN1 (farmyard manure @ 20 t ha-1 + N @ 75 kg ha-1), FN2 (farmyard manure @ 20 t ha-1 + N @ 150 kg ha-1), N1 ( N @ 75 kg ha-1) and N2 (N @ 150 kg ha-1) in main plots and two irrigation regimes i.e. Irrigation Water/ Cummulative Pan Evaporation I1 (IW/CPE ratio 0.6) and I2 (IW/CPE ratio 0.9) in sub plots. Significant differences due to amendments were reported for soil moisture retention, mean weight diameter and saturated hydraulic conductivity. Maximum soil moisture retention at 0.3 bar was observed in biochar treatment BN1 i.e. 30.0%, while the minimum was recorded in N2 i.e. 25.5%.Among plant parameters, maximum plant height, SPAD value, crop biomass, thousand grain weight, grain yield and water productivity were recorded in BN2 which were 12.3 %, 20.4 %, 25.2 %, 11.3%, 28.5 % and 41.3 % higher over control i.e. N2 treatment. Irrigation regime I2 significantly increased the relative leaf water content, crop biomass, thousand grain weight, harvest index and grain yield by 1.2 %, 2.0 %, 3.9 %, 5.2 % and 11.8 % over I1 regime. Hence, it is concluded that for improving soil physical health, crop growth and water productivity the biochar treatment i.e. BN2 along with IW/CPE ratio 0.9 is a suitable practice for northwest India, however, under limited resources BN1 along with IW/CPE ratio 0.6 may be suitable option for achieving optimum productivity.
Open Access
Soil carbon and nitrogen pools in different tree based systems
(Punjab Agricultural University, Ludhiana-, 2020) Jagmanjot Singh; Baljit Singh
Agroforestry systems improve carbon sequestration and regulate nutrients in the soil. The present study was conducted to investigate carbon and nitrogen pools, nutrient status and physico-chemical properties of soil in seven land use systems namely poplar (Populus deltoides) + fodder wheat, eucalyptus (Eucalyptus tereticornis) + fodder wheat, sole fodder wheat rotation, poplar + citrus, eucalyptus + citrus, sole citrus and fallow land at four depths (0-15, 15-30, 30-45 and 45-60 cm) in Hoshiarpur district of Punjab. Poplar + fodder wheat system had highest soil organic carbon (SOC) and total carbon (TC). In citrus based systems, poplar + citrus had higher SOC and TC than eucalyptus + citrus and sole citrus. The highest concentrations of very labile, labile, less labile and recalcitrant carbon were 2.75, 2.37, 2.97 and 2.69 g kg-1, respectively in poplar + fodder wheat and lowest were 0.51, 0.41, 0.91 and 0.33 g kg-1, respectively in fallow land. Water soluble carbon and microbial biomass carbon decreased with depth and ranged from 11.14-17.74 and 0.042-0.147 mg kg-1, respectively in 0-15 cm depth. Total nitrogen, NH4+-N, NO3--N, available N, P and K were higher in tree based systems. The DTPA extractable Zn, Cu, Fe, and Mn increased by 64.8, 54.0, 50.9, 46.1%, respectively in poplar + fodder wheat in surface depth over control. The WHC, EC, CEC reduced while pH and bulk density increased with soil depth. Hence, long term tree based systems enhanced soil carbon and nitrogen pools and improved nutrient status and physico-chemical properties of soil.
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Effect of long-term integrated nutrient management on the availability of micronutrients in soil under rice-wheat cropping system
(Punjab Agricultural University, Ludhiana, 2020) Prabhjot Singh; Saini, S.P.
The present research study was conducted to investigate the effect of long-term integrated nutrient management on the availability of micronutrients in soil under rice-wheat cropping system. The experiment was carried out in the ongoing long-term fertilizer experiment initiated during 1999 at research farm of Department of Soil Science, Punjab Agricultural University, Ludhiana. The experiment was conducted in randomized block design with nine treatments replicated three times for rice-wheat cropping system by growing PR 126 (rice) and Unnat PBW 550 (wheat) varieties during 2017-18. There were total of nine different treatments comprising control, 50% NPK+FYM, 50% NPK+GM, 100% NPK, 100% NPK (P wheat), 100% NPK+FYM, 100% NPK+GM, 100% NPK+SI and 150% NPK. The soil of the experimental area was loamy sand in texture, (Typic Ustrocherpt), low in soil organic C, available-N and K, medium in, P. Surface and sub-surface soil samples were collected after harvest of wheat crop and analyzed for different micronutrient cations (Zn, Fe, Mn and Cu) and various chemical properties of soil in 2018. Highest nutrient uptake, yield and yield contributing attributes in wheat and rice crop were recorded under treatments with conjunctive use of inorganic fertilizers and organic amendments. Micronutrients content and its uptake in both wheat and rice at different growth stages (max. tillering and anthesis) was increased with graded dose of fertilizers and highest content and uptake of micronutrients was recorded in 100% NPK+FYM treatment as compared to other treatments. Various soil properties such as SOC, available N, available P and available K improved with the continuous application of fertilizers and organic amendments. On the contrary, soil pH decreased with integrated nutrient management system. Use of organic amendments along with chemical fertilizers also led to Zn-fortification of grains in both wheat and rice crops. Availability of DTPA-extractable micronutrient cations also increased with long-term use of fertilizers and organic amendments. Periodic changes in micronutrients availability might be due to decrease in soil pH and increase in SOC over period of time.
Open Access
Effect of different cropping systems on manganese availability and transformations in soils
(Punjab Agricultural University, Ludhiana-, 2020) Mittal, Shreyansh; Saini, Sat Pal
The present research study was conducted to investigate the transformation and depth-wise distribution of manganese (Mn) in soils under different cropping systems viz. rice-wheat (RWCS), maize-wheat (MWCS) and cotton-wheat (CWCS). A total of 150 surface (0-15 cm, 50 samples per cropping system) and 18 profile (0-15, 15-30, 30-60, 60-90 cm, 6 per cropping system) samples were collected from three different districts viz. Ludhiana (for RWCS), Ropar (for MWCS) and Mansa (for CWCS) in Punjab (India). In addition, 150 plant leaf (flag leaf of rice, fully extended leaf of maize and a fully matured leaf of cotton (50 each for crop) and 150 wheat leaf samples were collected from each soil sampling location. Soils of MWCS had significantly higher mean DTPA-Mn and other fractions of variable solubility, compared with the soils of other two investigated cropping systems. On the other hand, DTPA-Mn and the concentration of different chemical fractions in soils under RWCS were significantly lower. The soils under CWCS had significantly (p<0.05) higher soil pH, E.C. and CaCO3 as compared to other cropping systems. The DTPA-Mn was lowest in the surface (0-15 cm) soil layer, and increased significantly with depth in RWCS, in contrast to a decrease in soils under other two cropping systems. The different fractions of variable solubility viz. WSEX-Mn, SpAD-Mn, OX-Mn, AFeOx-Mn, CFeOX-Mn, OM-Mn and residual-Mn showed significant linear relationship (p<0.05) with soil organic C (SOC) and soils’ fine fraction (silt and clay). The Res-Mn fraction comprised the largest proportion (67-70%) while the WSEX-Mn + SpAD-Mn fraction was the smallest Mn fraction in soils under different cropping systems. Data pooled for different locations revealed that leaf Mn concentration in wheat leaves was highest in crop sown in MWCS, followed by CWCS and the lowest in RWCS. Leaf Mn concentration showed a significant relationship with DTPA-Mn and different Mn fractions. Foliar application of Mn significantly influenced the wheat grain yield, Mn uptake and Mn use efficiency in wheat grown in different cropping systems. A significant response of foliar application of Mn at different growth stages (vegetative as well as ear initiation stage) was observed in all the three cropping systems. A quadratic response of relative grain yield to DTPA-Mn after harvest of wheat revealed that 90% of the maximum yield was achieved with foliar Mn application at 2.98, 3.69 and 3.82 mg DTPA-Mn kg-1 soil for RWCS, MWCS and CWCS, respectively. Soil and foliar application of MnSO4 (25 and 50 ppm) either alone or conjointly with FYM and PM (0.5%) in a pot experiment significantly increased the growth parameters and productivity of wheat cultivars (PBW 725 and PDW 314) and Mn fractions in soil. Soil application of MnSO4 either alone or conjointly with organic manures significantly increased the concentration of DTPA-Mn, totalMn, WSEX-Mn, SpAd-Mn, Ox-Mn, AFeOX-Mn and CFeOX-Mn, OM-Mn and Res-Mn. The relative preponderance of occurrence of different Mn fractions in soil followed an order: OM-Mn
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Geochemical assessment and remediation of arsenic in south-western Punjab
(Punjab Agricultural University, Ludhiana, 2020) Jyoti; Kuldip Singh
Geochemistry and assessment of arsenic (As) in groundwater and soil is an important factor for effective management of the groundwater resource. One hundred twenty groundwater samples, 60 soil samples and 120 paddy straw samples were collected from southern-western districts of Punjab, India: Mansa, Muktsar and Bathinda, during pre- and post-monsoon seasons. Significant and positive correlations were observed between As and RSC content of groundwater in premonsoon season. The paddy straw As content was positively and significantly correlated with As, RSC, redox of groundwater, total and available As content in soil. The available As was significantly and positively correlated with total soil As content. A laboratory investigation was carried out to examine the mechanism of As mobilization under flooded conditions (24 and 240 h) in 10 alluvial soils. Total dissolved As increased from a range of 3.14–16.14 µg l-1 (mean 8.95 µg l-1) to a range of 34.2–1768 µg l-1 (mean 871.5 µg l-1) with the increase in flooding period from 24 to 240 h. The amount of As mobilization varied depending upon redox potential (pe) created by flooding conditions. After 24 h of flooded conditions, pe of soil-water suspension ranged from 2.11 to -0.64 (mean -1.25), whereas, it decreased in the range of -5.23 to -2.55 (mean -3.52) after 240 h of flooding. A loamy sand and a clay soil were used to study adsorption behaviour of arsenate (AsV) by equilibrating soil with range of added concentration (50-2500 mg AsV kg-1 soil) in presence of background electrolyte 0.01 M NaNO3, under two temperatures (278 0K and 308 0 K) and two solution pH (5 and 8.5). Arsenate adsorption was found to increase with increase in temperature as well as with decrease in solution pH, however, amount of AsV adsorbed was relatively higher in clay soil as compared to loamy sand soil. Arsenate adsorption was highest at solution pH 5, 308 0K and lowest in solution pH 8.5, 278 0K, irrespective of soil. Arsenate adsorption data were well described by Langmuir and Freundlich isotherms. To study effect of added anions on AsV adsorption, at each added AsV concentration, 1000 mg anion kg-1 soil was also added. The addition of anions reduced the amount of AsV addition at both temperatures and pH in two soils in the order: phosphate > silicate > sulphate > bicarbonate. For removal of AsV from groundwater, effectiveness of iron-coated sand and iron-coated strips was investigated. Ironcoated strips were found to have relatively higher capacity to remove AsV as compared to ironcoated sand. To study kinetics of AsV adsorption by loamy sand soil, clay soil, iron-coated sand and iron-coated strips, the data were fitted to four kinetic models: Pseudo-first order, pseudosecond order, elovich and intra-particle diffusion models. Among these four kinetic models pseudo-second order gave best fit with high R2 value as well as lower error.

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