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ThesisItem Open Access “Management of nitrogen in dry direct seeded rice for higher yield and nitrogen use efficiency”(Punjab Agricultural University, Ludhiana, 2012) Goyal, Deepak; Thind, Dr. H SThis investigation was carried out to find out the management of nitrogen in dry direct seeded rice (D-DSR) for higher yield and nitrogen use efficiency under field conditions. The experiment consisted of fifteen treatment combinations comprised of three N rates (120, 150, 180 kg N ha-1), four schedules of three rates of N application, two LCC treatments (LCC-3 and LCC-4) and zero - N control. The schedules of N application comprised of N application in three equal split doses applying first dose at basal or 14 DAS (0, 35, 63 and 14, 35, 63 DAS) and application of N in equal four split doses applying first dose at basal or 14 DAS (0, 28, 49, 70 and 14, 28, 49, 70 DAS). It is inferred that 120 kg N ha-1 when applied in three split doses was sufficient to produce optimum grain yield of dry direct seeded rice as further application of 150 or 180 kg N ha-1 did not increase the grain yield significantly. Among the different schedules of N application, three split doses were found to produce significantly higher grain yield than four split doses, at all the N levels. The higher grain yield in three split doses was accompanied by higher N uptake in grain, total N uptake, effective tillers and N translocation efficiency than N applied in four split doses. Harvest index, nitrogen harvest index and translocated N were found to be maximum at 120 kg N ha-1 when applied in three split doses applying first dose at 14 DAS. Agronomic efficiency, physiological efficiency and recovery efficiency were also highest at 120 kg N ha-1when applied in three split doses applying first dose at 14 DAS.ThesisItem Open Access Management of nitrogen in dry direct seeded rice for higher yield and nitrogen use efficiency(Punjab Agricultural University, Ludhiana, 2012) Deepak GoyalThis investigation was carried out to find out the management of nitrogen in dry direct seeded rice (D-DSR) for higher yield and nitrogen use efficiency under field conditions. The experiment consisted of fifteen treatment combinations comprised of three N rates (120, 150, 180 kg N ha-1), four schedules of three rates of N application, two LCC treatments (LCC-3 and LCC-4) and zero - N control. The schedules of N application comprised of N application in three equal split doses applying first dose at basal or 14 DAS (0, 35, 63 and 14, 35, 63 DAS) and application of N in equal four split doses applying first dose at basal or 14 DAS (0, 28, 49, 70 and 14, 28, 49, 70 DAS). It is inferred that 120 kg N ha-1 when applied in three split doses was sufficient to produce optimum grain yield of dry direct seeded rice as further application of 150 or 180 kg N ha-1 did not increase the grain yield significantly. Among the different schedules of N application, three split doses were found to produce significantly higher grain yield than four split doses, at all the N levels. The higher grain yield in three split doses was accompanied by higher N uptake in grain, total N uptake, effective tillers and N translocation efficiency than N applied in four split doses. Harvest index, nitrogen harvest index and translocated N were found to be maximum at 120 kg N ha-1 when applied in three split doses applying first dose at 14 DAS. Agronomic efficiency, physiological efficiency and recovery efficiency were also highest at 120 kg N ha-1when applied in three split doses applying first dose at 14 DAS. Keywords: Agronomic efficiency, Dry direct seeded rice, Grain yield, Nitrogen rates, Physiological efficiency, Recovery efficiency, Schedules of N application.ThesisItem Open Access Evaluation of SUBSTOR-Potato model under different irrigation and fertilizer-nitrogen regimes(Punjab Agricultural University, Ludhiana, 2011) Jiban Chandra NathProper irrigation and fertilization practices are widely needed to improve water productivity, N use efficiency and to reduce the ground water depletion and contamination to groundwater. Crop simulation models provide an alternative, less time-consuming and inexpensive means of determining the optimum crop N and irrigation requirements. This study includes the evaluation of SUBSTOR-Potato model to analyze potato yield responses to water- and N-application for optimizing crop productivity under water limitations in a semi-arid irrigated environment. The treatments included combinations of three irrigation regimes- IW: PAN-E ratio of 2.0 (I1), 1.4 (I2) and 0.8 (I3) and four N rates- 0 (N0), 135 (N1), 180 (N2) and 225 (N3) kg ha-1. Evaluation analysis showed that performance of the model was reasonable as indicated by close agreement of simulated crop phenology, biomass, LAI, water use, soil water storage, tuber yield and N uptake with measured data. The normalized root mean square errors ranged between 10 and 20 % for most of the parameters. Using long term weather data, cumulative probability distribution of simulated tuber yield and ET showed that irrigation effects were greater under fertilized conditions. Scenario analysis also suggested that tuber yield and ET productivity were greater on sandy loam than loamy sand soil for comparable irrigation and N rates. Influence of initial soil water status on tuber yield was greater with increasing N rate. The ET productivity increased with increase in irrigation under low initial soil water status; whereas it increased to a point under high soil water status. Initial soil mineral-N influenced the amount of fertilizer N and post sown irrigation regime to realize a given tuber yield.ThesisItem Open Access OPTIMIZING IRRIGATION AND NITROGEN USE WITH STRAW MULCHING IN POTATO (Solanum tuberosum L.)(2011) Sukhwinder SinghWater and fertilizer are important factors influencing growth, development and tuber yield of potato. Depleting ground water and increasing cost of fertilizers necessitates that these inputs are used efficiently. Straw mulching is likely to enhance tuber yield and conserve irrigation water and fertilizer. A field experiment was conducted at the research farm of the Department of Soil Science, Punjab Agricultural University, Ludhiana on loamy sand soil to optimize irrigation and fertilizer N use of potato with straw mulching. Two rates of rice straw mulch (0 and 6 t ha-1) were imposed in the main plots, three irrigation levels based on IW/PAN-E = 1.0, 1.5 and 2.0 in sub plot and four levels of N @ 0, 135, 180 and 225 kg ha-1 in sub-sub plot. Results revealed that mulching helped to store 5-22 mm more soil moisture in 0-120 cm profile and the differences were larger in top 15 cm layer. Straw mulch lowered maximum soil temperature at 5 cm depth by 0.4 to 7.3°C and raised minimum temperature by 0.4 to 2.9°C. Irrigation water input with IW/PAN-E = 2.0, 1.5 and 1.0 was 24, 16 and 12 cm, respectively. Mulching recorded 25per cent improvement in tuber yield. The WUE improved with N levels and decreasing irrigation water inputs. Mulching also improved irrigation water use efficiency (WUE) by 26.2 kg tuber ha-1 mm-1. Optimum irrigation for maximum tuber yield was at IW/PAN-E =2.0 without mulch and 1.5 with mulch. Tuber yield improved with fertilizer N upto 225 kg ha-1 without mulch but only upto 180 kg N ha-1 in mulched plot. Mulching increased nitrogen use efficiency and it decreased with increasing N rate. Mulching reduced weed infestation and recorded larger size (>50mm) tubers. To conclude, mulching improved tuber yield besides saving irrigation water and fertilizer N.ThesisItem Open Access SOIL WATER DYNAMICS IN DIRECT DRY-SEEDED RICE (Oryza sativa L.) UNDER DIFFERENT IRRIGATION REGIMES(2011) Kanwar, Ajar SinghWater and Labour scarcity in Northwest India are main cause to find alternative management strategies that will increase water productivity and reduce labour requirement while maintaining land productivity. An experiment was conducted at farm of the Department of Soil Science, Punjab Agricultural University Ludhiana, during kharif 2010 to study soil water dynamics in direct dry-seeded rice with respect to different irrigation regimes and cultivars. The treatments comprised of cultivars (PR 114, PR 115 and PR 120) in main and irrigation levels (10, 20, 30 kPa and fixed 6 days interval) in sub-plots. The cultivar PR 120 produced highest crop biomass, root mass and length density, number of tillers, plant height and thousand grain weight. Root mass density increased as soil matric suction increased from 10 to 30 kPa irrigation treatments. The paddy yield was highest (5.7 t ha-1) in PR 120 followed by 5.2 t ha-1 in PR 115 and 4.9 t ha-1 in PR 114. The profile moisture storage was lowest in PR 120 whereas, it was comparable in other cultivars. The irrigation water productivity progressively increased with decrease irrigation water inputs and it was highest 1.03 g kg-1 with 30 kPa plots and lowest (0.54 g kg-1) in 10 kPa plots. The irrigation water productivity was highest in PR 115 (0.88 g kg-1) followed by (0.82 g kg-1) PR 120 and (0.58g kg-1) PR 114.The grain yield and yield attributes of rice decreased significantly at 30 kPa soil matric suction and 6 day interval from that in 10 and 20 kPa treatments. It is concluded that cultivar PR 120 and irrigation regime of 20 kPa at 15-20 cm soil depth was found to be suitable for direct dry-seeded rice.ThesisItem Open Access Effect of different agricultural land uses on carbon sequestration in soils of sub-montaneous districts of Punjab(Punjab Agricultural University, Ludhiana, 2012) Rajwinder KaurThe present study was conducted to study carbon sequestration and its distribution in different soil organic carbon pools and to study soil aggregation and organic carbon storage in different sized aggregates under different land use systems in sub-montaneous districts of Punjab. Two sites selected for the study were Takarla and Mukerian and four land-use systems were selected viz. cropland, forestry, agro-forestry and grassland. Soil pH varied from slightly alkaline to moderate alkaline at Takarla while at Mukerian, soil pH was slightly alkaline. At both sites, pH was higher in grassland and EC was higher in cropland. Forest soils had higher silt and clay content at Takarla, while grassland possessed higher clay content at Mukerian. Bulk density at both sites was higher in cropland. Available N was higher in forestry (234.78 kg ha-1) at Takarla while in Mukerian, it was higher in grassland (199.70 kg ha-1). At both sites, cropland possessed highest available P and K. At Takarla, CEC was higher in cropland (10.83 Cmol kg-1) and in Mukerian, it was highest in forestry (12.65 Cmol kg-1). In surface soils at both sites, the water-stable macro-aggregates (WSA>2mm) were highest in grassland soils while the micro-aggregates (<0.25mm) were highest in agro-forestry at both sites. Micro-aggregates had lower C as compared to macro-aggregates at both sites in all land use systems. Soil organic carbon (SOC) was more in forestry (5.00 g kg-1) in Takarla and at Mukerian, grassland possessed higher amount (15.88 g kg-1). Among the SOC fractions, the POC was most dominant but LC and HWC showed vulnerability to land use change. At Takarla, HWC (490 mg kg-1), LC (1626 mg kg-1), IC (7.00 mg kg-1), total POC (3389 mg kg-1) and mineralizable C (48.6 mg kg-1) were more in agro-forestry and mineralizable N ( 109.7 mg kg-1) was more in forestry. At Mukerian, HWC (1370 mg kg-1), LC (1963 mg kg-1), IC (5.75 mg kg-1), total POC (7991.6 mg kg-1) and mineralizable C (85.8 mg kg-1) were more in grassland and mineralizable N (116.7 mg kg-1) was more in forestry. Soil properties and physical, biological as well as functional pools of SOM are strongly influenced by different agricultural land-use. Carbon sequestration seems to be more in agro-forestry at Takarla and in grassland at Mukerian. Climatic conditions / temperature also influenced carbon fractions at both sites. At Mukerian, values for carbon fractions were high as compared to Takarla, due to comparatively low temperature which decreases the rate of decomposition of soil organic matter in Mukerian.ThesisItem Open Access HUMUS-SOIL MINERAL INTERFACE IN ORCHARD AND FARM SOILS: NANOSCALE APPROACH(Punjab Agricultural University, Ludhiana, 2012) GURJIT SINGHClay-Humus complexes are pivotal for understanding long-term carbon retention in soils and founding protocols for nutrients, water and tillage management. Very little attempts were made to decipher the complexes formed under cultivation. Therefore, the study was undertaken for looking at bonding that different clay-minerals made with humus, imaging and deciphering interfaces of clay–humus complexes, and their association with land-use. For this, clays were extracted from surface soils of mango orchard (S1), guava orchard (S2) and ricewheat cultivated field (S3) of Bahadurgarh (30°21 45 N; 76°28 03 E; 255 m) in Punjab, India. Clays were untreated, organic matter (OM) was removed, CaCO3 was removed, and both OM and CaCO3 were removed. They were analyzed by chemical means, by Infra-Red Spectroscopy (IR), and by Scanning Electron Microscopy and Energy Dispersive Spectroscopy. IR spectroscopy identified dioctahedral and trioctahedral illites, and vermiculite, kaolinite, Al-chlorite, and montmorillonite in clays. Humic acids, amides, quinine, ketones and polysaccharides, and fulvic acids were identified in OM. S1 had phenol, and CH2 and CH3 groups, while S2 had aliphatic humic and fulvic acids, and aldehyde of humic acids, and carboxyl and ketonic groups in fulvic acid, and alkenes. The ratio of Oxydizable OC to clay-humus OC was: S1 (0.049) < S3 (0.054) < S2 (0.060). Micrographs portrayed uniform spread, irregular spread, and scattered lump of humus on various clayminerals. The humus from guava field had higher C content (15.60 by atom %) than humus from mango (12.1 by atom %), and cultivated fields (9.78 by atom %). Strong bond between clay minerals and humus deforms OH of clay minerals, and causes COO- anti-symmetric stretching in humus. Presence of phenol compounds in humus on clay surfaces tender resistance of these complexes to microbial degradation, and could be a crucial factor for N management in soils.ThesisItem Open Access AVAILABILITY AND DIFFERENT FORMS OF IRON IN SALT-AFFECTED SOILS OF MUKTSAR DISTRICT OF PUNJAB(Punjab Agricultural University, Ludhiana, 2012) Opinder SinghTen representative salt-affected soils from different parts of the Muktsar district of Punjab were studied for their morphological, physical and chemical characteristics and different forms of iron (Fe). The concentration of different forms of iron in the samples collected from different profile depths were estimated with the help of atomic absorption spectrophotometer. The texture of these soils varied from silty clay loam, silt, silt loam through loam to sandy loam whereas soil pH ranged from 8.3 to 10.2, 8.6 to 10.0 and 8.2 to 9.4 in the saline, sodic and saline-sodic soils, respectively. DTPA-Fe in these different soil profiles ranged between 1.08 to 31.2 mg kg-1 and followed the order as sodic < saline-sodic < saline soils. The SpAd-Fe content was reported the highest in the saline and the lowest in the saline-sodic soils. Iron adsorbed on oxide surfaces followed the order as MnOX-Fe < AFeOX-Fe < CFeOX-Fe whereas OM-Fe followed the order as saline-sodic > saline > sodic soils. The RES-Fe was highest in the saline soils and lowest in the saline sodic soils. The DTPA- Fe was significantly and near significantly positively correlated with EC and OC respectively. Also the DTPA-Fe showed significant positive correlation with MnOX-Fe and AFeOX-Fe. Similarly significantly negative correlation was observed between WSEX-Fe and CFeOX-Fe, SpAd-Fe and CFeOX-Fe, SpAd-Fe and OM-Fe. Results of the study showed that the mean total content of Fe in different soils was 2.10 per cent which is lower than the mean global value of 3.50 per cent.ThesisItem Open Access Impact of inorganic fertilizers and organic matter recycling on soil organic carbon pools in rice-wheat system(Punjab Agricultural University, Ludhiana, 2011) Abha MundepiThe influence of long-term application of FYM, green manure and wheat straw on soil properties and soil organic C pools was studied after 27 cycles of rice-wheat cropping on a sandy loam soil at the research farm of P.A.U, Ludhiana. Each of the organic source viz. FYM, wheat straw and green manure was applied at two rates to supply 25 and 50% of the recommended N dose to rice. The application of organic amendments significantly lowered soil pH, electrical conductivity, bulk density and increased water holding capacity, water stable aggregates and mean weight diameter. Compared to unfertilized control application of organic manures and wheat straw significantly enhanced total C (26-35%), Walkley and Black soil organic C (22-28%), particulate organic C (48-65%), KMnO4-oxidizable C (11-47%), hot water soluble C (25-50%) and microbial biomass C (46-67%). When compared across all treatments, concentration of different pools of organic C was lower in 15-30 cm depth than 0-15 cm depth. The easily oxidizable organic C fractions, Cfrac1 and Cfrac2, together constituted about 67% of the total organic C. The other two less labile fractions accounted for only 33% of the total C. Application of organic amendments in conjunction with mineral fertilizers significantly increased the content of light fraction and heavy fraction organic matter. Heavy fraction C constituted about 64-82% of total C whereas light fraction C accounted for only 7-13% of total C. Application of wheat straw resulted in a greater (34%) increase in mineralizable C compared (25-29%) with FYM and green manure addition. The C and N density was higher in macroaggregates than microaggregates. Application of organic sources increased total N (42-72%), light fraction N (30-115%) and heavy fraction N (34-69%) compared to control. The use of recommended + sub-optimal rates of inorganic fertilizers did not influence soil properties and various organic C pools significantly. The study emphasized the importance of conjoined use of organic amendments along with inorganic fertilizers for maintaining soil fertility and increasing C sequestration in soil that can help in mitigating CO2 emissions.