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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 Restricted NITROGEN MANAGEMENT IN RICE USING CHLOROPHYLL METER AND GREENSEEKER OPTICAL SENSOR(Punjab Agricultural University, Ludhiana, 2011) Puneet SharmaTo increase fertilizer nitrogen (N) use efficiency in transplanted irrigated rice (Oryza sativa L.), gadgets like SPAD meter (chlorophyll meter) and GreenSeeker optical sensor can be used to guide application of fertilizer N when it is needed most by the crop. A threshold greenness of the first fully opened leaf from the top needs to be known to decide when to apply a dose of fertilizer N. The GreenSeeker can be employed to manage fertilizer N following an algorithm based on expected yield and response to applied N. Development of yield prediction curves to use optical sensor requires data from experiments conducted over several cultivars, locations and seasons, and thus does not allow using the optical sensor to manage fertilizer N immediately after its procurement. In this study an attempt has been made to use optical sensor following NDVI sufficiency index (ratio of NDVI of the test and over fertilized reference plots) approach which does not require prior calibration. A field experiment was conducted with rice cultivars PR118 and PR120 and 10 treatments to define the SPAD and NDVI sufficiency index thresholds when the crop needs fertilizer N application. It was found that after applying a basal dose of 30 kg N ha-1, application of 30 kg N ha-1 every time when colour of the first fully opened leaf from the top of rice plant was less than the SPAD threshold 40 or 42.5 can lead to production of high yield levels and higher fertilizer N use efficiency. In case of GreenSeeker optical sensor, after applying a basal dose of 30 kg N ha-1 at transplanting of rice and a dose 45 kg N ha-1 at 21 days after transplanting, application of a dose of 30 kg N ha-1 if the NDVI sufficiency index was less than 0.90 resulted in production of grain yield level equivalent to that produced by applying blanket fertilizer dose and fertilizer N use efficiency higher than that observed from the blanket recommendation.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 Restricted Sewage water quality and transformations of heavy metals added to soil through sewage sludge(Punjab Agricultural University, Ludhiana, 2011) MarinA study was conducted during 2010-11 to monitor the quality of untreated sewage water of Buddha Nullah (an unlined channel), Ludhiana and improvement in quality parameters after its treatment at Bhattian Sewage treatment plant (STP).The untreated sewage water analysis has showed that BOD, COD, TS, TDS and TSS were above the maximum permissible limits (MPL) for its use as irrigation or discharge into water body. However, after its treatment at Bhattian STP, these parameters approached well within their respective MPL. The heavy metal concentrations in untreated sewage water showed variable trend during different months depending primarily on the industrial flow. The concentration of Cr and Ni, decreased after its treatment at Bhattian STP. All heavy metals tested (Cd, Cr, Ni and Pb) in the monthly sewage sludge samples from the Bhattian STP got concentrated in sludge but highly varying, which corresponds with sewage water metal concentrations variability. Fractionation of heavy metals was carried out in soil samples collected from an on-going field experiment having different rates of Bhattian sludge application to rice-wheat rotation. The distribution of heavy metals between the different fractions in untreated and treated soils showed the non- residual fraction to be dominant over the residual fractions of Cd, Ni and Pb. Movement of Cd, Cr, Ni and Pb appears to be there from surface to sub-surface soil, however, there was not any particular trend of change in their various fraction. Continuous application of sludge for subsequent years could lead to increase in heavy metal concentrations in bioavailable pool making it hazardous for plants and humans.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.ThesisItem Restricted CHEMICAL POOLS AND DEPTHWISE DISTRIBUTION OF MICRONUTRIENTS IN SOILS UNDER DIFFERENT CROPPING SEQUENCES AND THEIR RELATIONSHIP WITH THE UPTAKE BY CROPS(Punjab Agricultural University, Ludhiana, 2011) Gurpreet SinghRice-wheat, maize-wheat and cotton-wheat are predominant cropping systems, being practised by majority of farmers in Punjab. The adoption of these three cropping systems depletes a huge amount of macronutrients (N, P and K) and micronutrients (Zn, Cu, Fe and Mn) causing deficiency of these nutrients mainly in light textured soils. So, to overcome the deficiency of Zn, Cu, Fe and Mn in such soils, alternative cropping systems like maize-potatao-mungbean, cotton-gobhi sarson, groundnut-toria+gobhi sarson etc., are required. Lot of research work has already been done on the predominant cropping systems without inclusion of short duration crops like mungbean, toria, gobhi sarson and onion crop. So, there is need to explore research on inclusion of short duration crops in the main cropping systems, which helps in mobilization of Zn, Cu, Fe and Mn. Therefore, the present research study has been conducted with a prime objective to investigate the transformation (chemical pools) and depthwise distribution of Zn, Cu, Fe and Mn under different cropping systems. Surface (0-15 cm) and profile (0-120 cm) soil samples were collected from an ongoing field experiment (in progress since 2000) with 10 cropping systems at research farm of Department of Agronomy, PAU, Ludhiana. The plant samples (grain and straw) from each cropping system were also collected both for Rabi and Kharif crops. These soil samples collected at different stages were analyzed for DTPA-extractable and total Zn, Cu, Fe, and Mn and their chemical fractions using atomic absorption spectrophotometer (Varion AAS-FS Model). The grain and straw samples were also analyzed for their Zn, Cu, Fe, and Mn concentration with Varion AAS-FS Model. The levels of DTPA-extractable Zn, Cu, Fe, and Mn were significantly higher in soil under all the 10 cropping systems as compared to their initial levels. Higher levels of DTPA-extractable Fe and Mn and Zn and Cu were observed in rice-wheat and cotton-wheat cropping systems, respectively. Among maize based cropping systems, maize-potato-mungbean cropping system reported significantly higher concentrations of DTPA-extractable Zn, Cu, Fe, and Mn. The DTPA-extractable Zn and Cu decreased and Fe and Mn increased in soil under maize-potato-mungbeen cropping system. The DTPA-extractable Zn, Cu and Fe decreased with increase in the soil depth. Among chemical fractions, higher levels of Fe and Mn (WSEX and SpAd) were reported in the rice-wheat cropping system. On the other hand higher fractions of Zn [WSEX, SpAd, MnOX and CFeOX] and Cu [WSEX and OM bound] were reported under maize-potato-mungbean and cotton-gobhi sarson cropping systems respectively. Higher uptake of Fe was reported in rice-wheat cropping system, whereas Zn, Cu and Mn reported their higher uptakes in groundnut-potato-bajra (fodder) cropping system. Our study further, investigated that inclusion of short duration crops like mungbean, toria, gobhi sarson and onion helps in mobilization of Zn, Cu, Fe and Mn to ameliorate their deficiencies. Among fractions, SpAd, held on organic sites, oxide bound and amorphous fractions of Zn, Cu, Fe and Mn contributed towards plant available (water soluble and exchangeable) fraction. However, WSEX, SpAd, oxide bound and organically bound fractions contributed towards uptake of Zn, Cu, Fe and Mn by plant grain and straw.ThesisItem Restricted Mechanism of Differential Manganese Efficiency in Wheat Cultivars(2011) Arun Shankar; U. S. SadanaWheat cultivars differ widely in their Mn efficiency. The present investigation was planned to study the manganese dynamics in the rhizosphere, root-shoot relations and the distribution of manganese in different plant parts of wheat cultivars. Under Mn deficiency conditions, superior Mn uptake efficiency of wheat cv. PBW 550 compared to durum cv. PDW 291 was due to higher Mn influx resulting from more depletion of Mn in the rhizosphere and superior root geometry. Comparison of cultivars for Mn partitioning in different plant parts revealed that at anthesis, PDW 291 retained highest proportion of Mn in the lower leaves (at both Mn levels) and the lowest in the spike indicating poor mobilization to the spike. After 18-days post anthesis, spikes of PBW 550 accumulated highest amount of Mn (42% of total), whereas PDW 291 had only 8.1%. Compared to other cultivars, the proportion retained in the lower leaves, stem and peduncle was highest in PDW 291. At maturity, maximum Mn was mobilized to the grain in cv. PBW 550 under Mn deficiency conditions. The data pertaining to partitioning quotient in different plant parts under Mn deficient conditions revealed that at anthesis, 18-days post anthesis, and at maturity, highest Mn accumulation in the spikes was recorded for cv. PBW 550. Hence higher Mn efficiency of wheat cv. PBW 550 compared to durum cv. PDW 291 could be attributed to its better uptake mechanism and greater partitioning to the grain.ThesisItem Open Access Evaluation of physical, chemical and morphological characteristics of Bhadiar micro-watershed in relation to soil erosion and crop productivity(Punjab Agricultural University, 2011) Vivekpal Singh; Hadda, M.S.The information on physical, chemical, and morphological characteristics is a prerequisite for efficient watershed management. The present study was undertaken to evaluate physical, chemical, and morphological characteristics of Bhadiar micro-watershed in relation to soil erosion and crop productivity. The studied pedons were either structure less or massive. The soils in the area were highly erodible as indicated by soil erodibility factor „K‟ of universal soil loss equation. The infiltration rate was higher in middle and lower slope position as compared with upper slope position. The soil pH increased with increase in soil depth whereas EC, organic carbon, available N, P and K decreased with increase in depth in all the pedons. Silt content in all the pedons decreased whereas sand and clay content increased. Aggregate content, water holding capacity, saturated hydraulic conductivity decreased with decrease in depth to lower layers of horizons. Bulk density increased with increase in depth. Maize yield reduced to 31.4 q ha-1 at upper slope position from 38.5 q ha-1 at lower slope position. The productivity index ranged from 0.08 to 0.30 in the examined pedons. The slope per cent was found to be most significant factor in affecting the yield of maize crop followed by pH and calcium carbonate content. The nomographic „K‟ is highly and significantly correlated with erosion ratio and most significantly and negatively correlated with clay/M.E. ratio. In the area, the water erosion, the distribution of water through rainfall and weathering interacts together and play a major role in affecting the soil texture of various slope positions and horizons. The relationships among organic matter content, runoff and sediment generation and transport needs to be investigated with different slope positions and transects. These relationships could help establish a link between easily measured topographic parameters and some specific soil properties needed to understand water flow along different slope positions which reduces time and cost of analysis.