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2005 - 20094
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Subject: Soil Science × End date: 2009 × Start date: 2000 × Type: Thesis × Thesis Type: M.Sc ×
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    Phosphorus Dynamics in Relation to Carbon Mineralization in Soils Under Different Moisture Regimes
    (College of Agriculture, Punjab Agricultural University, Ludhiana, 2005) Kaur, Harjinder; Saroa, GS
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    Impact of Continuous Cropping and Fertilization on Crop Yield and Soil Properties Under Maize-Wheat Sequenct
    (College of Agriculture, Punjab Agricultural University, Ludhiana, 2006) Kaur Brar, Kiranvir; Saroa, GS
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    ThesisItemOpen Access
    : Management of manganese deficiency in fodder crops through mobilization of manganese in rhizosphere
    (Punjab Agricultural University, Ludhiana, 2008) Sumeet Arneja
    To study the possibility of managing Mn deficiency in fodder crops through mobilization of Mn in the rhizosphere, berseem, oats, ryegrass and raya were grown in mixed cropping in a Mn-deficient loamy sand soil in two experiments conducted in screen house. Six cropping combinations were examined: berseem monoculture, berseem grown in mixed cropping with oats, ryegrass, raya, raya + oats and raya + ryegrass. Two sets of treatments were maintained; to one set, three foliar sprays of 0.5% MnSO4 solution were applied at weekly intervals after first cutting. In no-Mn treatment (no foliar sprays), root length (RL) and shoot dry weight (SDW) of berseem grown as monoculture was severely inhibited as compared to berseem grown in mixed cropping. In no-Mn berseem monoculture treatment, SDW and RL were, respectively, 71% and 68% of the maximum recorded at 60 days of growth after applying Mn. Corresponding values of SDW and RL of berseem when grown in mixed cropping with raya and ryegrass were 96 and 88% and 88 and 87%, respectively. Application of Mn significantly increased both SDW and RL. There was 1.7 and 1.3 times increase in root length of berseem grown in mixed cropping with ryegrass and raya, respectively as compared to berseem grown as monoculture. Mixed cropping with spray application of Mn resulted in maximum Mn uptake in berseem grown with ryegrass as well as with raya due to well developed root system with larger root surface area. High relative root growth rate and low relative shoot growth rate resulted in high Mn concentration in berseem grown with ryegrass and raya in mixed cropping. Infact, 3 times higher Mn influx in berseem grown with ryegrass or with raya as compared to berseem alone may be the reason of higher Mn content in the shoots. The high Mn influx resulted from high concentration gradient due to depletion of Mn at the root surface to a lower value in berseem grown under similar conditions. DTPA-extractable Mn increased from initial value of 2.72 to 2.76 and 2.78 mg kg-1 soil where berseem was grown in mixed cropping with ryegrass and raya, respectively after harvest of all the crops. This study suggests that mixed cropping of berseem with raya or ryegrass leads to sufficient mobilization of Mn in soil to counteract Mn deficiency.
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    ThesisItemOpen Access
    SOIL WATER FLOW CHARACTERIZATION AND PREDICTION IN TWO DIFFERENT SOIL TYPES.
    (Punjab Agricultural University, Ludhiana, 2009) Jagdish Singh
    The present investigation was carried out at Purdue University in partnership with National Soil Erosion Research Laboratory, West Lafayette, USA. Two sites in Ceder Creek watershed of northwestern Indiana, USA with varying soil texture were selected to characterize the water flow behavior in soils with varying clay content and to simulate and compare soil water flow using Hydrus_1D and Kamel models. Clay content of AS1 site varies from 20-37% with depth while clay content variation for AS2 was 28-40%. The present study shows that hydraulic conductivity of soil decreases with increase in clay content, and also decrease with depth. The pedostructure parameters for Kamel were estimated using a pedotransfer function named Kamelsoil and parameters for Hydrus-1D were estimated from SOILPAR2.The sensitivity analysis of Kamel model show that value of Kbs (slope of shrinkage curve for basic water content), Va (volume of pedostructure at dry state) and AlphaL (coefficient of high range of macropores) are the most sensitive parameter for Kamel model input. The calibration for Kamel and Hydrus-1D was carried out for 15 day time period. The calibrated parameters were used for the validation of both model under both sites AS1 and AS2. Both models were found to be in good agreement with measured water content at 5 cm and 20 cm layer for site AS1, but performance of Kamel was better than Hydrus-1D for deeper layers. For AS2 site, Kamel performed better than Hydrus-1D irrespective of the depth of soil. It was observed that both models were weak in simulating crop growth and to keep account of variable water uptake rates during different growth stages.