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20213
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Subject: Soil and Water Engineering × End date: 2021 × Start date: 2021 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Optimizing Lateral Depth and Spacing for Subsurface Drip Irrigated Rice-Wheat Cropping System under Conservation Agriculture Through Simulation of Water and Nitrate Movement
    (Punjab Agricultural University, Ludhiana, 2021) Bajpai, Arpna; Kaushal, Arun
    The research study was conducted at Borlaug Institute for South Asia, Ludhiana and Punjab Agricultural University Ludhiana, Punjab to optimize lateral depth and spacing for subsurface drip irrigated rice-wheat cropping system under conservation agriculture through simulation of water and nitrate movement during 2017-20. Experiments were laid out in randomized block design with eight treatments, (six drip irrigated (T1-T6), which were combination of lateral spacing X emitter spacing X dripline buried depth) and two control treatments (T7-T8) with three replication i.e. T1 (67.5 X 30 X 0 cm), T2 (45 X 40 X 0 cm), T3 (67.5 X 30 X 15 cm), T4 (45 X 40 X 15 cm), T5 (67.5 X 30 X 20 cm), T6 (45 X 40 X 20 cm), T7 (conventional flood irrigation method) and T8 (flood irrigation method with conservation agriculture). Grain yield and water productivity were maximum in treatment T4 (Wheat, 6.513 t/ha, 3.832 kg/m3 and Rice, 8.178 t/ha, 1.203 kg/m3 ) and minimum in T7 (Wheat, 5.620 t/ha, 1.406 kg/m3 and Rice, 7.410 t/ha, 0.492 kg/m3 ). Statistically T4 treatment was significantly at par with T6 treatment and higher than all other treatments for both rice and wheat crops. Most uniform soil moisture and nitrate movement were observed under T4. HYDRUS-2D model showed successful performance with Nash-sutcliffe model efficiency coefficient of 0.885 and coefficient of determination as 0.906. Economic analysis showed that treatment T4 (B:C-3.286) was economically viable and significantly higher than treatment T7 (B:C-3.157) only with 95% of drip irrigation subsidy.
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    Simulation of Nitrate-N movement through subsurface drainage system under cropping conditions
    (Punjab Agricultural University, Ludhiana, 2021) Dar, Mehraj U Din; Singh, J. P.
    The study was conducted to simulate the NO3-N movement through subsurface drainage in a field under cropping conditions using DRAINMOD-NII model and for predicting optimum depth and spacing for minimum nitrate leaching. The nitrogen balance was estimated using DNDC model for the area installed with the subsurface drainage system at Thehri village Muktsar district of Punjab. Both the models of DRAINMOD NII (v. 6.1) and DNDC (v.9.5) (Denitrification and Decomposition model) were calibrated and validated for the 2 years study period from 2018-2020. The reliability of the models was evaluated by comparing observed and simulated values of drain flow, nitrogen loss, water table depths and relative yields for the rice-wheat cropping system. The validated DRAINMOD-NII model was used to predict the optimal depth and spacing for minimum nitrate losses. The nitrogen balance for the area under subsurface drainage system was estimated using DNDC model for rice-wheat cropping system. The statistical performance of DRAINMOD-NII model was carried out and the range of statistical parameters viz, root mean square error (RMSE), Nash Sutcliffe modeling efficiency (NSE) and correlation coefficient (R2) were obtained to be 0.12 to 9.66, 0.47 to 0.88 and 0.53 to 1 respectively during the calibration and validation periods. The values of statistical parameters for DNDC model viz; RMSE, NSE and R2 ranged from 6.8 to 8.5, 0.78 to 0.88 and 0.84 to 0.90 respectively during the calibration and validation periods. The optimal depth and spacing of subsurface drainage system for the study area was obtained to be 1.3 m and 42 m respectively using DRAINMOD-NII model for minimum nitrate loss. The overall nitrogen balance was found to be -99.44 kg N ha-1 yr-1(negative) and 69.1 kg N ha-1 yr-1 (positive) for rice and wheat crops respectively using DNDC model. DRAINMODNII model and DNDC model performed a better simulation, and could be used for efficient nitrogen management in the region.
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    ThesisItemRestricted
    Development of customized automated fertigation system for soilless media in protected cultivation
    (Punjab Agricultural University, Ludhiana, 2021) Pandey, Kusum; Singh, K. G.
    A study was undertaken for the development of a low-cost customized automated fertigation system for the closed soilless system under protected conditions and tested for cucumber crop grown in different soilless media under naturally ventilated polyhouse at Dr. S. D. Khepar Laboratories of the Department of Soil and Water Engineering, Punjab Agricultural University, Ludhiana. This system consisted of mainly four units i.e. controller unit, sensor unit, fertigation unit, and pipeline unit. The controller unit comprises the programmable logic controller (PLC) which is used to automate the whole fertigation process i.e. to prepare and supply the fresh nutrient solution to the crop and reuse the drained nutrient solution after making the balance solution through the filtration from the polyhouse. The developed system was calibrated for dozing pumps, EC, pH sensors precision analysis, and time taken by the dozing pump with their respective treatments. The experiment was set in a factorial split-plot design included 9 treatments each under the developed automated and conventional fertigation systems with three fertigation levels viz. T1 = 100% fresh solution, T2 = 90% fresh solution with 10% leachate and T3 = 80% fresh solution with 20% leachate. Cucumber hybrid Multistar were planted under three different substrates of cocopeat i.e. S1 = 50% cocopeat with 50% cocochips, S2 = 70% cocopeat with 30% cocochips and S3 = 100% cocopeat in three replicates during three growing seasons. The performance of the system was measured by crop growth parameters (vine length, leaf area index, stem diameter, leaf chlorophyll content), yield parameters (fruit weight, fruit length, fruit diameter, yield per plant), and quality parameters (vitamin C, total phenol content, antioxidant capacity, total chlorophyll content, firmness). The economic analysis was carried out for a developed automated system with 50% subsidy on polyhouse and without subsidy and compared with conventional fertigation system. Customized automated fertigation system recorded significantly higher 17.1%, 10.8%, and 12.1% fruit yield per plant as compared to the conventional fertigation system in seasons 1, 2, and 3 respectively. Out of three different growing media, all the plant growth, yield, and quality parameters were recorded significantly higher under substrate S2 followed by S3 and S1. Among the fertigation treatments, T1 recorded significantly higher all the plant growth parameters as compared to T2 and T3 while there was no significant difference found in the fruit yield and quality parameters. For a customized automated fertigated system, BCR was found 2.16 & 2.19 (with subsidy) and 1.73 & 1.77 (without subsidy) for years 1 and 2. While, for conventional fertigation system, BCR was 1.89 & 2.0 (with subsidy) and 1.45 &1.59 (without subsidy) for years 1 and 2 respectively. Overall, the developed customized automated fertigation system crop grown under substrate S2 and with fertigation treatment T3 is recommended for achieving a statistically similar yield.