Effect of yttrium(Y) on structural, morphological and transport properties of CdO thin films prepared by spray pyrolysis technique

Cadmium oxide (CdO) and yttrium (Y) doped CdO (Y: CdO) thin films have been prepared onto glass substrate at temperature 300 °C by spray pyrolysis technique. The effects of yttrium (Y) doping on the structural, morphology, optical and electrical properties were studied systematically. The X-ray diffraction (XRD) study confirms that CdO films are polycrystalline in nature with cubic structure having lattice parameter of 0.4658 nm. Surface topographic and nano-structural analysis indicates cluster grain size and porosity decreased substantially with increase of yttrium (Y) content in CdO films. The optical transmittance exhibits excellent optical transparency, with an average transmittance of >70% in the visible range for 2 to 4% yttrium (Y) doping. The optical band gap widens in Y: CdO film from 2.24 to 2.62 eV through Burstein- Moss shift. Hall measurement confirms that material is of n type with a minimum resistivity of 4.7 × 10−4 Ω-cm with carrier concentration of 4.2 × 1021 cm−3 were achieved for 2% yttrium (Y) doping

Cropping system-based irrigation for improving crop and water productivity in the coastal zone of Bangladesh

The cropping intensity in the coastal zone of Bangladesh is significantly lower than the country’s average. The dominant crop grown in the saline areas is transplanted aman (T. aman) rice. The feasibility of intensified cropping patterns based more efficient water management and the production of two/three crops in a year has not been investigated in the salt-affected areas of Bangladesh. In this study, we tested five cropping patterns to understand their effects on grain yield, water use and water productivity, soil salinity and overall profitability. Field experiments were conducted in farmers’ fields at Amtali, Barguna, Bangladesh, during 2016-2017 and 2017-2018. The cropping patterns were (i) CP1: Mustard - T. aus - T. aman, (ii) CP2: Sunflower - T. aus - T. aman, (iii) CP3: Maize - T. aus - T. aman, (iv) CP4: Wheat - Mungbean - T. aman and (v) CP5: Fallow - Fallow - T. aman. Standard agronomic management practices for each crop were followed. The rice equivalent yield, production efficiency, total system productivity and profitability were all greater in CP2 than other cropping patterns. The marginal benefit-cost ratios were 1.28, 1.60, 1.46, 0.83 and 1.50 for CP1, CP2, CP3, CP4 and CP5, respectively. The soil water contents among the treatments in soil profiles decreased from sowing to harvest but the soil water content was found lower in treatment of CP5 (Fallow - Fallow - T. aman) followed by other cropping patterns. Salt accumulated in soil during the growing season rising from 4 dS m-1 (November) to 9 dS m-1 (March) in 0-60 cm soil profile. The highest soil salinity and osmotic solute potential were recorded in CP5 during February/March. Over the 2 years, the diversified cropping patterns incorporating mustard, sunflower and maize crops (CP1, CP2 and CP3) enhanced the productivity and profitability of the system and represent superior options to one crop per year in the salt-affected areas of Bangladesh

Cropping systems intensification in the coastal zone of the Ganges Delta: Opportunities and risks

The coastal zone of the Ganges delta has many constraints and threats that have hampered development. However, recent research indicates that there are numerous viable options for cropping systems intensification in the coastal zone that have yet to be fully exploited. The main opportunity involves changing the cropping season to use stored water with a low solute potential in the Rabi season and to harvest crops early to avoid crop stress from waterlogging, salinity/drought, heat and or storms. Early planting of Rabi season crops requires harvest of Kharif rice 15 to 30 days earlier in both West Bengal and Bangladesh. In both countries, several earlier maturing cultivars have been identified with yield gains of 0.5 to 1 t ha-1. The early harvest of Kharif rice opens up opportunities for promising new crops for the Rabi season such as Zero tillage potatoes. Moreover, for a range of other Rabi crops (e.g. wheat) early sowing results in higher yield potential. Realising the higher yield potential depends on firstly planned early drainage of excess floodwater, and a drainage system to mitigate the risk of heavy rainfall events in the Rabi season. Canal and pond water collected during the wet season remains mostly below 4 dSm-1 and hence is suitable for irrigation during the Rabi season. The main limitation is the volume available of such water rather than its quality. Low cost drip irrigation was shown in both Bangladesh and West Bengal to be highly profitable and is a potential technology for value addition of the scarce water supplies. In the coastal zone there still a high demand for rice production. Current Aman season rice supplies are not sufficient to meet food security needs. Aus rice was successfully grown at a number of locations and produced good yields (4.0—4.5 t ha-1). A diverse range of new crops were successful grown especially vegetables for which local markets exist. However, dry season cropping in the coastal zone does involve risks, particularly for heavy rainfall either at the end of the monsoon season or from February onwards and climate analysis suggests the frequency of these heavy rainfall events has increased in the last 40 years. The technologies developed and the risk management strategies required will need to be adapted to the variation in rainfall and river water salinity across the coastal zone of the Ganges delta