Diagnosing nutrient limitations to lentil and chickpea in acid soils of Bangladesh

Lentil and chickpea are dietary staple crops in Bangladesh but their local production has been markedly declining in recent decades, mainly due to competition with irrigated cereals. However, in northern Bangladesh, an additional problem to their cultivation is acid surface soil conditions, potentially causing deficiencies of molybdenum (Mo) and boron (B), and toxicities of aluminium (Al), manganese (Mn) or hydrogen ion (H+). In an attempt to rehabilitate lentil and chickpea in northern Bangladesh on-farm trials were conducted to determine the response of these crops to Mo, B, and lime and Rhizobium inoculation. Despite earlier reports of widespread B deficiency in the region a response to B was only found in chickpea. Responses to Mo and Rhizobium, applied through seed priming, were found. There were responses to lime even after B, Mo, and Rhizobium had been applied, suggesting Al toxicity. Recommendations for fertilizer requirement, to fit into an overall integrated crop management package for lentil and chickpea, were modified accordingly

Trends in autoionization of Rydberg states converging to the 4s threshold in the Kr-Rb⁺-Sr²⁺ isoelectonic sequence: theory and experiment

We have measured the photoabsorption spectra of the Kr-like ions Rb+ and Sr2+ at photon energies corresponding to the excitation of 4s-np resonances using, the dual laser plasma photoabsorption technique. Dramatic changes in the line profiles, with increasing ionization and also proceeding along the Rydberg series of each ion, are observed and explained by the trends in 4s-transition amplitudes computed within a framework of configuration-interaction Pauli-Fock calculations. Total photoionization cross sections show very good agreement with relative absorption data extracted from the measured spectra

Pulses de-husking mill for smallholders: A case study of commercialization of machinery for small entrepreneurs in Bangladesh

Pulse crops such as lentil, mungbean, blackgram and lathyrus are important in the traditional diet of Bangladesh. However, the production of pulses has been declining over the last two decades. The bulk of the pulse grains are consumed as dal and therefore need to be de-husked. Currently farm households de-husk pulses by locally-fabricated rudimentary devices, known as jata or daki, resulting in a high percentage of crushed (~35% dust), broken or split grain (>90%). Such dal receives a lower price than properly milled de-husked full grain. Thus, farmers sell unhusked pulses grain in the local market and ultimately that goes to a large mill for de-husking. The large pulse de-husking mills are mostly located in the bigger cities of Rajshahi and Dhaka division of Bangladesh which are remote from small pulse growers. There is a significant price gap between unhusked pulses at the farm gate and de-husked dal at the final point of sale. On the other hand, mechanized de-husking mills where farmers can de-husk pulses and produce quality dal for family consumption or to sell at higher price are not commonly available in small towns. The lack of mills to de-husk small quantities of pulses (~5 kg) has also discouraged farmers from growing pulses. These factors are contributing to decline in pulse production by small and marginal farmers. To overcome the problem, the pulse de-husking mill (Mini Mill) was developed in 2009 and commercialized in Bangladesh. The present paper is a case study of a development and commercialisation process for mechanisation of farm operations for smallholders in Bangladesh. In this short paper we describe the Mini Mill, its uses, initial experiences with its promotion and marketing

Mechanised minimum soil disturbance establishment and yield of diverse crops in paddy fields using a two-wheel tractor-mounted planter for smallholder cropping

Shortages of hired labour are leading to greater interest in mechanisation for crop establishment in smallholder agriculture. Due to small field sizes, mechanised planters mounted on four-wheel tractors are not a suitable technology. The Versatile Multi-crop Planter (VMP) was developed for zero tillage (ZT), strip planting (SP) or single pass shallow tillage (SPST) on flat land and for forming and planting on tops of beds, each in a single pass operation, when mounted on a two-wheel tractor (2WT). The aim of the present study was to evaluate the field performance of the VMP in comparison to conventional broadcast seeding and full rotary tillage (2 to 4 passes; called CT) for establishing chickpea (Cicer arietinum L.), jute (Corchorus olitorius L.), lentil (Lens culinaris Medikus), maize (Zea mays L.), mung bean (Vigna radiata L. R. Wilczek), rice (Oryza sativa L.) and wheat (Triticum aestivum L.) in 15 locations of Bangladesh. Plant populations emerging from all single pass operations viz. SP, ZT, and bed planting (BP) were generally satisfactory and in 12 out of 15 experiments plant populations after SP were similar to or greater than after CT. In addition, SP gave comparable or greater plant populations than SPST and BP planting methods. Overall, the SP planting achieved comparable yields and lower costs of establishment than CT. We conclude that effective and reliable planters are now available for sowing a range of crop species on small fields with minimum soil disturbance. This opens up realistic options for the development of mechanised conservation agriculture suited to small field sizes

PRACTICE CHANGE IN DRY SEASON CROPPING OF NON-SALINE AREAS IN SOUTHERN BANGLADESH: PERSPECTIVE ON PROJECT INTERVENTION

Australian Centre for International Agricultural Research (ACIAR) seeks to introduce pulse production as alternative of rice cropping and thus improve the socioeconomic status of the farm households in Southern Bangladesh. This study was carried out to assess the changes on agronomic practices, crop diversification and profitability, women empowerment, and food security and livelihood of non-saline areas’ farmers after the ACIAR project intervention (both cash and kind) at the end-line period. A total of 240 farmers (i.e., 120 focal and 120 control) was investigated during 2020-2021 following stratified random sampling technique from Patuakhali, Barisal, Jhalokathi, and Barguna districts. The collected data were analyzed using a combination of descriptive statistics (sum, averages and percentages) and mathematical analyses (Simpson’s index of cropping diversity, partial budget analysis, women’s empowerment index, food group consumption frequency score and German correlation sensitive poverty index). The majority of the farmers were found to follow the cropping patterns of Fallow – Aman rice – Pulses, Boro rice – Aman rice – Fallow and Aus rice – Aman rice – Pulses. Pulses covered around 37.0 and 33.0 percent of the total cropped area of focal and control farmers, respectively. The average cropping diversity was at medium level for both categories of farmers. The revenue from pulses production was found much higher than rice farming for both focal and control farmers. The extent of women empowerment was increasedat the end-line period by 2.8 and 0.8 percent for focal and control farmers, respectively after adopting the project intervention. The study found focal farm households more food secure compared to control farm households at the end-line period. As a response to the project support, the livelihood of focal farm households improved more than control farm households at the end-line period based on poverty dimensions (71.0 and 65.2 percent, respectively). The study concludes that the project intervention resulted in enhanced crop diversification and farm enterprise profitability, women empowerment, and food security, and livelihood improvement through poverty reduction in the non-saline areas of Southern Bangladesh. The study recommends direct input provision by the government to motivate the farmers continuing pulse production over rice monocropping, and time-to-time monitoring for bringing efficiency in cropping system

Donor impurity in vertically-coupled quantum-dots under hydrostatic pressure and applied electric field

In this work we make a predictive study on the binding energy of the ground state for hydrogenic donor impurity in vertically-coupled quantum-dot structure, considering the combined effects of hydrostatic pressure and in growth-direction applied electric field. The approach uses a variational method within the effective mass approximation. The low dimensional structure consists of three cylindrical shaped GaAs quantum-dots, grown in the z-direction and separated by Ga1-xAlxAs barriers. In order to include the pressure dependent Γ – X crossover in the barrier material a phenomenological model is followed. The main findings can be summarized as follows: 1) for symmetrical and asymmetrical dimensions of the structures, the binding energy as a function of the impurity position along the growth direction of the heterostructure has a similar behavior to that shown by the non-correlated electron wave function with maxima for the impurity in the well regions and minima for the impurity in the barrier regions, 2) for increasing radius of the system, the binding energy decreases and for R large enough reaches the limit of the binding energy in a coupled quantum well heterostructure, 3) the binding energy increases for higher Aluminum concentration in the barrier regions, 4) depending of the impurity position and of the structural dimensions of the system (well width and barrier thickness) – and because changing the height of the potential barrier makes possible to induce changes in the degree of symmetry of the carrier-wave function –, the electric field and hydrostatic pressure can cause the impurity binding energy increases or decreases, and finally 5) the line-shape of the binding energy curves are mainly given by the line-shape of the Coulomb interaction.

Thermal transport in free-standing silicon membranes: influence of dimensional reduction and surface nanostructures

Nanostructuring provides a viable route to improve the thermoelectric performance of materials, even of those that in bulk form have very low figure of merit. This strategy would potentially enable the fabrication of thermoelectric devices based on silicon, the cheapest, most integrable and easiest to dope Earth-abundant semiconductor. A drastic reduction of the thermal conductivity, which would lead to a proportional enhancement of the figure of merit, was observed for silicon low-dimensional nanostructures, such as nanowires and ultra-thin membranes. Here we provide a detailed analysis of the phononic properties of the latter, and we show that dimensionality reduction alone is not sufficient to hinder heat transport to a great extent. In turn, the presence of surface roughness at the nanoscale reduces the thermal conductivity of sub-10 nm membranes up to 10 times with respect to bulk

Measurement of the tt¯ charge asymmetry in events with highly Lorentz-boosted top quarks in pp collisions at s=13 TeV

The measurement of the charge asymmetry in top quark pair events with highly Lorentz-boosted top quarks decaying to a single lepton and jets is presented. The analysis is performed using proton-proton collisions at s=13TeV with the CMS detector at the LHC and corresponding to an integrated luminosity of 138 fb−1. The selection is optimized for top quarks produced with large Lorentz boosts, resulting in nonisolated leptons and overlapping jets. The top quark charge asymmetry is measured for events with a tt¯ invariant mass larger than 750 GeV and corrected for detector and acceptance effects using a binned maximum likelihood fit. The measured top quark charge asymmetry of (0.42−0.69+0.64)% is in good agreement with the standard model prediction at next-to-next-to-leading order in quantum chromodynamic perturbation theory with next-to-leading-order electroweak corrections. The result is also presented for two invariant mass ranges, 750–900 and >900GeV