Arsenic pollution became a great problem in the recent past in different countries including Bangladesh. The microlevel studies were conducted to see the spatial variation of arsenic in soils and plant parts contaminated through ground water irrigation. The study was performed in shallow tube well command areas in Sadar Upazila (subdistrict), Faridpur, Bangladesh, where both soil and irrigation water arsenic are high. Semivariogram models were computed to determine the spatial dependency of soil, water, grain, straw, and husk arsenic (As). An arsenic concentration surface was created spatially to describe the distribution of arsenic in soil, water, grain, straw, and husk. Command area map was digitized using Arcview GIS from the “mouza” map. Both arsenic contaminated irrigation water and the soils were responsible for accumulation of arsenic in rice straw, husk, and grain. The accumulation of arsenic was higher in water followed by soil, straw, husk, and grain. Arsenic concentration varied widely within command areas. The extent and propensity of arsenic concentration were higher in areas where high concentration of arsenic existed in groundwater and soils. Spherical model was a relatively better and appropriate model. Kriging method appeared to be more suitable in creating interpolated surface. The average arsenic content in grain was 0.08–0.45 mg/kg while in groundwater arsenic level it ranged from 138.0 to 191.3 ppb.

Forecasting of rice area and production is an essential procedure in supporting policy decision regarding food security and environmental issues. The main aim of this paper is to forecast Aus rice area and production in Bangladesh. Box-Jenkins Autoregressive Integrated Moving Average (ARIMA) time-series methodology is considered for modeling and forecasting country's Aus rice area and production data commencing from 1971-72 to 2013-14. It was observed that ARIMA (1, 1, 5) and ARIMA (1, 1, 4) model were performed better than the other ARIMA models for forecasting Aus area and production respectively. The Aus rice areas were forecasted 1041.12 and 499.31 thousand hectares and for production it was 2059.642 and 1781.545 thousand metric tons in 2014-15 and 2023-24 respectively. The forecasted Aus rice area and production both were showed a decreasing trend. Government should create an enabling environment to develop HYV rice varieties for Aus rice crop to ensure ongoing food security by increasing cultivated area and production.

Crop-cut is a widely used and well accepted procedure for estimating rice yield. This yield is then multiplied by the area planted under rice cultivation to determine rice production of the country. In Bangladesh, crop-cut is used to estimate transplanted rice yield. Department of Agricultural Extension (DAE) and Bangladesh Bureau of Statistics (BBS) as the public agencies provide estimate on area and production of rice but they use different methods of crop-cut. The estimates of these two agencies on area and production of rice are different posing a question to the users on the reliability of the estimates. An attempt has been made with the objective to formulate a protocol that provides reliable and unique estimates on rice area and production. It is suggested to make at least three cuts in each plot to minimize the chance of over or under estimation of the whole plot yield and the radius of the circle should be 178.5cm so that the cut area becomes 10 m 2 in order to easy conversion of the crop-cut yield to t ha -1 .

Abstract:2

An experiment was conducted using nine hybrid rice genotypes along with two inbred standard check varieties in five different locations of Bangladesh to assess their stability in terms of grain yield and maturity in diverse environments. For this, adaptability, stability, genotype × environment (G×E) interaction effect for grain yield and maturity of 11 rice varieties in five agro ecological zones in Bangladesh were assessed during T. Aman season of 2015. The analysis of variance for growth duration and grain yield (t/ha) for genotypes, environment and genotype-environment interaction were highly significant at 1% level of probability indicating the variable response of genotypes and environments. The hybrid genotypes IR79156A/BRRI20R, BRRI hybrid dhan3, BRRI33R/BRRI26R, BRRI hybrid dhan4, standard check variety BRRI dhan49 and BR11 had high yield performance and widely adapted to all environments and these were non sensitive to environmental interactive forces, while the hybrids BRRI7A/BRRI31R, IR79156A/BasmatiR and SL-8 were sensitive to environmental interaction. Environment such as Gazipur (E1) and Faridpur (E3) having positive IPCA1 score and positive interaction with the hybrids BRRI7A/BRRI13R, SL-8H and IR79156A/BasmatiR were considered as the favourable environments for these hybrids.Bangladesh J. Agril. Res. 43(1): 99-108, March 2018