No abstract

SUMMARYFertilizer application can play an important role in soil organic carbon (SOC) retention and dynamics. The mechanisms underlying long-term accumulation and protection of SOC in intensive maize cropping systems, however, have not been well documented for cool high-latitude rainfed areas. Based on a 23-year fertilization experiment under a continuous maize cropping system at Gongzhuling, Jilin Province, China, the effects of fertilization regimes on SOC content and soil aggregate-associated carbon (C) composition were investigated. Results showed that, within the 0–1·0 m soil profile, SOC contents decreased significantly with soil depth in all treatments. In the topsoil layer (0–0·2 m), SOC concentrations in balanced inorganic fertilizers plus farmyard manure (MNPK), fallow system (FAL) and balanced inorganic fertilizers plus maize straw residue (SNPK) treatments were significantly greater than initial levels by 61·0, 34·1 and 20·1%, respectively. The MNPK and SNPK treatments increased SOC content by 50·7 and 12·4% compared to the unfertilized control in the topsoil layer, whereas no significant differences were found between balanced inorganic nitrogen, phosphorus and potassium fertilizers (NPK) and the unfertilized control treatment. There were no significant differences in aggregate-size distribution among the unfertilized control, NPK and MNPK treatments, whereas the SNPK treatment significantly enhanced the formation of micro-aggregates (53–250 μm) and decreased the formation of silt+clay aggregates (<53 μm) compared to the unfertilized control, NPK and MNPK treatments. Moreover, SOC concentrations in all aggregate fractions in the MNPK treatment were the highest among treatments. Furthermore, the MNPK treatment significantly increased SOC stock in micro- and silt+clay aggregates, which may slow down C decomposition in the soil. These results indicate that long-term manure amendment can benefit SOC sequestration and stability in the black soil of Northeast China.

An experiment was conducted at farmers' field aimed to evaluate the water saving technologies in Boro rice. The experiment involved three plots at 33 m, 65 m and 100 m distance from the water source. Each plot was divided into two parts to accommodate two management practices as research management (RM) and farmer's management (FM). RM comprised of plastic pipe water distribution system to reduce conveyance loss and alternate wetting and drying (AWD) method for field water management. FM comprised of earthen canal water distribution system and conventional irrigation method. BRRI dhan28 was cultivated with recommended agronomic practices. In RM, irrigation was applied when water level went 15 cm down below the ground surface where FM included conventional practice. Result showed that conveyance loss of water in earthen canal increased with increasing the distance from water source to field. Conveyance loss found 6.1 and 0.5 l s -1 per 100 m in earthen canal and plastic pipe distribution system, respectively. Plastic pipe distribution system successfully minimized 91.6% water loss that occurred in earthen canal. AWD practice alone saved 20.2% field water over conventional practice. Combination of AWD and plastic pipe had saved 42% water, Tk 2,270 ha -1 as electricity cost and Tk 2,947 ha -1 as irrigation cost over farmer's management. RM had higher yield than FM due to better performance of yield contributing parameters. Water productivity increased from 0.35 kg m -3 in FM to 0.65 kg m -3 in RM. Both the technologies in RM are environment friendly for reducing groundwater use in the irrigated ecosystem.

Bovine tuberculosis (bTb) is endemic in Bangladesh but the true prevalence has not yet been reported. Our objectives for this study were to determine the true prevalence and identify risk factors for bTb at the animal- and herd-level in Bangladesh. A total of 510 cows were randomly selected during January 2018 to December 2018. Caudal fold (CFT) and comparative cervical tuberculin tests (CCT) were serially interpreted. Animal- and herd-level risk factor data were collected using a pre-tested questionnaire. The hierarchical true prevalence of bTb was estimated within a Bayesian framework. The herd- and animal-level risk factors were identified using mixed effects logistic regression. The apparent prevalence of bTb was 20.6% [95% Confidence Interval (CI): 17.3; 24.3] based on CFT. The animal-level true prevalence of bTb was 21.9 (13.0; 32.4). The herd-level true prevalence in different regions varied from 41.9% to 88.8%. The region-level true prevalence was 49.9 (13.8; 91.2). There is a 100% certainty that herds from Bhaluka and Mymensingh Sadar upazilas are not free from bTb. The odds of bTb were 3.9 times (1.2; 12.6) higher in herds having more than four cows than those with ≤ 4 cows. On the other hand, the risk of bTb was 3.3 times higher (1.0; 10.5) in non-grazing cows than grazing cows. Crossbred cows were 2.9 times (1.5; 5.9) more likely to be infected with bTb than indigenous cows. The risk of bTb in animals with cough was 2.3 times (1.2; 4.3) higher than those without cough. Crossbred, non-grazing cows with cough should be targeted for bTb surveillance. Herds of the Mymensingh, Sadar and Bhaluka regions should be emphasized for bTb control programs. Estimation of Bayesian hierarchical true prevalence facilitates identification of areas with higher prevalence and can be used to indicate regions that where true prevalence exceeds a pre-specified critical threshold.

We assessed the prevalence and seasonal variations of intestinal schistosomiasis in association with age, sex, breed and rearing system of cattle and goats in different districts of Bangladesh. Fecal samples from 240 cattle and 146 goats were examined. Schistosoma eggs were found in 47.5% cattle and 43.84% goats. Two species of schistosomes were identified. No mixed infection was recorded. Prevalence of Schistosoma indicum was higher in cattle (42.5%) than in goats (34.25%) whereas goats (9.59%) were more susceptible to Schistosoma spindale infection than cattle (5.0%). Age, sex, breed, rearing system and topography of the country had significant (P<0.01, P<0.05) effect on the prevalence of schistosomiasis among cattle, whether only seasons of the year had significant (P<0.01) effect on schistosome prevalence among goats of Bangladesh. Higher infection rate was found in rainy season, in older age group, in males, in local breeds (cattle) and animals reared under semi intensive system. Prevalence was highest in the Rangpur district and lowest in the Dhaka district. The prevalence of intestinal schistosomiasis was very high among cattle and goats in the study area irrespective of age, sex, breed, seasons and rearing system of cattle and goats.

The experiment was conducted in the Central Farm, Sher-e-Bangla Agricultural University, Dhaka from November 2015 to February 2016 with the aim of investigating the growth and yield attributes of cauliflower as influenced by different micronutrients and plant spacing. The experiment consisted of two factors, such as Factor A: Plant spacing (3 levels) as-S 1 : 50 cm × 50 cm, S 2 : 50 cm × 40 cm, S 3 : 50 cm × 30 cm and Factor B: Levels of micronutrients (4 levels) as-T 0 : B 0 Mo 0 (control), T 1 : B 1 . 0 Mo 0.5 kg/ha, T 2 : B 2 . 0 Mo 1.0 kg/ha, T 3 : B 3.0 Mo 1.5 kg/ha. The experiment was laid out in Randomized Complete Block Design with three replications. All the studied parameters were significantly influenced by micronutrients and plant spacing. In case of plant spacing, the highest curd yield (39.89 t/ha) was found from S 2 and the lowest curd yield (35.00 t/ha) was found from S 1 . For micronutrients, T 2 treatment produced the highest curd yield (46.85 t/ha) and the lowest (24.41 t/ha) was from control. In case of combined effect, the highest curd yield (51.56 t/ha) was obtained from Original Research Article

Faecal examination of 189 randomly selected rural calves in 12 villages of Rajoir upazila under Madaripur district of both sexes aged between < 3 months to 1 year old with or without the signs of gastroenteritis during three months periods from June to August 2003 revealed that 64.5 % calves were infected with Toxocara vitulorum. Significantly (p < 0.01) higher incidence of ascariasis was found in cross bred calves (64.28% - 75.67%) than in indigenous calves (46.66%). Age-wise analysis indicated that ascariasis was significantly (p < 0.01) prevalent in calves upto 3 months (81.35%) of age following by 3 to 6 months (70.58%) in comparison to > 6 to 12 months (41.93%) of age. Incidence of T. vitulorum infection was significantly (p < 0.01) higher in male calves (73.24%) than in female (57.92%). All the calves infected with ascariasis were diarrhoeic (100%), with pale mucous membrane (71.31%), rough body coat (74.59%) and emaciation (65.57%). Cachexia (19.67%) and erected hair (4.91%) were also recorded as clinical signs. Normal temperature was found in 95.08% calves while subnormal temperature recorded in 4.91% calves infected with T. vitulorum.

The study was conducted in three potato growing areas in nothern districts of Bangladesh namely Rajshahi, Rangpur and Thakurgaon. Data were collected during 2016-17 to assess the level of adoption, profitability, farmers attitude towards the cultivation of BARI released potato varieties and to explore the constraints to potato cultivation. The study revealed that 59% potato areas were covered by BARI Alu-7 variety. The varieties BARI Alu-13, BARI Alu-25 and BARI Alu-8 covered 14%, 14% and 12% of the potato areas respectively. The adoption level of seed rate, gypsum and boron were found high which adoption score were 95, 72 and 71. The level adoption of urea, TSP and MoP were over used which adoption score were 103,138 and 110. The adoption levels of cowdung and zinc sulphate were found medium which adoption score were 50 and 61. Only 37% farmers used potato seeds from their own source. Per hectare total cost of BARI released potato cultivation was Tk. 204003 and variable cost was Tk. 161033. The major share of cost was seed (31%) followed by fertilizer (13%) and land use (11%). Per hectare average yield of potato was 28 ton with gross return Tk. 249819 and gross margin Tk. 88786. The net return of potato cultivation was Tk. 45816 per hectare. The benefit cost ratio was 1.22. Infestation of insect and diseases, non-availability of quality seed, high price of seed and inadequate storage facilities were the major constraints to potato cultivation.Bangladesh J. Agril. Res. 43(2): 309-322, June 2018