Maize-rice cropping systems in Bangladesh： Status and research needs

Maize-rice cropping systems are expanding in Bangladesh. Hybrid maize has increasing demand and value, particularly for poultry feed, while rice remains the traditional dominant starch staple food. Bangladesh maize yields （with average farm yields around 5.7 t·ha^-1） are among the highest found in Asia. Cool winter （Rabi） season maize followed by T. Aman （monsoon） rice is the major cropping system; however it is now becoming diversified with many other crops including potato. Financially, hybrid maize is far more profitable than boro （irrigated） rice, wheat, or most other competing winter season Rabi crops. Although maize is relatively problem-free in Bangladesh, some constraints are intensifying with increased concern over input supply and soil-related environmental sustainability. An array of new technologies for sustainable intensive maize production systems is emerging in Bangladesh and some are being promoted and adopted. Continued sustainability of hybrid maize production in Bangladesh depends on optimization of planting time, quality seed of appropriate hybrids, balanced use of nutrient inputs along with soil fertility conservation and other management, for which further research would be high priority.

Integrated Nutrient Management Improves Productivity and Quality of Sugarcane(Saccharum Officinarum L.)

Sugarcane is one of the major important sugar yielding crops in Bangladesh.As an exhaustive crop,sugarcane removes a huge amount of plant nutrients from the soil.However,the combined use of organic and inorganic fertilizers can be a good approach to deal with nutrient depletion and promote sustainable crop production as well as improve soil health.Therefore,an attempt was made to identify the most fruitful and profitable integrated nutrient management on the aspects of growth,yield and quality of sugarcane in two consecutive growing seasons.Seven treatments:T_(1)=Control,T_(2)=165:55:120:30:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(3)=Poultry Litter(PL)at 5 t ha^(−1)+95:51:87:9:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(4)=Cow Dung(CD)at 15 t ha^(−1)+36:52:60:17:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(5)=Press Mud(PM)at 15 t ha^(−1)+10:50:43:0:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1),T_(6)=Mustard Oil Cake(MOC)at 0.5 t ha^(−1)+140:54:115:25:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1)and T_(7)=GM(Green Manure)at 5 t ha^(−1)+140:53:100:28:10:2.5:4 kg N:P:K:S:Mg:Zn:B ha^(−1)were used in this experiment.Two years data showed that treatment T_(3)produced the maximum amount of tillers,total dry matter yield,millable sugarcane,cane yield and sugar yield,followed by the T_(4)treatment.The highest stalk heights were recorded in the T_(3)treatment,which was statistically similar to all other treatments except T_(1)and T_(2).The juice quality parameters viz.,brix and pol in cane were found significant in treatment T_(3)while the highest purity was obtained in the T_(7)treatment.All the data of Jaggery(goor)quality parameters,the highest sucrose content,color transmittance,Jaggery(goor)recovery and the lowest ash content of Jaggery(goor)were observed in the T_(3)treatment,which was statistically similar to the T_(4)treatment in both seasons.The highest cost of production was obtained from the T_(6)treatment while the highest gross return,net return and BCR were recorded in the T_(3)treatment.No significant changes were found in one cycle of sugarcane in initial and post-harvest soil characteristics viz.,pH,organic carbon,total N,and available P,K and S contents due to integrated use of different fertilizer packages.From the experimental findings,it was concluded that treatment T_(3)followed by T_(4)treatment would be the better productive and profitable integrated nutrient management technology for ensuring higher yields and quality of sugarcane without soil fertility degradation in the High Ganges River Floodplain soils.

Amelioration of Salinity Stress in Maize Seed Germination and Seedling Growth Attributes through Seed Priming

Germination of seeds and growth of seedling respond to seed priming as priming can guard the damage of salinity stress. A study conducted in the net house of the Department of Agronomy, BAU, Mymensingh during the period from November 2012 to April 2013 investigated the ameliorative effect of seed priming on seed germination and seedling attributes of maize under various salinity stress conditions. The experiment consisted of five seed priming and four salinity levels (NaCl) and laid out in a Completely Randomized Design (CRD) with three replications. Seed germination and seedling attributes of maize varied due to salinity stress and priming. The highest seed germination (95.7%) was recorded when no stress was imposed under hydropriming (48 hours). The germination of seeds performed even well (92.3%) when treated with hydropriming (48 hours) and NaCl@0.25 dS&#183m-1 which was followed by hydropriming (24 hours) under no salinity imposed and NaCl@0.25 dS&#183m-1 salinity. Hydropriming for 48 hours without salt stress performed the best on number of leaves seedling-1 (8), shoot length (28.2 cm), root length (14.5 cm), fresh weight (100.8 g) and dry weight of seedling (50.3 g). The germination and seedling growth parameters were reduced with the increase in salinity levels irrespective of priming while all seed priming treatments showed ameliorative effects. However, reduction in seed germination and seedling attributes were minimal with hydropriming for 48 hours. The results revealed that priming of maize seeds could be used for amelioration of salinity stress and hydropriming for 48 hours appeared as the best seed priming treatment.

Improvement of Early Maturing and Climate Resilient Chickpea (Cicer arietinum L.) Cultivars Suitable for Multiple Environments in Bangladesh

Ensuring food security for the rapidly increasing population and changing climatic scenarios are requisites for exploiting the genetic divergence of food crops.A study was undertaken to sort out an early maturing chickpea variety for fitting easily between rice-rice cropping systems in the Eastern Indo-Gangetic Plain of Bangladesh.The trial was comprised of eight elite lines of chickpea and executed at various localities in Bangladesh from 2014–15 to 2017–18.The result explored the chickpea genotype,BARI Chola-11 remained superior to the rest of the elite genotypes for having a short maturity period(100–106 days),and lesser days to 50%flowering(47–55 days).The same genotype was recorded to have robust vegetative and reproductive yield attributes including plant height(49–57 cm),podsplant−1(37–50),and optimum 100 seed weight(19.5–20.6 g).Owing to better yield attributes,BARI Chola-11 resulted in the maximum seed yield(1200–1500 kg ha-1)of chickpea and might be recommended for general adoption in the region for boosting nutritional security status through improved productivity under changing climate.

Effect of Tillage and Residue Retention on Soil Properties and Crop Yields in Wheat-Mungbean-Rice Crop Rotation under Subtropical Humid Climate

The effects of conservation agriculture (CA) practices on soil properties along with crop yields of rice-based triple cropping systems have not been adequately assessed in Bangladesh. An experiment was conducted at Bangladesh Agricultural Research Institute, Gazipur, Bangladesh from 2009 to 2012 to assess the effects of tillage practices and crop residue retention on soil physical properties, soil organic carbon (SOC) and crop yields in a wheat-mungbean-rice system. Treatments consisted of three tillage practices (MT: minimum tillage;CT: conventional tillage and DT: deep tillage) and eight levels of crop residue management (S0—no residues retention, Sr—retention of 30 cm rice straw, Sm—whole mungbean stover retention, SW—30 cm wheat straw retention, Smr—whole mungbean stover & 30 cm rice straw retention, Srw—30 cm rice & wheat straw retention, Smw—whole mungbean stover & 30 cm wheat straw retention and Swrm—30 cm wheat and rice straw along with whole mungbean stover retention) were applied in split plot design with three replications. Bulk density (BD) and porosity responded positively to MT and increased residue retention of all crops (p > 0.05). Minimum tillage and Swrm also significantly accumulated SOC (p < 0.05;0.38% higher than DT with no residue retention) and retained soil moisture (p < 0.05). Minimum tillage practice performed better in upland crops (p < 0.05;wheat & mungbean yields) and CT outperformed MT in wetland rice crop (p < 0.05). The grain and straw yields of wheat and rice were also influenced by previous crop residue retentions (p < 0.05). The results, therefore, suggested that increased residue retention with minimum tillage practices improved soil properties and yield of upland crops but with deeper tillage practices consistently maintained wetland rice production.

Leaf Water Status and Its Relationship with Reproductive Responses of Common Bean (<i>Phaseolus vulgaris</i>L.) Genotypes under Water Stress

Two tolerant (BB24 and BB43) and two susceptible (BARI busbean-2 and BB04) genotypes of common bean (Phaseolus vulgaris L.) were evaluated for their water status and its relationship with reproductive responses under continuous water stress (50% field capacity) and control (80% field capacity) conditions in a net house covered with polyethylene sheet at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh. Under water stress condition, the susceptible genotype namely BB04 exhibited more negative leaf water potential (LWP) which was followed by that of BARI bushbean-2 in all the time of the day except at noon. The tolerant genotype namely BB24 exhibited less negative LWP at noon. The tolerant genotypes maintained higher relative water content (WRC) than the susceptible ones from dawn to dusk. The relationship between RWC and LWP was examined separately for four genotypes under water stress condition. The genotype BB24 showed a smaller decrease in RWC with more negative LWP than BB04. Water stress reduced pod setting ratio. The relationship between the leaf water status and reproductive responses showed that the genotype with a little reduction in mid-day drop of RWC or with high mid-day RWC displayed a high pod setting ratio.