Effects of Irrigation, Organic and Inorganic Nutrient Sources on the Growth, Yield and Soil Fertility Status With Rice-Rice Cropping

Continuous cultivation of highly exhaustive cropping sequence in most of the irrigated fertile lands has resulted in the decline of soil physico-chemical condition in general and particularly soil organic matter (SOM) content. The experiment was laid out inasplit- plot design with irrigation (I1: traditional irrigation i.e. continuous flooding, I2: saturated condition, I3: Alternate wetting and drying) in main plots and fertilizers treatments: T0 = Control, T1 =100% (Recommended dose of chemical fertilizer), T2 =50% RDCF + 5 ton cowdung ha- 1, T3=70% RDCF + 3 ton cowdung ha-1, T4 =50% RDCF + 5 ton compost ha-1, T5 =70% RDCF + 3 ton compost ha-1, T6 = 50% RDCF + 3.5 ton poultry manure ha-1, T7 =70% RDCF + 2.1 ton poultry manure ha-1to the sub - plots. The rice yields were not significantly affected by different irrigation but higher grain yields were obtained in continuous flooded irrigation. The treatment T7 gave higher Boro and T. Aman rice yields. The higher Boro rice grain yields were obtained from I1T7 (70% RDCF + 2.1 ton poultry manure ha-1 with continuous flooded irrigation) followed by I3T7 (alternate wetting and drying + 70% RDCF + 2.1 ton poultry manure ha-1). The 100% RDCF was applied to T. Aman rice resulted residual effects of fertilizer and the higher T. Aman rice yields were recorded in I2T2 (saturated condition + 50% RDCF + 3 ton cowdungha-1) followed by I2T3 (saturated condition + 50% RDCF + 3 ton cowdungha-1) treatment combinations due to more residual effects of inorganic plus manure application during Boro rice cropping. The highest organic matter level was found in post-harvest soils where inorganic fertilizer plus cowdung were used and soil pH increased by using poultry manure. The higher levels of available P and K concentrations were observed in the post experiment soils where fertilizer and manure were applied. Bangladesh Agron. J. 2021, 24(1): 71-81

Alternatives to Improve Operational Traffic in Roundabouts Using Microsimulation

Roundabout in urban arterials are likely to block roads or generate long queues of vehicles due to the constant changes on urban dynamics near to the interception. Several alternatives to modify the flow pattern or geometry and infrastructure need to be study previously to propose a final design solution of roundabout with traffic issues. In this study, a review of three alternatives to improve the operational traffic are discussed; signalized intersection, turbo-roundabouts and overpass/underpass. In addition, the application of these alternatives is evaluated in a “classic” roundabout located at Tunja city that has a maximum of 3691 Veh/h counted and it is operated in saturated condition. Microsimulation is used from a calibrated model with volume counted, vehicle composition and speeds in the VISSIM software. Results show that signalize the roundabout does not improve the operational traffic (with a reduction on 38% of approach speed) and, the turbo-roundabouts are a mid-term solution that meet the traffic demand on 15 years with a progressively loss of service (with a mean approach speed of 6.4 Km/h at 15 years). The constructions of underpass and overpass show to be the only solution that increase four times the travel speed throw the roundabout and keep acceptable speed at the end of cyclic live of intersection (18.7 Km/h at 20 years).

PENGARUH REKAYASA PENGAIRAN TERHADAP PRODUKTIVITAS BUDIDAYA PADI (ORYZA SATIVA) SAWAH

Rice farming always experiences water shortages in dry season which result in low productivity. In order to overcome this problem, efforts are needed in the form of irrigation technology (intermittent and water-saturated condition). The aims of this study is to determine the effect of intermittent irrigation and water-saturated condition irrigation on the production of rice plants. This study used a randomized block design (RCBD) as an environmental design with a split plot design. This study was conducted by making a plot of 4 x 6 meters, totaling to 24 plots. Between every two plots, there is a waterway 50 centimeters wide. Each plot has a waterway for water intake and discharge. Intermittent irrigation treatment was conducted by flooding the plots by water as high as 5 centimeters 3 times at 0–9 HST, 15–29 HST, 35–70 HST, and water drying was also carried out three times at 9–15 HST, 29–35 HST, and 70–80 HST. Water-saturated condition irrigation treatment was conducted by leaving the plots in a state of water saturation without any stagnant water from 0 HST until the production phase. During the treatment of intermittent and water-saturated condition irrigation, fertilizer had been given at a dose of 600 kg/ha, 800 kg/ha, 1.000 kg/ha and 1.200 kg/ha. The parameters observed in this study were the number of active tillers, the number of ears per panicle, the weight of a thousand grains, and the weight of the saplings. The results showed that intermittent and water-saturated condition irrigation did not have a significantly different effect on each parameter of rice production. The highest dry weight production both in intermittent and water-saturated condition irrigation was found in the plot with 1.200 kg/ha fertilizer and the lowest dry weight production was from the plot with 600 kg/ha fertilizer. Kegiatan pertanian padi sawah selalu mengalami kendala kekurangan air di musim kemarau yang berdampak pada produktivitas yang rendah. Guna mengatasi masalah ini maka diperlukan upaya berupa rekayasa pengairan. Tujuan penelitian ini untuk mengetahui pengaruh rekayasa pengairan berselang dan macak-macak terhadap hasil produksi padi sawah. Penelitian ini menggunakan rancangan acak kelompok (RAK) sebagai rancangan lingkungan dengan rancangan perlakuan petak terbagi (split splot). Penelitian dilakukan dengan membuat petakan sebesar 4 x 6 m berjumlah 24 petak. Di antara petakan terdapat saluran air dengan lebar 50 cm. Setiap petak dibuat pintu untuk pemasukan dan pengeluaran air. Perlakuan pengairan berselang dilakukan dengan cara petak digenangi air setinggi 5 cm yang dilakukan sebanyak 3 kali pada 0–9HST, 15–29 HST, 35–70 HST, dan pengeringan air yang juga dilakukan sebanyak tiga kali yaitu pada 9–15 HST, 29–35 HST, dan 70–80 HST. Perlakuan pengairan macak-macak dilakukan dengan membuat petak percobaan selalu dalam keadaan jenuh air tanpa ada air yang tergenang mulai dari 0 HST hingga fase produksi. Pada perlakuan pengairan berselang dan macak-macak, juga diberi pupuk dengan dosis 600 kg/ha, 800 kg/ha, 1.000 kg/ha dan 1.200 kg/ha. Parameter yang diamati pada penelitian ini adalah jumlah anakan aktif, jumlah bulir per malai, berat seribu butir, dan berat ubinan.Hasil penelitian menunjukan rekayasa pengairan berselang dan macak-macak tidak memberikan pengaruh yang berbeda nyata pada setiap parameter produksi padi. Produksi berat kering panen tertinggi baik pada pengairan berselang maupun macak-macak terdapat pada petak yang diberi pupuk 1.200 kg/ha dan produksi berat kering terendah terdapat pada petak yang diberi pupuk 600 kg/ha.

Relationship Performance of Cylindrical Detention Pond (CDP) as Depression Storage and Runoff Reduction Under Fully Saturated Condition

Permeable pavements are a key Storm water management measure employed both to attenuate surface runoff in urban areas and to filter urban storm water pollutants. Existing permeable pavements (PP) are design with the specific percentage porosity whereby enabling excess rainwater to infiltrate through the system and acting as a depression storage at the same time. Depression storage basically refers to the volume of water trapped in the depression when the precipitation of a storm reaches the ground and filled up all the depression before it can flow over the surface. Cylindrical Detention Pond (CDP) is an alternative paving material that may alleviate many of the hydrological problems caused by urban runoff from developed areas. CDP consist of three basic component; top cover, bottom cover and hollow cylindrical at centre (300 mm thickness). The hollow cylindrical has approximate 50 percent porosity from the total solid of component, which is every 1 inch (25 mm) of pavement depth can hold 0.5 inches (12.5 mm) of rain in theoretical. In this study, the depression storage rate of CDP was investigated under three different rainfall intensity scenarios which are 77 mm/hr (low), 153 mm/hr (medium), and 230 mm/hr (heavy) respectively whereby it function to monitoring the analytical trend line. The experiment was conducted in model box in the laboratory under fully saturated condition. It found that the CDP can performed to detent the water until 180 min of excess rainfall for all 2 year ARI, 5 year ARI, 10 year ARI, 20 year ARI, 50 year ARI and 100 year ARI with different rates. CDP’s able to reduce the runoff up to 77% of the total rainfall volume. The result was proved the hollow cylindrical at centre of CDP very effective in runoff volume reduction according to the different ARI trend line projection.

Effect of drainage and saturation on undrained shear strength for compacted sandy soils

Collapses of embankments have occurred due to heavy rainfall. It is very important to understand the strength properties under various unsaturated, partially saturated and fully saturated conditions of compacted materials. So, a series of unsaturated and saturated triaxial compression tests for compacted soils have been conducted to understand the effects of drainage and saturation on undrained strength. Soil samples were collected from several road embankments to carry out the experiments. The undrained (CU) strength of compacted material decreased with increase in the degree of saturation. Especially, the strength decreased from partially saturated condition to fully saturated condition was remarkable. The decrease of the materials with volume contractive behaviour was appeared clearly.

Response of rice grown in saline soil as influenced by the application of agricultural amendments and moisture regimes

The experiment was carried out with rice (BRRI dhan48) grown in saline soil at the premises of the Department of Soil, Water and Environment, University of Dhaka to evaluate the impacts of agricultural amendments, such as rice hull (RH), rice straw (RS) and sawdust (SD) each applied at the rates of 0, 4 and 8 t ha-1 in moist (80% moisture) and saturated soil conditions. Most of the growth and yield components of rice were found to increase significantly (p ≤0.05) with the increased rates regardless of kinds of organic treatments under both the moisture levels. The tallest plant heights (99 cm in moist, 105 cm in saturated condition) were recorded at maturity stage of rice with the RH8RS8SD8treatment, which received the highest rates of these three organic amendments. The shortest plant heights (79 cm in moist; 86 cm in saturated conditions) were recorded in control pot (RH0RS0SD0), where no amendment was made. The maximum numbers of tillers were observed in RH8RS8SD8followed by RH8RS8SD4, RH8RS4SD8, RH4RS8SD8 and RH4RS4SD8 treatments at saturated condition. The straw dry matter and grain yields of rice were also found to vary significantly (p ≤0.05) by the individual application of rice hull, rice straw, sawdust and moisture conditions, but their combined effects were found to be highly significant at their higher doses of combination. The highest grain yield (4.4 t ha-1) was recorded in RH8RS8SD8 treatment followed by RH8RS8SD4 (4.2t ha-1) and RH8RS4SD8 (4.1t ha-1) at saturated condition. Harvest index and 1000 grain weight of the rice were attained positive under both the moisture conditions, but at saturated condition of the soil, the amendments (RH, RS and SD) produced better response for these components compared to those of the moist soil condition. J. Biodivers. Conserv. Bioresour. Manag. 2018, 4(2): 33-42