Assessment of hydropower potential using GIS and hydrological modeling technique in Kopili River basin in Assam (India)

A hilly watershed in Kopili River basin in Assam (India) was considered for assessment of hydropower potential using spatial tool (GIS) and hydrological model (SWAT2000). The available data related to topography, soil, land use, weather and discharge pertaining to the study watershed were used to characterize the watershed. The characterization was required for water resources hence hydropower assessment. The hydrology of the study watershed was simulated through the model. The prediction accuracy of the model was confirmed through three well known efficiency criteria viz., coefficient of determination (R2 = 0.70), Nash-Sutcliffe efficiency (E = 0.64) and Index of agreement (d = 0.91). A total of 107 sites on 9 streams could be identified as potential location for hydropower generation in the study watershed using the model outputs. Distributed power availability through micro units (Hydrological modeling Soil and water assessment tool Hydropower

Evaluation of yield and physiological attributes of high-yielding rice varieties under aerobic and flood-irrigated management practices in mid-hills ecosystem

In the valley land of North-East Hill (NEH) ecosystems of India, about 70% area under rice ( Oryza sativa L.) is transplanted. Physiological attributes and yield performance of aerobic rice over conventional flood-irrigated rice need to be assessed while promoting water saving technology. A field experiment was conducted at the experimental farm, ICAR Research Complex for NEH Region, Umiam (950 m msl), Meghalaya during rainy seasons of 2006 and 2007 under aerobic and flooded conditions with aerobic rice variety collected from IRRI, Philippines. Some important high-yielding varieties (HYVs) recommended for the region were also included in the study. The objectives of this study were (i) to evaluate the influence of frequent mid-season drainage as a measure of water saving technique besides inducing the pre-conditioning effect on genotypes to withstand water stress during the subsequent growth period of crop ontogeny, (ii) to compare crop performance between aerobic and flooded rice management practices, and (iii) to identify attributes responsible for the yield gap between aerobic and flooded rice. The results revealed that the yield difference between aerobic (average yield, 1.67 t/ha) and flooded rice (average yield, 2.31 t/ha) ranged from 18.4 to 37.8% ( P < 0.05) depending on varieties, highest difference being observed with rice hybrid DRRH 1. Cultivation of rice under aerobic condition resulted in 27.5% yield reduction over flooded rice. Among the yield components assessed, sink size (spikelets per panicle) contributed more to the yield and is considered to be most important factor responsible for yield gap between aerobic and flooded rice. The study suggests that, variety Sahsarang 1 with its moderate values of photosynthesis rate, transpiration rate and water use efficiency (WUE) along with higher grain yield seems to be better choice for both stress (aerobic) as well as normal (flooded) condition. Aerobic rice varieties with minimum yield gap compared to flooded rice is the key for success of aerobic rice cultivation

Evaluation of yield and physiological attributes of high-yielding rice varieties under aerobic and flood-irrigated management practices in mid-hills ecosystem

In the valley land of North-East Hill (NEH) ecosystems of India, about 70% area under rice (Oryza sativa L.) is transplanted. Physiological attributes and yield performance of aerobic rice over conventional flood-irrigated rice need to be assessed while promoting water saving technology. A field experiment was conducted at the experimental farm, ICAR Research Complex for NEH Region, Umiam (950mmsl), Meghalaya during rainy seasons of 2006 and 2007 under aerobic and flooded conditions with aerobic rice variety collected from IRRI, Philippines. Some important high-yielding varieties (HYVs) recommended for the region were also included in the study. The objectives of this study were (i) to evaluate the influence of frequent mid-season drainage as a measure of water saving technique besides inducing the pre-conditioning effect on genotypes to withstand water stress during the subsequent growth period of crop ontogeny, (ii) to compare crop performance between aerobic and flooded rice management practices, and (iii) to identify attributes responsible for the yield gap between aerobic and flooded rice. The results revealed that the yield difference between aerobic (average yield, 1.67t/ha) and flooded rice (average yield, 2.31t/ha) ranged from 18.4 to 37.8% (PAerobic rice Flooded rice Photosynthesis Water use efficiency Biomass production Hill ecosystem

Effects of tillage and biomass on soil quality and productivity of lowland rice cultivation by small scale farmers in North Eastern India

•4-consecutive years results indicated that grain yield obtained with 2 spading+1 trampling+1 weeding (termed as minimum tillage-MT) was statistically at par with conventional tillage CT.•The weed biomass production was higher with MT than that under CT systems.•The amount of N, P and K recycled through rice straw was higher under CT, whereas, through weed biomass, it was higher under MT.•SOC, SMBC and dehydrogenase activity in MT were 5.7–13.3, 2.8–14.9 and 34.6–106.7%, respectively higher than CT.•The cost of cultivation increased with each increment in tillage. The net returns were higher with MT options. Intensive tillage-based production systems along with residue removal, grazing and/or burning of crop residues/biomass and poor nutrient replenishment through inadequate fertilizer and manure use are the major causes of soil degradation and unsustainable agriculture in hills of North Eastern India. Thus, a 4-year study (2003–07) was conducted during rainy (wet) seasons at Indian Council of Agricultural Research (ICAR) Research Complex for North Eastern Hill (NEH) Region, Umiam, India (950m a.s.l.). Objective of the study was to assess the effect of different tillage systems (individual or combinations of spading, trampling and hand weeding) on rice (Oryza sativa L.) productivity and soil (Typic Paleudalf) quality under in-situ residue management in lowland conditions. Transplanting in manually weeded unpuddled field was termed no-till (NT). In comparison, individual or combinations of spading, trampling (one partial manual puddling to incorporate weeds) and weeding was termed minimum tillage (MT). Treatment involving the maximum tillage included 4 spading+2 trampling+2 weedings, and was termed the conventional tillage (CT). The latter is practiced widely by farmers' in the region. Nine tillage treatments were laid out in a Randomized Block Design (RBD) and replicated thrice in a fixed plot size of 5m×5m. Increasing tillage intensity (combinations of spading along with trampling and weeding) increased grain yields. Agronomic yields obtained with 2 spading+1 trampling+1 weeding (MT option) was statistically (p=0.05) similar to that under CT. In general, the weed biomass was more under NT and MT than CT, and also contributed 2–4, 0.8–2 and 0.78–1.9 times more N, P and K, respectively, towards nutrient recycling than that under CT. However, the amount of N, P and K recycled through rice straw was more under CT than MT and NT. Weed biomass played a major role as a nutrient source in MT systems and contributed towards yield stabilization and improvement in soil quality. The soil organic carbon (25.2g/kg), soil microbial biomass carbon (198.7μg/g dry soil) and dehydrogenase activity (25.84μg TPF/g dry soil) in NT were 11.5, 17 and 107%, respectively, more than those under CT. These parameters under MT systems were 6–13, 2–15 and 35–88%, respectively, more compared to those under CT. The bulk density (ρb) under CT (1.18Mg/m3) was significantly higher than those observed under MT systems of only one spading or one trampling (1.15Mg/m3). The net return was the highest with MT system comprising of 2 spading+1 trampling+2 weeding ($367.5/ha), and that was 25.5% higher than that with CT. The net return per dollar (NRP) invested decreased with increasing tillage intensity. In-situ rice residue retention along with weed biomass recycling (MT) for 4-years improved soil quality, reduced cost of production and stabilized productivity in a low-input marginal (marginal soil and small scale farmers) hill agriculture

Not Available

Not AvailableNorth-East India is known for its complex, diverse, risk-prone, and fragile hilly ecosystem. Natural resources intermsofsoil,water,vegetation,andsoilorganiccarbon(SOC)aremuchdegraded.Effectsoflong-termperennialgrasses maintained at a permanent fodder block of the ICAR Research Complex, Meghalaya, on soil quality were examined after 15 cropping cycles. The aims were (i) to ascertain whether perennial grass primarily maintained as fodder source for ruminants could conserve resources and improve soil quality in the hilly ecosystem of North-East India, and (ii) to select a suitable perennial grass to minimise land degradation, restore SOC, and improve the soil quality. Soil samples were collected in 2007–08 (dry season) from plots of 8 perennial grasses [Setaria sphacelata (setaria), Brachieria rosenesis (congosignal), Thysanolaena maxima (broom), Penicum maximum var. Makunia and var. Hamil (guinea), Pennisetum purpureum (napier), Paspalum conjugalum (paspalam), Arachis pintoi (wild groundnut)] and analysed for physical, chemical, and biological properties. A control plot had no grass cover. Hamil and Makunia produced a large amount of green fodder, while Makunia, paspalam, setaria, and congosignal had greatest root biomass. Relative to the control, soil under perennial grasses showed increases of ~30% SOC, 70% mean weight diameter, 20% available soil water, 40% hydraulic conductivity, 63% infiltration rate, and 10% soil microbial biomass carbon. Among grasses, soil under setaria, congosignal, and Makunia had higher values of these attributes than under other species because of better soil binding through an extensive root system. Improvement of soil physical properties and processes under these grasses, coupled with complete ground cover, reduced soil erosion by ~33% and also signifiedecologicalbenefitsthroughC-sequestration.SoilqualitymanagementinthefragileecosystemofNorth-EastIndia should include permanent pastural grasses, particularly, setaria, congosignal, and Makunia.Not Availabl