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Dr. Subash Dahal
Colorado State University

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0 Precision Agriculture
0 Sustainable Agriculture
0 Grazing systems
0 Remote Sensing for agriculture
0 Remote sensing & GIS applications

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Grazing systems
Remote Sensing for agriculture
Remote sensing & GIS applications

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Journal article
Published: 26 April 2021 in Sustainability
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The study of interrelationships among soil health indicators is important for (i) achieving better understanding of nutrient cycling, (ii) making soil health assessment cost-effective by eliminating redundant indicators, and (iii) improving nitrogen (N) fertilizer recommendation models. The objectives of this study were to (i) decipher complex interrelationships of selected chemical, physical, and biological soil health indicators in pastures with history of inorganic or broiler litter fertilization, and (ii) establish associations among inorganic N, potentially mineralizable N (PMN), and soil microbial biomass (SMBC), and other soil health indicators. In situ soil respiration was measured and soil samples were collected from six beef farms in 2017 and 2018 to measure selected soil health indicators. We were able to establish associations between easy-to-measure active carbon (POXC) vs. PMN (R2 = 0.52), and N (R2 = 0.43). POXC had a noteworthy quadratic relationship with N and nitrate, where we found dramatic increase of N and nitrate beyond an inflection point of 500 mg kg−1 POXC. This point may serve as threshold for soil health assessment. The relationships of loss-on-ignition (LOI) carbon with other soil health indicators were discernable between inorganic- and broiler litter-fertilized pastures. We were able to establish association of SMBC with other soil variables (R2 = 0.76) and there was detectable difference in SMBC between inorganic-fertilized and broiler litter-fertilized pastures. These results could be useful for cost-effective soil health assessment and optimization of N fertilizer recommendation models to improve N use efficiency and grazing system sustainability.

ACS Style

Subash Dahal; Dorcas Franklin; Anish Subedi; Miguel Cabrera; Laura Ney; Brendan Fatzinger; Kishan Mahmud. Interrelationships of Chemical, Physical and Biological Soil Health Indicators in Beef-Pastures of Southern Piedmont, Georgia. Sustainability 2021, 13, 4844 .

AMA Style

Subash Dahal, Dorcas Franklin, Anish Subedi, Miguel Cabrera, Laura Ney, Brendan Fatzinger, Kishan Mahmud. Interrelationships of Chemical, Physical and Biological Soil Health Indicators in Beef-Pastures of Southern Piedmont, Georgia. Sustainability. 2021; 13 (9):4844.

Chicago/Turabian Style

Subash Dahal; Dorcas Franklin; Anish Subedi; Miguel Cabrera; Laura Ney; Brendan Fatzinger; Kishan Mahmud. 2021. "Interrelationships of Chemical, Physical and Biological Soil Health Indicators in Beef-Pastures of Southern Piedmont, Georgia." Sustainability 13, no. 9: 4844.

Journal article
Published: 16 November 2020 in Soil Systems
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A study of phosphorus accumulation and mobility was conducted in eight pastures in the Georgia piedmont, USA. We compared two potential grazing treatments: strategic-grazing (STR) and continuous-grazing-with-hay-distribution (CHD) from 2015 (Baseline) to 2018 (Post-Treatment) for (1) distribution of Mehlich-1 Phosphorus (M1P) in soil and (2) dissolved reactive phosphorus (DRP) and total Kjeldahl phosphorus (TKP) in runoff water. STR included rotational grazing, excluding erosion vulnerable areas, and cattle-lure management using movable equipment (hay-rings, shades, and waterers). After three years of treatment, M1P had significantly accrued 6- and 5-fold in the 0–5 cm soil layer and by 2- and 1.6-fold in the 5–10 cm layer for CHD and STR, respectively, compared to Baseline M1P. In STR exclusions, M1P also increased to 10 cm depth post-treatment compared to Baseline. During Post-Treatment, TKP runoff concentrations were 21% and 29% lower, for CHD and STR, respectively, in 2018 compared to 2015. Hot Spot Analysis, a spatial clustering tool that utilizes Getis-Ord Gi* statistic, revealed no change in Post-Treatment CHD pastures, while hotspots in STR pastures had moved from low-lying to high-lying areas. Exclusion vegetation retained P and reduced bulk density facilitating vertical transportation of P deeper into the soil, ergo, soil P was less vulnerable to export in runoff, retained in the soil for forage utilization and reduced export of P to aquatic systems

ACS Style

Anish Subedi; Dorcas Franklin; Miguel Cabrera; Amanda McPherson; Subash Dahal. Grazing Systems to Retain and Redistribute Soil Phosphorus and to Reduce Phosphorus Losses in Runoff. Soil Systems 2020, 4, 66 .

AMA Style

Anish Subedi, Dorcas Franklin, Miguel Cabrera, Amanda McPherson, Subash Dahal. Grazing Systems to Retain and Redistribute Soil Phosphorus and to Reduce Phosphorus Losses in Runoff. Soil Systems. 2020; 4 (4):66.

Chicago/Turabian Style

Anish Subedi; Dorcas Franklin; Miguel Cabrera; Amanda McPherson; Subash Dahal. 2020. "Grazing Systems to Retain and Redistribute Soil Phosphorus and to Reduce Phosphorus Losses in Runoff." Soil Systems 4, no. 4: 66.

Journal article
Published: 29 October 2020 in Sensors
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Inexpensive and no-maintenance biodegradable soil moisture sensors could improve existing knowledge on spatial and temporal variability of available soil water at field-scale. Such sensors can unlock the full potential of variable-rate irrigation (VRI) systems to optimize water applications in irrigated cropping systems. The objectives of this study were to assess (i) the degradation of soil moisture sensor component materials and (ii) the effects of material degradation on maize (Zea mays L.) growth and development. This study was conducted in a greenhouse at Colorado State University, Colorado, USA, by planting maize seeds in pots filled with three growing media (field soil, silica sand, and Promix commercial potting media). The degradation rate of five candidate sensor materials (three blends of beeswax and soy wax, balsa wood, and PHBV (poly(3-hydroxybutyrate-co-3-hydroxyvalerate))) was assessed by harvesting sensor materials at four maize growth stages (30, 60, 90, and 120 days after transplanting). All materials under consideration showed stability in terms of mass and dimension except PHBV. PHBV was degraded entirely within 30 days in soil and Promix, and within 60 days in sand. Balsa wood did now show any significant reduction in mass and dimensions in all growth media. Similarly, there was no significant mass loss across wax blends (p = 0.05) at any growth stage, with a few exceptions. Among the wax blends, 3:1 (beeswax:soy wax) was the most stable blend in terms of mass and dimension with no surface cracks, making it a suitable encapsulant for soil sensor. All materials under consideration did not have any significant effect on maize growth (dry biomass, green biomass, and height) as compared to control plants. These results indicated that 3:1 beeswax:soy wax blend, PHBV, and balsa wood could be suitable candidates for various components of biodegradable soil moisture sensors.

ACS Style

Subash Dahal; Wubengeda Yilma; Yongkun Sui; Madhur Atreya; Samantha Bryan; Valerie Davis; Gregory Lewis Whiting; Raj Khosla. Degradability of Biodegradable Soil Moisture Sensor Components and Their Effect on Maize (Zea mays L.) Growth. Sensors 2020, 20, 6154 .

AMA Style

Subash Dahal, Wubengeda Yilma, Yongkun Sui, Madhur Atreya, Samantha Bryan, Valerie Davis, Gregory Lewis Whiting, Raj Khosla. Degradability of Biodegradable Soil Moisture Sensor Components and Their Effect on Maize (Zea mays L.) Growth. Sensors. 2020; 20 (21):6154.

Chicago/Turabian Style

Subash Dahal; Wubengeda Yilma; Yongkun Sui; Madhur Atreya; Samantha Bryan; Valerie Davis; Gregory Lewis Whiting; Raj Khosla. 2020. "Degradability of Biodegradable Soil Moisture Sensor Components and Their Effect on Maize (Zea mays L.) Growth." Sensors 20, no. 21: 6154.

Journal article
Published: 09 October 2020 in Agronomy
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Nitrogen (N) and water continue to be the most limiting factors for profitable maize (Zea Mays L.) production in the western US Great Plains. Precision application of N and water has the potential to significantly enhance input use efficiency without impairing yields. The overall objective of this study was to determine the most productive and efficient nitrogen and water management strategy for irrigated maize by using site-specific management zones and a proximal remote sensing approach. This study was conducted over 2016, 2017, 2018 and 2019 crop growing seasons near Fort Collins, Colorado, USA. Six nitrogen rates (0, 56, 112, 168, 224, and 280 kg N ha−1) were applied along experimental strips across three delineated management zones (low, medium, and high productivity). Four rates of irrigation were applied to maize (60%, 80%, 100%, and 120% of evapotranspiration) using a center pivot precision irrigation system equipped with zone control. Optical proximal sensor readings were acquired on all experimental strips four times during the growing season to assess four nitrogen management strategies (uniform, management zone (MZ), remote sensing (RS), and management zone remote sensing (MZRS)) on grain yield and nitrogen use efficiency (NUE). Results from this three-year study showed the significant interaction (p = 0.05) of zone vs. irrigation and irrigation vs. nitrogen across all years. In two of the three years (2016 and 2018), the high productivity zone benefitted from high irrigation rates, demonstrated by 16% and 18% yield increase from the lowest irrigation rate. In 2016, yield plateau was reached at 168 kg N ha−1 with 80% and 100% irrigation rates, whereas the plateau was reached at 112 kg N ha−1 in the 120% irrigation rate. These results demonstrate the possibility of fine-tuning zones, irrigation, and nitrogen to achieve optimum yield. While uniform and MZ nitrogen management strategies produced the highest grain yield, the best NUE was achieved via the RS strategy, followed by the MZ strategy. In this study, the MZRS strategy (combined MZ and RS) did not produce superior yield and NUE as compared to uniform and other strategies. However, there is a tremendous opportunity to fine-tune these two strategies, using other algorithms that are not explored in this study to improve the sustainability of maize production under irrigated conditions.

ACS Style

Subash Dahal; Evan Phillippi; Louis Longchamps; Raj Khosla; Allan Andales. Variable Rate Nitrogen and Water Management for Irrigated Maize in the Western US. Agronomy 2020, 10, 1533 .

AMA Style

Subash Dahal, Evan Phillippi, Louis Longchamps, Raj Khosla, Allan Andales. Variable Rate Nitrogen and Water Management for Irrigated Maize in the Western US. Agronomy. 2020; 10 (10):1533.

Chicago/Turabian Style

Subash Dahal; Evan Phillippi; Louis Longchamps; Raj Khosla; Allan Andales. 2020. "Variable Rate Nitrogen and Water Management for Irrigated Maize in the Western US." Agronomy 10, no. 10: 1533.

Journal article
Published: 29 May 2020 in Agronomy
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Global nitrogen use efficiency (NUE) for cereal production is marginal and is estimated to be about 33%. Remote sensing tools have tremendous potential for improving NUE in crops through efficient nitrogen management as well as the identification of high-NUE genotypes. The objectives of this study were (i) to identify and quantify the variation in NUE across 24 winter wheat genotypes (Triticum aestivum L.) and (ii) to determine if the normalized difference vegetation index (NDVI) could characterize the variability in NUE across wheat genotypes. This study was conducted in 2010 and 2011 in the semi-arid climate of Northeastern Colorado across dryland and irrigated conditions. Our results indicate significant variation in the NUE among genotypes across two irrigation conditions. We observed a strong relationship between the NDVI and NUE—as PFP (partial factor productivity) and PNB (partial nitrogen balance)—across the 24 wheat genotypes under dryland conditions (average R2 for PFP and PNB = 0.84) at Feekes growth stage 11.1, for site year II. However, poor association was observed under irrigated conditions (average R2 for PFP and PNB = 0.29) at Feekes growth stage 3 to 4 for site year II. This study demonstrates the potential and limitations of active canopy sensing to successfully characterize the variability in NUE across wheat genotypes.

ACS Style

Mohammed A. Naser; Raj Khosla; Louis Longchamps; Subash Dahal. Characterizing Variation in Nitrogen Use Efficiency in Wheat Genotypes Using Proximal Canopy Sensing for Sustainable Wheat Production. Agronomy 2020, 10, 773 .

AMA Style

Mohammed A. Naser, Raj Khosla, Louis Longchamps, Subash Dahal. Characterizing Variation in Nitrogen Use Efficiency in Wheat Genotypes Using Proximal Canopy Sensing for Sustainable Wheat Production. Agronomy. 2020; 10 (6):773.

Chicago/Turabian Style

Mohammed A. Naser; Raj Khosla; Louis Longchamps; Subash Dahal. 2020. "Characterizing Variation in Nitrogen Use Efficiency in Wheat Genotypes Using Proximal Canopy Sensing for Sustainable Wheat Production." Agronomy 10, no. 6: 773.

Journal article
Published: 29 May 2020 in Remote Sensing
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Real-time fluoro-sensing is a promising crop sensing technology to support variable-rate nutrient management for precision agricultural practices. The objective of this study was to evaluate the potential of fluoro-sensing to detect the variability of nitrogen (N) and potassium (K) in the crop canopy at the early growth stages of maize (before the V6 crop growth stage). This study was conducted under greenhouse conditions in pots filled with silica sand, and maize plants were supplied with modified Hoagland’s solution with different rates of N and K. Sensor readings were collected using a Multiplex®3 fluorescence sensor and analyzed using ANOVA (analysis of variance) to test differences in crop response to nutrient rates. Regression analysis was used to assess the ability of fluorescence sensor-based indices to estimate N and K in the crop canopy. The results of this study indicate that all fluorescence indices under consideration enabled the detection of N variability in the maize canopy prior to the V2 crop growth stage. The NBI_B (nitrogen balance index blue) index enabled N uptake detection (R2 = 0.99) as early as the V2 crop growth stage. However, the fluorescence indices failed to identify K deficiency, as the maize plants with K treatments showed little to no variability of this nutrient at early crop growth stages as measured by plant tissue analysis. The results present a tremendous opportunity to assess N uptake at early growth stages of maize for precision nitrogen application. We recommend using fluorescence sensor-based NBI_B or NBI_R (Nitrogen balance index red) for early detection of nitrogen uptake in maize for precision nitrogen management.

ACS Style

Rafael Siqueira; Louis Longchamps; Subash Dahal; Raj Khosla. Use of Fluorescence Sensing to Detect Nitrogen and Potassium Variability in Maize. Remote Sensing 2020, 12, 1752 .

AMA Style

Rafael Siqueira, Louis Longchamps, Subash Dahal, Raj Khosla. Use of Fluorescence Sensing to Detect Nitrogen and Potassium Variability in Maize. Remote Sensing. 2020; 12 (11):1752.

Chicago/Turabian Style

Rafael Siqueira; Louis Longchamps; Subash Dahal; Raj Khosla. 2020. "Use of Fluorescence Sensing to Detect Nitrogen and Potassium Variability in Maize." Remote Sensing 12, no. 11: 1752.

Journal article
Published: 06 May 2020 in Applied Soil Ecology
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Local effective microorganism (LEM) is an inoculant produced using leaf litter collected from forest floors near the location where it is to be utilized. While this locally-sourced inoculant is used around the world, more research is needed to fully understand the potential benefits or drawbacks of its use in agricultural systems. The objectives of this study were to observe the effects of combining LEM with composted broiler litter to fertilize edamame (Glycine max L.) on plant-available nitrogen, nematode trophic group communities, and soybean productivity. The study was carried out in a randomized, complete block design on piedmont soils in the southeastern United States comparing broiler litter composted with LEM, False-LEM or water (Control) treatments which were applied at the beginning of each growing season (June 2015, 2016, 2017). In the first year of the study, soil (0–10 cm) that received the LEM treatment mineralized greater amounts of N and mineralized N faster than CONT soils (P = 0.0665 and P = 0.0717), respectively, during one week of incubation. In year 2 (2016) plots experienced drought stress, with soil moistures as low as 2%. In LEM plots soil samples taken during the drought contained significantly greater populations of all nematodes, excluding Mononchidae when compared to the other treatments. When calculated per unit of soil N, measured after application of treatments, no differences in edamame soybean yield were observed between treatments. Combining LEM with composted broiler litter jump-started N mineralization early in growing seasons and maintained abundance of multiple nematode trophic groups during drought. This signifies LEM's potential to strengthen a soil's food web resistance to drought stress – providing more security for a functional agroecosystem under uncertain climate conditions.

ACS Style

Laura Ney; Dorcas Franklin; Kishan Mahmud; Miguel Cabrera; Dennis Hancock; Mussie Habteselassie; Quint Newcomer; Subash Dahal. Impact of inoculation with local effective microorganisms on soil nitrogen cycling and legume productivity using composted broiler litter. Applied Soil Ecology 2020, 154, 103567 .

AMA Style

Laura Ney, Dorcas Franklin, Kishan Mahmud, Miguel Cabrera, Dennis Hancock, Mussie Habteselassie, Quint Newcomer, Subash Dahal. Impact of inoculation with local effective microorganisms on soil nitrogen cycling and legume productivity using composted broiler litter. Applied Soil Ecology. 2020; 154 ():103567.

Chicago/Turabian Style

Laura Ney; Dorcas Franklin; Kishan Mahmud; Miguel Cabrera; Dennis Hancock; Mussie Habteselassie; Quint Newcomer; Subash Dahal. 2020. "Impact of inoculation with local effective microorganisms on soil nitrogen cycling and legume productivity using composted broiler litter." Applied Soil Ecology 154, no. : 103567.

Journal article
Published: 03 March 2020 in Remote Sensing
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Crop breeders are looking for tools to facilitate the screening of genotypes in field trials. Remote sensing-based indices such as normalized difference vegetative index (NDVI) are sensitive to biomass and nitrogen (N) variability in crop canopies. The objectives of this study were (i) to determine if proximal sensor-based NDVI readings can differentiate the yield of winter wheat (Triticum aestivum L.) genotypes and (ii) to determine if NDVI readings can be used to classify wheat genotypes into grain yield productivity classes. This study was conducted in northeastern Colorado in 2010 and 2011. The NDVI readings were acquired weekly from March to June, during 2010 and 2011. The correlation between NDVI and grain yield was determined using Pearson’s product-moment correlation coefficient (r). The k-means clustering method was used to classify mean NDVI and mean grain yield into three classes. The overall accuracy between NDVI and yield classes was reported. The findings of this study show that, under dryland conditions, there is a reliable correlation between grain yield and NDVI at the early growing season, at the anthesis growth stage, and the mid-grain filling growth stage, as well as a poor association under irrigated conditions. Our results suggest that when the sensor is not saturated, i.e., NDVI < 0.9, NDVI could assess grain yield with fair accuracy. This study demonstrated the potential of using NDVI readings as a tool to differentiate and identify superior wheat genotypes.

ACS Style

Mohammed Naser; Raj Khosla; Louis Longchamps; Subash Dahal. Using NDVI to Differentiate Wheat Genotypes Productivity Under Dryland and Irrigated Conditions. Remote Sensing 2020, 12, 824 .

AMA Style

Mohammed Naser, Raj Khosla, Louis Longchamps, Subash Dahal. Using NDVI to Differentiate Wheat Genotypes Productivity Under Dryland and Irrigated Conditions. Remote Sensing. 2020; 12 (5):824.

Chicago/Turabian Style

Mohammed Naser; Raj Khosla; Louis Longchamps; Subash Dahal. 2020. "Using NDVI to Differentiate Wheat Genotypes Productivity Under Dryland and Irrigated Conditions." Remote Sensing 12, no. 5: 824.

Journal article
Published: 11 January 2020 in Sustainability
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Generally, improvement in the soil health of pasturelands can result in amplified ecosystem services which can help improve the overall sustainability of the system. The extent to which specific best management practices have this effect has yet to be established. A farm-scale study was conducted in eight beef-pastures in the Southern Piedmont of Georgia, from 2015 to 2018, to assess the effect of strategic-grazing (STR) and continuous-grazing hay distribution (CHD) on soil health indicators and runoff nitrate losses. In 2016, four pastures were converted to the STR system and four were grazed using the CHD system. Post-treatment, in 2018, the STR system had significantly greater POXC (by 87.1, 63.4, and 55.6 mg ha−1 at 0–5, 5–10, and 10–20 cm, respectively) as compared to CHD system. Soil respiration was also greater in the STR system (by 235 mg CO2 m-2 24 h−1) and less nitrate was lost in the runoff (by 0.21 kg ha−1) as compared to the CHD system. Cattle exclusion and overseeding vulnerable areas of pastures in STR pastures facilitated nitrogen mineralization and uptake. Our results showed that the STR grazing system could improve the sustainability of grazing systems by storing more labile carbon, efficiently mineralizing soil nitrogen, and lowering runoff nitrate losses.

ACS Style

Subash Dahal; Dorcas Franklin; Anish Subedi; Miguel Cabrera; Dennis Hancock; Kishan Mahmud; Laura Ney; Cheolwoo Park; Deepak Mishra. Strategic Grazing in Beef-Pastures for Improved Soil Health and Reduced Runoff-Nitrate-A Step towards Sustainability. Sustainability 2020, 12, 558 .

AMA Style

Subash Dahal, Dorcas Franklin, Anish Subedi, Miguel Cabrera, Dennis Hancock, Kishan Mahmud, Laura Ney, Cheolwoo Park, Deepak Mishra. Strategic Grazing in Beef-Pastures for Improved Soil Health and Reduced Runoff-Nitrate-A Step towards Sustainability. Sustainability. 2020; 12 (2):558.

Chicago/Turabian Style

Subash Dahal; Dorcas Franklin; Anish Subedi; Miguel Cabrera; Dennis Hancock; Kishan Mahmud; Laura Ney; Cheolwoo Park; Deepak Mishra. 2020. "Strategic Grazing in Beef-Pastures for Improved Soil Health and Reduced Runoff-Nitrate-A Step towards Sustainability." Sustainability 12, no. 2: 558.

Journal article
Published: 03 July 2019 in Journal of Soil and Water Conservation
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Sufficient and consistent distribution of carbon (C) across pastures can influence and improve production and sustainability in pasture-based grazing systems. The objective of this research was to determine spatial distribution of bulk density, soil C measured as loss-on-ignition (LOI) C, and permanganate oxidizable C (POXC), in continuously stocked Southern Piedmont pastures as affected by landscape position and management to enable producers to make better informed management decisions. Soil samples were collected from three depths (0 to 5, 5 to 10, and 10 to 20 cm), on a 50 m grid (matrix) and within areas of interest (AOIs, where cattle tended to frequent) from 10 pastures (ranging from 9.2 to 21.8 ha) fertilized with only mineral fertilizer. Mean soil bulk density was greatest (μ = 1.62 g cm−3) in the 5 to 10 cm soil layer. Median soil LOI and POXC were greatest in the 0 to 5 cm soil layer (medians = 6.16 g kg−1 and 776 mg kg−1, respectively), and both were strongly correlated to soil organic C. Soil phosphorus (P) was lowest in the 10 to 20 cm samples (median = 2.12 mg kg−1), regardless of sampling location. Multivariate analysis of variance (MANOVA) determined that bulk densities were lower closer to hay and water sources (usually within 0 to 39 m from sources) not located in areas vulnerable to erosion likely because of added C combined with the moderate hoof action to incorporate C into the soil. However, LOI values in the surface 0 to 5 cm soil layer associated with hay, water, and shade in areas vulnerable to erosion demonstrated relatively few differences in distance from a hay, water, or shade source, and these differences often did not occur until 200 m or greater from a pasture equipage. This research indicates that producers can more efficiently utilize nutrient resources and improve soil health measures with strategic placement of hay, waterers, or shade to facilitate best use of limited resources.

ACS Style

T. Hendricks; Dorcas Franklin; Subash Dahal; D. Hancock; L. Stewart; M. Cabrera; G. Hawkins. Soil carbon and bulk density distribution within 10 Southern Piedmont grazing systems. Journal of Soil and Water Conservation 2019, 74, 323 -333.

AMA Style

T. Hendricks, Dorcas Franklin, Subash Dahal, D. Hancock, L. Stewart, M. Cabrera, G. Hawkins. Soil carbon and bulk density distribution within 10 Southern Piedmont grazing systems. Journal of Soil and Water Conservation. 2019; 74 (4):323-333.

Chicago/Turabian Style

T. Hendricks; Dorcas Franklin; Subash Dahal; D. Hancock; L. Stewart; M. Cabrera; G. Hawkins. 2019. "Soil carbon and bulk density distribution within 10 Southern Piedmont grazing systems." Journal of Soil and Water Conservation 74, no. 4: 323-333.

Journal article
Published: 14 June 2019 in Soil Systems
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In order to ensure a soil system’s sustained ability to carry out ecosystem services, indicators that assess soil health are needed. We examined the capacity of nematode maturity index (MI), structure index (SI), enrichment index (EI), and trophic groups as measures of soil health, by determining soil nematodes’ sensitivity to cropping systems: rotation, perturbation, fertilization, and inoculation with local effective microorganisms (LEM). Plots were managed for two years under different rotations, annual ryegrass/fallow (ARF) and cereal rye/edamame soybean (CRS). In the third year of the study, all of the plots were managed exactly the same as a wheat/edamame rotation. Data were collected in both winter and summer of this year. In all three years, three inoculant treatments (LEM, False-LEM and No inoculate) were applied. In CRS plots, which received the most tillage and fertilization, there were greater SI values in soils that received LEM application. Nematode community structure described by each MI, SI, and EI were sensitive enough to reflect changes due to differences in soil management practices from previous years. Principal components analysis confirmed that nitrogen mineralization is an important measure to include when using nematode community analysis in the development of a soil health index.

ACS Style

Laura Ney; Dorcas Franklin; Kishan Mahmud; Miguel Cabrera; Dennis Hancock; Mussie Habteselassie; Quint Newcomer; Subash Dahal; Anish Subedi. Sensitivity of Nematode Community Analysis to Agricultural Management Practices and Inoculation with Local Effective Microorganisms in the Southeastern United States. Soil Systems 2019, 3, 41 .

AMA Style

Laura Ney, Dorcas Franklin, Kishan Mahmud, Miguel Cabrera, Dennis Hancock, Mussie Habteselassie, Quint Newcomer, Subash Dahal, Anish Subedi. Sensitivity of Nematode Community Analysis to Agricultural Management Practices and Inoculation with Local Effective Microorganisms in the Southeastern United States. Soil Systems. 2019; 3 (2):41.

Chicago/Turabian Style

Laura Ney; Dorcas Franklin; Kishan Mahmud; Miguel Cabrera; Dennis Hancock; Mussie Habteselassie; Quint Newcomer; Subash Dahal; Anish Subedi. 2019. "Sensitivity of Nematode Community Analysis to Agricultural Management Practices and Inoculation with Local Effective Microorganisms in the Southeastern United States." Soil Systems 3, no. 2: 41.

Journal article
Published: 01 November 2018 in Journal of Environmental Quality
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Uneven spatial distribution of soil N in conventionally managed pastures is a function of various biotic and abiotic factors and results in poor land use efficiency. In this study, we measured soil inorganic N (at depths of 0–5, 5–10, and 10–20 cm) in a 50-m grid and specific areas of interest from eight conventionally managed beef pastures (∼17 ha each), four near Eatonton and four near Watkinsville in the southern Piedmont of Georgia, USA, to assess the effects of management, landscape, and cattle locus in spatial distribution of soil inorganic N. Significant spatial autocorrelation was observed in the soil inorganic N indicating that the regions of high inorganic N deposition were near (within 91 m of) one or more pasture equipage (hay, shade, and water). In the Watkinsville pastures, inorganic N was 65% higher within 5 m of shade than the rest of the pastures, down to a 10-cm soil depth. In the Eatonton pastures, inorganic N (0–5 cm) was 22% higher within 30 m of a hay-feeding areas than the rest of the pasture. Cattle locus calculated as cattle density (cow ha−1 yr−1) was a function of pasture equipage and had a significant positive relationship with soil inorganic N. Landscape parameters (slope and elevation) significantly affected inorganic N distribution; however, the effect was small and was masked by management factors. Our results suggest that strategic placement of pasture equipage (hay, shade, and water) can effectively distribute N where needed in beef pastures, thereby increasing land use efficiency. Copyright © 2018. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

ACS Style

Subash Dahal; Dorcas H. Franklin; Miguel L. Cabrera; Dennis W. Hancock; Lawton Stewart; Laura C. Ney; Anish Subedi; Kishan Mahmud. Spatial Distribution of Inorganic Nitrogen in Pastures as Affected by Management, Landscape, and Cattle Locus. Journal of Environmental Quality 2018, 47, 1468 -1477.

AMA Style

Subash Dahal, Dorcas H. Franklin, Miguel L. Cabrera, Dennis W. Hancock, Lawton Stewart, Laura C. Ney, Anish Subedi, Kishan Mahmud. Spatial Distribution of Inorganic Nitrogen in Pastures as Affected by Management, Landscape, and Cattle Locus. Journal of Environmental Quality. 2018; 47 (6):1468-1477.

Chicago/Turabian Style

Subash Dahal; Dorcas H. Franklin; Miguel L. Cabrera; Dennis W. Hancock; Lawton Stewart; Laura C. Ney; Anish Subedi; Kishan Mahmud. 2018. "Spatial Distribution of Inorganic Nitrogen in Pastures as Affected by Management, Landscape, and Cattle Locus." Journal of Environmental Quality 47, no. 6: 1468-1477.

Journal article
Published: 09 October 2018 in International Journal of Applied Earth Observation and Geoinformation
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Mangroves are one of the most productive ecosystems known for provisioning of various ecosystem goods and services. They help in sequestering large amounts of carbon, protecting coastline against erosion, and reducing impacts of natural disasters such as hurricanes. Bhitarkanika Wildlife Sanctuary in Odisha harbors the second largest mangrove ecosystem in India. This study used Terra, Landsat and Sentinel-1 satellite data for spatio-temporal monitoring of mangrove forest within Bhitarkanika Wildlife Sanctuary between 2000 and 2016. Three biophysical parameters were used to assess mangrove ecosystem health: leaf chlorophyll (CHL), Leaf Area Index (LAI), and Gross Primary Productivity (GPP). A long-term analysis of meteorological data such as precipitation and temperature was performed to determine an association between these parameters and mangrove biophysical characteristics. The correlation between meteorological parameters and mangrove biophysical characteristics enabled forecasting of mangrove health and productivity for year 2050 by incorporating IPCC projected climate data. A historical analysis of land cover maps was also performed using Landsat 5 and 8 data to determine changes in mangrove area estimates in years 1995, 2004 and 2017. There was a decrease in dense mangrove extent with an increase in open mangroves and agricultural area. Despite conservation efforts, the current extent of dense mangrove is projected to decrease up to 10% by the year 2050. All three biophysical characteristics including GPP, LAI and CHL, are projected to experience a net decrease of 7.7%, 20.83% and 25.96% respectively by 2050 compared to the mean annual value in 2016. This study will help the Forest Department, Government of Odisha in managing and taking appropriate decisions for conserving and sustaining the remaining mangrove forest under the changing climate and developmental activities.

ACS Style

Shanti Shrestha; Isabel Miranda; Abhishek Kumar; Maria Luisa Escobar Pardo; Subash Dahal; Taufiq Rashid; Caren Remillard; Deepak R. Mishra. Identifying and forecasting potential biophysical risk areas within a tropical mangrove ecosystem using multi-sensor data. International Journal of Applied Earth Observation and Geoinformation 2018, 74, 281 -294.

AMA Style

Shanti Shrestha, Isabel Miranda, Abhishek Kumar, Maria Luisa Escobar Pardo, Subash Dahal, Taufiq Rashid, Caren Remillard, Deepak R. Mishra. Identifying and forecasting potential biophysical risk areas within a tropical mangrove ecosystem using multi-sensor data. International Journal of Applied Earth Observation and Geoinformation. 2018; 74 ():281-294.

Chicago/Turabian Style

Shanti Shrestha; Isabel Miranda; Abhishek Kumar; Maria Luisa Escobar Pardo; Subash Dahal; Taufiq Rashid; Caren Remillard; Deepak R. Mishra. 2018. "Identifying and forecasting potential biophysical risk areas within a tropical mangrove ecosystem using multi-sensor data." International Journal of Applied Earth Observation and Geoinformation 74, no. : 281-294.

Research article
Published: 22 November 2017 in Proceedings of the National Academy of Sciences, India Section A: Physical Sciences
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Mangroves around the world play a major role in coastal ecosystem processes by mitigating erosion and serving as a barrier against storm surges. India holds approximately 5% of the world’s mangroves, over half of which are found along its east coast. Situated in the state of Odisha, Chilika Lagoon and Bhitarkanika Wildlife Sanctuary are two wetlands of local importance in need of effective management. This study demonstrated the use of Terra, Landsat, and Sentinel-1 satellite data for spatio-temporal monitoring of mangrove health at these two sites. Several indices, including Normalized Difference Vegetation Index and Enhanced Vegetation Index, were examined to develop biophysical prediction tools and derive a 17-year time-series (from 2000 to 2016) of leaf chlorophyll (CHL), Leaf Area Index (LAI), and Gross Primary Productivity (GPP). The long-term analysis revealed phenological patterns in the biophysical characteristics such as high values during wet season and low values during the dry season. Correlations between biophysical characteristics and meteorological factors revealed a time lag exists in response to precipitation and associated runoff. In contrast, surface temperature did not show any lag in response time. This study also utilized Sentinel-1 radar data for the first time for Odisha mangroves to show seasonal variability in LAI, GPP, and CHL. The results from radar data were consistent with optical sensors and proved useful for capturing the rainy season, where data were limited due to cloud cover. This study revealed the advantages of using a multi-sensor approach for monitoring mangrove health and defining future monitoring protocols.

ACS Style

Abhishek Kumar; Patricia Stupp; Subash Dahal; Caren Remillard; Roger Bledsoe; Austin Stone; Christopher Cameron; Gurdeep Rastogi; Rabindro Samal; Deepak R. Mishra. A Multi-Sensor Approach for Assessing Mangrove Biophysical Characteristics in Coastal Odisha, India. Proceedings of the National Academy of Sciences, India Section A: Physical Sciences 2017, 87, 679 -700.

AMA Style

Abhishek Kumar, Patricia Stupp, Subash Dahal, Caren Remillard, Roger Bledsoe, Austin Stone, Christopher Cameron, Gurdeep Rastogi, Rabindro Samal, Deepak R. Mishra. A Multi-Sensor Approach for Assessing Mangrove Biophysical Characteristics in Coastal Odisha, India. Proceedings of the National Academy of Sciences, India Section A: Physical Sciences. 2017; 87 (4):679-700.

Chicago/Turabian Style

Abhishek Kumar; Patricia Stupp; Subash Dahal; Caren Remillard; Roger Bledsoe; Austin Stone; Christopher Cameron; Gurdeep Rastogi; Rabindro Samal; Deepak R. Mishra. 2017. "A Multi-Sensor Approach for Assessing Mangrove Biophysical Characteristics in Coastal Odisha, India." Proceedings of the National Academy of Sciences, India Section A: Physical Sciences 87, no. 4: 679-700.

Journal article
Published: 01 February 2015 in Nepal Journal of Science and Technology
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A study was carried out to standardize nitrogen application at different stages of tuberose (Polianthes tuberosa L.) (cv. Double) for improving growth, flowering and vase life in a farmer’s field at Gunjanagar VDC, Chitwan, Nepal, during May to September, 2012. The experiment was laid out in randomized complete block design with 10 treatments of nitrogen in split doses and replicating thrice. The cut flower and vase life characteristics of tuberose were studied and the economics of production was also analysed. Significant difference was found between treatments of split doses of nitrogen in flowering and post-harvest characteristics of this flower. Three equal split doses of nitrogen, 33% N basal + 33% N at 30 days after planting + 33% N at 50 days after planting resulted in the earliest spike initiation (60 days) and the first flower opening (95.17 days). The same treatments recorded longest vase life (16.47 days). The longest (91.69 cm), heaviest (87.97g) and thickest (0.89 cm) spikes with longest rachis (38.77 cm) were produced by three equal split doses of nitrogen, 33% N basal + 33% N at 50 days after planting + 33% N at 70 days after planting. The same treatments produced maximum net income (NRs. 214,250/-) and benefit-cost (B:C) ratio (1.29) per hectare. Thus, three equal split doses of nitrogen, 33% N basal + 33% N at 50 days after planting + 33% N at 70 days after planting are appropriate for commercial cultivation of tuberose in Nepal.DOI: http://dx.doi.org/10.3126/njst.v15i1.12006 Nepal Journal of Science and TechnologyVol. 15, No.1 (2014) 23-30

ACS Style

Subash Dahal; K. Mishra; U. K. Pun; D. D. Dhakal; M. Sharma. Evaluation of Split Doses of Nitrogen at Different Growth Stages of Tuberose (Polianthes tuberosa L.) for Improving Flowering and Vase-life. Nepal Journal of Science and Technology 2015, 15, 23 -30.

AMA Style

Subash Dahal, K. Mishra, U. K. Pun, D. D. Dhakal, M. Sharma. Evaluation of Split Doses of Nitrogen at Different Growth Stages of Tuberose (Polianthes tuberosa L.) for Improving Flowering and Vase-life. Nepal Journal of Science and Technology. 2015; 15 (1):23-30.

Chicago/Turabian Style

Subash Dahal; K. Mishra; U. K. Pun; D. D. Dhakal; M. Sharma. 2015. "Evaluation of Split Doses of Nitrogen at Different Growth Stages of Tuberose (Polianthes tuberosa L.) for Improving Flowering and Vase-life." Nepal Journal of Science and Technology 15, no. 1: 23-30.