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Dr. Rajan Ghimire
New Mexico State University

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0 Sustainability
0 soil organic carbon
0 Conservation agriculture
0 soil health
0 Nutrient Cycling,

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soil organic carbon
soil health
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Chapter
Published: 31 July 2021 in Soil Science: Fundamentals to Recent Advances
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Increased interest in soil health and sustainability in recent years emphasized the need to identify indicators and adopt improved management strategies in agroecosystems. This chapter discusses selected biogeochemical indicators of soil health, their linkages with soil ecosystem functions, and management strategies to increase crop yields and enhance environmental sustainability. Soil organic matter (SOM) components, greenhouse gas emissions (GHG), and microbial community structures and functions provide critical information on soil health and sustainability. Management approaches that minimize soil disturbance, maximize soil cover, and increase plant and animal diversity can increase SOM storage, mitigate GHG emissions, and support soil microbial community proliferation. Crop rotation, cover cropping, and livestock integration in cropping systems should be promoted to improve soil health and agro-environmental sustainability.

ACS Style

Rajan Ghimire; Vesh R. Thapa; Pramod Acharya; Jun Wang; Upendra M. Sainju. Soil Indicators and Management Strategies for Environmental Sustainability. Soil Science: Fundamentals to Recent Advances 2021, 127 -140.

AMA Style

Rajan Ghimire, Vesh R. Thapa, Pramod Acharya, Jun Wang, Upendra M. Sainju. Soil Indicators and Management Strategies for Environmental Sustainability. Soil Science: Fundamentals to Recent Advances. 2021; ():127-140.

Chicago/Turabian Style

Rajan Ghimire; Vesh R. Thapa; Pramod Acharya; Jun Wang; Upendra M. Sainju. 2021. "Soil Indicators and Management Strategies for Environmental Sustainability." Soil Science: Fundamentals to Recent Advances , no. : 127-140.

Conference article
Published: 27 July 2021 in Agronomy Journal
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Achieving the sustainable development goals of the United Nations requires innovations in agriculture and development of climate-smart and economically feasible approaches for smallholder farmers in developing countries. Historical climate data of Nepal, which include 116 years since 1901, has shown an increasing trend for average temperature by 0.016 o C yr–1 whereas precipitation has shown a decreasing trend by 0.137 mm yr–1. Such weather trends could enhance glacier melt associated flooding, and delayed monsoon rainfalls negatively impacting the agricultural production. The Nepalese government is promoting conservation agriculture (CA) through development of low-cost technologies that can be used effectively in difficult terrains. Such techniques include crop diversification, crop rotation, cover crops and minimum tillage, all of which can reduce soil degradation. In addition, increasing crop residue retention can result in greater C sequestration and crop yield and reductions in greenhouse gas emissions. However, there is still lack of consensus on the merits of CA in the context of smallholder farming systems in Nepal. This paper reviews existing literature and provides an overview of farming practices in Nepal, highlights near-term challenges associated with climate change and food security, and discusses the role of CA as a climate-smart strategy to minimize soil degradation and improve food security. This article is protected by copyright. All rights reserved

ACS Style

Deepak Joshi; Rajan Ghimire; Tulsi Kharel; Umakant Mishra; Sharon A. Clay. Conservation agriculture for food security and climate resilience in Nepal. Agronomy Journal 2021, 1 .

AMA Style

Deepak Joshi, Rajan Ghimire, Tulsi Kharel, Umakant Mishra, Sharon A. Clay. Conservation agriculture for food security and climate resilience in Nepal. Agronomy Journal. 2021; ():1.

Chicago/Turabian Style

Deepak Joshi; Rajan Ghimire; Tulsi Kharel; Umakant Mishra; Sharon A. Clay. 2021. "Conservation agriculture for food security and climate resilience in Nepal." Agronomy Journal , no. : 1.

Review
Published: 24 July 2021 in Agricultural Water Management
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Cover cropping is practiced to enhance soil health and sustain succeeding crop yield; however, the effect of cover crop on soil water storage, succeeding crop yield, and water-use efficiency (WUE) may not be consistent in all regions. A meta-analysis was carried out to evaluate the effect of cover crop on precipitation storage efficiency (PSE, the percent of precipitation that is stored in the soil during the fallow period), soil water storage at succeeding crop planting (SWSP), succeeding crop yield, and WUE from data collected from 117 studies across the world. Cover crop decreased PSE by 33.4% and soil water storage for the whole profile (SWSPT) at soil depth by 13.2%, but increased water storage to a depth of 30 cm (SWSP30) by 6.0% (P < 0.05) compared to no cover crop. Cover crop did not affect succeeding crop yield, but decreased evapotranspiration (ET) by 6.2% and increased WUE by 5.0% (P < 0.05) compared to no cover crop. The effect of cover crop on these parameters varied by soil and climatic conditions of various regions. Leaving cover crop residue at the soil surface or incorporating into the soil reduced PSE, SWSPT, and ET, but increased SWSP30 and WUE compared to residue removal. Maintaining cover crop biomass at 5 Mg ha−1 and leaving a 20-d interval between cover crop termination and succeeding crop planting, also enhanced PSE and SWSP30. Although cover crop had minimal impact on succeeding crop yield, WUE of succeeding crops can be increased with cover cropping by decreasing evapotranspiration.

ACS Style

Jun Wang; Shaohong Zhang; Upendra M. Sainju; Rajan Ghimire; Fazhu Zhao. A meta-analysis on cover crop impact on soil water storage, succeeding crop yield, and water-use efficiency. Agricultural Water Management 2021, 256, 107085 .

AMA Style

Jun Wang, Shaohong Zhang, Upendra M. Sainju, Rajan Ghimire, Fazhu Zhao. A meta-analysis on cover crop impact on soil water storage, succeeding crop yield, and water-use efficiency. Agricultural Water Management. 2021; 256 ():107085.

Chicago/Turabian Style

Jun Wang; Shaohong Zhang; Upendra M. Sainju; Rajan Ghimire; Fazhu Zhao. 2021. "A meta-analysis on cover crop impact on soil water storage, succeeding crop yield, and water-use efficiency." Agricultural Water Management 256, no. : 107085.

Journal article
Published: 14 April 2021 in Agronomy
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Cover crops can improve soil health by maintaining soil organic carbon (SOC) and nitrogen (N) contents, yet their dynamics in relation to crop yield in a semi-arid cropping system are poorly understood. The main objective of this study was to evaluate the response of diverse winter cover crop species and their mixture on SOC and N fractions and their relationship with sorghum (Sorghum bicolor L. Moench) yield in a winter wheat (Triticum aestivum L.)–sorghum–fallow rotation with limited irrigation management. Cover cropping treatments included pea (Pisum sativum L.), oat (Avena sativa L.), canola (Brassica napus L.), and mixtures of pea+oat (POM), pea+canola (PCM), peat+oat+canola (POCM), and a six-species mixture (SSM) of pea+oat+canola+hairy vetch (Vicia villosa Roth)+forage radish (Raphanus sativus L.)+barley (Hordeum vulgare L.) as cover crops and a fallow. Soil samples were analyzed for residual inorganic N, potentially mineralizable carbon (PMC) and nitrogen (PMN), SOC, and total N. Response of labile inorganic N, PMC, and PMN varied with cover crop treatments. The SOC and total N contents did not differ among treatments but were 20% and 35% higher in 2020 than in 2019, respectively. Sorghum grain yield was 25% and 40% greater with oats than with PCM and canola cover crops in 2019, while it was 33–97% greater with fallow and oats than other treatments in 2020. Oat as a cover crop could improve the resilience of limited-irrigation cropping systems by increasing SOC, soil N, and crop yield in semi-arid regions.

ACS Style

Vesh Thapa; Rajan Ghimire; Mark Marsalis. Cover Crops for Resilience of a Limited-Irrigation Winter Wheat–Sorghum–Fallow Rotation: Soil Carbon, Nitrogen, and Sorghum Yield Responses. Agronomy 2021, 11, 762 .

AMA Style

Vesh Thapa, Rajan Ghimire, Mark Marsalis. Cover Crops for Resilience of a Limited-Irrigation Winter Wheat–Sorghum–Fallow Rotation: Soil Carbon, Nitrogen, and Sorghum Yield Responses. Agronomy. 2021; 11 (4):762.

Chicago/Turabian Style

Vesh Thapa; Rajan Ghimire; Mark Marsalis. 2021. "Cover Crops for Resilience of a Limited-Irrigation Winter Wheat–Sorghum–Fallow Rotation: Soil Carbon, Nitrogen, and Sorghum Yield Responses." Agronomy 11, no. 4: 762.

Article
Published: 27 January 2021 in Agronomy Journal
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Winter canola (Brassica napus L.) is an economically viable alternative crop for the semiarid Southern Great Plains of the USA. Although acreage under winter canola has increased in recent years, an independent guideline on fertility recommendation and their effects on crop growth and soil health is not available for the semiarid Southern Great Plains region. This study aimed to evaluate winter canola growth, yield components, and nitrogen use efficiency with different N application timings (NATs) in a semiarid irrigated condition. A two‐year study was designed with two canola varieties (Riley and 46W94) and four NATs. Nitrogen treatments were F100 (100% of N applied in fall), S100 (100% of N applied in spring), FS50 (50% of N applied in fall and 50% in spring), and FSB25 (25% of N applied in fall, 25% in spring and 25% before flowering). The winter dry matter accumulation was greater with the F100 N application, whereas the forage quality was better with the FS50 treatment. The highest seed yield of 2539 kg ha–1 was from S100, which was not significantly different from FS50 and FSB25. The N use efficiency was the highest under FSB25, which uses 25% less N, followed by S100, FS50, and F100 treatments. The FS50 with 50% of N application in fall and 50% in spring was the most efficient N timing treatment when winter biomass accumulation, seed yield, and seed oil and protein contents were considered. This article is protected by copyright. All rights reserved

ACS Style

Wooiklee S. Paye; Sultan Begna; Rajan Ghimire; Sangamesh V. Angadi; Paramveer Singh; Mathada Rangappa Umesh; Murali Darapuneni. Winter canola yield and nitrogen use efficiency in a semiarid irrigated condition. Agronomy Journal 2021, 113, 2053 -2067.

AMA Style

Wooiklee S. Paye, Sultan Begna, Rajan Ghimire, Sangamesh V. Angadi, Paramveer Singh, Mathada Rangappa Umesh, Murali Darapuneni. Winter canola yield and nitrogen use efficiency in a semiarid irrigated condition. Agronomy Journal. 2021; 113 (2):2053-2067.

Chicago/Turabian Style

Wooiklee S. Paye; Sultan Begna; Rajan Ghimire; Sangamesh V. Angadi; Paramveer Singh; Mathada Rangappa Umesh; Murali Darapuneni. 2021. "Winter canola yield and nitrogen use efficiency in a semiarid irrigated condition." Agronomy Journal 113, no. 2: 2053-2067.

Research letter
Published: 01 January 2021 in Agricultural & Environmental Letters
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Effects of nitrogen (N) fertilization on soil organic carbon (SOC) and total N are well established, but their effects on soil acidification and emerging soil health indicators such as labile N and carbon (C) pools are not adequately documented. This research evaluated soil N and C pools and soil pH with long-term N management in continuous cotton (Gossypium hirsutum L.) production. Residual soil inorganic N, potentially mineralizable N and C, total N, SOC, pH, and electrical conductivity were measured after 17 yr of continuous N application. Comparison of five N rates (0, 56, 112, 168, and 224 kg ha–1) showed an increase in residual inorganic N pools and decrease in pH with an increase in N application rate, while other parameters did not change significantly. Soil acidification was significant with 168 and 224 kg N ha–1 rates. Soil pH dropped by 0.039 per kilogram increase in residual inorganic N. Optimizing N rate that minimizes residual inorganic N can reduce soil acidification.

ACS Style

Rajan Ghimire; Megha N. Parajulee; Pramod Acharya; Dol P. Dhakal; Abdul Hakeem; Katie L. Lewis. Soil acidification in a continuous cotton production system. Agricultural & Environmental Letters 2021, 6, e20048 .

AMA Style

Rajan Ghimire, Megha N. Parajulee, Pramod Acharya, Dol P. Dhakal, Abdul Hakeem, Katie L. Lewis. Soil acidification in a continuous cotton production system. Agricultural & Environmental Letters. 2021; 6 (2):e20048.

Chicago/Turabian Style

Rajan Ghimire; Megha N. Parajulee; Pramod Acharya; Dol P. Dhakal; Abdul Hakeem; Katie L. Lewis. 2021. "Soil acidification in a continuous cotton production system." Agricultural & Environmental Letters 6, no. 2: e20048.

Journal article
Published: 20 October 2020 in PeerJ
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Recent interest in improving soil health and agricultural sustainability recognizes the value of soil organic carbon (SOC) sequestration and nutrient cycling. The main goal of this study was to evaluate the response of various SOC and nitrogen (N) components in semiarid cropping systems transitioning from limited-irrigation to dryland and a restored grassland in the Southern High Plains of USA. Cropping systems evaluated include dryland winter wheat (Triticum aestivum L.)–sorghum (Sorghum bicolor L.)–fallow with conventional tillage (DLCTF) and no-tillage (DLNTF), limited-irrigation winter wheat–sorghum–fallow with no-tillage and cover cropping (LINTC) and no-tillage fallow (LINTF), and an undisturbed grassland (NG). Soil samples were collected from 0–15 cm and 15–30 cm depths and analyzed for SOC, total N, inorganic N, and soil microbial biomass carbon (SMBC) contents. The CO2 and N2O release during a eight-weeks long laboratory incubation were also analyzed. Results show 14% and 13% reduction in SOC and total N from 0–30 cm depth with the transition from limited-irrigation to dryland cropping systems while 51% more SOC and 41% more total N with the transition to grassland. The SMBC was 42% less in dryland cropping systems and 100% more in NG than the limited-irrigation cropping systems. However, the grassland was N limited, with 93% less inorganic N in NG compared to only 11% less in dryland cropping systems than in limited-irrigation cropping systems. The microbial respiration measured as CO2-C was highest in NG, followed by limited-irrigation and dryland cropping systems. The N2O-N release showed the lowest rate of N loss from dryland cropping systems, followed by NG and limited-irrigation cropping systems. This study demonstrated loss of SOC and N in agroecosystems transitioned to dryland crop-fallow systems, with greater magnitude of change observed in the biologically active fraction of soil organic matter. Grassland restoration could be an important strategy to increase SOC and nutrients in hot, dry, semiarid agroecosystems transitioning to dryland.

ACS Style

Rajan Ghimire; Babu Ram Khanal. Soil organic matter dynamics in semiarid agroecosystems transitioning to dryland. PeerJ 2020, 8, e10199 .

AMA Style

Rajan Ghimire, Babu Ram Khanal. Soil organic matter dynamics in semiarid agroecosystems transitioning to dryland. PeerJ. 2020; 8 ():e10199.

Chicago/Turabian Style

Rajan Ghimire; Babu Ram Khanal. 2020. "Soil organic matter dynamics in semiarid agroecosystems transitioning to dryland." PeerJ 8, no. : e10199.

Journal article
Published: 31 August 2020 in Applied Soil Ecology
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Cover crops are promoted to increase soil organic carbon (SOC) storage and improve soil biological health in agricultural systems. However, cover crop effects on soil microbial communities – key regulators of SOC and nutrients – and functioning are not clear in semiarid environments. This study investigated the response of soil microbial community structure and enzyme activities to cover crop integration under limited-irrigation winter wheat (Triticum aestivum)-sorghum (Sorghum bicolor)-fallow rotation. The study had a randomized complete block design with eight treatments and three replications. Treatments were pea (Pisum sativum); oat (Avena sativa); canola (Brassica napus L.); and mixtures of pea + oat (POmix), pea + canola (PCmix), pea + oat + canola (POCmix), and pea + oat + canola + hairy vetch (Vicia villosa) + forage radish (Raphanus sativus L.) + barley (Hordeum vulgare L.) (diverse-mix) as cover crops; and a fallow. Soil samples were collected in the summer of 2017 and 2018 from 0 to 15 cm depth of each plot established in fall 2015. Microbial community size and structure were evaluated via ester-linked fatty acid methyl ester (EL-FAME) analysis, which showed that total microbial community size and fungal community were similar between soils under oats and diverse-mix, and were 31% and 41% greater than fallow, respectively. The FAME marker for arbuscular mycorrhizal fungi (AMF) was 84% greater under oats than fallow. The combined enzyme activity of acid phosphatase, β-glucosidase, and β-glucosaminidase was 294 mg p-nitrophenol (PNP) kg−1 soil h−1 under diverse-mix, which was greater than fallow (204 mg PNP kg−1 soil h−1, p = 0.021) in 2018. Cover cropping during fallow period in a crop-fallow rotation could increase total microbial community size, fungal abundance, and enzyme activities associated with carbon (C) and nutrient cycling. Among cover crops, oat and its mixture with legumes (pea and hairy vetch) and brassicas (canola and forage radish) were most effective in improving soil health and biogeochemical cycling in a hot and dry semiarid climate.

ACS Style

Vesh R. Thapa; Rajan Ghimire; Verónica Acosta-Martínez; Mark A. Marsalis; Meagan E. Schipanski. Cover crop biomass and species composition affect soil microbial community structure and enzyme activities in semiarid cropping systems. Applied Soil Ecology 2020, 157, 103735 .

AMA Style

Vesh R. Thapa, Rajan Ghimire, Verónica Acosta-Martínez, Mark A. Marsalis, Meagan E. Schipanski. Cover crop biomass and species composition affect soil microbial community structure and enzyme activities in semiarid cropping systems. Applied Soil Ecology. 2020; 157 ():103735.

Chicago/Turabian Style

Vesh R. Thapa; Rajan Ghimire; Verónica Acosta-Martínez; Mark A. Marsalis; Meagan E. Schipanski. 2020. "Cover crop biomass and species composition affect soil microbial community structure and enzyme activities in semiarid cropping systems." Applied Soil Ecology 157, no. : 103735.

Journal article
Published: 27 July 2020 in Sustainability
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Declining water resources and soil degradation have significantly affected agricultural sustainability across the world. In the southern High Plains of USA, buffer strips of perennial grasses alternating with cultivated corn strips were introduced in center-pivot irrigated crop fields to increase agronomic production and ecosystem services. A study was conducted to evaluate soil carbon (C) and nitrogen (N) dynamics, greenhouse gas (GHG) emissions, and soil health benefits of integrating circular grass buffer strips in the center-pivot irrigated corn production system. Multiple parameters were assessed in the grass buffer strips, and at distances of 1.52, 4.57, and 9.14 m away from the edges of grass strips in corn strips. While grasses in the buffer strips depleted N compared to corn strips, grass strips accumulated 52.5% to 99.9% more potential C mineralization (PCM) than corn strips. Soil microbial biomass C (MBC) content was 36.7% to 52.5% greater in grass strips than in corn strips. Grass buffer also reduced carbon dioxide (CO2) and nitrous oxide (N2O) emissions from corn strips. Grass buffer strips can improve soil health and sustainability in center-pivot irrigated cropping systems by increasing soil C components and reducing GHG emissions.

ACS Style

Sk. Musfiq-Us-Salehin; Rajan Ghimire; Sangamesh Angadi; Omololu Idowu. Grass Buffer Strips Improve Soil Health and Mitigate Greenhouse Gas Emissions in Center-Pivot Irrigated Cropping Systems. Sustainability 2020, 12, 6014 .

AMA Style

Sk. Musfiq-Us-Salehin, Rajan Ghimire, Sangamesh Angadi, Omololu Idowu. Grass Buffer Strips Improve Soil Health and Mitigate Greenhouse Gas Emissions in Center-Pivot Irrigated Cropping Systems. Sustainability. 2020; 12 (15):6014.

Chicago/Turabian Style

Sk. Musfiq-Us-Salehin; Rajan Ghimire; Sangamesh Angadi; Omololu Idowu. 2020. "Grass Buffer Strips Improve Soil Health and Mitigate Greenhouse Gas Emissions in Center-Pivot Irrigated Cropping Systems." Sustainability 12, no. 15: 6014.

Original research article
Published: 01 January 2020 in Agrosystems, Geosciences & Environment
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Sorghum [Sorghum bicolor (L.) Moench] serves as a low‐cost alternative to corn (Zea mays L.) in semi‐arid regions of the world because of its high N and water use efficiencies. However, there has been a concern regarding N loss to the atmosphere as nitrous oxide (N2O) from semi‐arid drylands. This study investigated various soil C and N components, including CO2 and N2O emissions, and crop yield with a dairy compost (13.5 Mg ha−1) and four rates of chemical N fertilizer (0, 22.4, 44.8, and 67.3 kg ha−1) in dryland sorghum. There was no significant difference in soil C and N fractions among N fertilizer rates, although compost addition numerically increased soil C storage and 67.3 kg ha−1 N rate resulted the highest yield in both years. Potential nitrogen mineralization (PNM) was negatively related to crop yield and positively related to grain N content. Soils with greater inorganic N and PNM had a lower carbon dioxide (CO2) emissions, while soils with greater potential C mineralization (PCM) had lower N2O emissions. The results of this study show no significant improvements in yield of dryland sorghum in the semi‐arid environment of southern Great Plains in the short term. However, compost and 44.8 kg N ha−1 applications appeared to be beneficial when both yield and quality were compared.

ACS Style

Sk. Musfiq‐Us‐ Salehin; Rajan Ghimire; Sangamesh V. Angadi; Abdel Mesbah. Soil organic matter, greenhouse gas emissions, and sorghum yield in semi‐arid drylands. Agrosystems, Geosciences & Environment 2020, 3, 1 .

AMA Style

Sk. Musfiq‐Us‐ Salehin, Rajan Ghimire, Sangamesh V. Angadi, Abdel Mesbah. Soil organic matter, greenhouse gas emissions, and sorghum yield in semi‐arid drylands. Agrosystems, Geosciences & Environment. 2020; 3 (1):1.

Chicago/Turabian Style

Sk. Musfiq‐Us‐ Salehin; Rajan Ghimire; Sangamesh V. Angadi; Abdel Mesbah. 2020. "Soil organic matter, greenhouse gas emissions, and sorghum yield in semi‐arid drylands." Agrosystems, Geosciences & Environment 3, no. 1: 1.

Technical note
Published: 16 December 2019 in Agrosystems, Geosciences & Environment
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Cover crops improve soil health and environmental quality by enhancing soil organic carbon (SOC) and nutrient cycling compared to no cover crop in agroecosystems. This study evaluated the effect of cover crops on soil carbon dioxide (CO2) emissions, temperature, and water content during cover crop growth from April to October, 2017 and 2018. Treatments included fallow, pea (Pisum sativum L.), oat (Avena sativa L.), canola (Brassica napus L.), pea + oat (PO), pea + canola (PC), pea + oat + canola (POC), and POC + hairy vetch (Vicia villosa L.) + forage radish (Raphanus sativus L.) + barley (Hordeum vulgare L.) (Six species mixture; SSM). The CO2 emissions were monitored weekly from April to October of 2017 and 2018 using a portable infrared‐gas analyzer. Seasonal changes in CO2 emissions varied with cover crops and peaked as soil temperature and water content following precipitation increased. Average CO2 emissions across sampling dates was 46 to 70% greater under pea than under fallow, canola, and PO in 2017, but not different among cover crops in 2018. Although the emissions were higher than fallow, canola and PO plots had lower CO2 emissions than other cover crops.. Pea as sole cover crop or in mixtures (PC, POC, SSM) increased CO2 emissions and microbial activity while canola and PO mixture reduced the emissions during the period with higher precipitation. This article is protected by copyright. All rights reserved

ACS Style

Abdelaziz Nilahyane; Rajan Ghimire; Vesh Raj Thapa; Upendra M. Sainju. Cover crop effects on soil carbon dioxide emissions in a semiarid cropping system. Agrosystems, Geosciences & Environment 2019, 3, 1 .

AMA Style

Abdelaziz Nilahyane, Rajan Ghimire, Vesh Raj Thapa, Upendra M. Sainju. Cover crop effects on soil carbon dioxide emissions in a semiarid cropping system. Agrosystems, Geosciences & Environment. 2019; 3 (1):1.

Chicago/Turabian Style

Abdelaziz Nilahyane; Rajan Ghimire; Vesh Raj Thapa; Upendra M. Sainju. 2019. "Cover crop effects on soil carbon dioxide emissions in a semiarid cropping system." Agrosystems, Geosciences & Environment 3, no. 1: 1.

Journal article
Published: 12 December 2019 in Sustainability
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Cover cropping has been promoted for improving soil health and environmental quality in the southern High Plains (SHP) region of the United States. The SHP is one of the more productive areas of the country and covers a large landmass, including parts of Oklahoma, New Mexico, and Texas. This region faces challenges in sustainable crop production due to declining water levels in the Ogallala Aquifer, the primary source of water for irrigated crop production. This study examines the impact of integrating cover crops in the winter wheat (Triticum aestivum L)-based rotations on farm profitability and risk in the SHP. The study combines experimental yield data with other secondary information, including market prices, to conduct simulation analysis and evaluate the risk involved in introducing cover crops in a wheat-fallow cropping system. The results show that, due to the additional monetary costs involved, none of the cover crop options is economically viable. However, when secondary benefits (erosion control and green nitrogen) or government subsidies are included in the analysis, one of the cover crop options (peas) dominates the fallow alternative. Moreover, when the secondary benefits and a government subsidy are combined, two cover crop alternatives (peas and oats) emerge as more profitable options than leaving land fallow. These results highlight the importance of agricultural research and extension programs that are making a concerted effort to develop more productive farming techniques and increase public awareness about the long-term benefits of adopting soil health management systems such as cover cropping in the SHP region.

ACS Style

Ram N. Acharya; Rajan Ghimire; Apar Gc; Don Blayney. Effect of Cover Crop on Farm Profitability and Risk in the Southern High Plains. Sustainability 2019, 11, 7119 .

AMA Style

Ram N. Acharya, Rajan Ghimire, Apar Gc, Don Blayney. Effect of Cover Crop on Farm Profitability and Risk in the Southern High Plains. Sustainability. 2019; 11 (24):7119.

Chicago/Turabian Style

Ram N. Acharya; Rajan Ghimire; Apar Gc; Don Blayney. 2019. "Effect of Cover Crop on Farm Profitability and Risk in the Southern High Plains." Sustainability 11, no. 24: 7119.

Journal article
Published: 10 October 2019 in Agronomy
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Biochar can improve soil health and crop productivity. We studied the response of soil properties and wheat growth to four rates of wood biochar (0, 11.2, 22.4, and 44.8 Mg ha−1) and two fertilizer rates [no fertilizer and fertilizer (90 kg N ha−1, 45 kg P ha−1, and 20 kg S ha−1)]. Biochar application increased soil organic matter (SOM), soil pH, phosphorus (P), potassium (K), sulfur (S) contents, and the shoot and root biomass of wheat. However, these responses were observed at biochar rates below 22.4 Mg ha−1, particularly in treatments without fertilizer. In fertilizer-applied treatments, soil nitrate levels decreased with an increase in biochar rates, mainly due to better crop growth and high nitrate uptake. However, without N addition, the high C:N ratio (500:1) possibly increased nutrient tie-up, reduced plant biomass, and SOM buildup at the highest biochar rate. Based on these results, we recommend biochar rates of about 22.4 Mg ha−1 and below for Walla Walla silt loams.

ACS Style

Prakriti Bista; Rajan Ghimire; Stephen Machado; Larry Pritchett. Biochar Effects on Soil Properties and Wheat Biomass vary with Fertility Management. Agronomy 2019, 9, 623 .

AMA Style

Prakriti Bista, Rajan Ghimire, Stephen Machado, Larry Pritchett. Biochar Effects on Soil Properties and Wheat Biomass vary with Fertility Management. Agronomy. 2019; 9 (10):623.

Chicago/Turabian Style

Prakriti Bista; Rajan Ghimire; Stephen Machado; Larry Pritchett. 2019. "Biochar Effects on Soil Properties and Wheat Biomass vary with Fertility Management." Agronomy 9, no. 10: 623.

Journal article
Published: 21 August 2019 in Scientific Reports
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Soil organic carbon (SOC) is integral to soil health and agroecosystem resilience. Despite much research, understanding of temperature sensitivity of SOC under long-term agricultural management is very limited. The main objective of this study was to evaluate SOC and nitrogen (N) dynamics under grasslands and winter wheat (Triticum aestivum L)-based crop rotations in the inland Pacific Northwest (IPNW), USA, and measure SOC mineralization under ambient and elevated incubation temperatures. Soil samples were collected from 0–10 and 10–20 cm depths from an undisturbed grassland (GP), winter wheat-pea (Pisum sativum L) rotations under conventional tillage (WP-CT) and no-tillage (WP-NT), and winter wheat-fallow rotation under conventional tillage (WF-CT) and analyzed for SOC and N pools. Soil samples were incubated at 20 °C and 30 °C for 10 weeks, and SOC mineralization rates were estimated using the first order kinetic model. The GP had the greatest amounts of SOC, total N (TN), and microbial biomass carbon (MBC) and WP rotations had higher inorganic N content than other treatments. The SOC mineralization at elevated incubation temperature was 72–177% more than at the ambient temperature, and the greatest effect was observed in GP. The SOC storage under a given management did not have consistent effects on soil carbon (C) and N mineralization under elevated temperature. However, soil disturbance under WP-CT and WF-CT accelerated SOC mineralization leading to soil C loss. Reducing tillage, integrating legumes into crop rotations, and growing perennial grasses could minimize SOC loss and have the potential to improve soil health and agroecosystem resilience under projected climate warming.

ACS Style

Rajan Ghimire; Prakriti Bista; Stephen Machado. Long-term Management Effects and Temperature Sensitivity of Soil Organic Carbon in Grassland and Agricultural Soils. Scientific Reports 2019, 9, 1 -10.

AMA Style

Rajan Ghimire, Prakriti Bista, Stephen Machado. Long-term Management Effects and Temperature Sensitivity of Soil Organic Carbon in Grassland and Agricultural Soils. Scientific Reports. 2019; 9 (1):1-10.

Chicago/Turabian Style

Rajan Ghimire; Prakriti Bista; Stephen Machado. 2019. "Long-term Management Effects and Temperature Sensitivity of Soil Organic Carbon in Grassland and Agricultural Soils." Scientific Reports 9, no. 1: 1-10.

Journal article
Published: 28 June 2019 in Sustainability
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Dairy compost is utilized in agricultural fields to supplement nutrients, yet its role in optimizing nutrient supply and health of semiarid soils is not clear. A greenhouse study was conducted over two months to evaluate soil properties and forage sorghum production under various compost rates. The study had six treatments and four replications. Treatments included compost application rates at 6.7 (C1), 13.5 (C2), 20.2 (C3), 26.9 (C4), and 33.6 Mg ha−1 (C5) and a control (C0). Soil samples were analyzed for soil organic carbon (SOC), potentially mineralizable carbon (PMC), total nitrogen (N), inorganic N, potentially mineralizable N (PMN), available phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). Plant biomass production and biomass C, N, and lignin contents were also estimated. High compost rates improved soil properties significantly (p < 0.05) indicated by increased SOC, N, P, K, Ca, and cation exchange capacity (CEC). Sorghum biomass production did not increase significantly with compost rate, while shoot N content increased at higher rates of compost. A nutrient management plan that integrates dairy compost application has potential to improve soil health and support sustainable forage production in semiarid regions.

ACS Style

Pramod Acharya; Rajan Ghimire; Youngkoo Cho. Linking Soil Health to Sustainable Crop Production: Dairy Compost Effects on Soil Properties and Sorghum Biomass. Sustainability 2019, 11, 3552 .

AMA Style

Pramod Acharya, Rajan Ghimire, Youngkoo Cho. Linking Soil Health to Sustainable Crop Production: Dairy Compost Effects on Soil Properties and Sorghum Biomass. Sustainability. 2019; 11 (13):3552.

Chicago/Turabian Style

Pramod Acharya; Rajan Ghimire; Youngkoo Cho. 2019. "Linking Soil Health to Sustainable Crop Production: Dairy Compost Effects on Soil Properties and Sorghum Biomass." Sustainability 11, no. 13: 3552.

Journal article
Published: 11 May 2019 in Applied Soil Ecology
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Livestock integration in cropping systems and conversion of croplands into grazing lands has been increasingly considered to improve agricultural sustainability, yet their roles in soil health and resilience are not clear due to the complex interactions of soil, climate, and agricultural systems. A study was conducted to evaluate the effects of cropland and grassland management systems on soil organic carbon (SOC) and total nitrogen (N) across the soil profile (0–20, 20–40, 40–60, and 60–80 cm) and microbial community size, structure, and activity in the soil surface (0–20 cm) as indicators of soil health. Cropland systems compared included conventional-tilled winter-grazed cropland (CTGC) and no-tilled and strip-tilled croplands (NTC and STC) without livestock grazing. Grassland systems included grazed grassland (GGL) and ungrazed grassland (UGL). Grassland soils accumulated 18% greater SOC and 13% greater total N than cropland soils in the 0–80 cm profile. Microbial community size (sum of ester-linked fatty acid methyl esters [El-FAME]) in the surface 0–20 cm was 90% greater, and enzyme activities were 131–155% greater in the grasslands than in the croplands. Within grasslands, cattle (Bos taurus) grazing increased microbial community size by approximately 42%, which was mainly due to greater fatty acid methyl esters (FAME) markers for gram-positive bacteria (51%) and Actinobacteria (73%). Grazed cropland had 95% more β‑glucosaminidase activity than ungrazed croplands. This study suggests light grazing and grassland restoration has potential to improve soil health and resilience through an increase in SOC and microbial community responses related to nutrient cycling.

ACS Style

Rajan Ghimire; Vesh Raj Thapa; Amanda Cano; Veronica Acosta-Martinez. Soil organic matter and microbial community responses to semiarid croplands and grasslands management. Applied Soil Ecology 2019, 141, 30 -37.

AMA Style

Rajan Ghimire, Vesh Raj Thapa, Amanda Cano, Veronica Acosta-Martinez. Soil organic matter and microbial community responses to semiarid croplands and grasslands management. Applied Soil Ecology. 2019; 141 ():30-37.

Chicago/Turabian Style

Rajan Ghimire; Vesh Raj Thapa; Amanda Cano; Veronica Acosta-Martinez. 2019. "Soil organic matter and microbial community responses to semiarid croplands and grasslands management." Applied Soil Ecology 141, no. : 30-37.

Journal article
Published: 17 January 2019 in Agrosystems, Geosciences & Environment
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Biomass C inputs often limit agroecosystem C dynamics, nutrient cycling, and soil organic carbon (SOC) storage in semiarid drylands. This study evaluated SOC and net ecosystem carbon balance (NECB) of five cropping systems in the drylands of the Southern Great Plains. Cropping systems evaluated included corn (Zea mays)–sorghum [Sorghum bicolor (L.) Moench] rotation with conventional tillage without cover cropping (CTNC), strip tillage with and without cover cropping (STCC and STNC, respectively), and no tillage with and without cover cropping (NTCC and NTNC, respectively). After 4 yr of experimental tillage, we measured CO2 emissions, soil and soil surface air temperatures, soil moisture content, potentially mineralizable carbon (PMC), total SOC, total nitrogen (TN), and net primary productivity (NPP). Conservation systems (any treatments including no-till, strip till, or cover crops) had 5 to 6°C lower soil temperature and 2.8 to 4.9°C lower soil surface air temperature and stored 2.3 to 3.9% more soil moisture content than CTNC. Conservation systems also stored 15.2% more SOC than CTNC. Cropping systems that integrated cover crops in the rotation (STCC and NTCC) had greater NPP and positive NECB. Regardless of tillage management, cover cropping had a greater NECB, including SOC (NECBSOC) than CTNC. Reducing tillage and diversifying cropping systems through cover cropping can benefit semiarid dryland agroecosystems by increasing SOC storage and maintaining positive NECB. Copyright © 2019. . © 2019 The Authors.

ACS Style

Vesh Raj Thapa; Rajan Ghimire; Benjamin D. Duval; Mark A. Marsalis. Conservation Systems for Positive Net Ecosystem Carbon Balance in Semiarid Drylands. Agrosystems, Geosciences & Environment 2019, 2, 1 -8.

AMA Style

Vesh Raj Thapa, Rajan Ghimire, Benjamin D. Duval, Mark A. Marsalis. Conservation Systems for Positive Net Ecosystem Carbon Balance in Semiarid Drylands. Agrosystems, Geosciences & Environment. 2019; 2 (1):1-8.

Chicago/Turabian Style

Vesh Raj Thapa; Rajan Ghimire; Benjamin D. Duval; Mark A. Marsalis. 2019. "Conservation Systems for Positive Net Ecosystem Carbon Balance in Semiarid Drylands." Agrosystems, Geosciences & Environment 2, no. 1: 1-8.

Original article
Published: 05 July 2018 in Grass and Forage Science
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Reduced soil disturbance and increased organic matter inputs in forage production systems may improve soil quality and crop production through their effects on soil organic matter (SOM) dynamics and nutrient cycling. We evaluated the effects of conventional (CV), organic (OR) and reduced‐tillage (RT) management systems on SOM pools in perennial forage–annual crop rotations established on soils previously under long‐term monocropped corn (Zea mays L.) field. The SOM pools evaluated include potentially mineralizable carbon (PMC) and nitrogen (PMN), dissolved organic carbon (DOC) and nitrogen (DON), microbial biomass carbon (MBC) and nitrogen (MBN), inorganic nitrogen (inorganic‐N), soil organic carbon (SOC) and soil total nitrogen (STN). The crop rotation was 3 years of alfalfa (Medicago sativa L.)–grass mixture (2009‐2011) followed by a fourth year of corn (2012) across all management systems. While soils under the RT system had the highest rate of labile carbon (C) and nitrogen (N) accrual, all management systems accumulated SOC and STN during 2009‐2011. The response of different C and N pools was not consistent in 2012 when the fields were transitioned from alfalfa‐grass mixture to corn production. Soil PMN and inorganic‐N contents were significantly greater under CV than other management systems, whereas PMC and MBC remained greater under RT than other management systems. This suggests CV may provide immediate benefits to crop production by increasing N availability, but RT has potential to increase SOC accumulation and improve soil quality in the long‐term under perennial forage–annual crop rotations.

ACS Style

Rajan Ghimire; Jay B. Norton; Urszula Norton. Soil organic matter dynamics under irrigated perennial forage–annual crop rotations. Grass and Forage Science 2018, 73, 907 -917.

AMA Style

Rajan Ghimire, Jay B. Norton, Urszula Norton. Soil organic matter dynamics under irrigated perennial forage–annual crop rotations. Grass and Forage Science. 2018; 73 (4):907-917.

Chicago/Turabian Style

Rajan Ghimire; Jay B. Norton; Urszula Norton. 2018. "Soil organic matter dynamics under irrigated perennial forage–annual crop rotations." Grass and Forage Science 73, no. 4: 907-917.

Journal article
Published: 26 May 2018 in Agricultural Water Management
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Straw mulching is widely used to conserve soil water and increase crop yields. The effects of wheat straw mulching rate and method on dryland soil water storage, winter wheat (Triticum aestivum L.) growth and yield, and water-use efficiency (WUE) were examined from 2008 to 2015 in the Loess Plateau of China. Treatments included wheat straw mulching at a high rate of 9000 kg ha−1 (HSM) and low rate of 4500 kg ha−1 (LSM) throughout the year, straw mulching at a rate of 9000 kg ha−1 during summer fallow (FSM), and no mulching (CK). Soil water storage at wheat planting and precipitation-storage efficiency (PSE) were greater with straw mulching than without. Soil water storage at harvest was greater with HSM than CK and FSM. Wheat yield components such as number of wheat seedling, plant, tiller, and spike and thousand-grain weight varied with treatments and years, but wheat aboveground biomass and grain yields were usually greater with mulching than without during years with below-average precipitation. Harvest index and WUE were lower with LSM and HSM than other treatments in most years, but evapotranspiration did not vary with treatments. Overall, the increased PSE due to straw mulching did not increase yield and WUE, and straw mulching could sustain dryland wheat grain yield only in dry years.

ACS Style

Jun Wang; Rajan Ghimire; Xin Fu; Upendra M. Sainju; Wenzhao Liu. Straw mulching increases precipitation storage rather than water use efficiency and dryland winter wheat yield. Agricultural Water Management 2018, 206, 95 -101.

AMA Style

Jun Wang, Rajan Ghimire, Xin Fu, Upendra M. Sainju, Wenzhao Liu. Straw mulching increases precipitation storage rather than water use efficiency and dryland winter wheat yield. Agricultural Water Management. 2018; 206 ():95-101.

Chicago/Turabian Style

Jun Wang; Rajan Ghimire; Xin Fu; Upendra M. Sainju; Wenzhao Liu. 2018. "Straw mulching increases precipitation storage rather than water use efficiency and dryland winter wheat yield." Agricultural Water Management 206, no. : 95-101.

Review article
Published: 22 May 2018 in Geoderma
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The Ogallala Aquifer is one of the largest freshwater aquifers in the world. It acts as a valuable resource in agriculture, animal production, and public water supplies across eight Great Plains states. However, with high irrigation demand, low recharge rates across most of the region, and extreme climate variability, the Ogallala Aquifer has become an exhaustible resource. Some areas of the Ogallala Aquifer region (OAR) are challenged with the transition of irrigated crop systems to dryland production and how to select sustainable management practices to conserve water and soil health. The main goal of this review is to identify the role of soil health in adapting to extreme climate variability with reduced irrigated water. We will describe the OAR, define roles of microorganisms and soil organic matter (SOM) in soil health, outline potential soil health indicators and common methodology, and discuss the importance of soil health assessments and management challenges facing the OAR. Information on this arid to semiarid region will aid in future soil health assessments in regions facing similar challenges.

ACS Style

Amanda Cano; Agustín Núñez; Veronica Acosta-Martinez; Meagan Schipanski; Rajan Ghimire; Charles Rice; Charles West. Current knowledge and future research directions to link soil health and water conservation in the Ogallala Aquifer region. Geoderma 2018, 328, 109 -118.

AMA Style

Amanda Cano, Agustín Núñez, Veronica Acosta-Martinez, Meagan Schipanski, Rajan Ghimire, Charles Rice, Charles West. Current knowledge and future research directions to link soil health and water conservation in the Ogallala Aquifer region. Geoderma. 2018; 328 ():109-118.

Chicago/Turabian Style

Amanda Cano; Agustín Núñez; Veronica Acosta-Martinez; Meagan Schipanski; Rajan Ghimire; Charles Rice; Charles West. 2018. "Current knowledge and future research directions to link soil health and water conservation in the Ogallala Aquifer region." Geoderma 328, no. : 109-118.