Koffi Djaman | Africa Rice Center (original) (raw)
Papers by Koffi Djaman
PloS one, Mar 28, 2024
This study aimed to measure maize (Zea mays) plant nutrient content and nutrient removal in grain... more This study aimed to measure maize (Zea mays) plant nutrient content and nutrient removal in grain, and to evaluate the residual soil nitrogen, phosphorus, and potassium as impacted by planting date and density. Field experiments were conducted to evaluate six plant densities and seven planting dates using a split-split plot design with three replications. Besides the crop growth and yield parameters, six plants were collected at the maturity and soil was sampled from each plot for nutrient analysis. Plant N, P, and K concentrations varied with planting date and density and within the ranges of 0.6-1.024%, 0.054-0.127%, and 0.75-1.71%, respectively. Grain N, P, and K concentrations decreased with plant density and varied from 1.059 to 1.558%, 0.20 to 0.319%, and 0.29 to 0.43%, respectively. Soil residual nutrient varied with depth, planting density and date. Residual N concentration in the topsoil varied from 0.6 to 37.2 mg kg-1 in 2019 and from 1.5 to 11.2 mg kg-1 in 2020 and was high under the last two planting dates. Soil residual N concentration was higher in the second layer than in the topsoil. The N concentration in the third layer varied from 0.1 to 33.2 mg kg-1 and was impacted by plant density. Topsoil P did not vary among planting dates and densities. The second and third soil layers P concentration was not affected. There was 83% increase in topsoil K in 2020 compared to 2019, and a decrease of 65 and 23% in soil K was observed in the second and third soil layers, respectively. For maize production system sustainability, future research should use a holistic approach investigating the impact of planting date, plant density on crop growth, yield, nutrient uptake and remobilization, and soil properties under different fertilizer rates to develop the fertilizer recommendation for maize while reducing the environmental impact of the production system.
Transactions of the ASABE, 2015
Locally measured crop coefficients (K c) are critical for accurately quantifying and evaluating c... more Locally measured crop coefficients (K c) are critical for accurately quantifying and evaluating crop evapotranspiration (ET c) under local climate, soil, and crop management practices. Data and information on winter wheat K c values do not exist in Nebraska and are limited in the U.S. Great Plains in general. The objectives of this research were to measure ET c rates and develop growth-stage-specific single (normal) (K c) and basal (K cb) crop coefficients for winter wheat (Triticum aestivum L.) to provide data and information to producers, their advisors, and state and federal water regulatory and management agencies about the water use dynamics of winter wheat. Field experiments were conducted during two consecutive winter wheat growing seasons in
Applied Engineering in Agriculture, 2022
<p>Global warming impacts are known as increasing in rainfall magnitude and frequen... more <p>Global warming impacts are known as increasing in rainfall magnitude and frequency that lead to more intense and frequent river flooding. In recent years, there is an upward trend of floods in West African regions. As result, many countries like Togo and Benin have had catastrophic floods that affected thousands of people with loss of lives, damages, and properties. Mono catchment is indeed subject to flooding due to anthropogenic and natural climate changes impacts. This study aims to predict stream&#64258;ow for the period between 1990 and 2020 using hydrological modeling at gauge stations; to analyze flood frequency and magnitudes over the Mono catchment for the historical period through an investigation of hydroclimate indices. Moreover, projected changes in floods hydroclimate indices in the catchment under representative concentration pathway (RCP) from a multi-model ensemble model are investigated. The results show that hydrological modeling reproduces seasonal streamflow with acceptable performance with Kling-Gupta Efficiency (KGE) and percent over calibration and validation periods. Finally, an upward flood frequency and magnitude are observed both for historical and future periods. The outcomes of this study suggest an urgent need to improve the functionality of early warning systems and increase societal resilience to warming climates over the catchment through sustainable policy strategies and governance measures.</p><p><strong>Keywords</strong>: Flood Frequency and magnitude, Flood forecasting, Mono catchment, Togo-Benin</p>
2022 Houston, Texas July 17-20, 2022
Journal of Water and Climate Change, Apr 9, 2015
Reference evapotranspiration is a key parameter in hydrological and meteorological studies and us... more Reference evapotranspiration is a key parameter in hydrological and meteorological studies and used to determine the actual water use rate for various crops. The objectives of this study were to explore trend in the grass-reference evapotranspiration (ETo) through years 1961-2011 and to identify trend in the aridity index as an indicator of change in climate in Togo. ETo was calculated using the FAO-56 Penman-Monteith method, and trends analyses were performed with non-parametric statistics proposed by Mann-Kendall and the Sen slope estimator. Results showed that annual ETo varied from
2022 Houston, Texas July 17-20, 2022, 2022
Transactions of the ASABE, Oct 27, 2016
Field maize (Zea mays L.) grain yield, evapotranspiration (ET c), and crop water productivity can... more Field maize (Zea mays L.) grain yield, evapotranspiration (ET c), and crop water productivity can be substantially impacted by planting population density (PPD) and planting date, depending on the location and crop, soil, and irrigation management practices. Field experiments were conducted in the 2011 and 2012 growing seasons to measure grain yield and quantify ET c , irrigation water use efficiency (IWUE), and crop water use efficiency (CWUE) as well as develop irrigation-yield production functions (IYPF) and evapotranspiration-yield production functions (ETYPF) for three PPDs and planting dates under subsurface drip irrigation and rainfed conditions in south central Nebraska. Plant growth and development indicators [leaf area index (LAI) and plant height] were quantified.
Italian Journal of Agronomy, Jan 3, 2019
Lowland irrigated rice is the predominant crop produced in the Senegal River Valley characterised... more Lowland irrigated rice is the predominant crop produced in the Senegal River Valley characterised by very low annual rainfall, high temperatures, and low relative humidity. The Senegal River is shared by Senegal, Mali, Mauritania, and Guinea, and serves as the main source of irrigation water for the adopted double rice cropping system. Developing appropriate resource management strategies might be the key factor for the sustainability of rice production in the region. This study aims to estimate rice seasonal evapotranspiration (ETa), irrigation water requirement, and to develop rice growth stage specific crop coefficients (Kc) to improve rice water productivity. Field experiments were conducted during the hot and dry seasons in 2014 and 2015 at the AfricaRice research station at Fanaye in Senegal. Irrigation water inputs were monitored and actual crop evapotranspiration was derived using the water balance method. Daily reference evapotranspiration (ETo) was estimated using the Penman-Monteith equation and the weather variables were collected at the site by an automated weather station. The results showed that the ETo during the hot and dry season from February 15 th to June 30 th varied from 4.
Irrigation and Drainage Systems Engineering, 2018
Journal of Irrigation and Drainage Engineering-asce, Feb 1, 2023
Journal of Irrigation and Drainage Engineering-asce, Feb 1, 2023
Water, May 31, 2018
The objectives of this study were to investigate water saving strategies in the paddy field and t... more The objectives of this study were to investigate water saving strategies in the paddy field and to evaluate the performance of some of the newly released rice varieties. Field experiments were conducted at Fanaye in the Senegal River Valley during two rice growing seasons in 2015. Three irrigation regimes ((i) continuous flooding, (ii) trigging irrigation at soil matric potential (SMP) of 30 kPa, (iii) trigging irrigation at SMP of 60 kPa) were tested in an irrigated lowland rice field. Irrigation regimes (ii) and (iii) are alternate wetting and drying (AWD) cycles. Four inbred rice varieties (NERICA S-21, NERICA S-44, Sahel 210 and Sahel 222) and one hybrid rice (Hybrid AR032H) were evaluated under five nitrogen fertilizer rates (0, 50, 100, 150 and 200 kg N ha −1). The results showed that rice yield varied from 0.9 to 12 t ha −1. The maximum yield of 12 t ha −1 was achieved by NERICA S-21 under AWD 30 kPa at 150 kg N ha −1. The AWD irrigation management at 30 kPa resulted in increasing rice yield, rice water use and nitrogen use efficiency and reducing the irrigation applications by 27.3% in comparison with continuous flooding. AWD30 kPa could be adopted as a water saving technology for water productivity under paddy production in the Senegal River Middle Valley. Additional research should be conducted in the upper Valley, where soils are sandier and water is less available, for the sustainability and the adoption of the irrigation water saving practices across the entire Senegal River Valley.
Agronomy
Actual crop evapotranspiration (ETa) is measured or estimated using different methods, and its ac... more Actual crop evapotranspiration (ETa) is measured or estimated using different methods, and its accuracy is critical for water management under precision agriculture. The objective of this study was to compare maize ETa estimated by the two-step approach using a locally developed crop coefficient curve with satellite-retrieved evapotranspiration by six models incorporated in the OpenET to identify the best evapotranspiration estimation alternatives to the two-step approach for water management in northern New Mexico. Maize (Zea mays L.) was planted at the NMSU Agricultural Science Center at Farmington from 2017 to 2022 and uniformly managed across years. Water management in plants was based on maize’s actual evapotranspiration estimated as the product of the reference evapotranspiration and the local crop coefficient, which is described as a third-order polynomial function of the accumulated heat units by maize plants. For the same growing seasons, maize ETa was retrieved from satell...
Bulletin - Agricultural Experiment Station, New Mexico, 2018
International Soil and Water Conservation Research
Journal of New Seeds, 2010
The objective of this study was to optimize nitrogen fertilizer for higher yield and nitrogen use... more The objective of this study was to optimize nitrogen fertilizer for higher yield and nitrogen use efficiency of four aromatic rice varieties. Field experiments were conducted at Ndiaye and Fanaye (Senegal) during the hot and dry season 2012 and the wet season 2012 to evaluate the effect of nitrogen on rice yield and nitrogen use efficiency under phosphorus and potassium omission management. Five rates of nitrogen (0, 60, 90, 120 and 150 kg/ha) were associated with P (26 kg P/ha); or P-K (26 kg P/ha and 50 kg K/ha). Four aromatic rice varieties Pusa Basmati, Sahel 329, Sahel 177 and Sahel 328 and a non-aromatic variety Sahel 108 were evaluated. Results showed that across genotypes, rice yield varied from 3.3 to 8.6 Mg/ha under N-P fertilizer and from 3.5 to 8.8 Mg/ha under N-P-K fertilizer at Ndiaye. At Fanaye, rice yield varied from 3.7 to 8.6 Mg/ha under N-P fertilizer and from 3 to 10.3 Mg/ha under N-P-K fertilizer. The highest grain yield was obtained by Sahel 177 among the aromatic rice varieties. The optimum nitrogen dose varied with rice genotype and location. The PFPN and the ANUE were influenced by genotype and varied from 161 to 28 kg grain/kg N and from 105.9 to 0.9 kg grain/kg N, respectively. The highest PFPN was obtained by Sahel 108 followed by Sahel 177. K addition to N-P significantly increased ANUE from 6.4 to 20.78 kg grain/kg N. The aromatic rice variety Sahel 177 is the performing alternative to the non-aromatic rice Sahel 108 in Senegal.
Agronomy
Crop evapotranspiration (ETa) is the main source of water loss in farms and watersheds, and with ... more Crop evapotranspiration (ETa) is the main source of water loss in farms and watersheds, and with its effects felt at a regional scale, it calls for irrigation professionals and water resource managers to accurately assess water requirements to meet crop water use. On a multi-crop commercial farm, different factors affect cropland allocation, among which crop evapotranspiration is one of the most important factors regarding the seasonally or annually available water resources for irrigation in combination with the in-season effective precipitation. The objective of the present study was to estimate crop evapotranspiration for four major crops grown on the Navajo Agricultural Products Industry (NAPI) farm for the 2016–2010 period to help crop management in crop plant allocation based on the different objectives of the NAPI. The monthly and seasonal satellite-based ETa of maize, potatoes, dry beans, and alfalfa were retrieved and compared using the analysis of variance and the least si...
Irrigation & Drainage Systems Engineering, 2018
This study was conducted at four weather stations across New Mexico (USA) at Fabian-Garcia, Farmi... more This study was conducted at four weather stations across New Mexico (USA) at Fabian-Garcia, Farmington, Leyendecker and Tucumcari for the period of 2009-2017. The geographical coordinates and the long term average climatic variables are summarized in Table 1. Minimum temperature (Tmin), maximum temperature (Tmax), average tempetrature (Tmean), minimum relative humidity (RHmin), maximum relative humidity (RHmax), average relative humidity (RHmean), average wind speed (u 2), and solar radiation (Rs) were collected on the hourly basis and averaged over daily time step from
The effects of full and limited irrigation practices on maize growth parameters, yield, actual cr... more The effects of full and limited irrigation practices on maize growth parameters, yield, actual crop evapotranspiration (ETa), crop coefficients, and nutrient uptake dynamics were investigated. Field experiments were conducted under a 4-span hydraulic and continuous move center pivot irrigation system at the University of Nebraska-Lincoln, South Central Agricultural Laboratory (SCAL) during the growing seasons in 2009 and 2010. Four irrigation regimes 100% of the fully-irrigated treatment (FIT), 75% FIT, 60% FIT, 50% FIT and rainfed treatment were evaluated. Maize yields varied from 9.05 tons/ha for the rainfed treatment to 15.51 tons/ha for the 100% FIT in 2009 and 11.74 to 15.45 tons/ha for the same treatments in 2010. There was no statistically significant difference between the 75% FIT and the 100% FIT in terms of grain yield. Crop evapotranspiration increased with irrigation amounts and ranged from 509 to 645 mm in 2009 and from 690 to 748 mm in 2010. In terms of performance in crop water productivity, the 60% and 75% FIT treatments were comparable to the full irrigated treatment and are viable approaches in increasing crop water productivity of maize under these experimental, soil and crop management, and climatic conditions. On average, 60%FIT resulted in the highest irrigation water use efficiency of 4.53 kg/m3. Mid-season crop grass- and alfalfa-reference crop coefficients (Kco and Kcr) showed variability with the irrigation treatment. The mid-season Kco ranged from 1.08 to 1.26 and the mid-season Kcr ranged between 0.92 and 1.05. Nitrogen uptake ranged from 154 to 253 Kg/ha and 182 to 270 Kg/ha in 2009 and 2010 respectively. The FIT resulted in the highest and the rainfed treatment had the lowest nitrogen uptake in both years. The FIT had the highest phosphorus uptake with 39 Kg/ha and 53 Kg/ha in 2009 and 2010, respectively. Better potassium uptake was observed in 2010 and it ranged from 414 to 637 Kg/ha while it ranged from 333 to 367 Kg/ha in 2009
PloS one, Mar 28, 2024
This study aimed to measure maize (Zea mays) plant nutrient content and nutrient removal in grain... more This study aimed to measure maize (Zea mays) plant nutrient content and nutrient removal in grain, and to evaluate the residual soil nitrogen, phosphorus, and potassium as impacted by planting date and density. Field experiments were conducted to evaluate six plant densities and seven planting dates using a split-split plot design with three replications. Besides the crop growth and yield parameters, six plants were collected at the maturity and soil was sampled from each plot for nutrient analysis. Plant N, P, and K concentrations varied with planting date and density and within the ranges of 0.6-1.024%, 0.054-0.127%, and 0.75-1.71%, respectively. Grain N, P, and K concentrations decreased with plant density and varied from 1.059 to 1.558%, 0.20 to 0.319%, and 0.29 to 0.43%, respectively. Soil residual nutrient varied with depth, planting density and date. Residual N concentration in the topsoil varied from 0.6 to 37.2 mg kg-1 in 2019 and from 1.5 to 11.2 mg kg-1 in 2020 and was high under the last two planting dates. Soil residual N concentration was higher in the second layer than in the topsoil. The N concentration in the third layer varied from 0.1 to 33.2 mg kg-1 and was impacted by plant density. Topsoil P did not vary among planting dates and densities. The second and third soil layers P concentration was not affected. There was 83% increase in topsoil K in 2020 compared to 2019, and a decrease of 65 and 23% in soil K was observed in the second and third soil layers, respectively. For maize production system sustainability, future research should use a holistic approach investigating the impact of planting date, plant density on crop growth, yield, nutrient uptake and remobilization, and soil properties under different fertilizer rates to develop the fertilizer recommendation for maize while reducing the environmental impact of the production system.
Transactions of the ASABE, 2015
Locally measured crop coefficients (K c) are critical for accurately quantifying and evaluating c... more Locally measured crop coefficients (K c) are critical for accurately quantifying and evaluating crop evapotranspiration (ET c) under local climate, soil, and crop management practices. Data and information on winter wheat K c values do not exist in Nebraska and are limited in the U.S. Great Plains in general. The objectives of this research were to measure ET c rates and develop growth-stage-specific single (normal) (K c) and basal (K cb) crop coefficients for winter wheat (Triticum aestivum L.) to provide data and information to producers, their advisors, and state and federal water regulatory and management agencies about the water use dynamics of winter wheat. Field experiments were conducted during two consecutive winter wheat growing seasons in
Applied Engineering in Agriculture, 2022
<p>Global warming impacts are known as increasing in rainfall magnitude and frequen... more <p>Global warming impacts are known as increasing in rainfall magnitude and frequency that lead to more intense and frequent river flooding. In recent years, there is an upward trend of floods in West African regions. As result, many countries like Togo and Benin have had catastrophic floods that affected thousands of people with loss of lives, damages, and properties. Mono catchment is indeed subject to flooding due to anthropogenic and natural climate changes impacts. This study aims to predict stream&#64258;ow for the period between 1990 and 2020 using hydrological modeling at gauge stations; to analyze flood frequency and magnitudes over the Mono catchment for the historical period through an investigation of hydroclimate indices. Moreover, projected changes in floods hydroclimate indices in the catchment under representative concentration pathway (RCP) from a multi-model ensemble model are investigated. The results show that hydrological modeling reproduces seasonal streamflow with acceptable performance with Kling-Gupta Efficiency (KGE) and percent over calibration and validation periods. Finally, an upward flood frequency and magnitude are observed both for historical and future periods. The outcomes of this study suggest an urgent need to improve the functionality of early warning systems and increase societal resilience to warming climates over the catchment through sustainable policy strategies and governance measures.</p><p><strong>Keywords</strong>: Flood Frequency and magnitude, Flood forecasting, Mono catchment, Togo-Benin</p>
2022 Houston, Texas July 17-20, 2022
Journal of Water and Climate Change, Apr 9, 2015
Reference evapotranspiration is a key parameter in hydrological and meteorological studies and us... more Reference evapotranspiration is a key parameter in hydrological and meteorological studies and used to determine the actual water use rate for various crops. The objectives of this study were to explore trend in the grass-reference evapotranspiration (ETo) through years 1961-2011 and to identify trend in the aridity index as an indicator of change in climate in Togo. ETo was calculated using the FAO-56 Penman-Monteith method, and trends analyses were performed with non-parametric statistics proposed by Mann-Kendall and the Sen slope estimator. Results showed that annual ETo varied from
2022 Houston, Texas July 17-20, 2022, 2022
Transactions of the ASABE, Oct 27, 2016
Field maize (Zea mays L.) grain yield, evapotranspiration (ET c), and crop water productivity can... more Field maize (Zea mays L.) grain yield, evapotranspiration (ET c), and crop water productivity can be substantially impacted by planting population density (PPD) and planting date, depending on the location and crop, soil, and irrigation management practices. Field experiments were conducted in the 2011 and 2012 growing seasons to measure grain yield and quantify ET c , irrigation water use efficiency (IWUE), and crop water use efficiency (CWUE) as well as develop irrigation-yield production functions (IYPF) and evapotranspiration-yield production functions (ETYPF) for three PPDs and planting dates under subsurface drip irrigation and rainfed conditions in south central Nebraska. Plant growth and development indicators [leaf area index (LAI) and plant height] were quantified.
Italian Journal of Agronomy, Jan 3, 2019
Lowland irrigated rice is the predominant crop produced in the Senegal River Valley characterised... more Lowland irrigated rice is the predominant crop produced in the Senegal River Valley characterised by very low annual rainfall, high temperatures, and low relative humidity. The Senegal River is shared by Senegal, Mali, Mauritania, and Guinea, and serves as the main source of irrigation water for the adopted double rice cropping system. Developing appropriate resource management strategies might be the key factor for the sustainability of rice production in the region. This study aims to estimate rice seasonal evapotranspiration (ETa), irrigation water requirement, and to develop rice growth stage specific crop coefficients (Kc) to improve rice water productivity. Field experiments were conducted during the hot and dry seasons in 2014 and 2015 at the AfricaRice research station at Fanaye in Senegal. Irrigation water inputs were monitored and actual crop evapotranspiration was derived using the water balance method. Daily reference evapotranspiration (ETo) was estimated using the Penman-Monteith equation and the weather variables were collected at the site by an automated weather station. The results showed that the ETo during the hot and dry season from February 15 th to June 30 th varied from 4.
Irrigation and Drainage Systems Engineering, 2018
Journal of Irrigation and Drainage Engineering-asce, Feb 1, 2023
Journal of Irrigation and Drainage Engineering-asce, Feb 1, 2023
Water, May 31, 2018
The objectives of this study were to investigate water saving strategies in the paddy field and t... more The objectives of this study were to investigate water saving strategies in the paddy field and to evaluate the performance of some of the newly released rice varieties. Field experiments were conducted at Fanaye in the Senegal River Valley during two rice growing seasons in 2015. Three irrigation regimes ((i) continuous flooding, (ii) trigging irrigation at soil matric potential (SMP) of 30 kPa, (iii) trigging irrigation at SMP of 60 kPa) were tested in an irrigated lowland rice field. Irrigation regimes (ii) and (iii) are alternate wetting and drying (AWD) cycles. Four inbred rice varieties (NERICA S-21, NERICA S-44, Sahel 210 and Sahel 222) and one hybrid rice (Hybrid AR032H) were evaluated under five nitrogen fertilizer rates (0, 50, 100, 150 and 200 kg N ha −1). The results showed that rice yield varied from 0.9 to 12 t ha −1. The maximum yield of 12 t ha −1 was achieved by NERICA S-21 under AWD 30 kPa at 150 kg N ha −1. The AWD irrigation management at 30 kPa resulted in increasing rice yield, rice water use and nitrogen use efficiency and reducing the irrigation applications by 27.3% in comparison with continuous flooding. AWD30 kPa could be adopted as a water saving technology for water productivity under paddy production in the Senegal River Middle Valley. Additional research should be conducted in the upper Valley, where soils are sandier and water is less available, for the sustainability and the adoption of the irrigation water saving practices across the entire Senegal River Valley.
Agronomy
Actual crop evapotranspiration (ETa) is measured or estimated using different methods, and its ac... more Actual crop evapotranspiration (ETa) is measured or estimated using different methods, and its accuracy is critical for water management under precision agriculture. The objective of this study was to compare maize ETa estimated by the two-step approach using a locally developed crop coefficient curve with satellite-retrieved evapotranspiration by six models incorporated in the OpenET to identify the best evapotranspiration estimation alternatives to the two-step approach for water management in northern New Mexico. Maize (Zea mays L.) was planted at the NMSU Agricultural Science Center at Farmington from 2017 to 2022 and uniformly managed across years. Water management in plants was based on maize’s actual evapotranspiration estimated as the product of the reference evapotranspiration and the local crop coefficient, which is described as a third-order polynomial function of the accumulated heat units by maize plants. For the same growing seasons, maize ETa was retrieved from satell...
Bulletin - Agricultural Experiment Station, New Mexico, 2018
International Soil and Water Conservation Research
Journal of New Seeds, 2010
The objective of this study was to optimize nitrogen fertilizer for higher yield and nitrogen use... more The objective of this study was to optimize nitrogen fertilizer for higher yield and nitrogen use efficiency of four aromatic rice varieties. Field experiments were conducted at Ndiaye and Fanaye (Senegal) during the hot and dry season 2012 and the wet season 2012 to evaluate the effect of nitrogen on rice yield and nitrogen use efficiency under phosphorus and potassium omission management. Five rates of nitrogen (0, 60, 90, 120 and 150 kg/ha) were associated with P (26 kg P/ha); or P-K (26 kg P/ha and 50 kg K/ha). Four aromatic rice varieties Pusa Basmati, Sahel 329, Sahel 177 and Sahel 328 and a non-aromatic variety Sahel 108 were evaluated. Results showed that across genotypes, rice yield varied from 3.3 to 8.6 Mg/ha under N-P fertilizer and from 3.5 to 8.8 Mg/ha under N-P-K fertilizer at Ndiaye. At Fanaye, rice yield varied from 3.7 to 8.6 Mg/ha under N-P fertilizer and from 3 to 10.3 Mg/ha under N-P-K fertilizer. The highest grain yield was obtained by Sahel 177 among the aromatic rice varieties. The optimum nitrogen dose varied with rice genotype and location. The PFPN and the ANUE were influenced by genotype and varied from 161 to 28 kg grain/kg N and from 105.9 to 0.9 kg grain/kg N, respectively. The highest PFPN was obtained by Sahel 108 followed by Sahel 177. K addition to N-P significantly increased ANUE from 6.4 to 20.78 kg grain/kg N. The aromatic rice variety Sahel 177 is the performing alternative to the non-aromatic rice Sahel 108 in Senegal.
Agronomy
Crop evapotranspiration (ETa) is the main source of water loss in farms and watersheds, and with ... more Crop evapotranspiration (ETa) is the main source of water loss in farms and watersheds, and with its effects felt at a regional scale, it calls for irrigation professionals and water resource managers to accurately assess water requirements to meet crop water use. On a multi-crop commercial farm, different factors affect cropland allocation, among which crop evapotranspiration is one of the most important factors regarding the seasonally or annually available water resources for irrigation in combination with the in-season effective precipitation. The objective of the present study was to estimate crop evapotranspiration for four major crops grown on the Navajo Agricultural Products Industry (NAPI) farm for the 2016–2010 period to help crop management in crop plant allocation based on the different objectives of the NAPI. The monthly and seasonal satellite-based ETa of maize, potatoes, dry beans, and alfalfa were retrieved and compared using the analysis of variance and the least si...
Irrigation & Drainage Systems Engineering, 2018
This study was conducted at four weather stations across New Mexico (USA) at Fabian-Garcia, Farmi... more This study was conducted at four weather stations across New Mexico (USA) at Fabian-Garcia, Farmington, Leyendecker and Tucumcari for the period of 2009-2017. The geographical coordinates and the long term average climatic variables are summarized in Table 1. Minimum temperature (Tmin), maximum temperature (Tmax), average tempetrature (Tmean), minimum relative humidity (RHmin), maximum relative humidity (RHmax), average relative humidity (RHmean), average wind speed (u 2), and solar radiation (Rs) were collected on the hourly basis and averaged over daily time step from
The effects of full and limited irrigation practices on maize growth parameters, yield, actual cr... more The effects of full and limited irrigation practices on maize growth parameters, yield, actual crop evapotranspiration (ETa), crop coefficients, and nutrient uptake dynamics were investigated. Field experiments were conducted under a 4-span hydraulic and continuous move center pivot irrigation system at the University of Nebraska-Lincoln, South Central Agricultural Laboratory (SCAL) during the growing seasons in 2009 and 2010. Four irrigation regimes 100% of the fully-irrigated treatment (FIT), 75% FIT, 60% FIT, 50% FIT and rainfed treatment were evaluated. Maize yields varied from 9.05 tons/ha for the rainfed treatment to 15.51 tons/ha for the 100% FIT in 2009 and 11.74 to 15.45 tons/ha for the same treatments in 2010. There was no statistically significant difference between the 75% FIT and the 100% FIT in terms of grain yield. Crop evapotranspiration increased with irrigation amounts and ranged from 509 to 645 mm in 2009 and from 690 to 748 mm in 2010. In terms of performance in crop water productivity, the 60% and 75% FIT treatments were comparable to the full irrigated treatment and are viable approaches in increasing crop water productivity of maize under these experimental, soil and crop management, and climatic conditions. On average, 60%FIT resulted in the highest irrigation water use efficiency of 4.53 kg/m3. Mid-season crop grass- and alfalfa-reference crop coefficients (Kco and Kcr) showed variability with the irrigation treatment. The mid-season Kco ranged from 1.08 to 1.26 and the mid-season Kcr ranged between 0.92 and 1.05. Nitrogen uptake ranged from 154 to 253 Kg/ha and 182 to 270 Kg/ha in 2009 and 2010 respectively. The FIT resulted in the highest and the rainfed treatment had the lowest nitrogen uptake in both years. The FIT had the highest phosphorus uptake with 39 Kg/ha and 53 Kg/ha in 2009 and 2010, respectively. Better potassium uptake was observed in 2010 and it ranged from 414 to 637 Kg/ha while it ranged from 333 to 367 Kg/ha in 2009