Artificial capillary barriers (CBs) are used to improve root zone conditions as they can keep wat... more Artificial capillary barriers (CBs) are used to improve root zone conditions as they can keep water and nutrients in the root zone by limiting downward percolation. Numerical analysis is one of the promising tools for evaluating CB systems’ performance during the cultivation of leafy vegetables. This study aims to investigate the effects of the CB system on soil water dynamics during spinach cultivation in a soil column under different irrigation scenarios using HYDRUS (2D/3D) by comparing uniform (UNI), line-source (LSI), and plant-targeted (PTI) irrigations combined with alternative irrigation schedules. Simulation results of volumetric soil water contents were generally corresponding to measured data. Simulation results with various hypothetical irrigation scenarios exhibited that the CB was an effective system to diminish percolation losses and improve the root zone’s soil water storage capacity. On the other hand, evaporation loss can be increased as more water is maintained ne...
Soil salinization of irrigated lands is a global problem in providing the necessary food and feed... more Soil salinization of irrigated lands is a global problem in providing the necessary food and feed to meet the needs of a growing world population. Salinization in arid and semiarid areas can occur when the water table is three and more meters above the soil surface. Nowadays, innovative technologies are widely implemented in agriculture to increase yields and monitor changes in any area timely. Advanced technologies such as remote sensing (R.S.) data have become an economically efficient tool for assessing, detecting, mapping, and monitoring saline areas. This study aims to develop a spatial database for evaluating salinization using R.S. and GIS. This research employs various soil salinity indices based on Landsat 8 OLI images and other related geospatial datasets of the study areas. It aims to predict soil salinity using four machine learning methods (Gaussian Mixture Model (GMM), Random Forest (R.F.), Support Vector Machines (SVM), and K-Nearest Neighbors (KNN)). Results showed t...
Proceedings of the 12th International Conference on Agents and Artificial Intelligence
Due to climate change and population growth, the agriculture sector has been faced with two chall... more Due to climate change and population growth, the agriculture sector has been faced with two challenges; securing water and food and transferring into sustainable resource management. To systematize resource management which currently mainly relies on farmers' experience, digital technologies have been developed. Considering current tighter resource availability, it is desirable to examine resource management behavior of beneficiaries using scarce resources to analyze resilience and adaptability of institutions. In this study, we analyzed factors of water use behavior of Water Users Associations (WUAs) to solve water allocation problem with Agent-Based Model (ABM). The simulation results show that factors of water use behavior were water resources and the existence of different water use laws, and downstream WUAs developed adaptation methods. To enhance sustainable resource management, ABM can be applied to analyze factors and their rules and/or laws to understand what enhances resilience and adaptability of institutions.
Water productivity of rice is imperative for global water security. Currently, water saving manag... more Water productivity of rice is imperative for global water security. Currently, water saving management techniques have been proposed and applied to rice systems. The crop water stress index (CWSI) is a major index for evaluating crop water use. The utility of the CWSI in rice in a humid temperate climate has been given little attention. Previous studies have focused on upland crops and readily available constant reference baselines, primarily the water stressed baseline (WSB), which does not inherently reflect transpiration flux. This study examined the performance of the estimated non-water stressed baseline (NWSB) and WSB for rice in a humid climate and the CWSI sensitivity under variable reference baseline scenarios in a 2-year pot trial under phytotron and field environment conditions with two rice genotypes (IRAT109 and Takanari) in a flooded (FL) and aerobic (AR) water regime. We observed that the dynamics of CWSI is dependent not only on the water regimes but could be strongl...
Journal of Developments in Sustainable Agriculture, 2012
The Nganjuk District experiences a tropical monsoon regime characterized by annual rainy and dry ... more The Nganjuk District experiences a tropical monsoon regime characterized by annual rainy and dry seasons, and the area receives approximately 80% of annual precipitation within the 5 to 6 months of the rainy season. The district has three planting seasons, the wet season (November-February), first dry season (March-June), and second dry season (July-October). A main factor of agricultural production sustainability is managing for climatic variability. The main cause of variability is the El Niño Southern Oscillation, with El Niño years having below-average rainfall and La Niña years having above-average rainfall. Water shortages in the dry season are a problem, especially in El Niño years, whereas flooding occurs in La Niña years. We analyzed trends in agricultural production and the impact of El Niño and La Niña events in a tropical monsoon region by performing a case study of Nganjuk District in eastern Java Island. Groundwater use for conjunctive irrigation in the dry season increased agricultural production by about 0.5 crops yr −1. In El Niño years, groundwater was required for irrigation in the dry season, whereas in La Niña years surface water was almost sufficient or exceeded the demand for irrigation water in the dry season. The harvest index of rice was relatively stable, with a small increasing tendency from 1982 to 2010 (1.22 to 1.82 crops yr −1), and was not influenced by El Niño or La Niña events. Secondary crop production fluctuated, and the failed-harvest index increased in La Niña years. Agricultural production was more secure when farmers applied conjunctive irrigation. Because secondary crops are vulnerable to waterlogging under excess water conditions, early warning of a La Niña year is important so farmers can adopt a farming strategy that will avoid harvest failure in the dry season.
Food security is often threatened by droughts during rice production. Although most of the rice i... more Food security is often threatened by droughts during rice production. Although most of the rice is produced in lowland or irrigated “wet” rice fields, terraced paddy fields are important in the rice production system in island or mountainous countries. With the intensifying frequency of El Niño periods in recent decades, there has been a risk of droughts in terraced paddy areas. To mitigate drought, remote sensing data analysis could be an efficient and reliable tool for obtaining scarce ground monitoring data. In this study, crop water stress index (CWSI) and temperature vegetation dryness index (TVDI) were applied to evaluate the drought intensity, and hydrological monitoring data was provided as a support for the evaluation. The results indicated that droughts normally occurred during the dry season, and intensified during El Niño periods. CWSI and TVDI were visible to predict drought occurrences in the watershed area. TVDI overestimated the drought inside Keduang watershed compa...
Nowadays, it has become very common to find in Japan that nitrate nitrogen concentrations are ver... more Nowadays, it has become very common to find in Japan that nitrate nitrogen concentrations are very high in spring water and in well water where the land use of a watershed is agricultural. We have often observed around 50 mg/L of nitrate nitrogen in the spring water where we live. Crops produced in those fields are mainly vegetables such as celery, cabbage, lettuce, carrots, and so on. Green tea is also popular in Japan. In order to produce good quality green tea, farmers apply a great amount of nitrogen fertilizer. This amount can reach up to 1,000 kg/ha in some areas, although the average application amounts to 628 kg/ha in Japan. As a result, ground water that is rich in nitrate flows into the river, which results in a high nitrogen concentration in river water and ground water. Further, this causes a low pH in river water in some tributary rivers in Japan, though this kind of case is very rare. We knew from field tests that if water contained a high nitrogen concentration and wa...
A distributed water quality tank model was developed to evaluate nitrogen load reduction by artif... more A distributed water quality tank model was developed to evaluate nitrogen load reduction by artificial wetlands in the A10 area, located in the Lake Kasumigaura watershed in Japan. In order to collect data for model calibration and verification, a year-long field investigation was conducted. The study area was divided into a 50 m × 50 m grid, and attributes and the model are added to each cell. The model simulates the runoff and the total nitrogen (TN) concentration with average relative errors of 10% and 2%, respectively, except for no-rain periods. Scenario analyses were conducted considering artificial wetlands at different locations. The three scenarios are as follows: no artificial wetland, cell located at the head of the valley and cell located on a flow path through animal waste cell. Compared with case 1, the annual TN concentration was lower by 4% and 11% in cases 2 and 3, respectively. The results suggest that artificial wetlands on water flow paths with a large nitrogen load effectively reduce these loads and that the model quantitatively evaluates the difference in the nitrogen concentration across locations.
Water quality is degraded due to urbanization because it causes population growth and land-use ch... more Water quality is degraded due to urbanization because it causes population growth and land-use changes in a watershed. These changes are usually simulated using a linear equation; however, in reality, population and land use are very closely related. A watershed system dynamics model (WSD model) was developed in the simulation of the relation among population, land use (paddy fields, upland fields, forest, and household), and runoff. The model comprised of three sectors: the agricultural sector, nature sector, and urban sector. The elements in the WSD model were selected based on interviews with local government officers and references. The WSD model simulated population, land use, and runoff with an average relative error of about 5%. Total nitrogen (T-N) and total phosphorus (T-P) were simulated using the results of the WSD model and unit effluent loads. Field surveys were conducted to determine the rate of mitigation in paddy fields. In addition, correction equations for runoff and phosphate-containing detergent were introduced. The model simulated T-N with an average relative error of 9%, and T-P with 27%; a sensitivity analysis for the principal elements in the WSD model showed reasonable results.
To solve the problem of diffuse pollution brought about of eutrophication in lakes, an investigat... more To solve the problem of diffuse pollution brought about of eutrophication in lakes, an investigation was conducted in lotus paddy fields, at which little research had been conducted. The study area consisted of low-land lotus paddy fields around the Lake Kasumigaura watershed in Ibaraki Prefecture. The area is well known as the largest production center of lotus roots in Japan. The results of the study show that the mass balance loads of total nitrogen(T-N), total phosphorus(T-P), chemical oxygen demand(COD), and suspended solids from the lotus paddy fields were -3.22 , 1.87, 75.36 and 552 kg·km-2·d-1, respectively. Comparing these values to the unit reported in "The Fifth Plan for Water Quality Conservation in the Lakes and Ponds related to Lake Kasumigaura", it was found that T-N was purified, T-P was 2.1 times higher and COD was 4.8 times higher. It was found that the major cause of the effluent loads was the outflow of suspended matters during puddling and lotus planti...
Methane fermentation digestion liquid (MFDL) possesses sufficient nitrogen contents to use as fer... more Methane fermentation digestion liquid (MFDL) possesses sufficient nitrogen contents to use as fertilizer and can be produced at farm sites, however, the existence of insoluble contents and high viscosity makes the application difficult in a greenhouse. Therefore, the authors first developed a trial model of a filtering device based on a screen filter and an application device using water pressure. Next, a field trial was conducted in a summer greenhouse using a drip fertigation system. The MFDL amount that was periodically applied to plants was decided by counting the number of leaves. Urea application was prepared as a control. As a result, the physical treatability of MFDL application improved for drip fertigation without any stacking problems throughout the cropping season. There were no significant differences in leaf counts, applied amount of nitrogen or yield between MFDL and urea application. Applied MFDL was considered to be absorbed in cucumber via degradation and nitrification soon after application. In conclusion, MFDL is available as a nitrogen fertilizer if applied appropriately.
Nganjuk District experienced fast growth in agricultural sector during 1991-1998. Cropping intens... more Nganjuk District experienced fast growth in agricultural sector during 1991-1998. Cropping intensity was increasing from 2.31 crops/year in 1991 become to 2.93 crops/year in 1998. The increasing caused increasing water consumption, especially from groundwater with irrigation wells. Objective of this research is to analysis groundwater exploitation for irrigation by using GIS. Data was collected from a government office and other studies (i.e. irrigation wells, earth shape map and hydrogeology). All hardcopy of map was transformed to digital spatial data with digitizing process. Field data were input as spatial data. Land-use/land-cover map was developed from LANDSAT data using ERDAS 8.4. Overlay analysis was used to get actual utilization of irrigation well in dry season. The number of irrigation wells until year 2006 was more than 15,741 wells with discharge varied at 4-60 l/s. Radius influent of well in the research areas are varied at 118-348 m (Prastowo 2007 and Liyantono 2001) and these values are using as assumption for developed irrigation well density (IWD) criteria. IWD varied from 0-2.995 well/ha. Very high exploitation (IWD >1 well/ha) has conducted in 29 villages and high exploitation (IWD >0.5-1 well/ha) has conducted in 50 villages. Both areas should be integrated management of wells and pumps to reduce exploitation. Potential areas in 47 villages can be developed irrigation wells around 82-292 wells. Based on land-use/land-cover 2004 classification (Landsat ETM + , August 19, 2004), irrigated areas are distributed in central of Nganjuk with area around 43, 094.61 ha. Irrigated area with crop and IWD >0.05 well/ha has 82.68% of area. Irrigated with crop and IWD ≤0.05 well/ha has 17.32% of area. This state showed that irrigation wells were used in dry season. The further research will continue to estimate irrigation water requirement and groundwater withdraw to supplement the surface water irrigation in this area.
Artificial capillary barriers (CBs) are used to improve root zone conditions as they can keep wat... more Artificial capillary barriers (CBs) are used to improve root zone conditions as they can keep water and nutrients in the root zone by limiting downward percolation. Numerical analysis is one of the promising tools for evaluating CB systems’ performance during the cultivation of leafy vegetables. This study aims to investigate the effects of the CB system on soil water dynamics during spinach cultivation in a soil column under different irrigation scenarios using HYDRUS (2D/3D) by comparing uniform (UNI), line-source (LSI), and plant-targeted (PTI) irrigations combined with alternative irrigation schedules. Simulation results of volumetric soil water contents were generally corresponding to measured data. Simulation results with various hypothetical irrigation scenarios exhibited that the CB was an effective system to diminish percolation losses and improve the root zone’s soil water storage capacity. On the other hand, evaporation loss can be increased as more water is maintained ne...
Soil salinization of irrigated lands is a global problem in providing the necessary food and feed... more Soil salinization of irrigated lands is a global problem in providing the necessary food and feed to meet the needs of a growing world population. Salinization in arid and semiarid areas can occur when the water table is three and more meters above the soil surface. Nowadays, innovative technologies are widely implemented in agriculture to increase yields and monitor changes in any area timely. Advanced technologies such as remote sensing (R.S.) data have become an economically efficient tool for assessing, detecting, mapping, and monitoring saline areas. This study aims to develop a spatial database for evaluating salinization using R.S. and GIS. This research employs various soil salinity indices based on Landsat 8 OLI images and other related geospatial datasets of the study areas. It aims to predict soil salinity using four machine learning methods (Gaussian Mixture Model (GMM), Random Forest (R.F.), Support Vector Machines (SVM), and K-Nearest Neighbors (KNN)). Results showed t...
Proceedings of the 12th International Conference on Agents and Artificial Intelligence
Due to climate change and population growth, the agriculture sector has been faced with two chall... more Due to climate change and population growth, the agriculture sector has been faced with two challenges; securing water and food and transferring into sustainable resource management. To systematize resource management which currently mainly relies on farmers' experience, digital technologies have been developed. Considering current tighter resource availability, it is desirable to examine resource management behavior of beneficiaries using scarce resources to analyze resilience and adaptability of institutions. In this study, we analyzed factors of water use behavior of Water Users Associations (WUAs) to solve water allocation problem with Agent-Based Model (ABM). The simulation results show that factors of water use behavior were water resources and the existence of different water use laws, and downstream WUAs developed adaptation methods. To enhance sustainable resource management, ABM can be applied to analyze factors and their rules and/or laws to understand what enhances resilience and adaptability of institutions.
Water productivity of rice is imperative for global water security. Currently, water saving manag... more Water productivity of rice is imperative for global water security. Currently, water saving management techniques have been proposed and applied to rice systems. The crop water stress index (CWSI) is a major index for evaluating crop water use. The utility of the CWSI in rice in a humid temperate climate has been given little attention. Previous studies have focused on upland crops and readily available constant reference baselines, primarily the water stressed baseline (WSB), which does not inherently reflect transpiration flux. This study examined the performance of the estimated non-water stressed baseline (NWSB) and WSB for rice in a humid climate and the CWSI sensitivity under variable reference baseline scenarios in a 2-year pot trial under phytotron and field environment conditions with two rice genotypes (IRAT109 and Takanari) in a flooded (FL) and aerobic (AR) water regime. We observed that the dynamics of CWSI is dependent not only on the water regimes but could be strongl...
Journal of Developments in Sustainable Agriculture, 2012
The Nganjuk District experiences a tropical monsoon regime characterized by annual rainy and dry ... more The Nganjuk District experiences a tropical monsoon regime characterized by annual rainy and dry seasons, and the area receives approximately 80% of annual precipitation within the 5 to 6 months of the rainy season. The district has three planting seasons, the wet season (November-February), first dry season (March-June), and second dry season (July-October). A main factor of agricultural production sustainability is managing for climatic variability. The main cause of variability is the El Niño Southern Oscillation, with El Niño years having below-average rainfall and La Niña years having above-average rainfall. Water shortages in the dry season are a problem, especially in El Niño years, whereas flooding occurs in La Niña years. We analyzed trends in agricultural production and the impact of El Niño and La Niña events in a tropical monsoon region by performing a case study of Nganjuk District in eastern Java Island. Groundwater use for conjunctive irrigation in the dry season increased agricultural production by about 0.5 crops yr −1. In El Niño years, groundwater was required for irrigation in the dry season, whereas in La Niña years surface water was almost sufficient or exceeded the demand for irrigation water in the dry season. The harvest index of rice was relatively stable, with a small increasing tendency from 1982 to 2010 (1.22 to 1.82 crops yr −1), and was not influenced by El Niño or La Niña events. Secondary crop production fluctuated, and the failed-harvest index increased in La Niña years. Agricultural production was more secure when farmers applied conjunctive irrigation. Because secondary crops are vulnerable to waterlogging under excess water conditions, early warning of a La Niña year is important so farmers can adopt a farming strategy that will avoid harvest failure in the dry season.
Food security is often threatened by droughts during rice production. Although most of the rice i... more Food security is often threatened by droughts during rice production. Although most of the rice is produced in lowland or irrigated “wet” rice fields, terraced paddy fields are important in the rice production system in island or mountainous countries. With the intensifying frequency of El Niño periods in recent decades, there has been a risk of droughts in terraced paddy areas. To mitigate drought, remote sensing data analysis could be an efficient and reliable tool for obtaining scarce ground monitoring data. In this study, crop water stress index (CWSI) and temperature vegetation dryness index (TVDI) were applied to evaluate the drought intensity, and hydrological monitoring data was provided as a support for the evaluation. The results indicated that droughts normally occurred during the dry season, and intensified during El Niño periods. CWSI and TVDI were visible to predict drought occurrences in the watershed area. TVDI overestimated the drought inside Keduang watershed compa...
Nowadays, it has become very common to find in Japan that nitrate nitrogen concentrations are ver... more Nowadays, it has become very common to find in Japan that nitrate nitrogen concentrations are very high in spring water and in well water where the land use of a watershed is agricultural. We have often observed around 50 mg/L of nitrate nitrogen in the spring water where we live. Crops produced in those fields are mainly vegetables such as celery, cabbage, lettuce, carrots, and so on. Green tea is also popular in Japan. In order to produce good quality green tea, farmers apply a great amount of nitrogen fertilizer. This amount can reach up to 1,000 kg/ha in some areas, although the average application amounts to 628 kg/ha in Japan. As a result, ground water that is rich in nitrate flows into the river, which results in a high nitrogen concentration in river water and ground water. Further, this causes a low pH in river water in some tributary rivers in Japan, though this kind of case is very rare. We knew from field tests that if water contained a high nitrogen concentration and wa...
A distributed water quality tank model was developed to evaluate nitrogen load reduction by artif... more A distributed water quality tank model was developed to evaluate nitrogen load reduction by artificial wetlands in the A10 area, located in the Lake Kasumigaura watershed in Japan. In order to collect data for model calibration and verification, a year-long field investigation was conducted. The study area was divided into a 50 m × 50 m grid, and attributes and the model are added to each cell. The model simulates the runoff and the total nitrogen (TN) concentration with average relative errors of 10% and 2%, respectively, except for no-rain periods. Scenario analyses were conducted considering artificial wetlands at different locations. The three scenarios are as follows: no artificial wetland, cell located at the head of the valley and cell located on a flow path through animal waste cell. Compared with case 1, the annual TN concentration was lower by 4% and 11% in cases 2 and 3, respectively. The results suggest that artificial wetlands on water flow paths with a large nitrogen load effectively reduce these loads and that the model quantitatively evaluates the difference in the nitrogen concentration across locations.
Water quality is degraded due to urbanization because it causes population growth and land-use ch... more Water quality is degraded due to urbanization because it causes population growth and land-use changes in a watershed. These changes are usually simulated using a linear equation; however, in reality, population and land use are very closely related. A watershed system dynamics model (WSD model) was developed in the simulation of the relation among population, land use (paddy fields, upland fields, forest, and household), and runoff. The model comprised of three sectors: the agricultural sector, nature sector, and urban sector. The elements in the WSD model were selected based on interviews with local government officers and references. The WSD model simulated population, land use, and runoff with an average relative error of about 5%. Total nitrogen (T-N) and total phosphorus (T-P) were simulated using the results of the WSD model and unit effluent loads. Field surveys were conducted to determine the rate of mitigation in paddy fields. In addition, correction equations for runoff and phosphate-containing detergent were introduced. The model simulated T-N with an average relative error of 9%, and T-P with 27%; a sensitivity analysis for the principal elements in the WSD model showed reasonable results.
To solve the problem of diffuse pollution brought about of eutrophication in lakes, an investigat... more To solve the problem of diffuse pollution brought about of eutrophication in lakes, an investigation was conducted in lotus paddy fields, at which little research had been conducted. The study area consisted of low-land lotus paddy fields around the Lake Kasumigaura watershed in Ibaraki Prefecture. The area is well known as the largest production center of lotus roots in Japan. The results of the study show that the mass balance loads of total nitrogen(T-N), total phosphorus(T-P), chemical oxygen demand(COD), and suspended solids from the lotus paddy fields were -3.22 , 1.87, 75.36 and 552 kg·km-2·d-1, respectively. Comparing these values to the unit reported in "The Fifth Plan for Water Quality Conservation in the Lakes and Ponds related to Lake Kasumigaura", it was found that T-N was purified, T-P was 2.1 times higher and COD was 4.8 times higher. It was found that the major cause of the effluent loads was the outflow of suspended matters during puddling and lotus planti...
Methane fermentation digestion liquid (MFDL) possesses sufficient nitrogen contents to use as fer... more Methane fermentation digestion liquid (MFDL) possesses sufficient nitrogen contents to use as fertilizer and can be produced at farm sites, however, the existence of insoluble contents and high viscosity makes the application difficult in a greenhouse. Therefore, the authors first developed a trial model of a filtering device based on a screen filter and an application device using water pressure. Next, a field trial was conducted in a summer greenhouse using a drip fertigation system. The MFDL amount that was periodically applied to plants was decided by counting the number of leaves. Urea application was prepared as a control. As a result, the physical treatability of MFDL application improved for drip fertigation without any stacking problems throughout the cropping season. There were no significant differences in leaf counts, applied amount of nitrogen or yield between MFDL and urea application. Applied MFDL was considered to be absorbed in cucumber via degradation and nitrification soon after application. In conclusion, MFDL is available as a nitrogen fertilizer if applied appropriately.
Nganjuk District experienced fast growth in agricultural sector during 1991-1998. Cropping intens... more Nganjuk District experienced fast growth in agricultural sector during 1991-1998. Cropping intensity was increasing from 2.31 crops/year in 1991 become to 2.93 crops/year in 1998. The increasing caused increasing water consumption, especially from groundwater with irrigation wells. Objective of this research is to analysis groundwater exploitation for irrigation by using GIS. Data was collected from a government office and other studies (i.e. irrigation wells, earth shape map and hydrogeology). All hardcopy of map was transformed to digital spatial data with digitizing process. Field data were input as spatial data. Land-use/land-cover map was developed from LANDSAT data using ERDAS 8.4. Overlay analysis was used to get actual utilization of irrigation well in dry season. The number of irrigation wells until year 2006 was more than 15,741 wells with discharge varied at 4-60 l/s. Radius influent of well in the research areas are varied at 118-348 m (Prastowo 2007 and Liyantono 2001) and these values are using as assumption for developed irrigation well density (IWD) criteria. IWD varied from 0-2.995 well/ha. Very high exploitation (IWD >1 well/ha) has conducted in 29 villages and high exploitation (IWD >0.5-1 well/ha) has conducted in 50 villages. Both areas should be integrated management of wells and pumps to reduce exploitation. Potential areas in 47 villages can be developed irrigation wells around 82-292 wells. Based on land-use/land-cover 2004 classification (Landsat ETM + , August 19, 2004), irrigated areas are distributed in central of Nganjuk with area around 43, 094.61 ha. Irrigated area with crop and IWD >0.05 well/ha has 82.68% of area. Irrigated with crop and IWD ≤0.05 well/ha has 17.32% of area. This state showed that irrigation wells were used in dry season. The further research will continue to estimate irrigation water requirement and groundwater withdraw to supplement the surface water irrigation in this area.
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Papers by Tasuku Kato