Home

Paddy and Water Environment

Publisher Springer Berlin / Heidelberg
ISSN 1611-2490 (Print) 1611-2504 (Online)
Subject Collection Biomedical and Life Sciences
Subject Earth and Environmental Science, Life Sciences, Agriculture, Hydrogeology, Geoecology/Natural Processes, Monitoring/Environmental Analysis/Environmental Ecotoxicology, Soil Science & Conservation and Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution
SpringerLink Date Sunday, July 13, 2003

Abstracts of Recent Papers

  • Parameterization of canopy resistance for modeling the energy partitioning of a paddy rice field -

    Abstract

    Models for predicting hourly canopy resistance (r c) and latent heat flux (LET) based on the Penman–Monteith (PM) and bulk transfer methods are presented. The micrometeorological data and LET were observed during paddy rice-growing seasons in 2010 in Japan. One approach to model r c was using an aerodynamic resistance (r a) and climatic resistance (r *), while another one was based on a relationship with solar radiation (SR). Nonlinear relationships between r c and r *, and between r c and SR were found for different growing stages of the rice crop. The constructed r c models were integrated to the PM and bulk transfer methods and compared with measured LET using a Bowen ratio–energy balance method. The root mean square errors (RMSEs) were 155.2 and 170.5 W m−2 for the bulk transfer method with r c estimated using r * and with a function of SR, respectively, while the RMSEs were 87.4 and 85.7 W m−2 for the PM method with r c estimated using r * and SR, respectively. The r c integrated PM equation provided better performance than the bulk transfer equation. The results also revealed that neglecting the effect of r a on r c did not yield a significant difference in predicting LET.

  • Functions of indigenous animals in paddy fields: an in situ experiment on their effects on water quality, phytoplankton, weeds, soil structure, and rice growth -

    Abstract

    Paddy fields are used for growing semiaquatic rice and are also important habitats for a diversity of aquatic animals, which may be beneficial for rice production. However, studies on changes in environmental conditions such as water quality and community structure, and eventually in rice yield, made by animals in paddy fields are rare or have not used indigenous animals at natural densities in situ. We separately introduced the common paddy field species of loaches, tadpoles, and snails into 12 in situ enclosures at naturally occurring densities and examined their effects on paddy field environment and rice growth. Our results showed that rice growth did not increase in the presence of animals but was negatively correlated with weed biomass. Loaches increased turbidity and decreased the concentration of phosphate in surface water, probably because of their high bioturbation rates. Snails decreased the dissolved oxygen concentration in surface water. Total phytoplankton and weed biomass as well as soil density were not affected by the animals. These results show that nurturing animals in paddy fields could change the environment but does not cause higher rice production. The value of nurturing high animals in paddy fields may be found in other aspects besides rice growth.

  • A new and simple method for measuring in situ field-saturated hydraulic conductivity using a falling-head single cylinder -

    Abstract

    Hydraulic properties of soil play important roles in water and temperature regimes. Measuring hydraulic properties has been studied for decades in the laboratory and in the fields. In 1989 the Guelph Permeameter was introduced to measure in situ field-saturated hydraulic conductivity, K fs, but it required an empirical constant. Until recently, no procedure had been introduced to in situ measure K fs without an empirical constant. In this article, we proposed a new simple method to measure K fs. Field and laboratory measurements for volcanic ash origin Kanto loam, loess, and Toyoura sand were taken using a metallic cylinder (30 cm long and 4.5 cm inner diameter) or a PVC cylinder (30 cm long and 5.0 cm inner diameter) installed into soil down to a 5 cm depth. Temporal changes in water depth or hydraulic head inside the cylinder were measured with a laser measure. Values of K fs measured with this proposed method agreed well with saturated hydraulic conductivity measured in the laboratory for undisturbed soil cores. New analytical solution was derived for a future automated device for this purpose.

  • Plant species identification using fecal DNAs from red-eared slider and Reeves’ pond turtle in agricultural canals for rural ecosystem conservation -

    Abstract

    Fecal DNA samples from the red-eared slider and Reeves’ pond turtle, suspected pests of lotus root paddies, were used to identify the plant species eaten by these turtles in order to develop a strategy for rural ecosystem conservation. The fecal samples were obtained from young and adult individuals (mostly female) of both species living in agricultural canals surrounding lotus root paddies in Tokushima Prefecture, Japan. The samples were screened for the presence or absence of DNA from nine plant species using PCR and plant species-specific primers for the rbcL gene of chloroplast DNA. In the red-eared slider, our analysis identified seven plant species in the fecal DNA samples of adults and three plant species in those of young individuals. In Reeves’ pond turtle, our analysis identified two plant species from adult fecal samples and one species from those of young individuals. Thus, adult red-eared sliders consume a greater range of plants than young red-eared sliders or Reeves’ pond turtles. Both turtle species, independently of age, consumed lotus plants and were likely to cause feeding damage to lotus roots. Considering the plant species detected in adult red-eared sliders and these plant habitats, we suggest that this adult turtle is likely to travel between the agricultural canals and the lotus root paddies. These findings will help the development of strategies for preventing damage to lotus roots by these turtles; furthermore, they indicate that fecal DNA analysis will be applicable to investigation of the feeding habits of other animal species.

  • Tracing the fate of nitrogen with 15 N isotope considering suitable fertilizer rate related to yield and environment impacts in paddy field -

    Abstract

    While the application rate of nitrogen fertilizer is believed to dramatically influence rice fields and improve the soil conditions in paddy fields, fertilization with low use efficiency and nitrogen loss may cause environmental pollution. In this paper, 15N-labeled urea was used to trace the fate of nitrogen at four rates (0, 75, 225 and 375 kg N/ha) of urea fertilizer over three split applications in Hangzhou, Zhejiang, in 2014. Plant biomass, the soil nitrogen content of different layers, NH3 volatilization and N2O emissions were determined using the 15N abundance to calculate the portion from nitrogen fertilizer. The results indicated that rice yields increased with the application rate of nitrogen fertilizer. NH3 volatilization is the main nitrogen loss pathway, and N2O emissions were significantly associated with nitrogen application rates in the paddy. The percent of nitrogen loss by NH3 volatilization and N2O emissions increased with the nitrogen application rate. This study showed that the suitable N fertilizer in a loam clay paddy, considering the yield requirements and environmental issues, is approximately 225 kg N/ha in Hangzhou, with a distribution of 50.06% of the residual in the rice and soil and 48.77% loss as NH3 volatilization and N2O emissions. The nitrate from fertilization mainly remained in the 0–20 cm level of the topsoil.

  • Assessment of paddy performance under BGREI initiative using RISAT SAR data -

    Abstract

    Bringing Green Revolution in Eastern India (BGREI) is a large-scale Department of Agriculture and Co-operation, Ministry of Agriculture (MoA), Government of India funded project with the aim to increase crop productivity through improved package of practices in low-productivity zones of eastern India. Assessment of the BGREI plots with respect to crop vigour variability using space-based observations was planned for 2011–2014 years. A new approach based on Synthetic Aperture Radar (SAR) data was used to assess the rice crop growth pattern and crop vigour. A methodology was developed to evaluate the effect of BGREI programme in the state of Odisha, India. The peak green biomass estimated from SAR data was found to be 10–30% higher in BGREI plots compared to the controlled plots during 2012–2013 and 2013–2014. The improvement was higher in traditionally low productive rainfed zones in coastal and southern Odisha as compared to the irrigated tracts of the northern plateau. Uniformity in growth in terms of growth rate, transplantation time and duration was observed in BGREI plots in both the years, but magnitude was found to be higher in 2012–2013. The impact of the BGREI programme in Odisha indicates that the scheme proved to be a breakthrough in improving rice productivity in low-productivity pockets of eastern India and the SAR-based methodology was able to pickup this with high accuracy.

  • Modeling the water and nitrogen transports in a soil–paddy–atmosphere system using HYDRUS-1D and lysimeter experiment -

    Abstract

    Efficient water and fertilizer use is of paramount importance both in rain-fed and irrigated rice cultivation systems to tread off between the crop water demand during the dry spell and the fertilizer leaching. This lysimeter study on paddy in a lateritic sandy loam soil of the eastern India, to simulate the water and solute transports using the HYDRUS-1D model, reveals that this model could very well simulate the soil depth-specific variations of water pressure heads and nitrogen (N) concentrations with the efficiency of >86 and 89%, respectively. The change in the level of water ponding depth did not have a significant effect on the time to peak and the temporal variability of N concentration in the bottom soil layer. The lysimeter-scale water balance analysis indicated that the average deep percolation loss and crop water use were 35.01 ± 2.03 and 39.74 ± 1.49% of the total water applied during the crop growth period, respectively. Similarly, the amount of N stored in the plant and lost through soil storage, deep percolation, and other losses (mineralization, denitrification, and gaseous N loss to the atmosphere through plant leaves) were 1.60 ± 0.16, 0.17 ± 0.04, 12.00 ± 0.48, and 86.23 ± 0.41% of the total applied nitrogen, respectively. The simulation results reveal that a constant ponding depth of 3 cm could be maintained in paddy fields to reduce the N leaching loss to 7.5 kgN/ha.

  • Water productivity, nutrients uptake and quality of aerobic rice as influenced by varieties and iron nutrition -

    Abstract

    Field experiments were carried out at the research farm of ICAR-Indian Agricultural Research Institute (ICAR-IARI), New Delhi, India, during Kharif (June–October) seasons of 2011 and 2012 to study the effect of rice varieties and iron fertilization on water productivity, nutrient uptake and quality of aerobic rice. Treatments comprised of two rice varieties (PRH-10 and PS-5) and eight sources and modes of iron fertilization—control (no iron), iron sulphate @ 50 kg/ha + one foliar spray of 2.0% iron sulphate, iron sulphate @ 50 kg/ha + one foliar spray of 0.5% iron chelate, iron sulphate @ 100 kg/ha, two foliar sprays of 2.0% iron sulphate, three foliar sprays of 2.0% iron sulphate, two foliar sprays of 0.5% iron chelate and three foliar sprays of 0.5% iron chelate. Study results indicated that variety PRH-10 had higher concentration and uptake of nitrogen, phosphorus, potassium and iron than PS-5 variety in grain, straw and grain + straw. Three foliar sprays of 2.0% iron sulphate or 0.5% iron chelate favoured higher NPK and iron concentration and uptake in grain and straw of aerobic rice. Grain quality in respect of hulling, milling and head rice recovery was, however, superior in PS-5 than PRH-10. But the protein content was significantly higher in PRH-10 than in PS-5. Application of three foliar sprays of 2% iron sulphate and three foliar sprays of 0.5% iron chelate recorded significantly higher hulling, milling and head rice recovery as compared to control and remained statistically similar with each other. Irrigation and total water productivity was substantially higher in PRH-10 over PS-5. Growing of rice with PRH-10 recorded ~7.7% higher total water productivity as compared to PS-5, across iron fertilizations. Three or two foliar sprays of 2.0% iron sulphate or 0.5% iron chelate favoured higher irrigation and total water productivity of aerobic rice over control (no iron).

  • Numerical modeling based on a finite element method for simulation of flow in furrow irrigation -

    Abstract

    In this study, a zero-inertia finite element model (ZIFEM) is developed and applied for simulating all phases of furrow irrigation based on Saint–Venant equations. The complexity and nonlinear behavior of the Saint–Venant equations are the major difficulty in developing a finite element model to simulate furrow irrigation. Therefore, through the Galerkin FEM approach, the model assesses the free surface flow on a variable cell length at each time step and determines the suitable element length for each individual cell and the model solves the equations by using an iterative method. Along with the free surface flow phase, the infiltration phase is estimated by the Kostiakov–Lewis equation. The ZIFEM model is verified using seven experimental data sets collected from the literature and observed data from the farm consisting of two free drainage furrows with a length of 72 m, a top width of 0.8 m, a depth of 0.25 m and a slope of 0.2%. The model accuracy is studied to simulate advance and recession trajectories and runoff by calculating the root-mean-square error (RMSE), relative error and percentage error. It is observed that in all irrigation events, the proposed model reasonably agreed with field measurements. An evaluation of the RMSE shows that in 81.25% irrigation events the ZIFEM is more accurate than the WinSRFR model. In overall, the results of the model suggest that the ZIFEM can be introduced as a potential numerical tool for analyzing and evaluating furrow irrigation.

  • Predicting adoption of double cropping in paddy fields of northern Iran: a comparison of statistical methods -

    Abstract

    Factors affecting the adoption of double cropping were explored in rice farms of Fouman County of Guilan Province in northern Iran using artificial neural networks (ANNs), linear discriminant analysis (LDA), and logistic regression (LGR). Eleven factors (age, education, occupation, family size, type of farm ownership, distance to the agricultural service center, attending agricultural extension courses, use of financial resources and bank loans, number of domestic animals, area under cultivation, and social participation) were examined. An additional objective was to compare the ability of the three models in predicting the adoption of double cropping. ANNs showed an overall predictive power of 89.8%. LDA showed an overall predictive power of 83.2%, with seven of the eleven independent variables being effective on the adoption of double cropping. LGR indicated an overall predictive power of 87.6%, with eight of the eleven independent variables being effective on the adoption of double-rice cropping. ANNs showed higher power than LGR and LDA in predicting the adoption of double cropping. Based on all three methods used for analysis, the most important independent variables were social participation and area under cultivation (positive factors) as well as distance to the agricultural service center and family members (negative factors). Establishment of cooperatives or other kinds of farmers’ associations to foster social participation could motivate adoption of double cropping, particularly among small-scale farmers. To increase agricultural services, more local centers should be created in rural areas. The government should promote double cropping through effective incentives and technology transfer to small-scale farmers.