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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

  • Analysis of hydrological drought characteristics using copula function approach -

    Abstract

    Drought is a natural phenomenon which starts with decreased precipitation and can disrupt the environmental systems by changing the hydrological cycle. This is more conspicuous in hydrological drought. In analysis of hydrological drought, two factors of severity (intensity) and duration play eminent role. These characteristics are highly related and therefore their combined analysis contributes to better understanding of the drought situation. In this research, by using 40-year (1974–2014) daily discharge data of Tajan River, located in Mazandaran province, Iran, and low-flow indices, the best evaluation index of hydrological drought was determined and 10 past hydrological drought events in the region were identified. Then, the best statistical distribution of both drought variables (duration and severity) was selected, based on the goodness-of-fit tests. Five copula functions were fitted to the data. Results showed that Galambos function with the highest maximum log-likelihood (− 8.934) was selected as the best copula function. Results of the bivariate (duration and severity) statistical distribution could be used to analyze the probability of hydrological drought in the region. This bivariate and conditional probability for the worst drought, with duration of 5 months and severity of 0.32, was 6.1 and 28.5%, respectively.

  • Leaf litter decomposition and diversity of arthropod decomposers in tropical Muyong forest in Banaue, Philippines -

    Abstract

    The Muyong forest, an indigenous secondary forest in Banaue, Ifugao, Philippines, plays a crucial role in the Muyong–Payoh system, a continuum of secondary forest and rice terrace, of the Banaue rice terraces by providing water and nutrients to the rice plants in the Payoh terraces. In recent decades, the planting of introduced tree species in the Muyong forest has threatened the sustainable provision of ecosystem services such as water balance and nutrient cycling. To further understand nutrient cycling in the Muyong–Payoh systems, this study was conducted in Poitan, Banaue, Ifugao to gather preliminary baseline data on floral diversity, leaf litterfall rate, leaf litter decomposition rate, and diversity and succession of arthropods in decomposing leaf litter in a Muyong forest. Vegetation analysis was done by identifying and describing the trees growing inside the five 10 m × 10 m quadrat sampling plots. Monthly leaf litter fall was collected in 1 m × 1 m litter traps, and the dry weight was determined after oven-drying at 65 °C for 48 h. Leaf litter decomposition experiment was established by laying out 12 nylon mesh bags containing fresh leaf litter in each of the four sites on the forest floor and one bag was retrieved every month to determine the change in dry weight of the leaf litter. Six bulk soil samples were collected from the Muyong forest floor and analyzed for organic matter, pH, available P and exchangeable K. Fresh leaf litter samples were analyzed for total N, P and K contents. Arthropods in the collected decomposing leaf litter were extracted using Berlese funnel and later identified up to families level using arthropod taxonomic key. The diversity of plants in the Muyong forest includes thirty-eight tree species belonging to 19 families dominated by indigenous tree species. Results showed that the monthly leaf litter fall was higher during the dry months of March to May and lower during the wet months. The estimated total leaf litter fall in Muyong forest was comparable to published litter fall from tropical secondary forests. The N, P and K contents of fresh leaf litter range from 1.0 to 1.2, 0.11 and 0.40%, respectively. The first month of decomposition has the fastest rate while the decomposition rate during the next 4 months ranged from 0.125 to 0.251. Complete decomposition or mass lost in the leaf litter in the Muyong forest took place within 5 months. The soil arthropods identified in the decomposing leaf litter were composed of 13 orders and 28 families. Majority of the collected arthropods were insects while other species including mites, spiders, millipedes and sowbugs were also present. Detrivore and fungivore Families were found to be dominant in the decomposing leaf litter. Moreover, the composition and succession of arthropod decomposer community varied in the three sampling methods and with the changing quality of the litter material as decomposition progressed. The wide diversity and succession of leaf litter decomposers consisting of detritivores, predators, fungivore and herbivore coupled with abundant rainfall and warm temperature are the two main factors that contribute to the fast rate of leaf litter decomposition and nutrient turn over in the Muyong forest. Thus, the Muyong forest can sustain the productivity of rice planted in the adjoining downstream Payoh terraces. Hence, the conservation and management of the Muyong forest is critical in maintaining the ecological functions of the Muyong–Payoh continuum.

  • Effects of detritivorous invertebrates on the decomposition of rice straw: evidence from a microcosm experiment -

    Abstract

    Decomposition of crop residues is a key process in agricultural systems that influences nutrient cycling and productivity. To clarify the roles of different groups of invertebrates in decomposition in paddy fields, we conducted a microcosm experiment, testing the effects of soil eluate filtered through a 21 μm mesh (control treatment) against the effects of microfauna (< 0.1 mm) and small gastropods (juvenile golden apple snails (Pomacea canaliculata), ca. 2 mm shell diameter), both separately and in combination, on rice straw decomposition. Rice straw in litterbags was incubated at the soil surface and in the soil together with standardized amounts of the respective detritivores for 10 and 21 days. Compared to the control treatment, snails and microfauna enhanced the reduction in straw mass on the soil surface by 19 and 22%, respectively. Both groups combined increased the reduction in straw biomass by 30%. Below the soil surface, the contribution of detritivores to decomposition was smaller, reducing straw biomass by just 1% (snails), 11% (microfauna) and 14% (snails + microfauna) compared to the control. The effects of microfauna and snails on decomposition were not fully additive, a pattern that could be due to competition or trophic interactions. Model selection using Akaike’s information criterion on nested linear mixed effects models led to a model including the main effects (snails, microfauna, position and time), several two-way interactions and the three-way interaction snails * microfauna * litterbag_position as the most parsimonious description of the data. Keeping straw accessible to aquatic invertebrate detritivores should be a suitable management strategy to enhance decomposition in paddy fields, although trade-offs with other management issues such as pest control need to be considered.

  • Variance of microbial composition and structure and relation with soil properties in rhizospheric and non-rhizospheric soil of a flooded paddy -

    Abstract

    Soil microbial structure and nutrient properties varied with fertilization and plant growth simultaneously in the rhizosphere. However, the relationships between rhizospheric microbial community structure and soil characteristics were still unclear. This study aimed to explore the impact of nitrogen (N) fertilizer and rice growth on microbial community structure and their relation with soil physiochemical properties. A pot experiment for rice-planting with two levels of N fertilization was conducted in a flooded paddy soil. At tillering and ripening stages, both rhizospheric and non-rhizospheric soils were sampled separately for physiochemical analysis, real-time quantitative PCR assay and terminal restriction fragment length polymorphism (T-RFLP) analysis. The results showed that both N addition and growth stage of rice could affect physiochemical properties of rhizosphere and non-rhizosphere soil simultaneously. At tillering stage, no significant difference of bacterial and archaeal gene abundance was observed, but rhizospheric abundance of microorganisms was significantly different with non-rhizosphere at ripening stage. One-way ANOVA analysis indicated that N addition has greater effect on microbial structure diversity of bacteria rather than archaea, non-rhizosphere than rhizosphere, respectively. Non-metric multidimensional scaling analysis showed two groups of bacterial community both in rhizospheric and in non-rhizospheric soils at tillering stage differing much, but similar at ripening stage. Redundancy analysis showed that the microbial community compositions at tillering stage were most correlated with NH4 +, total N (TN), pH, microbial biomass N (Nmic) and microbial biomass carbon (Cmir) whereas at ripening stage were more or less lined with Olsen-P, C/N ratio, total C (TC) and available K. Our research suggested that the N addition has more influence on community composition diversity of bacteria and non-rhizosphere. The growth stage might be the main factor affecting bacterial community structure both in rhizospheric and in non-rhizospheric soils affected by different soil parameters.

  • Evaluation of two types of superabsorbent polymer on soil water and some soil microbial properties -

    Abstract

    In this study, two types of superabsorbent polymers, Luquasorb (Luqua) and Stockosorb (Stock), at 180 kg ha−1 were applied by scattering and mass treatments in an experimental farm to assess their influences on spring wheat growth (Dez variety) and on the physical characteristics and microbial plenty of soil. The following treatments were used in this study: the control (C, without SAPs), Luqua with mass application (Luqua-M), Stock with mass application (Stock-M), Luqua with scattered application (Luqua-S), and Stock with scattered application (Stock-S). Approximately 0.3 m3 of irrigation water was supplied for every subplot. The results indicated that adding superabsorbent polymers could improve the soil water-holding capacity and enable the soil to retain more water. Besides, superabsorbent polymers significantly enhanced the soil water content in the three growth stages compared with the control. The use of superabsorbent polymers did not have obvious opposite influences on the soil microbial colony and might even increase soil microbial movement.

  • Enhancing field scale water productivity for several rice cultivars under limited water supply -

    Abstract

    Rice production is one of the largest consumer of water in agriculture. In general, the irrigation water productivity (WPI) is low in paddy fields. In order to improve WPI, a field experiment was conducted in central of Iran during 2009–2010. The experiment was consisted of three irrigation managements and eight advanced rice cultivars (Gerdeh (V 1), Zayande-roud (V 2), Sazandegi (V 3), Hasani (V 4), 67–97 (V 5), 67–113 (V 6), 67–47 (V 7), and 67–72 (V 8)) in a split plot design with three replications. The irrigation treatments were I 1 and I 2: permanent flooding under 3.5 and 2.2 cm water depth, respectively, and I 3: 0–1.5 cm alternative wetting and drying. To explore deficit irrigation for improved WPI, SWAP model was calibrated using intensive measured data for the foregoing years. The average normalized root-mean-square deviation of yield during calibration was 0.03% and during validation was 4.94% indicating acceptable calibration and validation of the model. WPI for all cultivars were enhanced up to 61% by applying 50% deficit irrigation. On this irrigation regime, V 2 and V 6 provided the highest WPI (0.84 and 0.79 kg m−3, respectively) whereas V 4 and V 8 yielded the lowest (0.50 and 0.57 kg m−3, respectively). The results indicated that rice cultivars (V 2 and V 6) are the best option with the highest WPI in the irrigation district and calibrated model was able to effectively simulate the crop growth under water deficit conditions.

  • Response of N 2 O emission to straw retention under two contrasting paddy water conditions: a field experiment over rice–rice-fallow rotation -

    Abstract

    Few studies are available on comprehensive impacts of straw retention and water regimes on nitrous oxide (N2O) emission from rice–rice-fallow rotation systems. A field experiment with or without rice straw (5000 kg ha−1 each rice season) retention under two contrasting water regimes (1. continuous flooding; 2. rain-fed with exception flooding irrigation about 15 days after transplanting) was conducted in south China. N2O emission was monitored using the closed chamber method over the entire rice–rice-fallow rotation. The results demonstrate that there were significant differences in the responses of N2O emission to water regime, straw retention, and their interaction. N2O emission was negligible in the continuously flooded treatments, with annual N2O emission of 0.052 kg ha−1 with straw and − 0.008 kg ha−1 without straw, respectively. In contrast, substantial N2O fluxes were observed under rain-fed condition when water layer disappeared, with annual N2O emission of 0.969 kg ha−1 with straw and of 0.618 kg ha−1 without straw, respectively. About 50–60% of annual N2O emission occurred in fallow season under rain-fed treatments. The results indicate that rice straw retention has a potential to accelerate N2O emission depending on paddy water conditions.

  • 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.