Rice Field Ecosystem Research Articles

Conversion of Rice Field Ecosystems from Conventional to Ecological Farming: Effects on Pesticide Fate, Ecotoxicity and Soil Properties.

Rice is an important staple food around the world, the cultivation as sustainable agriculture and food supply are key to achieving the Sustainable Development Goals (SDGs) of 2030. In order to analyze the sustainability of the rice paddy ecosystem, a comparative study was carried out during the rice growing season between paddies with conventional agriculture (CA) and ecological agriculture (EA), integrating analysis of physico-chemical characteristics of soil and soil pore water, pesticide residues, acute toxic effects and potential ecological risk, as well as aquatic invertebrate community structure dynamics. Our study found that total carbon and nitrogen present in soil were significantly higher in CA than in EA, while opposite results were found in soil pore water, implying the improvement on soil properties in EA. Neonicotinoid pesticides (thiamethoxam and thiacloprid) were still detected in EA, although no pesticides were applied after conversing CA to EA. Additionally, toxic effects to zebrafish embryos with a peak toxicity in summer (July, LC50 = 55.26 mg soil equivalent/L) were also found in EA, which was lower than in CA. The dynamics of the aquatic invertebrate community structure were correlated with the toxicity results, with higher diversity recorded in EA. Therefore, for the purpose of ecosystem sustainability, the long-term implementation of EA is highly recommended.

Multidimensional analysis for assessing sustainability determinants of rice farming in Siak, Riau

Abstract This study was conducted in five villages in Bunga Raya District (Kemuning Muda, Bunga Raya, Tuah Indrapura, Jayapura, and Buantan Lestari), the rice production centers of Siak Regency, Riau. The research location was selected based on the largest percentage of rice field area. The research was conducted from January to July 2019. This research aims to determine sustainable lowland rice farming management variables for future lowland rice farming development in Bunga Raya District, Siak Regency. Purposive sampling was used to choose the 82 sample farmers, who were selected using the Slovin equation. The respondents are selected with a margin of error of 7% of the total population of farmer families. Data was gathered through the use of interview techniques, questionnaires, and field observations. Multi-dimensional scaling (MDS) was used to analyze sustainable rice farming management factors after updating the Rapfish program. According to the findings of the sustainability study of 42 studied variables, 12 of them show sensitivity. Five of the ten stakeholder needs attributes were examined to provide sensitivity. The combined analysis of current prospective sustainability with stakeholders yielded five attributes determining factors for the sustainability of lowland rice farming in Bunga Raya: land conversion, participation in training/extension services, pesticide use, agro-tourism potential, and farmer capital availability. Another recommendation that policy makers need to consider, which is no less important, is to always preserve the rice field ecosystem by developing natural and human resources, so that increasing the welfare of farmers and increasing regional income can be achieved.

<span>Some data about the food composition of amphibians in Cao Lanh city, Dong Thap province </span>

On the rice field ecosystem in Cao Lanh district, Dong Thap province, there are 6 species of amphibians distributed: Duttaphrynus melanostictus, Kaloula pulchra and Hylarana guentheri have the most diversity of feed ingredients; Fejervarya limnocharis, Hoplobatrachus rugulosus and Ichthyophis bannanicus have less food diversity; Scolopendomorpha and Polydesmoidea are the least, accounting for 1,2%. Amphibians have the most food frequency in Coleoptera, followed by Hymenoptera and Orthoptera. Amphibians are usually terrestrial, eating mainly insects. The frequency of pests was lowest in the period from sowing seeds until the rice had 3 leaves germinated, the lowest in the period of yellow rice until after harvest, the highest at the stage of rice with milk in the grain to the stage of green - ripened rice. The frequency of encounters of Hoplobatrachus rugulosus and Fejervarya limnocharis is lowest at the stage of seeding until rice germination, decrease gradually in the period of ripe rice until after harvest, stage 4 (Rice with milk in the grain until green ripening) has the highest frequency. In stage 1, there is the lowest frequency of encountering amphibians and pests, frequency increases gradually to stage 2 and peaks at stage 4, decreasing at stage 5.

The diversity of soil insects in rice field ecosystems

<p>Soil insects live in the soil or even both on the surface of the soil. Soil surface insects are one of the important animals in the soil ecosystem because their role is very important in the survival of the vegetation above them. Soil insects act as decomposers of organic materials, which will be useful as nutrients for plants. Apart from that, soil insects can also be used as indicators of soil fertility. The aim of this research is to determine the diversity of soil insects in the rice field ecosystem of Palembang City. This research was conducted in a rice field ecosystem using the pitfall trap method, 4 traps for 30 days. The results of the research obtained 14 species of soil insects from 11 families and the diversity index level of soil insects was classified as medium with a diversity index value of 1.057 with the dominating species, namely <em>Camponotus laevigatus</em> (Hymenoptera: Formicidae). Soil insects are an important part of an ecosystem or habitat. The diversity of ground surface insects and ecosystem functions show a very complex relationship and not much is known with certainty. A decrease in diversity and changes in the role of ground surface insects will occur due to changes in land use systems and habitats that are degraded due to development. The level of soil insect diversity needs to be maintained or increased to ensure soil fertility and overall ecosystem health and function remain optimal.</p>

Design of a Portable Analyzer to Determine the Net Exchange of CO2 in Rice Field Ecosystems.

Global warming is influenced by an increase in greenhouse gas (GHG) concentration in the atmosphere. Consequently, Net Ecosystem Exchange (NEE) is the main factor that influences the exchange of carbon (C) between the atmosphere and the soil. As a result, agricultural ecosystems are a potential carbon dioxide (CO2) sink, particularly rice paddies (Oryza sativa). Therefore, a static chamber with a portable CO2 analyzer was designed and implemented for three rice plots to monitor CO2 emissions. Furthermore, a weather station was installed to record meteorological variables. The vegetative, reproductive, and maturation phases of the crop lasted 95, 35, and 42 days post-sowing (DPS), respectively. In total, the crop lasted 172 DPS. Diurnal NEE had the highest CO2 absorption capacity at 10:00 a.m. for the tillering stage (82 and 89 DPS), floral primordium (102 DPS), panicle initiation (111 DPS), and flowering (126 DPS). On the other hand, the maximum CO2 emission at 82, 111, and 126 DPS occurred at 6:00 p.m. At 89 and 102 DPS, it occurred at 4:00 and 6:00 a.m., respectively. NEE in the vegetative stage was -25 μmolCO2 m2 s-1, and in the reproductive stage, it was -35 μmolCO2 m2 s-1, indicating the highest absorption capacity of the plots. The seasonal dynamics of NEE were mainly controlled by the air temperature inside the chamber (Tc) (R = -0.69), the relative humidity inside the chamber (RHc) (R = -0.66), and net radiation (Rn) (R = -0.75). These results are similar to previous studies obtained via chromatographic analysis and eddy covariance (EC), which suggests that the portable analyzer could be an alternative for CO2 monitoring.

Mitigating atmospheric methane emissions from Asian rice fields: a review of potential and promising technical options

Agriculture serves as a significant anthropogenic source of methane emissions. Numerous recent studies have examined the factors influencing methane emissions and have developed emission models. However, there is no a bridging review study related to methene emissions in Asia as one of the primary methane emitters. This review is divided into two manuscripts. In this first manuscript, I explore the process of methane emission and the factors that impact methane production and emissions. Meanwhile, the present state of studies conducted in various Asian countries and knowledge gaps are elaborated in the second manuscript. I elaborate several factors that influence methane production and their roles in the emission process. Further, I highlight that the gas is mostly produced in zero oxygen condition, although, a little concentration of methane also can be generated in oxic condition. This finding provides basic knowledge that contribute to the future research on methane emissions in rice field ecosystems. Eventually, I also explore various recommended technical solutions to reduce the gas emission.

Insect Diversity of Some Hybrid Rice Genotypes in Sleman-Yogyakarta Irrigated Agroecosystem

Diversity of insect at the rice field gives a main impact to the stability of ecosystem. Index of diversity reflects the relationship of species abundance in the community. This research was aimed to determine the diversity of insect at some hybrid rice varieties in irrigated rice agroecosystem. Research was conducted in Sleman, Yogyakarta Indonesia from April to August 2018. The experiment was conducted using purposive random sampling. Insect samples were obtained using swing net and visual observation. Diversity index was analysed using Shanon (H), while diversity and uniformity of insect was examined using Evennes index (E). Result showed pest insects found during vegetative stage of rice consist of more species, while lower numbers were found at generative stage with less species. They were belongs to 6 orders (more than 10 families) such as Diptera, Lepidoptera, Coleoptera, Orthoptera, Hemiptera and Hymenoptera. The dominant pest was Cicadellidae, followed by Delphacidae and Alydidae. Based on the diversity data analysis (H), pest insects and natural enemies were between moderate and high, with a range between 1.5 to 2.5. It indicates the rice field ecosystem planted with hybrid rice gave good impact and balance species diversity in the agroecosystem of irrigated rice area in Sleman Yogyakarta.

Exploration of The Species Richness of Butterfly (Hexapoda: Odonata) in The Rice Field Ecosystem of Perian village, Montong Gading, East Lombok

Several Odonata studies on Lombok Island still focus on forest and river habitat types. This causes the diversity of this insect group to be unknown in other habitats such as rice fields. This research aims to explore the richness of dragonfly species in the rice field ecosystem of Perian village, Montong Gading subdistrict, East Lombok district. Sample collection was carried out in May – June 2022. Dragonfly searches were carried out in the morning from 08.00 – 12.00, and in the afternoon from 14.00 – 18.00 on two transects determined purposively. The odonata found were documented using a digital camera, and captured using insect nets. Samples that were successfully collected were identified to the species taxon. The total odonata we found were 2 suborders, 5 families and 11 species. The suborder Zygoptera is the group with the highest species richness. For families, Libellulidae and Coenagrionida are the families with the highest species richness compared to other families. Of the 11 species that we found, 1 species is endemic, namely Euphaea lara lombokensis. Compared with the results of previous research conducted in Suranadi and Batu Bolong River, there are 5 species which are new records. The five species are Copera ciliata, Rhinocypha bisignata, Ischnura senegalensis, Ischnura heterosticta, and Brachythemis contaminata. The results of this study indicate that there are more species from the Odonata order on Lombok Island compared to previous reports.

Simulated Nitrogen Deposition Decreases the Ratios of Soil C to P and N to P, Changes Soil Enzyme Activity, and Reduces Soil Microbial Biomass in Paddy Soil in Southern China

There have been few studies on the impact of nitrogen deposition on paddy field ecosystem; therefore, we evaluated the effects of different N deposition levels (0, 40, and 120 kg N·ha−1) with the conventional nitrogen rate (180 kg N·ha−1) on rice field ecosystem through two-season experiments. The results showed that 40 and 120 kg·ha−1 nitrogen deposition had no significant effect on rice yield, although the rice grains per panicle and the 1000-grain weight increased. The 40 and 120 kg·ha−1 nitrogen deposition levels had no significant effect on rice and soil total carbon/total nitrogen (TC/TN) in the two-season experiment; however, 40 and 120 kg·ha−1 nitrogen deposition significantly increased TP content of the rice root and soil in a short time, and continuous 120 kg·ha−1 nitrogen deposition significantly decreased TP content of the rice root and significantly increased TP content of the rice stem. In addition, nitrogen deposition significantly reduced total carbon/total phosphorus (TC/TP) and total nitrogen/total phosphorus (TN/TP) in the soil. The activities of soil acid phosphatase (S-ACP), β-glucosidase (S-β-GC), and N-acetyl-β-D-glucosidase (S-NAG) increased under 40 kg·ha−1 nitrogen deposition, while the activities of S-β-GC and S-NAG decreased under 120 kg·ha−1 nitrogen deposition compared with 40 kg·ha−1. The microbial carbon, microbial nitrogen, microbial phosphorus, and fungal microbial biomass reduced under 40 and 120 kg·ha−1 nitrogen deposition. These findings suggest that, under short-term N deposition, rice and soil can adjust the C, N, P, and even the nutrient balance by themselves; however, continuous nitrogen deposition may have adverse reactions to microorganisms, thereby disrupting this balance and ultimately leading to the deterioration of paddy soil environment and a reduction in rice yield in the long term.

Viability of zooplankton resting eggs in rice field sediment after pesticide applications.

Many herbicide products are commonly used in agricultural areas to prevent and eliminate weeds. Contamination from these toxicants in water might affect aquatic organisms not only in the active stage, but also in the diapause stage. To test the effect of herbicide on the resting eggs of zooplankton, we prepared two rice fields: one field without the application of pesticides (RF-NPA) and one with the application of pesticides (RF-PA) in a sampling year. We conducted a hatching experiment for 30 days. Twenty-four taxa of zooplankton were found. Sixteen species of these were rotifers, seven species were cladocerans and one taxon was an unidentified nauplius copepod. The species richness of zooplankton between RF-NPA (17 taxa) and RF-PA (16 taxa) was close, but species compositions between RF-NPA and RF-PA were different, indicated by the similarity index of 0.545. Lecanidae was the most diverse family of rotifers in both rice fields with nine species, while Chydoridae was the most diverse family of cladocerans (four species). The total abundance of zooplankton of RF-NPA was higher than RF-PA with 1,897 and 1,286 individuals, respectively. The Shannon-Wiener diversity index (H´) and Pielou's evenness (J) in RF-NPA were higher than in RF-PA. The high species richness of zooplankton in both rice fields occurred on days 18 to 30. On the other hand, the highest abundance was recorded on day 18 for RF-NPA and on day 24 for RF-PA. The non-metric multidimensional scaling (NMDS) demonstrated significant differences in zooplankton community composition between RF-NPA and RF-PA (p < 0.05; ANOSIM test). According to the diversity indices, the RF-NPA has more diversity than the RF-PA, which might be a result of herbicide application in the sampling year. This study suggests that the toxicity of glyphosate should be a concern in terms of the biodiversity of rice field ecosystems.

Biochar Implementation in Rice Paddies for Addressing Greenhouse Gas Emissions and Nutrient Loss: A Review

Eco-challenges like greenhouse gas (GHG) emissions and nutrient depletion are key threats to the health of rice field ecosystems. Biochars (BCs) - porous, carbon-dense materials with substantial surface areas and an abundance of surface functional groups - are emerging as a viable solution for these issues, offering a way to increase rice production and address environmental concerns. Despite this potential, there is still a need for a comprehensive understanding of BCs' performance characteristics and their environmental interactions with rice paddy soils. The beneficial outcomes of using BCs, including enhanced rice growth and yield, decreased nutrient loss, and reduced GHG emissions. Factors like biomass type, pyrolysis temperature, and modification process significantly influence BCs' performance. The use of BCs can boost rice production while mitigating emissions of CO2, N2O, and CH4. They do this by improving soil properties, encouraging microbial diversity, supplying nutrients, and minimizing nutrient losses. However, the potential ecological hazards related to the use of BCs in rice paddies. These hazards include inconsistent research outcomes and the possibility of secondary pollution. Future research must address these challenges to ensure the sustainable application of BCs.

Assessing Stakeholders’ Preferences for Future Rice Farming Practices in the Mekong Delta, Vietnam

Rice farming is the dominating agriculture activity in the Mekong Delta and has been of significant importance for the region’s economic development, but it has also had an impact on the environment. Recent governmental policies emphasize the need for sustainable and climate-resilient agriculture; however, policy reforms pushing for transformation towards sustainable socio-agricultural systems are compounded by a lack of coherent and shared visions. Gaps between policy making and implementation and stakeholders’ divergent visions of what is meant by sustainable agriculture and how that can be achieved hinder progress. To address this, the Q-methodology was used to elucidate and integrate different perspectives from 41 stakeholders on 35 statements related to agriculture developments in the Mekong Delta. Under the theoretical lens of sustainability, and ecosystem services, the results unveiled four major development schemes, namely production through intensification, sustainable intensification, production through nature, and people and nature in balance. The majority of the stakeholders in this study believed that future agriculture strategies in the Mekong Delta should be designed to promote more diverse and integrated farming methods, emphasizing the environmental and social dimensions of sustainable development. They acknowledged the multifunctional benefits of rice field ecosystems and emphasized the importance of supporting, regulating, and cultural ecosystem services for a long-term and healthy production of food and increased resilience of the Delta’s social-ecological systems.

Soil and microbial C:N:P stoichiometries play vital roles in regulating P transformation in agricultural ecosystems: A review

Stoichiometry plays a crucial role in biogeochemical cycles and can modulate soil nutrient availability and functions. In agricultural ecosystems, phosphorus (P) fertilizers (organic or chemical) are often applied to achieve high crop yields. However, P is readily fixed by soil particles, leading to low P use efficiency. Therefore, understanding the role of carbon:nitrogen:P stoichiometries of soil and microorganisms in soil P transformation is of great significance for P management in agriculture. This paper provides a comprehensive review of the recent research on stoichiometry effect on soil P transformation in agricultural ecosystems. Soil microorganisms play an important role in the transformation of soil non-labile inorganic P to microbial biomass P by regulating microbial biomass stoichiometry. They also mobilize soil unavailable organic P into available P by changing ecoenzyme stoichiometry. Organic materials, such as manure and straw, play an important role in promoting the transformation of insoluble P into available P as well. Additionally, periphytic biofilms can reduce P loss from rice field ecosystems. Agricultural stoichiometries are different from those of natural ecosystems and thereby should receive more attention due to the influences of anthropogenic factors. Therefore, it is necessary to conduct further stoichiometry research on the soil biochemical mechanisms underlying P transformation in agricultural ecosystems. In conclusion, understanding stoichiometry impact on soil P transformation is crucial for P management in agricultural ecosystems.

Manifesting a sustainable circular economy in waste management by linking to Paddy Farming in Gianyar Regency, Bali

Bali is a province that has a source-based waste management program that is in line with the concept of a circular economy, in the form of a waste management facility at the village level (called Tempat Pembuangan Sampah Reduce, Reuse, and Recycle or TPS3R). TPS3R is still in the stage of looking for a sustainable form of business. One of the main products of the waste management facility is compost, which although it is good for improving soil quality and rice field ecosystem, but is still difficult to find consumers, making the continuity of its business in question. By having sustainable business, we can generate more sustainable environmental benefits. The action research was conducted in three villages, i.e., Sayan, Taro, and Pejeng, in Gianyar Regency. It aims to bridge the use of compost for the initiation of healthier paddy farming, while identifying ongoing business processes, potential environmental benefits, opportunities for mainstreaming healthier paddy farming, as well as the role of relevant stakeholders in realizing a circular economy business model that is sustainable and more independent. We interviewed 22 key informants. The results show that all villages have the same business model, viz. utilizing organic waste for composting, plastic waste for sorting and resale, and residual waste that will be sent to landfill because it has no economic value. Although the sale of compost is still an obstacle, there are opportunities if it can be synergized in the practice of paddy farming. This mainstreaming can be further synergized into food security projects that must be allocated from village funds. So, the role of the village government in this case is huge, followed by TPS3R management capabilities, while other parties such as NGOs, academics, and agricultural activists are only limited to functioning as encouragement and companions. If the TPS3R is successful, the village community will receive environmental, social, and economic benefits.

Exploring cattle sheds as complementary avifaunal habitat niches in rice dominated agricultural areas in Punjab, India

Avian diversity has often been studied in agricultural habitats, but ornithological aspect of cattle sheds has never been studied. This exploratory study was conducted with the objective of studying the potential of cattle sheds for sustaining avian abundance and diversity in rice dominated agricultural areas. The study was done in Rice Field Ecosystem (System I) and Cattle Shed Ecosystem (System II) during 2019 and 2020 monsoon crop season from selected villages, namely, Dangon, Pakhowal and Sarabha (district Ludhiana), Punjab. It was recorded that 26 avian species (mainly of grassland habitat) were present in cattle sheds from a total 34 avian species (wetland, grassland and open countryside inhabiting species) observed in rice fields, which reflected that cattle sheds support a wide proportion of avian fauna and complement rice fields in supporting and preserving avian abundance and diversity. There is immense need to explore and accordingly lay emphasis on boosting dairy as allied sector so that cattle sheds can be exploited in preservation of diverse avian populations and thereby reinforcing approach of sustainable agriculture. Keywords: Avian diversity, Avian feeding guilds, Cattle Shed, Grassland birds, Rice crop

An ecological economic comparison between integrated rice-fish farming and rice monocultures with low and high dikes in the Mekong Delta, Vietnam.

This study makes an ecological economic comparison between three different rice farming strategies in the Mekong Delta. Interviews were made with 30 farmers with two crops of rice and low dikes (2RLd), 30 farmers with three crops of rice and high dikes (3RHd) and 18 farmers with two crops of rice and one crop of fish (2RF). 2RF farmers had the highest annual net income and benefit cost ratio, because oflow production costs and high yields of rice and fish. 2RLd farmers had the lowest annual net income. 3RHd had the highest annual rice yield, but also used the highest amount of rice seeds and agrochemicals, generating the lowest benefit cost ratio. Most farmers (70%) preferred two crops because of a higher production efficiency. High dikes and frequent use of pesticidesand fertilizers were seen to decrease the water and rice quality, connectivity and biodiversity in farms with three crops. It is concluded that rice farming with two crops, and especially if integrated with fish and applying IPM, provides a sustainable alternative to rice farming with three crops and high dikes, because it makes use of the high connectivity within the rice-field ecosystem for an efficient production of healthy food through increasedrecycling of nutrients and natural pest control mechanisms.

Temporal variation of aquatic insects biodiversity in selected rice fields of Saran district of Bihar

Rice is a major food crop of India. The rice cultivation has maintained its priority status in the agricultural sector of the country. The intensive management practices adopted by the practitioners have resulted in genetic erosion, thus affecting the species composition of the rice field ecosystems. There is obvious difference in species composition and community structure in upland and lowland rice fields and lowland fields has minimum pests affecting production of yield per hectare. This paper presents a work carried out on the biological diversity of lowland rice field ecosystems of India, and proposes the need for conservation strategies to ensure the sustainability of these rice growing ecosystems in the long run.

A Critical Review of Biochar Application for the Remediation of Greenhouse Gas Emissions and Nutrient Loss in Rice Paddies: Characteristics, Mechanisms, and Future Recommendations

Greenhouse gas emissions (GHG) and nutrient loss are considered to be critical environmental issues facing rice field ecosystems. Biochars (BCs), as carbon-rich materials with porous structures, large specific surface areas, and enriched surface functional groups, have shown great potential for improving environmental problems in rice fields and increasing rice yields. However, thus far, we still lack an adequate summary and review of the performance characteristics of BCs and their environmental behavior in paddy soils. In this paper, we critically review the positive effects of BC application on the growth and yield of rice, nutrient loss reduction, and GHG reduction. Biomass type, pyrolysis temperature, and modification method are considered to be the key factors that determine the performance characteristics of BCs. The application of BCs could promote rice yield and mitigate CO2, N2O, and CH4 emissions by improving soil physicochemical properties and microbial communities, providing nutrient sources, and reducing nutrient losses. Finally, this paper illustrates the potential ecological risks of BC application on paddy fields, including the risks of inconclusive research results and secondary pollution. These shortcomings need to be addressed in future research to ensure the sustainability of BC application.

ECOLEXICON OF BIOTA IN THE RICE FIELD ECOSYSTEM CONTEXT IN THE DIALECTICS OF AGRARISING CULTURE SHIFT OF SUMUR DISTRICT COMMUNITIES

The lexicon of biota in the rice field ecosystem is important and interesting to study. This paper aims to describe the form, function, and survival of the flora and fauna lexicon in the rice field ecosystem in the cultural context of the Sumur District, Pandeglang Regency, Banten Province. This paper utilizes the insights of ecolinguistic theory. Data collection was carried out using two techniques, namely (1) observation to obtain data on the form of the lexicon and (2) interviews with informants spread over seven villages to obtain data on the form, function, and persistence of the lexicon. The data analysis methods used are the translational equivalent method and the referential equivalent method. The data analysis technique used is the determining element sorting technique in the form of translational sorting power and referential sorting power. This paper has urgency as a form of documenting local culture and language that is beneficial for environmental or ecosystem conservation. The results of this study indicate that there is a rich flora and fauna ecolexicon which is expressed in Sundanese lingual units. Grammatically, the ecolexicon is in the form of words and phrases. However, the survival of the eco-collection has shifted due to changes in farming patterns and people's living culture.

Biodiversity and Distribution pattern of Hemipteran insect bugs associated with Rice field Ecosystem of Sivaganga, TamilNadu, India

Biodiversity and Distribution pattern of Hemipteran insect bugs associated with Rice field Ecosystem of Sivaganga, TamilNadu, India