Organic Rice Fields Research Articles

Potential Production of CH4 And N2O in Soil Profiles from Organic and Conventional Rice Fields

The horizons in soil profile will determine the magnitude of greenhouse gas production due to the difference of total organic carbon and other chemical properties. This study aimed to determine the potential production of methane (CH<sub>4</sub>) and nitrous oxide (N<sub>2</sub>O) in each horizon of soil profile from organic and conventional rice fields. Soil samples which were taken from Imogiri Bantul D.I. Yogyakarta were used to determine soil properties, the potential of CH<sub>4</sub>, and N<sub>2</sub>O productions. The correlation analysis was used to determine the relationship between the production of CH<sub>4</sub> and N<sub>2</sub>O with soil properties. The results showed that production of CH<sub>4</sub> and N<sub>2</sub>O will be decreased with the increase of soil depth. Production of CH<sub>4</sub> and N<sub>2</sub>O was higher in organic rice field than in conventional rice field. The total organic carbon (TOC) correlated positively with CH<sub>4</sub>-production (<em>r=0</em><em>.89, P<0.001, n=8</em>) and N<sub>2</sub>O-production (<em>r=0</em><em>.87, P<0.001, n=8</em>). The nitrogen content also correlated positively with CH<sub>4</sub>-production (<em>r=0</em><em>.87, P<0.001, n=8</em>) and N<sub>2</sub>O-production (r=0.94, P<0.001, n=8). Mitigation of CH<sub>4</sub> and N<sub>2</sub>O emissions should consider of C and N in the soil.

Incorporation of fallow weed increases phosphorus availability in a farmer’s organic rice fields on allophanic Andosol in eastern Japan

ABSTRACTWe investigated the amount of soil phosphorus (P) in a farmer’s paddy fields under organic farming (OF) for various periods from 0 to 22 years as well as other farmers’ fields under conventional farming. All the fields are located in allophanic Andosol with long history of P fertilizer application, and some of them have been converted to OF across years. After conversion to OF, P was supplied only with winter fallow weeds mainly Foxtail (Alopecurus aequalis), rice residues (rice bran and straw), and guano. We determined total-P (Tot-P) and plant-available P (Av-P), which consists of Truog-P (Tru-P) and Bray-2-P under reducing condition with ascorbic acid (Asc-P), in soils of each field. For both Av-Ps, the ratio to Tot-P increased across years under OF following quadratic functions with both linear and quadratic terms being statistically significant. The ratios showed little changes for the initial 15 (Tru-P) or 10 (Asc-P) years and increased rapidly thereafter. These temporal changes in Av-P were consistent with the rapid increase of the amount of P accumulated in the winter fallow weeds and incorporated in the fields after beginning of OF. These results led us to the hypothesis that the incorporation of winter weeds has contributed to the increase of Av-P in the organic fields across years. We tested this hypothesis by investigating temporal changes of Av-P after suspending the weed incorporation for 2 consecutive years in plots of the organic fields. Both Av-Ps were significantly greater in plots with continued weed incorporation (CWI) than those in plots with its suspension. We further found that the increase of Asc-P in plots with CWI was 4.9-fold the input of total P in the incorporated weeds. This suggests that the incorporation of winter fallow weeds enhanced soil-P availability beyond the supply of P accumulated in the weeds.

Dynamics of N-NH4+, N-NO3-, and total soil nitrogen in paddy field with azolla and biochar

Nitrogen (N) is one of macronutrients which is dynamic in the soil and becomes constraint factor for rice crops. The addition of nitrogen fertilizers and its absorption in paddy field causes the dynamics of nitrogen, thus declines of N absorption efficiency. The aim of this research is to know influence Azolla, biochar and different varieties application on N-NH4+, N-NO3-, and total soil N in paddy field. This research was conducted in a screen house located in Jumantono Laboratory, Faculty of Agriculture, Universitas Sebelas Maret (UNS) with altitude 170 m asl from April to June 2016. Treatment factors that were examined consisted of azolla (0 and 10 tons/ha), biochar (0 and 2 tons/ha), and rice varieties (Cisadane, Memberamo, Ciherang, IR64). The results of this research showed that there was no interaction between azolla, biochar and varieties. Nevertheless, azolla treatment with dose of 10 tons/ha increased soil NH4+ content (41 days after planting, DAP) by 13.4% but tend to decrease at 70 and 90 DAP. Biochar treatment with dose of 2 ton/ha increases NO3- soil content (70 DAP) by 1.7% but decreases total N soil by 5.8% (41 DAP) and 4.7% (90 DAP). Different rice varieties generated different soil NH4+ content (41 DAP) and rice root volume. Cisadane variety can increase soil NH4+ content (41 DAP) by 52.08% and root volume by 51.80% (90 DAP) compared with Ciherang variety. Organic rice field management with azolla and biochar affects the availability of N in the soil and increase N absorption efficiency through its role in increasing rice root volume.

Keanekaragaman dan Kelimpahan Semut sebagai Predator Hama Tanaman Padi di Lahan Sawah Organik dan Anorganik Kecamatan Karanganom Kabupaten Klaten

Ants potentially as predators that become natural enemies of insect pests in rice fields with paddy cultivation. This study aims to know the diversity and abundance of ants, the role of ants, the population of ants, and the influence of physical and chemical factors in organic and inorganic rice fields. The ants were collected using pit fall trap method with insect bait, fish meat, and sugar solution. The results showed that the number of species and the number of individuals in organic rice fields was higher (429 individuals, 11 species) than inorganic rice fields (193 individuals, 10 species). In general, the index of diversity in organic rice fields was higher (ranging from 0.73 to 1.65) compared to inorganic rice fields (ranging from 0 to 1.28). The index of evenness in organic rice fields ranged from 0.63 to 0.99 (evenly distributed), whereas in inorganic rice fields ranged from 0 to 0.99 (uneven until evenly distributed). The dominant ants in organic rice fields were Camponotus sp, Solenopsis geminata, Anoplolepis gracilipes, and Paratrechina longicornis, whereas in the inorganic rice fields were Tapinoma sp, Solenopsis geminata, and Camponotus sp. The index of similarity between organic and inorganic rice fields showed a high and very high degree of similarity based on the type of feed. Physical factors of high soil and air humidity environment, high soil and air temperature increased the diversity and abundance of ants in the rice fields ecosystem. Factors soil pH in accordance with the growth of soil Arthropods were neutral or slightly acidic. Chemical factors of organic matter content, Nitrogen (N), the content of C organic, and a high P total content increased the diversity and abundance of ants. Keywords: diversity and abundance, ants, organic and inorganic rice fields

Impact of water management on root morphology, growth and yield component of lowland rice varieties under the organic system of rice intensification

Water management is one of the keys to success in increasing rice production in paddy fields. Paddy rice production will decrease if the rice plants suffer from water stress, and conversely conventional cultivation is very wasteful of water. Local aromatic varieties have deeper rooting character than improved varieties making it more efficient in using water. The purpose of this study was to obtain more efficient and more productive aromatic local varieties in the use of irrigation water in the SRI organic cultivation system. This research was conducted in organic rice fields in Kebonagung village, Imogiri, Bantul with split plot design of 2 factors with 4 replications. Factor I: The mode of irrigation consists of (a) intermittent irrigation, and (b) continuous irrigation and Factor II: varieties consisting of (a) Mentikwangi, (b) Gabusan, (c) Sintanur and (d) IR64. The observation parameters included (1) root characters i.e. surface area of root, total length of root, and dry weight of root, (2) plant growth analysis i.e. specific leaf weight, net assimilation rate, plant growth rate, (3) and yield components i.e. weight 1000 grains, grain weight per hill, and grain weight per plot. The results showed that intermittent irrigation increased the surface area of root and the dry weight of root of Mentikwangi variety, and increased the specific leaf weight and weight of 1000 grains of IR64 variety, and increased the specific leaf weight and the net assimilation rate of Sintanur variety. Grain weight per hill and per plot showed no difference between intermittent irrigation and continuous irrigation. Grain weight per hill and per plot in intermittent irrigation achieved by Gabusan variety were 35.69 g and 14.28 kg respectively, while in continuous irrigation the grain weight achieved by Gabusan variety were 37.69 g and 15.08 kg respectively. In conclusion, there was no difference in yield between intermittent irrigation and continuous irrigation, so that the use of intermittent irrigation is more efficient in water use.

Complete Genome Sequence of Bacillus altitudinis P-10, a Potential Bioprotectant against Xanthomonas oryzae pv. oryzae, Isolated from Rice Rhizosphere in Java, Indonesia.

ABSTRACTBacillus altitudinis P-10 was isolated from the rhizosphere of rice grown in an organic rice field and provides strong antagonism against the bacterial blight caused by Xanthomonas oryzae pv. oryzae in rice. Herein, we provide the complete genome sequence and a possible explanation of the antibiotic function of the P-10 strain.

Methane production potential of soil profile in organic paddy field

The use of organic fertilizers in the organic paddy/rice field can increase methane (CH<sub>4</sub>) production, which leads to environmental problems. In this study, we aimed to determine the CH<sub>4</sub> production potential (CH<sub>4</sub>-PP) by a soil profile from samples using flood incubation. Soil properties (chemical, physical, and biological) were analyzed from soil samples of three different paddy farming systems (organic, semi-organic, and conventional), whilst soil from teak forest was used as the control. A significant relationship was determined between soil properties and CH<sub>4</sub>-PP. The average amount of CH<sub>4</sub>-PP in the organic rice field profile was the highest among all the samples (1.36 µg CH<sub>4</sub>/kg soil/day). However, the CH<sub>4</sub> oxidation potential (CH<sub>4</sub>-OP) is high as well, as this was a chance of mitigation options should focus on increasing the methanotrophic activity which might reduce CH<sub>4</sub> emissions to the atmosphere. The factor most influencing CH<sub>4</sub>-PP is soil C-organic (C<sub>org</sub>). C<sub>org</sub> and CH<sub>4</sub>-PP of the top soil of organic rice fields were 2.09% and 1.81 µg CH<sub>4</sub>/kg soil/day, respectively. As a consequence, here the mitigation options require more efforts than in the other farming systems. Soil with various amounts of C<sub>org</sub> reached a maximum point of CH<sub>4</sub>-PP at various time after incubation (20, 15, and 10 days for the highest, medium, and the lowest amounts of C<sub>org</sub>, respectively). A high amount of C<sub>org</sub> provided enough C substrate for producing a higher amount of CH<sub>4</sub> and reaching its longer peak production than the low amount of C<sub>org</sub>. These findings also provide guidance that mitigation option reduces CH<sub>4 </sub>emissions from organic rice fields and leads to drainage every10–20 days before reaching the maximum CH<sub>4</sub>-PP.

Correlation of Ecological Characteristics of Rice Stem Borer (Lepidoptera) with Biotic and Abiotic Environment Factors in the Organic and Non-Organic Rice Fields

Correlation of Ecological Characteristics of Rice Stem Borer (Lepidoptera) with Biotic and Abiotic Environment Factors in the Organic and Non-Organic Rice Fields

Insect diversity in organic rice fields under two management systems of levees vegetation

Simplified environments characterize agroecosystems, reducing the diversity of associated plants, which are not cultivated for economic purposes, causing unbalances that can promote the emergence of cultivated plants pests, as well as the reduction of their natural enemies. Management systems that increase diversity in agroecosystems can extend the action of natural enemies of pests. Studies to understand the diversity of insects associated with rice cultivation and determine their ecological guilds can provide information about the composition and structure of such ecosystems, which can be applied to integrated pest management. Therefore, the study aimed to describe and compare groups of insects in irrigated rice fields, with organic management using two different systems of levees vegetation management, and relate them to the phenological states of rice cultivation (seedling, vegetative, and reproductive). Samples were taken in a plantation located in Águas Claras district of Viamão, RS. The total area of 18 ha was divided into two. A subarea called not cut (NC), where wild vegetation of levees was maintained, and the subarea named cut (C), where monthly cuts were made to levees vegetation, from the beginning of soil preparation until the harvest. From October 2012 to March 2013 were held weekly collections in quadrats randomly located in both the rice fields and the levees. A total of 800 insects were collected, 429 in the C subarea and 371 in the NC. There were identified 97 morphospecies in the C and 108 in NC, being 54 shared between the subareas. The captured insects were grouped into guilds: saprophages (C = 38.2%; NC = 27.5%), phytophagous (C = 28.5%; NC = 33.2%), entomophagous (grouping parasitoids and predators) (C = 29.4%; NC = 35%) and finally other insects (C = 4 %; NC = 4.3%). The peak abundance of phytophagous and entomophagous was registered in the vegetative stage of rice. At the same stage the UPGMA analysis showed that similarity in species composition was greater than 90% in the groups obtained in the paddy fields of C and NC subareas. The vegetation of levees can positively influence the presence of entomophagous in the field. Although the abundance did not change clearly, the greatest diversity in the NC areas of all the groups, may contribute to the maintenance of ecological services expanding the system resilience.

Hymenoptera parasitoids in protected area of Atlantic Forest biomes and organic rice field: compared assemblages

One way to improve the sustainability of agricultural systems is to generate similar characteristics to those in natural ecosystems by maintaining energy flows and habitat diversity, thereby ensuring the presence of natural enemies and other beneficial organisms that can regulate pest populations and maintain crop productivity with fewer environmental impacts. The objectives of this study were to identify and compare the diversity of parasitoid assemblages in irrigated rice crops under organic management in a nearby protected area; to compare the efficiency of two kinds of parasitoid traps; and to compare temporal variation in parasitoid species at the two sites. The study was developed in the Banhado dos Pachecos Wildlife Refuge (BPWR) and in Viamão, RS organic rice fields (OR). Specimens were collected monthly from May 2011 to April 2012. Two Malaise and four Moericke traps were used in each area. In the BPWR area, Platygastridae, Ichneumonidae and Braconidae showed the highest abundance (30 %, 21 % and 11 %, respectively), and in the OR area, the dominant taxa were Platygastridae (26 %), Braconidae (18 %) and Encyrtidae (15 %). Malaise traps captured the largest number of parasitoids (58 %). The richness estimators Chao 1, Jack 1 and Bootstrap, pointed to a richness of 229 to 122 species in the OR area and of 454 to 260 in the BPWR area. Parasitoid diversity was higher in the BPWR than in the OR. Parasitoid abundance was highest in the rice crop during months in which crops were growing at the site.

Organic rice: potential production strategies, challenges and prospects

Organic farming is rapidly gaining recognition worldwide as a promising means to offer healthier food and to ensure environmental sustainability. Currently, organic produce including organic rice is in huge demand owing to its potential to fetch premium price in the global market. Despite the fact that rice performs well under organic production system, a set of constraints including nitrogen stress at critical growth stages, unavailability of rapidly mineralizable organic amendments, lack of appropriate varieties and intense crop–weed competition pose major challenges to realize the potential yield. Use of diverse organic nutrient sources including the split application of fast mineralizable nutrient-rich manures (vermicompost, poultry manure), green manures and bio-fertilizers can supply optimum nutrients in organic rice system. In parallel, development and deployment of rice varieties having response to organic nutrient inputs, resistance to diseases/insects and ability to compete with weeds can help minimize the risk of crop failure. Further, higher emission of greenhouse gases (GHGs) in organic rice field deserves greater attention in view of environmental sustainability. Strategic water management and selection of appropriate organic amendments could help address this issue. However, a substantial research gap still exists demanding a deeper understanding of the organic rice system in order to register higher yield gains. This review article outlines the latest advances in organic rice production system with an emphasis on nutrient supply and ensuing dynamics, the outflow of GHGs, pest dynamics, produce quality and key attributes of rice cultivars for organic cultivation. We underscore the urgency for alignment of modern agricultural techniques with organic rice production to improve both the system productivity and the produce quality along with effectively avoiding the risks associated with in discriminate use of chemicals in agriculture.

A pmoA-based study reveals dominance of yet uncultured Type I methanotrophs in rhizospheres of an organically fertilized rice field in India

Rice fields are one of the important sources of anthropogenic methane. Methanotrophs can oxidize up to 30 % of the produced methane and thus have a pivotal environmental role in methane mitigation. India occupies the largest region under rice cultivation; however, most of the studies done on methanotrophic communities have focused on the Northern region. We studied methanotrophic community of a flooded, organically fertilized rice field using pmoA clone library approach. Organic rice fields impose a more serious threat as they produce more methane. pmoA gene is the main functional gene which is primarily used for taxonomical analysis of methanotrophs. Our results showed that the pmoA clone libraries from two growth stages of rice were dominated by pmoA sequences which were very distant from cultivated Type Ia methanotrophic genera (80–82 % nucleotide similarity) indicative of the presence of a putatively novel genus. We designated this group of clones as ‘rice field clones’ as this also includes many pmoA sequences originating from other rice fields. Thus, our current knowledge of methanotroph diversity from Indian rice fields has been expanded revealing that a substantial portion of methanotrophic diversity is unexplored.Electronic supplementary materialThe online version of this article (doi:10.1007/s13205-016-0453-3) contains supplementary material, which is available to authorized users.

Influence of the vegetation management of the leeves in irrigated rice organic in diversity of Hymenoptera parasitoids.

Among the natural enemies of insect pests in rice fields, parasitoids are especially notable. To better understand the space-time dynamics of these insects, the objectives of this study were to describe and compare groups of parasitoids in organic irrigated rice fields using two management approaches for levee vegetation, and to relate them to the phenological stages of rice cultivation (the seedling, vegetative, and reproductive stages). The samples were taken in a plantation located in Viamão, RS, Brazil. The total area of 18 ha was divided into two parts: a no-cut (NC) subarea in which the wild vegetation of the levees was maintained, and a cut (C) subarea in which the levee vegetation was cut monthly. In each subarea, four Malaise traps considered as pseudo-replicas were installed and remained in the field for 24 hours at each sampling location. Collections occurred twice a month from the beginning of cultivation (October 2012) until harvest (March 2013). A total of 3,184 Hymenoptera parasitoids were collected: 2,038 individuals in the NC subarea and 1,146 in the C subarea. We identified 458 morphospecies distributed in 24 families. Mymaridae was the most abundant and Eulophidae was the richest in both subareas. A total of 198 morphospecies was shared between the subareas, including Platygastridae, Eulophidae, and Mymaridae, which were the families with the highest number of shared species. The richness and abundance of parasitoids varied according to their phenological developmental stages, with peak abundance registering during the vegetative period. The Morisita index identified three groupings, indicating a similarity that was related to the three phases of rice growth and development: seedling, vegetative and post-harvest.

ALIRAN BAHAN ORGANIK PADA SAWAH PADI ORGANIK DI DUSUN JAYAN DESA KEBONAGUNG KEC. IMOGIRI KAB. BANTUL D.I. YOGYAKARTA

<p><em>Organic farming uses natural resources to improve the health and productivity of soil and plants. Nutrients are lost or transported through crops, erosion, leaching and volatilization must be replaced naturally and through the return of organic matter. This research aims to study the conditions of organic rice fields, specifically in terms of organic matter flow, in Jayan Kebonagung Imogiri Bantul. The organic rice field data obtained from interviews and archive farmers. The results indicate that the organic rice field in Jayan under a transition from conventional to organic rice field. Dose of organic fertilizer 10 tons/ha were given during the transition period. Organic fertilizer 5-10 tons/ha have been giving during the organic rice fields. Returns organic matter to agricultural land through land-crop-land, land-plant-livestock-land and land-crop-livestock-biogas-land. Manure, weeds and paddy field plants, crop waste, waste from agricultural products processing and non-agricultural organic wastes involved in the flow of organic matter. Farmers monitor the health and productivity of soil and plants as the basis in the management of organic rice field.</em></p>

Diversity of Aquatic Insects in the Organic and Conventional Rice Fields in Khon Kaen Thailand

Diversity of Aquatic Insects in the Organic and Conventional Rice Fields in Khon Kaen Thailand

How does the management of rice in natural ponds alter aquatic insect community functional structure?

Changes to biodiversity have mainly been assessed using taxonomic diversity indices. Although these approaches contribute to our scientific understanding of species richness and composition patterns, trait-based metrics may be more useful for detecting responses to land-use change. We compared functional diversity of aquatic insect communities along a gradient of agricultural intensification. Our goal was to compare functional redundancy, functional richness, functional evenness and functional divergence among natural ponds, and organic and conventional rice fields. We recorded 15606 aquatic insects distributed across 61 genera. The highest functional redundancy and richness were observed in the natural ponds, followed by organic rice fields and conventional ones. The functional composition varied among natural ponds and rice fields, and differed between organic and conventional rice fields. Organic management favoured the establishment of some pond insect traits, such as predatory taxa, in rice agroecosystems. Our analysis suggests that the conversion of ponds to rice fields results in a shift to less specialised aquatic insect communities with altered functional composition groups. Nevertheless, this result should not be seen as a negative reflection on organic rice fields, because organic rice production affords a better compromise between agricultural production and ecosystem function than conventional agriculture.

Agroedutourism and Ecopreneurship Activities on the Organic Farming Practice in Lawang, Malang Regency, East Java, Indonesia

Five farmer groups in Lawang, Malang Regency, East Java Provinces, established organic agricultural practices almost two decades. They were visited frequently for farmer benchmarking activities; therefore they had planned to develop agroedutourism. The aims of this research were to identify potential organic farming activities as agroedutourism attractions as well as farmer ecopreneurship, to find out the existing agroedutourism facilities profile and to propose some strategies for further sustainable development. The data were gathered by interviewing key person of each farmer group in Lawang. Their agroedutourism profiles compared with a developed local agro-tourism using gap analysis. Farmer groups offered some distinct attractions and become their strengths such as out door activities in the organic perfumed and pigmented rice field, fruits and vegetable garden, zero waste management, biological pest control and healthy agricultural products. Establishment of this agroedutourism would be advantageous to lesson sharing among farmers and students, to be ecopreneur activity shown by an effective market system, to show real benefits of healthy agro-ecosystem and its products, as well as to show promising green business or ecopreneurship. Collaboration among them would improve available attractions and length of visit. Moreover, the results showed that 80% of farmer groups were visited regularly 5-10 times per month by potential visitors such as other farmer groups, house wives, staffs of agricultural departments and students. All farmer groups planned to develop agroedutourism; however the policy was only issued by 60% of farmer groups. Most of farmer groups showed a high variability in providing edutourism tours and guides. For sustainable development, farmer groups should provide more interesting attractions and facilities, develop their human resource, net working, and public promotion. Keywords: agroedutourism, attraction, ecopreneurship, farmer groups

Morphological Variation of Six Pigmented Rice Local Varieties Grown in Organic Rice Field at Sengguruh Village, Kepanjen Subdistrict, Malang District

Indonesia is the third richest country for pigmented rice source. Morphological character of pigmented rice in Indonesia is less reported since recent publications and descriptions of pigmented rice are only limited to black rice of Cempo Ireng variety and red rice of Aek Sibundong variety. Pigmented rice varieties in Indonesia are cultivated in an organic way. These varieties are Wojalaka black rice of East Nusa Tenggara (NTT), Manggarai of NTT, Toraja of South Sulawesi, Cempo Ireng of Central Java and red rice of Aek Sibundong (leading variety) and Baubau of Southeast Sulawesi. The objective of research was to compare the morphological variation of root, stem, leaf, panicle, floret and the colour of milk mature grain and mature grain by observing the vegetative and generative parts of six local rice varieties. Research had been conducted from February 2012 to February 2014 in Sengguruh Village, Kepanjen District, Malang Regency. This study type was quasi-experiment with eleven replications. Group Random Design was used. The observation was given upon vegetative, reproductive and maturity phases as groups. Independent variables in this research were six rice varieties, while the dependent variable was morphological variation (root, stem, leaf, panicle, floret, milk mature grain and mature grain). The data of morphological variation were tabulated through MS Excel 2007 for windows. Descriptive data analysis was used to determine the average rate and the deviation standard of each variable. Data were analyzed by ANOVA at a cut off value of α of 0.05. It was followed by HSD Tukey Test facilitated by SPSS 16.0. The analysis of multivariate data in cluster and biplot was carried out with PAST. The result of the study indicated that there was morphological difference on stem, leaf, panicle, floret, milk mature grain and mature grain. The colour of the stem in Aek Sibundong variety was purple, while that of other varieties was green. Toraja and Manggarai varieties had the highest height with 163-168 cm, followed by Cempo Ireng with 139 cm, Wojalaka and Baubau with 110-112 cm. Aek Sibundong Variety had the lowest height with 99 cm. Aek Sibundong and Wojalaka varieties had 6-7 internodes which were the greatest number of internode, while other varieties only had 4-5 internodes. Some varieties, such as Aek Sibundong, Wojalaka and Baubau had short and small leaf. The leaflet angle of Aek Sibundong and Baubau were 140 and it might be said as upright, while that of Wojalaka was 430 or moderate. Cempo Ireng, Manggarai and Toraja had its 63-880 of the leaflet angle or it was said as flat. Cempo Ireng and Wojalaka were included into Rice Indica Group while Toraja, Manggarai, Cempo Ireng and Baubau belonged to Rice Javanica Group. There were two morphological groups. Group 1 included Toraja, Manggarai and Cempo Ireng, while Group 2 consisted of Aek Sibundong, Baubau and Wojalaka.

Can organic rice crops help conserve aquatic plants in southern Brazil wetlands?

AbstractQuestionsAre organic rice crops better than convention crops for aquatic plant conservation? We tested three hypotheses: (1) richness, diversity and biomass of aquatic macrophytes are higher in organic rice fields than in conventional ones; (2) aquatic macrophyte species composition in organic rice fields is more similar to that of natural wetlands than to conventional rice fields; and (3) aquatic macrophyte richness, diversity, biomass and species composition in natural wetlands will differ from those of organic and conventional rice fields.LocationCoastal plain of southern Brazil.MethodsWe sampled macrophytes at four conventional crops, four organic crops and four natural intermittent wetlands. We sampled at six different times at each site throughout the rice cultivation cycle.ResultsA total of 55 species was recorded in natural wetlands and 36 species in rice fields, with 23 found in conventional crops and 27 found in organic crops. The richness, biomass and species composition of macrophytes was similar in the two rice production systems and lower than that of natural wetlands over the cultivation cycle studied. Species composition of natural wetlands differed from that of rice crops mainly through the presence of hydrophytes and rushes.ConclusionsSome macrophyte species used rice crops as a complementary habitat, but diversity was lower and composition was different from that of natural wetlands. Both conventional and organic systems negatively impacted macrophyte biodiversity. However, the similar richness and biomass of plants in organic and conventional crops indicated that natural techniques with less impact could be efficient in reducing undesirable plant diversity in agricultural systems.

Greenhouse gases from early flooded and organic paddy rice field around the lake Miyajimanuma

Greenhouse gases from early flooded and organic paddy rice field around the lake Miyajimanuma