Potential remediators in the rice production area of Zambales, Philippines contaminated with mine tailing

High concentration of cadmium and lead are hazardous to environment. The study isolated and identified potential fungal, bacterial and hyperaccumulating plants as bioremediators in contaminated rice ecosystem. Fungi were identified morphologically and with the use of internal transcribed spacer (ITS) region sequencing. Bacteria were identified using 16S ribosomal RNA sequences. Plants were analyzed for Cadmium and Lead accumulation in root and shoot tissues using atomic absorption spectrophotometer (AAS). Fungal species including Penicillium janthinellum, Trichoderma hamatum, Trichoderma harzianum, and Curvularia lunata along with bacterial species such as Bacillus cereus, Bacillus thuringiensis, Pseudomonas gessardii, Lysinibacillus xylanilyticus, Lysinibacillus sphaericus, and two species of unidentified bacteria were identified. Plants predominant in the area includes Cyperus difformis, Scirpus juncoides, Fimbristylis miliacea, Centella asiatica, Sphagneticola trilobata, and Monochoria vaginalis. Cadmium was detected in the shoots of S. trilobata (3.2 mg kg−1) and roots of C. asiatica (3.6 mg kg−1). Lead was found in the shoots of C. asiatica (2.8 mg kg−1) and roots of both S. juncoides (15.00 mg kg−1) and F. miliacea (15.00 mg kg−1). Phytoremediation potential of S. juncoides, F. miliacea, C. asiatica and S. trilobata was observed. Heavy metal resistant microbes can be harnessed as a very useful biological tool for in-situ bioremediation.

Impact of sowing methods and weed control practices on yield and economics of wet direct seeded rice

Wet direct seeding is proved as a viable alternate to conventional transplanting method of rice. Maintenance of optimum population by adopting an appropriate sowing method followed by judicious weed control practices ensures profitability of wet direct seeded rice (W-DSR). A field experiment was carried out to find out a suitable sowing technique and weed control options for enhancing productivity and economics of W-DSR. The W-DSR was infested with twelve numbers of weed species comprising of eight families under different sowing methods. The composition of sedges, broadleaved (BLW) and grassy weeds was 83.07, 11.0 and 5.93%, respectively. Irrespective of sowing methods, weeds such as, Echinochloa glabrescens and Leptochloa chinensis among grasses, Cyperus difformis and Scirpus juncoides among sedges and Lindernia anagallis among BLW were dominant. Drum seeding recorded 6.9 and 12.7% higher gross and net return, respectively than broadcasting, but it was at par with spot seeding. Highest B: C ratio of 2.07 was recorded with drum seeding, whereas spot seeding recorded lowest B: C ratio (1.99). Crop-weed competition caused 31.7% reduction in grain yield with W-DSR. Application of early post-emergent herbicide bensulfuron-methyl + pretilachlor @ 60+600 g/ha at 10 DAS, azimsulfuron @ 35 g/ha at 20 DAS, and bispyribac sodium @ 30 g/ha at 20 DAS recorded increase in grain yield 40.3, 40.1 and 39.8%, respectively over the weedy check. Ready mix bensulfuron-methyl + pretilachlor @ 60+600 g/ha at 10 DAS registered highest B: C ratio (2.16) but it did not vary significantly with bispyribac sodium @ 30 g/ha and azimsulfuron @ 35 g/ha.

Resistance in Smallflower Umbrella Sedge (Cyperus difformis L.) to Acetolactate Synthase-Inhibiting Herbicides in Rice - First Case in India

Smallflower umbrella sedge is one of the problematic weeds in direct-seeded rice in India. Bispyribac-sodium (acetolactate synthase-inhibiting herbicide) is a commonly used in rice, but recently growers have reported lack of smallflower umbrella sedge control with this herbicide. An extensive survey was carried out in two rice growing states, Chhattisgarh and Kerala, where 53 putative bispyribac-sodium resistant (BR) biotypes were collected. Studies were conducted to confirm resistance to bispyribac-sodium and to test the efficacy of newly developed synthetic auxin herbicide florpyrauxifen-benzyl on putative BR biotypes. Whole-plant bioassay revealed that bispyribac-sodium is no longer effective. Of 53 putative BR biotypes, 17 biotypes survived recommended label rate of 25 g ai ha−1. Effective bispyribac-sodium rate required to control 50% of the plants in most of the BR biotypes (ED50) ranged from 19 to 96 g ha−1 whereas it was 10 g ha−1 in susceptible biotype. In two highly resistant biotypes, ED50 was beyond the maximum tested rate, 200 g ha−1. This suggests 2 to >20-fold resistance in BR biotypes. Acetolactate synthase (ALS) enzyme activity assay suggests altered target site as mechanism of resistance to bispyribac-sodium. This study confirms the first case of evolved resistance in smallflower umbrella sedge for bispyribac-sodium in India. However, the newly developed synthetic auxin, florpyrauxifen-benzyl effectively controlled all BR biotypes at the field use rate 31.25 g ae ha−1.

Analisis Vegetasi Gulma Pada Lahan Pertanaman Kacang Kedelai (Glycine max L.Merill)

Pengendalian gulma yang tepat merupakan faktor penentu keberhasilan budidaya tanaman pertanian. Efektifitas teknik pengendalian gulma sangat tergantung pada jenis gulmanya. Penelitian terhadap analisis vegetasi gulma pada lahan pertanman kacang kedelai telah dilakukan selama 3 bulan terhitung Agustus hingga november 2020. Metode kuadran digunakan dalam penelitian ini yaitu identifikasi gulma, menghitung nilai penting, Summed Domminance Ratio (SDR), Indeks keanekaragaman (H’). Hasil penelitian menunjukan terdapat 10 jenis gulma Cynodon dactylon L., Eleusine indica L., Ischaemum rugosum, Cyperus rotundus,dan Cyperus difformis L., Amaranthus spinosus L., Commelina diffusa Burm F., Marselina minuta., Portulaca oleracea L.,dan Alternanthera sp. Nilai indeks keanekaragaman (H’) masuk kedalam kategori rendah yaitu <1 ( 0,15) jenis gulma Cynodon dactylon L.

Potential Forage of Animal Feed on Rice Fields Lora Village District Mata Oleo Bombana District

Research has been conducted for 2 months, namely March to April 2020 aims to find out the type of forage animal feed on the rice fields lora village District Mata Oleo Bombana District Southeast Sulawesi Province. Determination of research locations by purposive sampling with observation variables in the form of forage type of animal feed, botanical composition, weight of fresh materials and capacity of capacity. The results showed the type of fodder forage consists of 10 types namely Cyperus esculentus, Bixa orellana, Cyperus iria L., Fimbristylis moliaceae (L.) Vahl, Digitaria sp., Echinocloa colona, Digitaria setigera, Monochoria vaginalis, Cyperus difformis L. and Desmodium triflorum. Botanical composition with an important value comparison dominated feed forage type Cyperus esculentus (18.72) and the lowest dominance Bixa orellana (1.72). Fresh weight production is 590.40 kg/ha with a capacity of 0.3 UT/ha/month.

An Overview of Rice Cultivation in Spain and the Management of Herbicide-Resistant Weeds

Spain is the second highest rice-producing country in the European Union, with approximately 105,000 ha used to grow this crop. The major rice-producing regions in Spain are Andalusia, Extremadura, Catalonia, and Valencia, followed by Aragon and Navarre. The main soil texture throughout Spanish rice areas is silty clay loam, with alkaline soils (pH > 7.5)—except in the Extremadura area (pH = 5.5–6)—and a low organic matter content. Water quality in terms of salinity is acceptable, although in some coastal rice areas salinity issues occasionally appear to be a determining factor for high yield achievement. According to a survey carried out on farmers and technicians, the most problematic weeds found in rice crops today in Spain are Echinochloa spp., Leptochloa spp., and Cyperus difformis. Most of the currently authorized herbicides can be classified according to two modes of action: ALS-inhibiting and ACCase-inhibiting. Repeated field applications of herbicides with the same mode of action have resulted in the selection of herbicide-resistant weeds. At present, resistance has been confirmed in different regions of Spain to ALS inhibitors in Echinochloa spp., Leptochloa spp., and Cyperus difformis, and to ACCase inhibitors in Echinochloa spp. and Leptochloa spp. The mechanism of resistance in these species is a mutation in the target site of these herbicides. Several mutations have been found in the ALS gene, both in Echinochloa spp. and Cyperus difformis, distributed in the different rice-growing regions considered in this work. ACCase gene mutations have been mainly found in Leptochloa spp. individuals from Extremadura and Valencia. These different mutations have resulted in different patterns of cross-resistance to ALS- and ACCase-inhibiting herbicides. It is likely that the repeated use of these two modes of action in rice will result in the evolution of more resistant weed populations. The possible availability of new herbicides with alternative modes of action in a short space of time seems very limited, suggesting the need for a more appropriate use of the available alternative strategies (crop rotation, dry sowing, manual weeding, etc.). This work presents a review of the main characteristics of rice cultivation in Spain, emphasizing the current problems in this crop and the management of herbicide-resistant weeds.

Hasil Padi dan Kelimpahan Gulma dengan Aplikasi Jenis Pupuk Berbeda di Lahan Kering Tadah Hujan pada Musim Kemarau

Rice yield and proper weed control need to be increased through an environmentally friendly agricultural system approach in rainfed land during the dry season by reducing the dosage of synthetic fertilizers. This study aims to determine the effect of different fertilizer applications on rice yield and weed abundance in rainfed land during the dry season. The study used a split-plot design, with the main plot of rice variety, i.e., Situ Bagendit and IR-64, and subplots of fertilizer, namely synthetic fertilizers (N, P, K), organic fertilizers + P60 + ½ dose of synthetic fertilizers, organic fertilizers + PGPR + ½ dose of synthetic fertilizer and organic fertilizer + P60 + PGPR + ½ dose of synthetic fertilizer with three replications. The variables observed were rice yield components, namely panicle length, total empty grain and content per panicle, grain weights per hill, effective plot and hectare, 1000 grain weight, harvest index, and weeds summed dominance ratio (SDR). The synthetic fertilizers and three various organic fertilizers, biological fertilizers, and synthetic fertilizers gave different results on the SDR of weeds. The weeds of Sphenoclea zeynalica and Cyperus difformis showed consistent dominance with higher SDR than other weeds, i.e.,> 15 and > 10, respectively. The application of organic and biological fertilizers with half the recommended dosage of the synthetic fertilizers is equivalent to applying the recommended dosage of synthetic fertilizers on rice yield during the dry season on the rainfed dryland with low rainfall intensity and a low yield of 1.3–1.7 t/ha. Keywords: biological fertilizer, inorganic fertilizer, organic fertilizers, rice, weeds

Floristic Composition and Diversity of Weeds in Organic Rice Fields in Langkong, M’lang, Cotabato

This study investigated the floristic composition and diversity of weeds in organic rice fields in Langkong, Mlang, Cotabato covering an area of 2.5 hectares within which 100 quadrats were randomly assigned. Identification of weeds showed thirteen species belonging to six families eight of which are annuals and five perennials comprising five broadleaf, three grass, and five sedge types. All weed species had <50% uniformity which may imply less competitiveness against rice or effective control by weed management practices. Fimbristylis littoralis and Cyperus difformis have the highest frequencies and the highest field uniformities and highest mean field densities indicating that these weeds are the most difficult to control. The weed density of fields in which the species occurred increased compared to densities from all fields for all weed species that may mean that site-specific or management-specific factors contribute to the survival of those species. Relative abundance values showed that Fimbristylis littoralis and Cyperus difformis are the two most dominant weed species. Weed species diversity is medium and equivalent to 5 equally abundant species.

Cyperus difformis (small-flowered nutsedge).

C. difformis is a sedge which is listed in Holm's list of the world's worst weeds, being a problem especially in rice, sugarcane, tea and maize. It is a dominant weed in direct-seeded rice when it occurs in high plant densities; forms dense mats of vegetation in the young crop and can cause rice yield losses of 12-50%. It is native to the tropics of the Old World, but is spreading well outside its native range. It has a relatively short generation period of as little as 4 to 6 weeks from seed to seed. It can spread along waterways and grow in disturbed sites, lake margins and on river banks.

Phenology and thermal requirements of the species Cyperus difformis L. in southern Brazil

Cyperus difformis L. is a Cyperaceae, annual, of natural occurrence in marshy environments in southern Brazil, considered a weed in irrigated rice crops. Studies on its development are scarce, especially regarding its cycle and thermal requirements. Therefore, the objective of this work was to determine the base temperature, the thermal sum and the duration of the different sub-periods of the biological cycle of the species. The experiment was carried out at the Campus of the Universidade Federal de Santa Maria – UFSM, Santa Maria, Rio Grande do Sul, in four sowing seasons. In a completely delineated design and factorial scheme involving five soil water conditions (water depth and 50% soil water retention capacity [WRC]) from the sowing, water depth and 50% WRC introduced 21 days after emergence and 100% WRC during the whole cycle, with six repetitions each. Each experimental unit consisted of a cultivated in pot plant with 11 L capacity filled with soil. The cycle of the plants was subdivided into the sowing-emergence sub-periods, emergence-emission of the floral tassel and emission of the floral-maturing physiological tassel, being estimated the thermal requirements for the species. The conditions of the soil water condition the base temperature, the sum of the degree-days and the duration of the species cycle. The base temperature varies for each treatment, the sum of degrees-day decreases with the water deficit and the plants under flood accelerate the biological cycle.