Dry Field Conditions Research Articles

Screening of carrot wild relatives in warm, dry and saline field conditions with respect to root and seed production

Screening of carrot wild relatives in warm, dry and saline field conditions with respect to root and seed production

Genetic Diversity Analysis of Soybean Collection Using Simple Sequence Repeat Markers.

Soybean [Glycine max (L.) Merr.] is a nutrient-rich crop that offers a sustainable source of dietary protein and edible oil. Determining the level of genetic diversity and relationships between various genetic resources involved in breeding programs is very important in crop improvement strategies. This study evaluated 100 soybean accessions with diverse origins for 10 important agronomic traits, including plant height (PH), an important plant adaptation-related trait impacting yield, in conditions in southeastern Kazakhstan for 2 years. The comparison of different groups of PH (tall, middle, and short) using a t-test suggested that the group of plants with the tallest PH provided a higher yield (p < 0.001) in relatively dry field conditions. The genetic diversity of the accessions was estimated using 25 simple sequence repeat (SSR) markers previously known to be associated with plant height. The results showed a significant variation among different groups of origin for all measured agronomic traits, as well as high genetic diversity, with the PIC (polymorphism information content) varying from 0.140 to 0.732, with an average of 0.524. Nei's diversity index ranged between 0.152 and 0.747, with an average of 0.526. The principal coordinate analysis (PCoA) of the studied soybean collection showed that Kazakhstan accessions were genetically distant from European, East Asian, and North American cultivars. Twelve out of twenty-five SSR markers demonstrated significant associations with ten studied agronomic traits, including PH (p < 0.05). Six SSRs with pleiotropic effects for studied traits were selected, and their haplotypes with phenotypic effects were generated for each soybean accession. The obtained results can be used in soybean improvement programs, including molecular-assisted breeding projects.

Top-dressing treatment of spring barley to modify its quality

New barley products can be developed by modifying the content of bioactive components in the grain through breeding, as well as improving its quality at lower fertilizer costs. We aimed to study the effects of the genotype, growth conditions, and top-dressing application of nitrogen and organo-mineral fertilizers on the chemical composition of barley grain.&#x0D; The barley varieties Novichok, Rodnik Prikamya, and Pamyaty Rodinoy were grown under normal (2020) and dry (2021) field conditions. The plants were top-dressed with mineral (CAS; SpetsKhimAgro, Kirovo-Chepetsk, Russia) or organo-mineral (Amino Start and Alfastim; Polydon® Agro, Moscow, Russia) fertilizers in the tillering or heading phases. The contents of protein, starch, fat, and crude fiber in the grain were analyzed with an INFRAMATIC 8620 instrument (Perten Instruments, Stockholm, Sweden).&#x0D; The CAS fertilizer reduced protein, fat, and fiber by 4.5–8.3% (Novichok) during the drought and increased starch by 2.1% (Novichok), fiber by 14.2% (Rodnik Prikamya), and fat by 18.9% (Pamyaty Rodinoy) under normal humidity. Amino Start applied under normal conditions increased starch by 2.9% and reduced protein and fat by 7.8–8.9% in Rodnik Prikamya, as well as increased protein and fat by 14.4 and 6.3%, respectively, but reduced starch by 5.1% in Pamyaty Rodinoy. Alfastim applied under normal conditions reduced the content of protein by 10.7% (Rodnik Prikamya), but increased it by 3.6–7.2% in the other cultivars. It also increased fiber by 22.8% in Rodnik Prikamya, but decreased it by 18.6% in Pamyaty Rodinoy. Finally, this fertilizer decreased fat by 12.7% in Rodnik Prikamya, but increased it by 9.8% in Pamyaty Rodinoy. In the drought, the fertilizers Alfastim and Amino Start increased the protein content by 5.2–12.2% in Rodnik Prikamya and Pamyaty Rodinoy.&#x0D; Top-dressing barley plants with mineral or organo-mineral fertilizers can modify the grain composition (up to 10.4% of fiber, 3.6% of starch, and 7.5% of protein and fat), depending on the consumer’s requirements.

Cyclic swell shrink behaviour of lime and lignosulphonate amended expansive soil—An experimental quantification and comparison

The behaviour of expansive soils is majorly influenced by the mineralogy and the environmental conditions contributed by the seasonal moisture changes. Many structures found on the expansive soil depict severe distress due to the volume change behaviour of the soil. The volume changes correspond to moisture fluctuations which occur with the wetting–drying cycles associated with climatic variations. The wetting–drying​ cycles also impact the chemical treatment methods adopted to curtail swelling and shrinkage. The present study evaluates and compares the magnitude of swelling and shrinkage depicted by Lime and Lignosulphonate amended soils under wetting and drying cycles imposed under laboratory conditions. A specially modified oedometer apparatus was adopted to simulate the field drying conditions. The untreated soil exhibits higher swelling strain than the shrinkage strains with cycles of wetting and drying. There is a decrease of nearly 9% in swelling and 5% in shrinkage from the first cycle to steady state cycle. The swelling strain followed a decline to the steady state, however lime and LS amended soil depicted an initial decrease and then an increase in swelling strains before steady state. The treated and untreated soils also attain equilibrium characterized by different bandwidths and also exhibit difference in swelling and shrinkage rates, with untreated soil exhibiting a longer time to complete the swell-shrink cycles. The study further quantifies these variations for treated and untreated soil and the respective rates of primary and secondary swelling and shrinkage. The results are also justified with a physicochemical analysis of the leachate collected during the wetting–drying cycles.

Vitality of primed rice seeds sown under prolonged dry soil conditions in an upland field

AbstractDuring rainfed upland rice (Oryza sativa) cultivation, unpredictable drought events can hinder the rice growth. Although drought tolerance is a reported effect of seed priming treatment, we hypothesized that plants from primed seeds would die because they would begin to emerge in dry soil. We also expected that nonemerged primed seeds would show decreased seed vigor because their metabolism was activated by priming before sowing. Therefore, we investigated the vigor of hydroprimed and nonprimed seeds during prolonged drought after sowing during upland rice cultivation. A field experiment was conducted on a rainfed upland field that had insufficient rainfall at the beginning of the season. Plant emergence, establishment, and vigor in resown nongerminated seeds were also investigated. A subsequent growth chamber experiment was conducted to investigate the relationship between sown seed deterioration, soil moisture, and temperature. Contrary to the hypothesis, plants from primed as well as control seeds could survive under prolonged drought after emergence. In the nongerminated primed seeds, oxidative damage was increased. However, the percentage of plant emergence in resown seeds did not differ between treatments. Overall, the performance of primed seeds was better than or similar to that of the control seeds. In conclusion, primed seeds have advantages even under extreme drought conditions in rainfed upland fields.

The effect of Epichloë endophyte on phyllosphere microbes and leaf metabolites in Achnatherum inebrians

SummaryUpon exposure to the prevailing environment, leaves become increasingly colonized by fungi and bacteria located on the surface (epiphytic) or within (endophytic) the leaves. Many cool season grasses, including Achnatherum inebrians, host a seed-borne, intercellular, mutualistic Epichloë fungal endophyte, the growth of which is synchronized with the host grass. A study utilizing illumina sequencing was used to examine the epiphytic and endophytic microbial communities in Epichloë endophyte-infected and endophyte-free A. inebrians plants growing under hot dry field conditions. The presence of Epichloë endophyte increased the Shannon and decreased Simpson diversity of bacterial and fungal communities. Sphingomonas and Hymenobacter bacteria and Filobasidium and Mycosphaerella fungi were growing largely epiphytically, whereas Methylobacterium, Escherichia-Shigella, and the fungus Blumeria were mostly found within leaves with the location of colonization influenced by the Epichloë endophyte. In addition, leaf metabolites in Epichloë-infected and Epichloë-free leaves were examined using LC/MS. Epichloë was significantly correlated with 132 metabolites.

Cotton Emergence and Yield Response to Planter Depth and Downforce Settings in Different Soil Moisture Conditions

US cotton producers are motivated to optimize planter performance to ensure timely and uniform stand establishment early in the season, especially when planting in sub-optimal field conditions. Field studies were conducted in 2017, 2018 and 2019 to evaluate the effect of seeding depth and planter downforce on crop emergence and yield in cotton planted in different soil moisture conditions. Field conditions representative of dry, normal and wet soil moisture conditions were attained by applying 0, 1.27 and 2.54 cm of irrigation within the same field. Two cotton cultivars (representing a small-seeded and a large-seeded cultivar, 9259–10,582 and 11,244–14,330 seeds kg−1, respectively), were planted at seeding depths of 1.3, 2.5 and 3.8 cm with each seeding depth paired with three different planter downforces of 0, 445 and 890 N in each block. Cotton was planted in plots that measured 3.66 m (four-rows) wide by 10.67 m long. Results indicated that crop emergence was affected by the seeding depth across most field conditions and higher crop emergence was observed in the large-seeded cultivar at 1.3 and 3.8 cm seeding depths in dry and wet field conditions, respectively. Lint yield was also higher for the large-seeded cultivar at the 3.8 cm seeding depth across all field conditions in 2017, and in dry field conditions in 2018. Planter downforce effect on crop emergence varied among the cultivars where the large-seeded cultivar exhibited higher crop emergence than the small-seeded cultivar at 445 and 890 N downforce. Planter downforce of 445 N yielded greater than the 0 and 890 N treatment in dry field conditions in 2017. The study results suggest that matching planter depth and downforce settings for prevalent soil moisture conditions at planting along with appropriate cultivar selection can help in achieving optimal emergence and yield in cotton.

Effect of body lipid content is linked to nutritional adaptation in the acclimation responses of mesic-adapted Paederus to seasonal variations in desiccation stress

Desiccation stress causes mesic-adapted arthropods to lose their body water content. However, mesic-adapted Paederus beetles can survive over prolonged periods under dry field conditions, suggesting that these beetles adopt an array of water conservation mechanisms. We investigated the water balance mechanisms of field-collected Paederus adults over a 14-month sampling period. We also assessed their nutritional adaptations by performing a stable isotope analysis to examine their diet. The water loss rate (WLR) of the beetles was significantly associated with the rice crop cycle and saturation deficit. The cuticular permeability (CP) of adult beetles was maintained at < 30 µg cm−2h−1 mmHg−1; however, CP increased significantly with the WLR. This result indicates that CP might play a minor role in reducing excessive water loss in beetles. The beetles’ body water content and percentage total body water content increased when the WLR was high. Trehalose, glucose, and glycogen did not appear to play a central role in enhancing the water reserves in the insects. The body lipid content ranged from 0.22 ± 0.06 to 0.87 ± 0.07 mg and was negatively associated with the WLR. This association indicates that the increase in internal metabolic water was mediated by lipid catabolism. Stable isotope analysis results revealed that the Paederus beetles shifted their diet to carbohydrate-rich plants when the saturation deficit increased and the associated WLR reached its peak; otherwise, they consumed a high amount of staple carbohydrate-poor herbivore prey. The accumulation of energy reserves in the form of lipids through seasonal dietary shifts may exert major effects on the survival and population success of mesic-adapted Paederus beetles.

Field calibration of DFM capacitance probes for continuous soil moisture monitoring

This study was undertaken to derive textural and lumped site-specific calibration equations for Dirk Friedhelm Mercker (DFM) capacitance probes and evaluate the accuracy levels of the developed calibration equations for continuous soil moisture monitoring in three selected soil types. At each site, 9 probes (3 per plot) were installed in 2 m2 plots, for continuous soil moisture measurements at 5 different depths (viz. 10, 20, 30, 40 and 60 cm) under dry, moist and wet field conditions. Textural site-specific calibration equations were derived by grouping the same soil textural classes of each site regardless of soil depth, while lumped site-specific calibration equations were derived by grouping all datasets from each site, regardless of soil depth and textural classes. Sensor readings were plotted against gravimetrically measured volumetric soil moisture (θv) for different textural classes as a reference. The coefficient of determination (r2) was used to select the best fit of the regression function. The developed calibration equations were evaluated using an independent dataset. The results indicated that all developed textural and lumped site-specific calibration equations were linear functions, withr2 values ranging from 0.96 to 0.99. Relationships between the measured and estimated θv from calibration equations were reasonable at all sites, with r2 values greater than 0.91 and root mean square error (RMSE) values ranging from 0.010 to 0.020 m3∙m-3. The results also indicated that textural site-specific calibration equations (RMSE &lt; 0.018 m3∙m-3) should be given preference over lumped site-specific calibrations (RMSE &lt; 0.020 m3∙m-3) to attain more accurate θv measurements. The findings of this study suggest that once DFM capacitance probes are calibrated per site, they can be reliably used for accurate in-situ soil moisture measurements. The developed calibration equations can be applied with caution in other sites with similar soil types to attained reliable in-situ soil moisture measurements.

Heat Stress and Cardiac Strain in French Vineyard Workers.

Agricultural workers often produce considerable excess heat due to the physically demanding nature of their activities, increasing their risk of thermal stress in even moderately warm conditions. Few studies have examined the physiological responses to heat load in agriculture. We aimed to assess the heat strain experienced by vineyard workers during canopy management in dry field conditions, and to disentangle the effects of the heat produced by the body and the thermal environment. Thirty workers from five Bordeaux vineyards of southern France were monitored during vine-lifting and trellising (June 2012). The mean heart rate, net cardiac cost, relative cardiac cost, and cardiac workload score were assessed during field activity. As the workers were nested within vineyards, multilevel linear regression models were used for correct inference. Skin temperature increased by an average of 1.0°C. Cardiac indices showed marked differences between individuals. The workload was evaluated as 'heavy' or 'very heavy' for more than one-third of the workers, of whom one experienced heat exhaustion. Above some individual characteristics, we highlighted a contextual effect (air temperature) for the mean heart rate (P = 0.03), the relative cardiac cost (P = 0.01) and, to a lesser extent, a cardiac workload score (P = 0.07). Canopy management by hand in vineyards causes considerable cardiac and thermoregulatory strain. Appropriate instruments should be developed to simultaneously evaluate work intensity, work quality, and productivity at the vineyard level to raise the awareness of both managers and employees about taking preventive measures.

Abrasive wear characteristics and microstructure of Fe-based overlaid ploughshares in different field conditions

In the present research, two different Fe-based claddings, namely SZ (Fe–Cr, Fe–33.37Cr–3.83C) and ZK (Fe–Mo, Fe–8.18Mo–4.5Cr–0.65C) were overlaid on EN-42 steel substrate by Manual Metal Arc Welding (MMAW) process with an aim to enhance the abrasive wear characteristics of the steel. The microstructural and abrasive wear behavior of overlaid samples was investigated in comparison with bare steel (EN-42) in actual field conditions at two different moisture levels (0–3% and 14–17%). Optical microscopy, scanning electron microscope (SEM), X-ray diffraction (XRD), and hardness testing were performed to characterize the microstructural and mechanical properties of bare and overlaid steel samples. The effect of moisture content on abrasive wear resistance of tillage tools and tillage quality has also been evaluated. The results revealed that the variables such as carbide shape, size, distribution, and matrix structure of hardfacing influence the wear resistance of hardfacings. The SZ alloy showed higher abrasive wear resistance than ZK alloy due to the formation of M23C6 and M7C3 carbides in the hardfaced layer. The moisture content of the soil also affected the abrasive wear resistance of the substrate and different hardfacings materials, which in turn influence the tillage efficiency of the tool. The wear rate of bare and overlaid ploughshares is almost 3 times higher in dry field conditions (0-3% moisture) as compared to moist conditions (14–17%). The wear resistance indices (WRI) for SZ and ZK overlaying were found to be 1.85 and 1.48 respectively for low moisture conditions, and 1.9 and 1.54 for the moist condition.

Successful field performance in warm and dry environments of soybean expressing the sunflower transcription factor HB4.

Soybean yield is limited primarily by abiotic constraints. No transgenic soybean with improved abiotic stress tolerance is commercially available. We transformed soybean plants with genetic constructs able to express the sunflower transcription factor HaHB4, which confers drought tolerance to Arabidopsis and wheat. One line (b10H) carrying the sunflower promoter was chosen among three independent lines because it exhibited the best performance in seed yield, and was evaluated in the greenhouse and in 27 field trials in different environments in Argentina. In greenhouse experiments, transgenic plants showed increased seed yield under stress conditions together with greater epicotyl diameter, larger xylem area, and increased water use efficiency compared with controls. They also exhibited enhanced seed yield in warm and dry field conditions. This response was accompanied by an increase in seed number that was not compensated by a decrease in individual seed weight. Transcriptome analysis of plants from a field trial with maximum difference in seed yield between genotypes indicated the induction of genes encoding redox and heat shock proteins in b10H. Collectively, our results indicate that soybeans transformed with HaHB4 are expected to have a reduced seed yield penalty when cultivated in warm and dry conditions, which constitute the best target environments for this technology.

Spatial prediction of near surface soil water retention functions using hydrogeophysics and empirical orthogonal functions

The hydrological community often turns to widely available spatial datasets such as the NRCS Soil Survey Geographic database (SSURGO) to characterize the spatial variability of soil properties. When used to spatially characterize and parameterize watershed models, this has served as a reasonable first approximation when lacking localized or incomplete soil data. Within agriculture, soil data has been left relatively coarse when compared to numerous other data sources measured. This is because localized soil sampling is both expensive and time intense, thus a need exists in better connecting spatial datasets with ground observations. Given that hydrogeophysics is data-dense, rapid, non-invasive, and relatively easy to adopt, it is a promising technique to help dovetail localized soil sampling with spatially exhaustive datasets. In this work, we utilize two common near surface geophysical methods, cosmic-ray neutron probe and electromagnetic induction, to identify temporally stable spatial patterns of measured geophysical properties in three 65 ha agricultural fields in western Nebraska. This is achieved by repeat geophysical observations of the same study area across a range of wet to dry field conditions in order to evaluate with an empirical orthogonal function. Shallow cores were then extracted within each identified zone and water retention functions were generated in the laboratory. Using EOF patterns as a covariate, we quantify the predictive skill of estimating soil hydraulic properties in areas without measurement using a bootstrap validation analysis. Results indicate that sampling locations informed via repeat hydrogeophysical surveys, required only five cores to reduce the cross-validation root mean squared error by an average of 64% as compared to soil parameters predicted by a commonly used benchmark, SSURGO and ROSETTA. The reduction to five strategically located samples within the 65 ha fields reduces sampling efforts by up to ∼90% as compared to the common practice of soil grid sampling every 1 ha.

Foliar application of benzovindiflupyr shows non-fungicidal effects in wheat plants.

BACKGROUNDThe fungicide benzovindiflupyr belongs to the class of succinate dehydrogenase inhibitors (SDHIs). Certain SDHIs have shown plant physiological effects, so‐called secondary effects, that appeared to be related to the plant water status. Therefore, the effect of benzovindiflupyr on transpiration of leaves and whole wheat plants was studied under controlled conditions. Furthermore, wheat yield trials under controlled and natural drought stress in the field were conducted.RESULTSTranspiration of detached wheat leaves was reduced by benzovindiflupyr in a dose‐dependent manner. Similarly, whole‐plant transpiration decreased for several days following application of this fungicide. In 16 field trials under drought stress conditions that were classified as disease‐free, treatment of wheat plants at the flag leaf stage or at heading with benzovindiflupyr showed a grain yield increase (+5.2%; P ≤ 0.01) that was partially attributed to an increased thousand‐grain weight.CONCLUSIONSWater saving during pre‐anthesis as a result of benzovindiflupyr application may be associated with better seed setting and filling under dry field conditions in wheat. The results of this research provide new insights into secondary effects of SDHIs that lead directly to yield improvements. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Estrés osmótico y germinación de Yucca elata y Menodora scabra, dos especies de plantas nativas del desierto Chihuahuense

La propagación de plantas es esencial para la restauraciónde ecosistemas degradados. Las zonas áridas presentan especies vegetales altamente resistentes a la sequía como Yucca elata (Engelm.) Engelm. y Menodora scabra A. Gray. Generalmente se acepta que, como parte del cambio climático, la sequía puede intensificarse en duración y frecuencia en estas zonas. Por lo tanto, la germinación de las dos especies se evaluó en diferentes niveles de estrés osmótico para determinar su respuesta a diferentes niveles de humedad. La germinación en las dos especies se redujo a medida que se incrementó el estrés osmótico, pero en Y. elata no se presentó inhibición (13 % germinación), a -1.5 MPa, mientras que en M. scabra si se presentó inhibición (0 % germinación) a este nivel de potencial osmótico. Estas respuestas muestran que la germinación de Y. elata es menos afectada por la sequía que la germinación de M. scabra. Esto representa diferentes potencialidades de manejo en programas de restauración ecológica. Mientras que Y. elata pudiera tener éxito germinando directamente en el suelo en estrés por sequía, M. scabra pudiera establecerse trasplantándola en campo en etapa de plántula o con el uso de nodrizas.

Overexpression of an Arabidopsis thaliana galactinol synthase gene improves drought tolerance in transgenic rice and increased grain yield in the field.

Drought stress has often caused significant decreases in crop production which could be associated with global warming. Enhancing drought tolerance without a grain yield penalty has been a great challenge in crop improvement. Here, we report the Arabidopsis thaliana galactinol synthase 2 gene (AtGolS2) was able to confer drought tolerance and increase grain yield in two different rice (Oryza sativa) genotypes under dry field conditions. The developed transgenic lines expressing AtGolS2 under the control of the constitutive maize ubiquitin promoter (Ubi:AtGolS2) also had higher levels of galactinol than the non‐transgenic control. The increased grain yield of the transgenic rice under drought conditions was related to a higher number of panicles, grain fertility and biomass. Extensive confined field trials using Ubi:AtGolS2 transgenic lines in Curinga, tropical japonica and NERICA4, interspecific hybrid across two different seasons and environments revealed the verified lines have the proven field drought tolerance of the Ubi:AtGolS2 transgenic rice. The amended drought tolerance was associated with higher relative water content of leaves, higher photosynthesis activity, lesser reduction in plant growth and faster recovering ability. Collectively, our results provide strong evidence that AtGolS2 is a useful biotechnological tool to reduce grain yield losses in rice beyond genetic differences under field drought stress.

Darkling beetles (Coleoptera: Tenebrionidae) of forest sites and agricultural fields in the south Western Ghats (South India)

Data on the abundance, feeding guilds, flightlessness and endemic status of darkling beetles from selected forest sites and agriculture fields in the moist south Western Ghats in south India are provided. Overall abundance, diversity and evenness were higher in agriculture fields than in forest. Luprops tristis was the major species in agriculture field and Gonocephalum bilineatum in forest. Mycetophagous and detritivorous guilds were reported from the agriculture fields and detritivorous guild alone from the forests. Epigean, subterranean, corticolous, dung associated and mycetophagous darkling beetles were present in agriculture fields in contrast to the record of epigean and subterranean forms in forests. Higher abundance of flightless platynotine genus Menearchus, endemic to the Indian subcontinent in the agricultural field is attributed to the decaying organic matter availability in the open, dry environment conditions in agriculture field.

Comparative study of hyoscine doses as antisialagogue for patients receiving ketofol sedation undergoing colonoscopy procedures.

Objective:To compare the effects of different regimens of hyoscine as antisialagogue in patients undergoing ketofol sedation for colonoscopy procedures.Patients and Methods:In this prospective double-blind randomized controlled trial 200 American Society of Anesthesiologists I-II aged 20–60-year-old undergoing colonoscopy were randomly assigned into four equal groups, group A received 5 mg hyoscine intravenous, group B received 10 mg, group C received 20 mg intravenous, and control group (D) that was received saline. All patients were sedated using ketofol titrated to achieve Ramsey Sedation Score 4, hemodynamic variables and occurrence of increased secretions were evaluated and recorded.Results:Hyoscine in a dose of 10 mg was the optimum dose to achieve least salivation with the least side effect while hyoscine 5 mg was not efficient to achieve dry field or good surgical conditions. However, hyoscine 20 mg achieved dry field and fair surgical conditions in expenses of tachycardia.Conclusion:Hyoscine 10 mg was the least effective dose that significantly reduced hypersalivation in patients receiving ketofol sedation for colonoscopy procedures, this dose was as effective as 20 mg in draying secretion but with significantly less tachycardia.

Measuring Dew and Its Effect on Ammonia Volatilization from Surface‐Applied Broiler Litter in the Southeastern United States

Core IdeasDew deposition is often overlooked in humid regions but may play an important role in nutrient cycling for surface‐applied fertilizers and broiler litter.Dew accumulated during the measurement period accounted for 6% of the precipitation measured with heaviest dew recorded in the spring and winter months.Under laboratory conditions, simulated dew led to increased ammonia loss for surface‐applied broiler litter.Incorporation of dew as a significant weather variable may better aid in predicting NH3loss using simulation models.Dew deposition is often overlooked in humid regions, such as the southeastern USA, but may play an important role in nutrient cycling for surface‐applied fertilizers and broiler litter. The objectives of this study were to measure dew in a pasture and to evaluate the effect of simulated dew on NH3volatilization in a laboratory study. A microlysimeter method was used to measure dew in a tall fescue (Festuca arundinaceaSchreb.) and bermudagrass (Cynodon dactylonL.) pasture over 206 d. In the 206 d measured, 119 d received dew with an average dew fall of 0.19 mm and greater events observed in the cooler spring and fall months. Dew accumulated during the measurement period accounted for 6% of the precipitation measured. Under lab conditions, the effect of simulated, daily dew (0.2 mm) on NH3volatilization from surface‐applied broiler litter to air‐dry soil was evaluated under diurnal fluctuations of temperature (6–27°C) and relative humidity (26–91%) for 15 d. Dew application significantly increased NH3volatilization losses (31% of the applied NH4–N and 5% of the applied total nitrogen [TN]) when compared with NH3losses in the absence of dew (15% of the applied NH4–N and 2.4% of the applied TN). These results suggest that dew may affect NH3losses from surface‐applied broiler litter under dry field conditions.

Popularizing Direct Seeded Rice: Issues and Extension Strategies

Direct Seeded Rice (DSR) is the technology which is water, labour and energy efficient along with eco-friendly characteristics. Flooded rice is a major source of methane emission, while the use of nitrogen fertilizers produces nitrous oxide; both are greenhouse gases linked to global warming. The dominant method of rice establishment is transplanting in the rice-wheat growing areas of the Indo-Gangetic Plains (IGP). However, rising labour costs for establishing a nursery, puddling fields, and transplanting have increased costs for transplanting in the region. Direct seeding of rice was a common practice before green revolution in India and is becoming popular once again because of its potential to save water and labor. However, high weed infestation is the major bottleneck in DSR, especially in dry field conditions and, availability of several nutrients including N, P, S and micro-nutrients such as Zn and Fe, is likely to be a constraint. Extension activities can play very important role in popularization of DSR, which includes training, demonstration of DSR in farmer’s field, on farm trial related to various potential problems faced by farmers and exposure visit of farmers to field. Coordination is also required within the different disciplines/specializations, between institutions and departments as well as functional areas like research, extension and training along with people’s participation and new thrust on participatory research and development to bring farmers in the framework of interactions at all levels.With the increase in prices of inputs and low rice prices, rice production does not provide farmers with high income. Rice food security needs clear national policy that allows right investment in all phases of rice development. There must be right policies on input availability, output marketing and prices. The following paper tries to look into the issues affecting DSR adoption and suggests extension strategies to popularize it.