Plant mediated methane efflux from a boreal peatland complex

Purpose Aerenchymous plants are an important control for methane efflux from peatlands to the atmosphere, providing a bypass from the anoxic peat and avoiding oxidation in the oxic peat. We aimed to quantify the drivers of aerenchymous peatland species methane transport and the importance of this process for ecosystem-scale methane efflux. Methods We measured seasonal and interspecies variation in methane transport rate per gram of plant dry mass at a boreal fen and bog, which were upscaled to ecosystem-scale plant methane transport. Results Methane transport rate was better explained by plant species, leaf greenness and area than by environmental variables. Leaves appeared to transport methane even after senescence. Contrary to our expectations, both methane transport rate and the proportion of plant transport were lower in the fen (with greater sedge cover) than in the bog site. At the fen and bog, average methane transport rate was 0.7 and 1.8 mg g−1 d−1, and the proportion of seasonally variable plant transport was 7–41% and 6–90%, respectively. Species-specific differences in methane transport rate were observed at the ecosystem-scale: Scheuchzeria palustris, which accounted for 16% of the aerenchymous leaf area in the fen and displayed the greatest methane transport rate, was responsible for 45% of the ecosystem-scale plant transport. Conclusion Our study showed that plant species influence the magnitude of ecosystem-scale methane emissions through their properties of methane transport. The identification and quantification of these properties could be the pivotal next step in predicting plant methane transport in peatlands.

Bisphenol A—A Dangerous Pollutant Distorting the Biological Properties of Soil

Bisphenol A (BPA), with its wide array of products and applications, is currently one of the most commonly produced chemicals in the world. A narrow pool of data on BPA–microorganism–plant interaction mechanisms has stimulated the following research, the aim of which has been to determine the response of the soil microbiome and crop plants, as well as the activity of soil enzymes exposed to BPA pressure. A range of disturbances was assessed, based on the activity of seven soil enzymes, an abundance of five groups of microorganisms, and the structural diversity of the soil microbiome. The condition of the soil was verified by determining the values of the indices: colony development (CD), ecophysiological diversity (EP), the Shannon–Weaver index, and the Simpson index, tolerance of soil enzymes, microorganisms and plants (TIBPA), biochemical soil fertility (BA21), the ratio of the mass of aerial parts to the mass of plant roots (PR), and the leaf greenness index: Soil and Plant Analysis Development (SPAD). The data brought into sharp focus the adverse effects of BPA on the abundance and ecophysiological diversity of fungi. A change in the structural composition of bacteria was noted. Bisphenol A had a more beneficial effect on the Proteobacteria than on bacteria from the phyla Actinobacteria or Bacteroidetes. The microbiome of the soil exposed to BPA was numerously represented by bacteria from the genus Sphingomonas. In this object pool, the highest fungal OTU richness was achieved by the genus Penicillium, a representative of the phylum Ascomycota. A dose of 1000 mg BPA kg−1 d.m. of soil depressed the activity of dehydrogenases, urease, acid phosphatase and β-glucosidase, while increasing that of alkaline phosphatase and arylsulfatase. Spring oilseed rape and maize responded significantly negatively to the soil contamination with BPA.

Growth and Yield Responses of Pot-Grown Long Bean and Luffa to Nitrogen Rates

Optimizing nitrogen (N) input rates for vegetable production is crucial in Florida to reducing production costs and enhancing environmental sustainability. Asian vegetables emerging and expanding in Florida not only increase profit for growers, but also enhance food diversity for consumers. The objective of this study was to gain a better understanding of the partitioning and usage of N and carbohydrates in two Asian vegetable crops: long bean (Vigna unguiculata ssp. sesquipedalis (L.) Verdc.) and angled luffa (Luffa acutangular (L.) Roxb.). Four N rates (0, 0.91, 1.36, and 1.81 g N pot−1) were compared in a high tunnel trial to understand the influence of N fertilization on the two crops. For long bean, plant biomass was highest at the highest N input, and N-fertilized plants had significantly higher leaf greenness than the control at the flower initiation and mid-reproductive stages. However, N inputs had no apparent effect on yield, nitrogen use efficiency (NUE), blade total N concentration, roots (length, volume, dry biomass, and root-to-shoot ratio), or nodules (number plant−1 and biomass). For luffa, the highest N input had significantly greater total yield, fruit number, and leaf greenness at the flower initiation and mid-reproductive stages, although there was no significant difference in shoot biomass, blade total N content, or NUE among treatments. Within the range of these N rates, our results suggest that higher N inputs promoted vegetative growth of long bean, whereas reproductive growth was promoted in luffa. This study highlights differences in the sink–source relationship of N for long bean and luffa production in high tunnel, which can guide N input decisions for these two crops that are rapidly expanding in the USA.

Intercropping and Nitrogen Fertilization Altered the Patterns of Leaf Senescence in Sorghum

Leaf senescence regulates grain yield. However, the modulation of leaf senescence in sorghum under legume-based intercrop systems and nitrogen (N) fertilization is not known. The objective of the study was to investigate the effect of intercropping two sorghum (Gadam and Serena) and cowpea (K80, M66) varieties and sole cropping systems and different fertilizer N rates (0, 40, and 80 kg·N·ha−1) on the time course of postflowering sorghum leaf senescence and understand how senescence modulates grain yield. The experiment was laid out in a randomized complete block design with a split-plot arrangement with three replications. Leaf senescence was assessed from flowering to maturity at (a) whole-plant level by the visual scoring of green leaves and (b) flag leaf scale by measuring leaf greenness with a SPAD 502 chlorophyll meter. A logistic function in SigmaPlot was fitted to estimate four traits of leaf senescence, including minimum and maximum SPAD (SPADmin, SPADmax), time to loss of 50% SPADmax (EC50), and the rate of senescence. Irrespective of the cowpea variety, intercropping reduced sorghum grain yield by 50%. The addition of N increased yield by 27% but no effect was detected between 40 and 80 kg·N ha−1. Intercropping delayed leaf senescence at the whole plant by 0.2 leaves plant−1 day−1 but reduced SPADmax of the flag by 8 SPAD units and rate of senescence by 4 SPAD units day−1 compared with sole crop system. Fertilizer N delayed leaf senescence ( P ≤ 0.05 ) at whole-plant and flag leaf scales. Cropping System × nitrogen modulated senescence at whole-plant and flag leaf scales and sorghum grain yield but marginally influenced other traits. While EC50 did not correlate with grain yield, faster rates of senescence and leaf greenness were associated with high yield under the sole crop system. Overall, N was the main factor in driving sorghum leaf senescence while the intercropping effect on senescence was nonfunctional. Effects of competition in sorghum-legume intercropping and source-sink relationships on the patterns of leaf senescence deserve further investigation.

Mineral Materials as a Neutralizing Agent Used on Soil Contaminated with Copper

The aim of the investigation was to evaluate the response of plants, using black mustard (Brassica nigra L. Koch) as a model plant, to soil contamination with copper (0, 200, 400, 600 mg Cu kg−1 of soil), and to determine the effectiveness of the Cu immobilization with mineral neutralizing materials, such as lime, clay and zeolite. The plant yield depended on soil contamination and mineral amendments. In the series without neutralizing materials, the level of 600 mg Cu kg−1 reduced the yield and increased leaf greenness. Lime alleviated the toxicity of Cu in objects with 200 mg Cu kg−1. Zeolite slightly mitigated the harmful effects of Cu at the level of 400 and 600 mg kg−1. Zeolite lowered the SPAD index. In the chemical composition of plants, the content of Cu, K, Mg, Na and Ca in plants increased to 400 mg Cu kg−1, while the content of P decreased to 600 mg Cu kg−1. Among the materials, lime reduced the Cu accumulation in plants the most, followed by clay. Cu narrowed the majority of ratios and widened the Ca:P and K:Ca ratios in plants. The applied mineral materials, except lime, did not significantly affect the formation of these indicators.

Pengaruh Aplikasi Arang Sekam dan Pupuk Organik Cair terhadap Pertumbuhan Tanaman Pakcoy (Brasicca rapa L.)

This research aims to determine: 1) the effect of the comparison of the use of husk charcoal growing media with soil on the growth of pakcoy plants, 2) the effect of the application of liquid organic fertilizer (SO-Kontan Fert) on the growth of pakcoy plants, 3) the effect of a combination of rice husk planting media with soil and POC (SO-Kontan Fert) application to the growth of pakcoy plants. This research was conducted from January to March 2020 at the screen house of Melung Village, Baturraden District, Banyumas Regency, Central Java and the Agronomy and Horticulture Laboratory of the Faculty of Agriculture, Jenderal Soedirman University, with Andisol soil types. The experimental design used was a completely randomized block design (RAKL) with a 2-factor factorial design. The first factor is husk charcoal (M), namely, M0 = without husk charcoal, M1 = soil + husk charcoal (1: 1), M2 = soil (2: 1), soil + husk charcoal (3: 1). The second factor is the concentration of POC SO-Kontan Fert (P), namely, P0 = 0 ml POC SO-Kontan Fert / Lt water, P1 = 5 ml POC SO-Kontan Fert / Lt water, P2 = 10 ml POC SO-Kontan Fert / Lt water, P3 = 15 ml POC SO-Kontan Fert / Lt water. Results of the research showed that giving husk charcoal to pakcoy plant media at a ratio of 3: 1 was able to increase plant height by 47.19 cm and leaf length by 26.13 cm ,. A ratio of 2: 1 can increase leaf greenness by 2.8 units. The application of liquid organic fertilizer (SO-Kontan Fert) with a concentration of 5 ml / l was able to increase the number of leaves by 6.59.

Visual Quality, Gas Exchange, and Yield of Anemone and Ranunculus Irrigated with Saline Water

In response to the growing demand for specialty cut flowers, floral crops are increasingly produced in semiarid areas where soil salinity can impact crop timing, reduce stem length, and decrease yield. The goal of this study was to investigate the salinity sensitivity of ‘Carmel’ and ‘Galilee’ anemone (Anemone coronaria), and ‘Amandine’ and ‘LaBelle’ ranunculus (Ranunculus asiaticus) with respect to physiological characteristics and marketable yield. Nine plants were irrigated weekly for 8 weeks with a nutrient (control) solution with an electrical conductivity (EC) of 0.5 dS⋅m–1 or saline solutions prepared by adding sodium chloride and calcium chloride dihydrate to a nutrient solution to obtain an EC of 1.5, 2.5, 3.5, 4.5, or 5.5 dS⋅m–1. Yield was evaluated by dividing stems into marketable and cull grades based on length and bloom quality. At the end of the study, the visual quality of the plants was scored, and gas exchange data were collected using a portable photosynthesis system. Cultivars of each species responded similarly, and marketable yields were low across all treatments, with average marketable yields (mean ± sd) of 1.7 ± 0.6 stems/plant for anemone and 1.2 ± 0.1 stems/plant for ranunculus. Visual quality (0–5 scale, with 0 = dead and 5 = excellent) decreased from 3 to 1 for anemone and 3 to 2 for ranunculus as EC increased from 0.5 to 4.5 dS⋅m–1 and 0.5 to 5.5 dS⋅m–1, respectively. Anemone leaf greenness decreased by 48%, stomatal conductance (gS) decreased by 79%, transpiration (E) decreased by 75%, and net photosynthesis (Pn) decreased by 92% when irrigation solution EC increased from 0.5 to 4.5 dS⋅m–1. The ranunculus growth index decreased by 17%, leaf greenness decreased by 45%, and E decreased by 23% as irrigation solution EC increased from 0.5 to 5.5 dS⋅m–1. Both anemone and ranunculus can be considered sensitive to salinity, indicating the importance of careful soil management in cut flower production systems in semiarid areas that are at risk for elevated soil salinity.

By-Plant Prediction of Dry Matter Yields at Various Growth Stages of Maize Plants (Zea mays L.) Using Leaf Greenness Indicator in Climatic Conditions of Poland

Predicting yield at an early growth stage allows one to optimize the amount and timing of nitrogen fertilization to maximize crop yield. The aim of the study was to determine how different nitrogen doses would affect the nutrition of two maize varieties (Zea mays L.) with this element and their yields, and to demonstrate the potential of using the SPAD index as an early-stage predictor of dry matter yield (DMY) of maize biomass. The field experiment, with different pre- and post-sown N fertilizer doses, was conducted for two years in Poland. The two-factor experiment was set up in a randomized block design with three field replicates. There were four mineral fertilization variants: (I) 120 kg N·ha−1 without P and K fertilization, (II) 120 kg N·ha−1 + PK, (III) 160 kg N·ha−1 + PK, and (IV) 200 kg N·ha−1 + PK. The second-order factor was two stay-green maize varieties: Delitop (FAO 240) and Magitop (FAO 270). The mean values of the SPAD index of maize depended on the nitrogen dose. When the dose was increased from 120 kg·ha−1 to 200 kg·ha−1 with constant P and K fertilization, the value of the leaf greenness index increased significantly. The plants of both maize varieties fertilized with nitrogen at a dose of 120 kg N·ha−1 without P and K were characterized by the lowest values of the SPAD index, regardless of the year of the experiment. When the nitrogen dose was supplemented with P and K, the plants’ nutrition with nitrogen improved significantly. The values of the SPAD index in the maize plants of the variety Magitop were significantly greater than in the plants of the variety Delitop. The coefficients of correlation calculated for both maize varieties were highly significant at all measurement dates. Therefore, it is possible to conclude that the SPAD leaf greenness index can be used as an important, reliable, and non-invasive indicator for maize yield prediction. Nutrition of maize plants with nitrogen proved to be the main determinant of variability of the biomass yield. For this reason, it was the basis for the verification of individual mineral fertilization variants. The lack of phosphorus and potassium in the dose of mineral fertilizer limited the yield regardless of the variety, as compared to the variant that was optimally balanced with the nitrogen dose.

Supporting Physiological Trait for Indirect Selection for Grain Yield in Drought-Stressed Popcorn

The identification of traits associated with drought tolerance in popcorn is a contribution to support selection of superior plants under soil water deficit. The objective of this study was to choose morphological traits and the leaf greenness index, measured on different dates, to estimate grain yield (GY) and popping expansion (PE), evaluated in a set of 20 popcorn lines with different genealogies, estimated by multiple regression models. The variables were divided into three groups: morpho-agronomic traits—100-grain weight (GW), prolificacy (PR), tassel length (TL), number of tassel branches, anthesis-silking interval, leaf angle (FA) and leaf rolling (FB); variables related to the intensity of leaf greenness during the grain-filling period, at the leaf level, measured by a portable chlorophyll meter (SPAD) and at the canopy level, calculated as the normalized difference vegetation index (NDVI). The inbred lines were cultivated under two water conditions: well-watered (WW), maintained at field capacity, and water stress (WS), for which irrigation was stopped before male flowering. The traits GY (55%) and PE (28%) were most affected by water restriction. Among the morpho-agronomic traits, GW and PR were markedly reduced (>10%). Under dry conditions, the FA in relation to the plant stalk tended to be wider, the FB curvature greater and leaf senescence accelerated (>15% at 22 days after male flowering). The use of multiple regression for the selection of predictive traits proved to be a useful tool for the identification of groups of adequate traits to efficiently predict the economically most important features of popcorn (GY and PE). The SPAD index measured 17 days after male flowering proved useful to select indirectly for GY, while, among the morphological traits, TL stood out for the same purpose. Of all traits, PR was most strongly related with PE under WS, indicating its use in breeding programs. The exploitation of these traits by indirect selection is expected to induce increments in GY and PE.