Soil Nitrogen Research Articles

The Fate of Deep Permafrost Carbon in Northern High Latitudes in the 21st Century: A Process‐Based Modeling Analysis

AbstractWarming in permafrost regions stimulates carbon (C) release through decomposition, but increasing atmospheric CO2 and available soil nitrogen enhance plant productivity at the same time. To date, a large uncertainty in the regional C dynamics still remains. Here we use a process‐based biogeochemical model by considering C exposure from thawed permafrost and observational data to quantify permafrost C emissions and ecosystem C budget in northern high latitudes in the 21st century. Permafrost degradation will make 119.3 Pg and 251.6 Pg C available for decomposition by 2100 under the Shared Socioeconomic Pathway (SSP)126 and SSP585, respectively. However, only 4–8% of the newly thawed permafrost C is expected to be released into the atmosphere by 2100. Cumulatively, permafrost degradation will reduce ecosystem C stocks by 3.37 Pg and 15.37 Pg under the SSP126 and SSP585, respectively. Additionally, CO2 fertilization effects would stimulate plant productivity and increase ecosystem C stocks substantially. The combined effects of climate change, CO2 fertilization, and permafrost degradation on C fluxes are typically more profound than any single factor, emphasizing the intricate interplay between these elements in shaping permafrost C‐climate feedbacks. Our study suggests that the majority of the thawed C will remain sequestered in previously frozen layers in this century, posing a significant challenge to climate change mitigation efforts once any process accelerates the decomposition of this huge amount of thawed C.

Effects of the Application of Organic Fertilizers on the Yield, Quality, and Soil Properties of Open-Field Chinese Cabbage (Brassica rapa spp. pekinensis) in China: A Meta-Analysis

With the development of sustainable agriculture, trials on the benefits of the application of organic fertilizers around the world have been conducted. Herein, we investigated the impact of the pure chemical fertilizers (CFs) combined with organic fertilizers compared with the application of CFs (100% CFs) and no fertilizers (NFs) on soil properties as well as the yield and quality of Chinese cabbage through meta-analysis. Results indicate that: (1) Compared with NFs, the application of organic fertilizers can significantly improve the yield and quality of Chinese cabbage and increase soil nutrients. (2) Compared with CFs, the application of organic fertilizers can increase the fresh weight, number of leaves, transverse diameter, leaf length, and development of Chinese cabbage per plant, with increases of 8.54%, 6.6%, 9.905%, 8.42%, and 10.03%; Meanwhile, organic fertilizers can significantly increase the yield (total amount of above-ground parts produced) and commercial yield (the portion that meets the required quality standards and is intended for sale) of Chinese cabbage to increase the yield and commercial yield by 10.08% and 35.56%, respectively. However, it has no significant impact on the income from growing Chinese cabbage. (3) Compared with CFs, the application of organic fertilizers can significantly increase the content of vitamin C (11.06%), soluble sugar (19.16%), and soluble protein (8.83%) and reduce the content of nitrate and nitrite in Chinese cabbage, with a reduction of up to 19.02% and 20.9%, respectively. The application of organic fertilizers will also have a certain impact on the absorption of heavy metals in Chinese cabbage. (4) Compared with CFs, the application of organic fertilizers can significantly improve soil organic matter, soil carbon sequestration, nitrogen absorption, and potassium absorption, showing increases of 12.73%, 13.19%, 7.91%, and 7.37%, and the application of organic fertilizers reduces soil electrical conductivity and available nitrogen, showing decreases of 36.78% and 38.75%, respectively. (5) The application of organic fertilizers significantly increased the content of soil urease and soil sucrase, increasing by 9.42% and 17.16%, respectively. This study helps inform the application of organic fertilizers in Chinese cabbage production.

Effects of Water–Nitrogen Interaction on Sandy Soil, Physiology, and Morphology of Tall Fescue (Festuca arundinacea Schreb) Turf

The soil water and nitrogen (N) levels are the important factors affecting turfgrass growth. However, the impact of the water–N interaction on tall fescue (Festuca arundinacea Schreb) in terms of the N metabolism and plant morphology remains uncertain. Therefore, the objective of this study was to investigate the impacts of different N and water levels on the physiological and morphological responses of tall fescue. The experiment was designed with N (N0, N2, and N4 representing N application rates of 0, 2, and 4 g m–2, respectively) and irrigation [W1, W2, W3, W4, and W5 representing field water capacities (FWCs) of 90~100%, 75~85%, 60~70%, 45~55%, and 30~40%, respectively] treatments, and the relevant indexes of the soil water content and soil NH4+–N and NO3−–N levels as well as the physiology and morphology of the tall fescue were determined. The results demonstrated significant changes in the contents of soil water (SWC) and N and the physiological and morphological indexes, except for the enzymes related to N metabolism, including nitrite reductase (NiR), glutamate dehydrogenase (GDH), and glutamate synthetase (GOGAT). The water stress significantly enhanced the water and N use efficiencies (WUE and NUE), except the NUE in the W5 treatment. The N stress significantly influenced the SWC, soil NO3−–N content, and physiological and morphological indexes, excluding malondialdehyde, NiR, GOGAT, and above- (AGB) and below-ground biomass, resulting in the increased WUE and NUE. The application of a low N rate effectively alleviated the detrimental impacts of water stress on the SWC and glutamine synthetase activity. In conclusion, W2 and N2 are deemed more appropriate treatments for the low-maintenance measures of tall fescue turf. Among all the treatments, N2W2 is recommended as the optimal water–N interaction treatment due to its ability to conserve resources while still ensuring high turf quality.

Влияние азотного питания на урожайность и аккумулирование нитратов отечественными и зарубежными сортами столовой свеклы в условиях Ленинградской области

The selection of varieties and the level of nitrogen nutrition are important technological elements that determine the yield and quality of table beets when grown on sod-podzolic soil. The article discusses the varietal response of table beet varieties to an increased level of nitrogen nutrition N180 and deficient N0. The varieties that accumulate the maximum and minimum amount of nitrates in different phases of growth and development, more effectively using soil nitrogen compounds or nitrogen fertilizers are identified. The varieties Golden Beet (9.12 kg/m2), Kholodostoykaya 12 (8.94 kg/m2) turned out to be more responsive than others to the application of an increased dose of nitrogen fertilizers, and the greatest increase in the yield of root crops to the background N0 was obtained in the varieties Kholodostoykaya 19, Tsilindra, Egyptian flat and PabloF1. Keywords: TABLE BEET, NITROGEN NUTRITION, VARIETIES, NITRATES, YIELD

The Influence of a Practical Remediation Medium on the Relationship of Exchange Reaction in Soil to Hazardous Lead and Inorganic Forms of Nitrogen

Abstract The objective of this research was to analyse soil and garden compost as a remediation medium at the foothill´s locality of the Tribeč Mountains, Southwestern Slovakia, to determine the pH/KCl, Pb, NO3 −-N, NH4 +-N contents in soil and soil affected by compost (the ratio 1 : 1), to evaluate the statistical significance of pH/KCl in relation to Pb and inorganic forms of nitrogen, and to find whether garden compost affects the monitored parameters. The analyses were carried out using Atomic Absorption Spectrometry, and Colorimetric and Potentiometric methods. Ascertained values of exchange reactions in soil ranged from 5.74 to 6.83 and exchange reactions in soil affected by garden compost ranged from 6.78 to 7.98. According to the calculated indices of dependencies, the development of pH/KCl values can be evaluated as moderately dynamic. The obtained results were evaluated statistically using the SAS 9.4 software method by the Spearman‘s correlation coefficient. The results in the observed three-year period showed that NO3 −-N contents in soil had reached 14.73 mg.kg−1, NH4 +-N 9.50 mg.kg−1, Nin 23.05 mg.kg−1, Pb 67.38 mg.kg−1, soil affecting by remediation medium – garden compost (the ratio 1 : 1) showed that NO3 −-N contents had reached 23.93 mg.kg−1, NH4 +-N 26.42 mg.kg−1, Nin 42.63 mg.kg−1, Pb 64.71 mg.kg−1 dry matter. Statistical dependence was high (P <0.01), which was demonstrated for soil pH : soil + compost Pb, soil + compost pH : soil + compost Pb. The garden compost influenced pH/KCl, reduced Pb levels, and increased the proportion of inorganic forms of nitrogen in soil.

Potent Nitrogen-containing Milkweed Toxins are Differentially Regulated by Soil Nitrogen and Herbivore-induced Defense.

Theories have been widely proposed and tested for impacts of soil nitrogen (N) on phytochemical defenses. Among the hundreds of distinct cardenolide toxins produced by milkweeds (Asclepias spp.), few contain N, yet these appear to be the most toxic against specialist herbivores. Because N- and non-N-cardenolides coexist in milkweed leaves and likely have distinct biosynthesis, they present an opportunity to address hypotheses about drivers of toxin expression. We tested effects of soil N and herbivore-damage on cardenolide profiles of two milkweed species differing in life-history strategies (Asclepias syriaca and A. curassavica), and the toxicity of their leaves. In particular leaf extracts were tested against the target enzymes (Na+/K+-ATPase extracted from neural tissue) from both monarch butterflies (Danaus plexippus) as well as less cardenolide-resistant queen butterflies, D. gilippus. Increasing soil N enhanced biomass of Asclepias syriaca but had weak effects on cardenolides, including causing a significant reduction in the N-cardenolide labriformin; feeding by monarch caterpillars strongly induced N-cardenolides (labriformin), its precursors, and total cardenolides. Conversely, soil N had little impact on A. curassavica biomass, but was the primary driver of increasing N-cardenolides (voruscharin, uscharin and their precursors); caterpillar induction was weak. Butterfly enzyme assays revealed damage-induced cardenolides substantially increased toxicity of both milkweeds to both butterflies, swamping out effects of soil N on cardenolide concentration and composition. Although these two milkweed species differentially responded to soil N with allocation to growth and specific cardenolides, leaf toxicity to butterfly Na+/K+-ATPases was primarily driven byherbivore-induced defense. Thus, both biotic and abiotic factors shape the composition of phytochemical defense expression, and their relative importance may be dictated by plant life-history differences.

Analysis of the composition and function of rhizosphere microbial communities in plants with tobacco bacterial wilt disease and healthy plants

ABSTRACT To explore the factors influencing the occurrence of bacterial wilt, the differences in the physicochemical properties, microbial community composition and function between rhizosphere soil of tobacco plants with bacterial wilt and healthy plants in the tobacco planting area of Fuzhou City, Jiangxi Province were analyzed and compared. The results showed that the rhizosphere soil of diseased tobacco exhibited significantly reduced levels of exchangeable potassium, water-soluble potassium, nitrate nitrogen, total nitrogen and pH, in comparison to the rhizosphere soil of healthy plants. Conversely, the available phosphorus content of the rhizosphere soil of diseased tobacco was significantly increased. The amount of Ralstonia solanacearum in soil was negatively correlated with pH, nitrate nitrogen and total nitrogen, and positively correlated with exchangeable potassium and water-soluble potassium. A total of 43 genera were significantly different between the two groups of rhizosphere soil, of which 24 genera were enriched in the rhizosphere of healthy plants, including Ideonella , Rhizophagus , Rhizobacter , Altererythrobacter and Ignavibacterium associated with plant disease resistance, Thermodesulfovibrio , Syntrophorhabdus , Syntrophus , Chlorobium , Hydrogenophaga and Limnohabitans associated with soil sulfur metabolism, as well as Ignavibacterium , Ideonella , Derxia and Azohydromonas associated with soil nitrogen cycling. Kyoto Encyclopedia of Genes and Genomes functional analysis of the unigenes obtained by metagenomic sequencing also showed that the differential unigenes were significantly enriched in the sulfur metabolism pathway. In addition, the rhizosphere soil of diseased tobacco plants exhibited a higher abundance of antibiotic-producing actinomycetes and an increased load of antibiotic resistance genes compared to that of healthy plants. In general, lower pH value, less content of nitrate nitrogen and total nitrogen, and more content of exchangeable potassium and water-soluble potassium could contribute to onset of bacterial wilt. Twenty-four genera, including Ideonella and Rhizophagus , may construct a healthy microecological network in the rhizosphere of tobacco plants. All these factors may interact with each other to control the development of bacterial wilt. This complicated interaction network needs to be explored further. IMPORTANCE Previous studies have mainly focused on the differences in microbial species composition between healthy and diseased soils, but the differences in microbial community functions between two types of soil have not been well characterized. In this study, soil samples in diseased and healthy plant rhizospheres were collected for physicochemical property testing and metagenomic sequencing. We focused on analyzing the differences in physicochemical properties and microbial community functions between these soils, as well as the correlation between these factors and pathogen content. The results of this study provide a theoretical basis for further understanding the occurrence of tobacco bacterial wilt in the field.

Effects of nitrogen fertilization and micro-sprinkler irrigation on soil water and nitrogen contents, their productivities, bulb yield and economics of winter onion production

Effects of nitrogen fertilization and micro-sprinkler irrigation on soil water and nitrogen contents, their productivities, bulb yield and economics of winter onion production

Synthesis and Evaluation of Starch-Grafted-Poly[(Acrylic Acid)-Co-Acrylamide] Based Nanoclay Polymer Composite Fertilizers for Slow Release of Nitrogen in Soil.

Nitrogen (N) losses from conventional N fertilizers contribute to environmental degradation and low N use efficiency. Highlighting the need for slow-release fertilizers (SRFs) to mitigate these problems, this study aims to develop slow-release N fertilizers using starch-grafted-poly[(acrylic acid)-co-acrylamide] based nanoclay polymer composites (NCPCs) and investigate their efficacy for slow N delivery in soil. Three types of NCPCs, NCPC(A) (poly [(acrylic acid)-co-acrylamide]), NCPC(W) (wheat starch-grafted-poly[(acrylic acid)-co-acrylamide), and NCPC(M) (maize starch-grafted-poly[(acrylic acid)-co-acrylamide) were prepared and characterized using FTIR spectroscopy and X-ray diffraction techniques. N-release behaviour of the products was assessed under two distinct soils, i.e., Assam (Typic Hapludults, pH 4.2) and Delhi (Typic Haplustepts, pH 7.9) soils. Additionally, the effects of varying soil moisture and temperature levels on N release were studied in the Assam soil. The N-release kinetics of the synthesized fertilizers were assessed using zero-order, first-order, Higuchi, and Korsmeyer-Peppas models. Degradability of the NCPCs was evaluated by measuring evolved CO2-C under various soil conditions as an indicator of microbial degradation. The results indicated that NCPC fertilizers significantly slowed down the release of N compared to urea. According to the R2 values obtained, it was evident that the first-order kinetic model most accurately describes the N release from both urea and NCPC-based N fertilizers in the studied soils. Among the formulations, NCPC(A) exhibited the lowest N release (42.94-53.76%), followed by NCPC(M) (51.05-61.70%), NCPC(W) (54.86-67.75%), and urea (74.33-84.27%) after 21 days of incubation. The rate of N release was lower in the Assam soil compared to the Delhi soil, with higher soil moisture and temperature levels accelerating the release. Starch addition improved the biodegradability of the NCPCs, with NCPC(W) showing the highest cumulative CO2-C evolution (18.18-22.62 mg g-1), followed by NCPC(M) (15.54-20.97 mg g-1) and NCPC(A) (10.89-19.53 mg g-1). In conclusion, NCPC-based slow-release fertilizers demonstrated a more gradual N release compared to conventional urea and the inclusion of starch enhanced their degradability in the soil, which confirms their potential for sustainable agricultural applications. However, soil properties and environmental factors influenced the N release and degradation rates of NCPCs.

Effect of Different Irrigated Crop Successions on Soil Carbon and Nitrogen–Phosphorus–Potassium Budget Under Mediterranean Conditions

Sustainability in agroecosystems relies on the optimized use of resources to achieve consistent yields while maintaining or improving soil health. The monitoring of soil quality is crucial when changes from rainfall-fed to irrigated crop systems occur. The objective of this study was to assess the impact of different crop successions in the Mediterranean area under irrigation and different technical practices. The soil nitrogen–phosphorous–potassium (NPK) and soil organic carbon (SOC) balances were observed in four fields with irrigated annual crops in a two-year succession timeframe, namely, sunflower–maize (P1), sunflower–clover (P2), maize–sunflower (P3), and alfalfa–alfalfa (P4). The SOC and nutrient balance, integrating the total irrigation, mineral fertilizers, and exported yield, was calculated for each farm. Except for maize–sunflower succession (P3), all fields presented a negative SOC balance at the end of the two-year crop succession, indicating losses from 2.84 to 4.91 Mg SOC ha−1 y−1. While in N-fixing plants the soil N decreased, in the remaining crops a surplus was observed, possibly leading to future N losses. The continuous depletion of soil P revealed a potential underestimation of this nutrient. Soil K appears to be related to specific crop management practices, namely, crop residue incorporation after harvest. In annual irrigated crops under Mediterranean conditions, crop succession can induce soil fertility degradation if conservation practices are absent.

EFFECT OF VERMICOMPOST AND BIOFERTILIZATION ON THE AVAILABILITY OF SOME SOIL NUTRIENTS, GROWTH AND YIELD OF SQUASH (Cucurbita pepo L.)

A field experiment was carried out to evaluate the effect of four application methods of vermicompost tea (without application, ground application, foliar spray, combination of - ground application + foliar spray) , four types of biofertilization (without application, Stenotrophomonas maltophilia, Bacillus megaterium, the combination consisting of S. maltophilia + B. megagaterium), and two levels (0, 50%) of the fertilizer recommendation in the availability of some soil nutrients and on the growth and yield of squash using as randomized complete block design with three replications. The results showed that the triple interaction of the combination of application vermicompost tea with the combination of biofertilizer and 50% of mineral fertilizer was effect significantly and gave the highest values for some vegetative growth parameters. Which included the dry weight of the vegetative part, the length and weight of the root, and total yield which amounted 196.35 g plant-1, 65.33 cm, 60.31 g plant-1, 45.14 Mgha-1, respectively. the available of nitrogen, phosphorous and potassium in soil at the end of the experiment, which amounted 60.56, 38.20 and 191.38 mg kg-1soil in comparison with the treatment without addition, which gave the lowest rates.

Impacts of the coexistence of polystyrene microplastics and pesticide imidacloprid on soil nitrogen transformations and microbial communities

The pollution of agricultural soils by microplastics (MPs) and pesticides has attracted significant attention. However, the combined impact of MPs and pesticides on soil nitrogen transformation and microbial communities remains unclear. In this study, we conducted a 28-day soil incubation experiment, introducing polystyrene microplastics (PS-MPs) at concentrations of 0.1% and 10% (w/w) and pesticide imidacloprid at concentrations of 0.1 mg/kg and 1.0 mg/kg. Our aim was to investigate the individual and combined effects of these pollutants on nitrogen transformations and microbial communities in agricultural soils. Imidacloprid accelerated the decline in soil pH, while PS-MPs slowed the process. Imidacloprid hindered soil nitrification and denitrification processes, however, the presence of PS-MPs mitigated the inhibitory effects of imidacloprid. Based on microbial community and functional annotation analyses, this is mainly attributed to the different effects of PS-MPs and imidacloprid on soil microbial communities and the expression of key nitrogen transformation-related genes. Variance partitioning analysis and partial least squares path modeling analyses revealed that PS-MPs and imidacloprid indirectly influenced the microbial community structure, primarily through changes in soil pH. This study elucidates the mechanism through which the combined stress of MPs and pesticides in agricultural soils influence soil nitrogen transformation and microbial communities. The findings offer valuable insights for the systematic evaluation of the ecological risks posed by the coexistence of these pollutants.

Organic cropping systems balance environmental impacts and agricultural production

Agriculture provides food to a still growing population but is a major driver of the acceleration of global nutrient flows, climate change, and biodiversity loss. Policies such as the European Farm2Fork strategy aim to mitigate the environmental impact of land-use by fostering organic farming. To assess long-term environmental impact of organic food production we synthesized more than four decades of research on agronomic and environmental performance of the oldest system comparison experiment on organic and conventional cropping systems (DOK experiment). Two organic systems (bioorganic and biodynamic) are compared with two conventional (manure-based integrated and mineral-based) systems all with the same arable crop rotation including grass-clover, and manure from livestock integrated in all except the mineral-based system. Organic systems used 92% less pesticides and 76% less mineral nitrogen than conventional systems. Nitrogen use efficiency, that also considers biological nitrogen fixation, was above 85% for all systems. Organic fertilization with farmyard manure maintained or increased soil carbon and nitrogen stocks in the long term, especially in the biodynamic system with manure compost. Conventional mineral-based cropping reduced soil organic carbon and nitrogen stocks. Higher soil organic carbon stocks in organic cropping did not translate to increased N2O emissions, which were the main driver for 56% lower soil-based, area-scaled climate impact compared to the integrated conventional system with manure. Organic cropping systems, especially compost-based biodynamic, showed enhanced soil health, richness of micro- and macrofauna and weed species. Highest yields were achieved in integrated conventional system, with highest total nitrogen inputs and enhanced soil health compared to pure mineral fertilization. Yet, these benefits come at the cost of lower nitrogen use efficiency and higher N2O emissions. Despite a rigorous reduction of inputs yields of the organic systems achieved 85% of the conventional systems. We demonstrate at field level that organic cropping systems with reduced external nutrient inputs have less climate impact and a larger in-situ biodiversity, while providing a fertile ground for the future development of sustainable agricultural production systems.

Carbon Storage and Fluxes from Sphagnum Peatlands of the Bogong High Plains, Australia

Australian alpine peatlands are critically important ecosystems that deliver a range of valuable services. However, our understanding of these services in Australia, particularly peatland carbon cycling, is lacking. Here, we quantified peat soil carbon (C) and nitrogen (N) concentrations, C:N ratios, and C density in eight Sphagnum-dominated peatlands on the Bogong High Plains, southeastern Australia. Soil C and N concentrations averaged 16.5 ± 13.2% and 0.6 ± 0.4%, respectively. C:N ratios averaged 30.9 ± 20.4, and C density averaged 46.6 ± 20.7 mg C cm− 3. Our findings suggest that (1) peat biogeochemistry is highly variable between sites, even at small spatial scales; and (2) while not a direct focus of the study, peat depths in this area were relatively shallow, ranging from 30 to 60 cm, most likely due to previous disturbance causing peat removal and carbon loss. Additionally, we present preliminary data investigating CO2 and CH4 fluxes at these sites. We recommend that future research includes (1) age dating peat cores to better understand the role of disturbance in rates of peat accumulation and loss; and (2) long-term carbon flux studies at multiple peatland sites.

Effect of Various Nitrogen Doses and Plant Growth Regulators on Nutrient Uptake and Productivity of Wheat (Triticum aestivum L)

A field experiment was conducted at Research Farm of Bihar Agricultural University, Sabour, Bhagalpur, Bihar, during season of 2019-20, to find out the effect of optimization of nitrogen doses for high yield potential of wheat with plant growth regulators. The experiment was laid out in randomized block and replicated thrice. The experiment ten treatment of different doses of fertilizer with plant growth regulators chlormequat chloride and tebuconazole applied at 0.2% and 0.1% respectively. Experimental revealed that application of 150% recommended doses of NPK resulted significantly higher available nitrogen (171.82 kg ha-1), available phosphorus (27.01 kg ha-1) and available potassium (192.27 kg ha-1) in soil after the harvest of wheat significantly highest nitrogen, phosphorus and potassium uptake by wheat recorded with 150% RDF of NPK with chlormequat chloride (0.2%) and tebuconazole (0.1%). Significantly highest grain and straw yield recorded with 150% NPK + chlormequat chloride (0.2%) and tebuconazole (0.1%) at par with 100% RDF as compare to other treatments harvest index was recorded 125% RDF of N and chlormequat chloride (0.2%) and tebuconazole (0.1%) and 150% RDF of N and chlormequat chloride (0.2%) and tebuconazole (0.1%). The uptake of key nutrients, nitrogen, phosphorus and potassium followed a similar pattern, with 150% recommended doses of NPK along chlormequat chloride (0.2%) and tebuconazole (0.1%). optimal NPK application resulted in positive nutrient balance in the soil. This investigation that managing nutrient with growth regulator in wheat is an economically viable and ecologically sound approach to improve both crop production and soil health through balanced nutrition.

Genetic Diversity of Maize (Zea mays L.) Genotypes under Low Level of Nitrogen

Maize (Zea mays L.) is India's second most significant crop, behind rice. As a cross-pollinated crop, hybrid vigour is commonly used to achieve the best production potential. The selection of various genotypes is a primary goal in the maize hybrid breeding programme. Maize is a voracious feeder and requires a lot of fertiliser. The biggest limits on maize production in India are low soil nitrogen and high fertiliser costs. Jharkhand consumes only 82.5 kg of total fertiliser nutrients per acre. In order to discover genetically varied maize genotypes for nitrogen usage efficiency, the current study evaluated 121 maize genotypes in a randomised block design with two replications at low nitrogen levels. Plant height, days to 50% pollen shed, days to 50% silk, anthesis-silking interval (ASI), days to75% maturity, number of leaves per plant, root length, stover yield per plant, grain yield per plant, and harvest index were all recorded. Statistical analysis was performed using the morphological trait data. Analysis of variance revealed substantial (p≤0.05) variations in morphological features between maize genotypes. For statistical analysis, a clustering method was used to locate various genotypes with greater genetic distance in order to develop good heterotic combinations. One hundred twenty one genotypes were divided into six clusters using the dendogram-by-ward minimum variance approach. Cluster III and V had the greatest inter-cluster distance (79.26), followed by cluster III and VI (74.77) and cluster II and III (73.80). The many heterotic combinations developed from these clusters can be employed in subsequent breeding programmes to produce low nitrogen-requiring hybrids with a low yield penalty.

Endophytic fungus regulates the root secretion of IAA and ABA to increase rice nitrogen accumulation by promoting soil nitrogen fixation

Endophytic fungus regulates the root secretion of IAA and ABA to increase rice nitrogen accumulation by promoting soil nitrogen fixation

Cenchrus spinifex Invasion Alters Soil Nitrogen Dynamics and Competition

Invasive plants often alter biological soil conditions to increase their own competitiveness. Through indoor simulated nitrogen deposition culture experiments, we investigated the differences in growth indicators and nutrient content levels between the invasive plant Cenchrus spinifex Cav. and the native symbiotic plant Agropyron cristatum (L.) Gaertn. under diverse nitrogen application modes and planting-competition ratios. Furthermore, we examined the alterations in key microbial communities involved in soil nitrogen cycling of C. spinifex. The results indicated that the invasion of C. spinifex could inhibit the growth of native plants, and in fact altered the accumulation and transformation processes related to soil nitrogen, resulting in reduced rates of soil nitrogen transformation. The overarching aim of this research was to construct a theoretical foundation for the scientific comprehension of the invasion mechanisms of C. spinifex, in order to better prevent the further spread of this invasive plant and mitigate its pernicious impact on the current environment.

Yield and Economic Analysis of Rice (Oryza sativa L.) as Influenced by the Nano Forms of Nitrogen and Zinc

A field experiment was conducted at College Farm of College of Agriculture located in Rajendranagar, Hyderabad, Telangana, conducted research during the rabi season of 2020-21, focusing on the effects of nano nitrogen and nano zinc in sandy loam soils. The experimental design employed was a randomized block design (RBD), comprising ten distinct treatments, each replicated three times. The treatments viz., Control (T1), 100% N through urea (T2), T2 + soil application of ZnSO4 at transplanting (T3), T2 + foliar spray of 4 ml L-1 nano nitrogen at tillering and before panicle initiation stage (T4), T2 + foliar spray of 2 ml L-1 nano zinc at tillering and before panicle initiation stage (T5), T2 + foliar spray of 4 ml L-1 nano nitrogen at tillering and before panicle initiation stage + foliar spray of 2 ml L-1 nano zinc at tillering and before panicle initiation stage (T6), 75% N through urea + foliar spray of 4 ml L-1 nano nitrogen before panicle initiation stage. (T7), T7 + foliar spray of 2 ml L-1 nano zinc at tillering and before panicle initiation stage (T8), 50% N through urea + foliar spray of 4 ml L-1 nano nitrogen at tillering and before panicle initiation stage (T9), T9 + foliar spray of 2 ml L-1 nano zinc at tillering and before panicle initiation stage (T10). The results indicated that the highest grain yield (6810 kg ha-1) was registered with treatment T10 which is on par with T9. The highest net returns (86649 Rs ha-1) and B:C ratio (2.99) were noticed by the application of T10.

Effects of Decabromodiphenyl Ethane and Cadmium Coexposure on Their Bioaccumulation, Oxidative Stress, Root Metabolism, and Rhizosphere Soil Microorganisms in a Soil-Rice System.

Decabromodiphenyl ethane (DBDPE) and cadmium (Cd) are typical pollutants in e-waste, seriously threatening crop growth. This study investigated the bioaccumulation and toxicity mechanisms of DBDPE and Cd in a soil-rice system. The results showed that 50 mg/kg DBDPE could reduce the level of accumulation of Cd in rice roots. DBDPE and Cd induced the antioxidant system (SOD, POD, and MDA) in rice seedlings. The combined exposure reduced the contents of carbohydrates, lipids, amino acids, and organic acids. Phenylalanine and phenylpropanoid metabolisms were identified as the key detoxification metabolic pathways under combined exposure. DBDPE and Cd disrupted the functional cycling of carbon and nitrogen in rhizosphere soil, while Gemmatimonadetes, Actinobacteria, and Bacteroidetes were the key bacterial groups responding to DBDPE and Cd stress. This work provides data for the toxicity risk evaluation of DBDPE and Cd combined exposure to food crops.