N2 Treatment Research Articles

Effect of Nitrogen on Microbial Communities of Purple Mudstone Weathering Products in Southwest China: A Column Experiment.

Nitrogen application significantly affects microorganisms in agricultural ecosystems. However, it is still unclear how nitrogen application affects soil chemical properties and microbial communities in purple mudstone weathering products. In this study, a field soil column experiment was conducted in a typical purple soil area with four nitrogen fertilizer application gradients of 0 [CK], 280 [N1], 560 [N2], and 840 [N3] N kg ha-1. Nitrogen addition decreased the bacterial chao1 value and increased the bacterial evenness index. For both α- and β-diversity, the effect of nitrogen addition on bacteria was much greater than that on fungi. Nitrogen addition significantly increased the relative abundance of Proteobacteria, Gemmatimonadetes, Bacteroidetes, and Ascomycota and decreased the relative abundance of Actinobacteria, Cyanobacteria, and Basidiomycota. Both pH and TC are the most important soil chemical properties influencing the bacterial and fungal communities. With the increases in the nitrogen application rate, the co-occurrence network complexity increased and then decreased. In summary, nitrogen fertilizer application could significantly change the soil chemical properties, microbial community diversity, composition, and co-occurrence network of purple mudstone weathering products. Among them, the N2 treatment (560 N kg∙ha-1) can more effectively stimulate the soil nutrients, enhance microbial network complexity, and promote further weathering of purple mudstone.

Castor Bean Meal Fertilizer Improves Peanut Yield and Quality by Regulating the Soil Physicochemical Environment and Soil Enzyme Activities

PurposeFertilization is important for improving crop yield and soil quality. Elucidation of the effects of castor bean meal (CBM) fertilizer on peanut yield and quality and soil fertility can lead to additional fertilization options for peanut and provide a theoretical reference for achieving a high-quality, high-yielding peanut.MethodsDuring 2022–2023, a two-year long-term field experiment was conducted in Tongliao city, Inner Mongolia, China. No fertilizer (CK) was used as the control, and the effects of different treatments, i.e., CBM fertilizer (B1: 2520 kg ha-1, B2: 5040 kg ha-1, and B3: 10,080 kg ha-1), chemical fertilizer alone (F1: 175 kg ha-1, F2: 350 kg ha-1, and F3: 700 kg ha-1), and cow manure alone (N1: 3724 kg ha-1, N2: 7448 kg ha-1, and N3: 14,896 kg ha-1) on peanut yield and quality and soil fertility were investigated.ResultsThe results showed that CBM fertilizer application improved soil ecology. Compared with other fertilization treatments, the soil pH of B3 treatment decreased by 8.5%, but significantly increased the contents of organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzed nitrogen (AN), basic phosphorus (AP) and rapidly available potassium (AK) in the soil, which increased by 86.4%, 64.6%, 70.5%, 11.3%, 75.8%, 150.1%, and 116.2%, respectively, compared with CK. Meanwhile, B1, B2, N1 and N2 treatments also led to the elevation of the above indexes. In addition, the activities of urease (URE), sucrase (SUC), phosphatase (PPL), catalase (CAT), amylase (AMY) and protease (PRO) in the B3 treatment were significantly greater than those in the other fertilization treatments, with increases of 256.4%, 248.4%, 68.2%, 96.8%, 267.3%, and 155.7%, respectively, compared with CK. The B3 treatment also significantly increased the rootlet length(PRL), number of branches(BN), plant height(PLH) and lateral branch length(LBL) of the peanut plants. Compared with the other treatments, the B3 treatment had a greater peanut yields, reaching 8059.5 kg ha-1 and 9935.7 kg ha-1 in 2022 and 2023, respectively. Compared with the other treatments, the B1 treatment significantly increased the contents of protein (Pro), fat (FAT), unsaturated fatty acid (UFA) and vitamin E (VE), which increased by 23.3%, 6.1%, 1.0%, 29.1%, respectively, compared with CK, but the total sugar (TS) content was reduced by 9.1%. Correlation analysis further confirmed that peanut yield and quality were significantly correlated with soil nutrients and enzyme activities.ConclusionsThis study showed that the application of CBM fertilizer has certain positive effects. For example, the B3 treatment has certain potential for increasing peanut yield, and the B1 treatment can be used for peanut quality improvement. Therefore, CBM fertilizer is recommended as a new type of organic fertilizer for improving the peanut quality and yield.

Nitrogen fertilization affected microbial carbon use efficiency and microbial resource limitations via root exudates

Root exudation and its mediated nutrient cycling process driven by nitrogen (N) fertilizer can stimulate the plant availability of various soil nutrients, which is essential for microbial nutrient acquisition. However, the response of soil microbial resource limitations to long-term N fertilizer application rates in greenhouse vegetable systems has rarely been investigated. Therefore, we selected a 15-year greenhouse vegetable system, and investigated how N fertilizer application amount impacts on root carbon and nitrogen exudation rates, microbial resource limitations and microbial carbon use efficiency (CUEST). Four N treatments were determined: high (N3), medium (N2), low (N1), and a control without N fertilization (N0). Compared to the control (N0), the results showed that the root C exudation rates decreased significantly by 42.9 %, 57.3 % and 33.6 %, and the root N exudation rates decreased significantly by 29.7 %, 42.6 %, and 24.1 % under N1, N2, and N3 treatments, respectively. Interactions between fertilizer and plant roots altered microbial C, N, P limitations and CUEST; Microbial C and N/P limitations were positively correlated with root C and N exudation rates, negatively correlated with microbial CUEST. Random Forest analysis revealed that the root C and N exudation rates were key factors for soil microbial resource limitations and microbial CUEST. Through the structural equation model (SEM) analysis, soil NH4+ content had significant direct effects on the root exudation rates after long-term N fertilizer application. An increase in root exudation rates led to enhanced microbial resource limitations in the rhizosphere soils, potentially due to increased competition. This enhancement may reduce microbial carbon use efficiency (CUE), that is, microbial C turnover, thereby reducing soil C sequestration. Overall, this study highlights the critical role of root exudation rates in microbial resource limitations and CUE changes in plant-soil systems, and further improves our understanding of plant-microbial interactions.

Evaluating the Influence of Different Agronomic Strategies on the Growth and Development of Maize (Zea mays L.) Grown in Rice Fallows of Northern Telangana Zone

Aims: To study the changes in plant height, dry matter production, leaf area and plant population under different tillage practices, irrigation and nitrogen levels in rice fallow maize. Study Design: Split- split plot design. Place and Duration of Study: Regional Agricultural Research Station farm, Polasa, Jagtial during rabi 2022-23 and 2023-24. Methodology: The experiment was laid out in split- split plot design with twelve treatment combinations that includes 2 main plot, 3 sub plot and 2 sub-sub plot treatments which are replicated thrice. The treatments are as follows: Main plots: T1- Zero tillage, T2- Conventional tillage (tillage with cultivator twice fb rotovator twice); Sub plots: I1- Irrigation at 60% ASM, I2- Irrigation at 40% ASM and I3- Irrigation at six critical stages; and Sub-sub plot treatments: N1- 100% RDN (240 kg ha-1) and N2- 120% RDN (288 kg ha-1). Results: Results indicated that highest mean plant height was recorded in conventional tillage (65.8, 204.4 & 210.9 cm) and in N2 treatment (64.6, 201.3 & 207.6 cm) during sixth leaf, silking and physiological maturity respectively. Irrigations showed non-significant effect during sixth leaf and during other two stages I3 treatment has recorded higher plant height (200.1 & 206.6 cm). Similar results were obtained in case of leaf area. The mean dry weight was also higher in conventional tillage (17915 kg ha-1), I3 treatment (16789 kg ha-1) and N2 (16418 kg ha-1). The initial plant population was higher in conventional tillage (7.2 plants m-2) than that of zero tillage and irrigation & nitrogen levels has no effect on population. Conclusion: All the growth parameters were significantly affected by tillage, irrigation and nitrogen levels at all the stages except the influence of irrigation on plant height at sixth leaf stage. Plant population was significantly affected by tillage but non-significant effect was recorded by irrigation an nitrogen levels. Interaction was found between irrigation and nitrogen levels in-case of dry matter production.

Effects of Nitrogen Application and Planting Density Interaction on the Silique-Shattering Resistance and Yield of Direct-Seeding Rapeseed (Brassica napus L.) in Sichuan

Rapeseed siliques easily shatter after ripening, resulting in a significant amount of grain loss, which delimits the development of rapeseed machine harvest. However, the effect of nitrogen (N) and density interaction on the characteristics of rape siliques and shattering resistance index is still vague. During the 2021–2022 and 2022–2023 growing seasons, we selected the Jiayou No. 5 rapeseed variety and set three N application levels (N1: 90 kg ha−1, N2: 180 kg ha−1, N3: 270 kg ha−1) and two density treatments (M1: 150,000 plants ha−1, M2: 300,000 plants ha−1) to research the effects of N and density interaction on morphological indexes, physiological indexes, shatter resistance index and yield of direct-seeding rapeseed siliques. The silique shatter resistance index, silique’s length, weight, moisture content, silique shell’s weight, thickness, lignin content, cellulose content and phenylalaninase (PAL) activity all increased first and then decreased with the increase in the N application rate; the N2 treatment increased by 18.38% and 26.92%, respectively, compared to the N1 and N3 treatments; 3.65%, 2.48%; 6.70%, 3.58%; 20.46%, 18.33%; 5.97%, 5.96%; 8.82%, 9.60%; 9.12%, 19.90%; 43.85%, 69%; 2.10%, 11.04%. Compared with the M1 treatment, the silique shatter resistance index, silique’s length, weight, moisture content, silique shell’s weight, thickness, lignin content, cellulose content and PAL activity were lower under M2 treatment. Correlation analysis demonstrated that the silique’s length, water content, silique shell’s weight, thickness, lignin content, cellulose content and PAL activity were significantly positively correlated with the silique shatter resistance index. Therefore, this study shows that N2M1 treatment can carry off synergy between silique shatter resistance and yield.

تأثير إضافة الاسمدة الحيوية وسماد خث زهرة النيل والرش بمستخلصه في الصفات النوعية لحاصل البطاطا

The field experiment was carried out in Horticulture Development Station in the Kut district of the Directorate of Agriculture of Wasit Governorate at spring season 2022, This study was aimed to demonstrate the effect of inoculation some Bio-fertilizers, adding Nile flower peat fertilizer and spraying with its extract on qualitative characteristics potato yield, The experiment was implemented using factorial experiment(4×3×2) within Randomized Complete Block Design with three replicates, The First factor included the inoculation with Biofertilizers and cod it (M), which is(M0) Don’t be discouraged , (M1) inoculation the Mycorrhiza in pollen density of 25 g.tuber-1 ,(M2) inoculation the Trichoderma pollen density of 4 g.tuber-1and (M3)Mixture Mycorrhiza and Trichoderma fungi together, The second factor included the addition of Nile flower peat fertilizer and cod it (N), which is (N0) without adding, (N1)added 15 ton.ha-1 and (N2) added 30 ton.ha-1, The third factor included spraying with Nile flower peat fertilizer extract and cod it (E), spraying with distilled water(E0) and spraying with extract 2 ml.L-1 (E1), The results showed that biofertilization was significantly superior in qualities characteristics of the yield represented by dry matter percentage, starch percentage ,specific density, soluble solids percentage and tuber hardness, compared with control (M0(, M3 treatment produced greatest value of this characteristics which reached 16.84%, 11.01%, 1.0640 g cm-2, 6.459%, 8.167 kg cm-2. Organic fertilization showed significant increase in the above characteristics, N2 treatment produced greatest value which reached 17.20%, 11.33%, 1.0657g cm-2, 6.633%, 8.179 , kg cm-2. Spraying treatment had amoral superiority on above characteristics if produced 16.50%, 10.70%, 1.0623 g cm-2, 6.407 %, 7.944 kg cm-2.

Effect of nitrogen fertilizer on the quality traits of Indica rice with different amylose contents.

Nitrogen is a key factor affecting the quality of rice. Studying the impact of nitrogen fertilizer on the taste, physicochemical properties, and starch structure of Indica rice with different amylose contents is of great significance for scientifically fertilizing and cultivating high-quality rice varieties for consumption. The results indicate that increasing nitrogen fertilizer application reduces the amylose content and increases the protein content, resulting in a decrease in taste quality. Simultaneously, it reduces the intergranular porosity of starch particles, improving the appearance and milling quality of rice. Compared to the N1 treatment (nitrogen fertilizer application rate of 90 kg ha-1), the taste of low-amylose rice (Yixiangyou 2115) and high-amylose rice (Byou 268) decreased by 14.24% and 19.79%, respectively, under N4 treatment (nitrogen fertilizer application rate of 270 kg ha-1). The effect of nitrogen fertilizer on low-amylose rice is mainly reflected in increased rice hardness, enthalpy value, and setback viscosity, resulting in a decline in taste. The effect of nitrogen fertilizer on high-amylose rice is mainly reflected in a decrease in peak viscosity, an increase in gelatinization temperature, and crystallinity under high nitrogen levels. Increasing nitrogen fertilizer application can improve the appearance and milling quality of rice, but it also leads to an increase in protein content, hardness, gelatinization enthalpy, decrease in breakdown value, and a decline in palatability. In practical production, different production measures should be taken according to different production goals. © 2024 Society of Chemical Industry.

Effect of Varieties and Nutrient Management on Growth and Yield of Wheat Crop under Irrigated Condition (Triticum aestivum L.)

Wheat (Triticum aestivum L.) is the third most crucial staple food globally, providing essential nutrients and being widely utilized in various applications. A field experiment was conducted during the rabi season of 2022–2023 at Lovely Professional University's Agriculture Research Farm in Jalandhar, Punjab, to investigate the impact of different wheat varieties and nutrient treatments on growth and grain yield. The study utilized a factorial randomized block design with three replications and eight treatment combinations involving two wheat varieties: V1 (Unnat PBW 550) V2 (WH 1105) and four nutritional levels: N1 (control), N2 (100% RDF Recommended dose of fertilizer), N3 & 15% VC (Vermicompost), and N4 (70% RDF & 30% VC). The results showed that the N3 treatment significantly enhanced growth parameters, including plant height, number of leaves, tiller count, and dry matter accumulation. V2 (WH 1105) exhibited superior growth, with greater plant height (93.6 cm), leaf count (24.1 leaves/plant), and dry matter accumulation (54.57 g at 90 DAS).Yield attributes such as the number of effective tillers per plant, grains per spike, and 1000-grain weight were highest in the N3 treatment, with V2 (WH 1105) against outperforming V1 (Unnat PBW 550). Specifically, N3 treatment resulted in the highest number of effective tillers (6.0), grains per spike (58.16), and 1000-grain weight (39.40 g). Grain yield was maximized with the N3 treatment (57.15 q/ha), with V2 (WH 1105) producing a significantly higher grain yield (50.5 q/ha) compared to V1 (Unnat PBW 550). Additionally, the N3 treatment led to the highest straw yield (78.96 q/ha) and biological yield (136.11 q/ha). The harvest index was highest with the N2 treatment (42.35%), while V2 (WH 1105) showed a higher harvest index (41.97%) than V1 (Unnat PBW 550). These findings underscore the importance of nutrient management and variety selection in optimizing wheat growth and yield.

Combined effects of nitrogen fertilizer and biochar on the growth, yield, and quality of pepper.

A pot experiment was conducted to investigate the combined effects of different nitrogen fertilizer levels (5, 25, and 45 kg of pure nitrogen per 667 m²) and biochar concentrations (0, 0.7, 1.4, and 2.1%) on the growth, yield, and fruit quality of pepper. The findings indicated that a combination of 25 kg/667 m2 of nitrogen and either 0.7% or 1.4% biochar significantly enhanced plant growth, yield, and fruit quality. Specifically, the N2 treatment (25 kg of pure nitrogen per 667 m²) increased substrate porosity, alkali-hydrolyzed nitrogen content, and available phosphorus content. It also boosted root activity and superoxide dismutase activity in pepper leaves, resulting in increased yield and better fruit quality. Furthermore, the proper addition of biochar (0.7-1.4% by weight) enhanced the physical and chemical properties of the substrate, including increased chlorophyll content and enzyme activity in plants, thereby leading to improved overall plant growth, yield, and fruit quality.

Maize and legume intercropping enhanced crop growth and soil carbon and nutrient cycling through regulating soil enzyme activities

Maize intercropped with leguminous green manure (LGM) has been proven as a sustainable plantation practice for enhancing crop yield and soil fertility. However, a comprehensive understanding of how intercropped legumes coordinate the above- and below-ground performance during maize growth under low to high N application remains elusive. This study aimed to investigate the effects of biological C and N input on soil fertility and maize growth by regulating soil enzyme activities in maize/LGM intercropping systems. A three-year field trial was conducted in northwestern China, where maize was intercropped with two LGMs, namely common vetch and pea, under no N (N0, 0 kg ha−1) and conventional N (N330, 330 kg ha−1) applications. The grain yield of intercropped maize ranged from 10.54 to 11.08 t ha−1, representing a significant increase of 6.6–12.1 % compared to monoculture maize in the N0 treatment. Nitrogen application substantially increased maize grain yield by 39.2–52.0 % across cropping systems relative to the N0 treatments, while minor differences were observed in maize yield between cropping systems in the N330 treatments. Compared with monoculture maize, intercropped with LGMs increased C input by 16.7–79.2 % at maize V9 stage and 81.1–140.3 % at the R6 stage. The biological N fixation of intercropped LGMs was 62.7–89.5 kg ha−1 and 8.0–12.8 kg ha−1 in the N0 and N330 treatments, respectively. Biological C and N input greatly facilitated soil enzyme activities and the associated nutrient cycling, consequently improving soil fertility. Soil organic matter and total N in the intercropping systems significantly increased by 4.4–14.3 % relative to monoculture across maize growth stages, irrespective of N levels. Furthermore, increased soil fertility was closely associated with nutrient stoichiometry, which in turn facilitated maize nutrient uptake and shoot recovery growth in the intercropping systems. Overall, these findings highlight that increased biological C and N input to belowground enhances soil C and nutrient cycling by regulating the involved enzyme activities, which in turn improves maize nutrient uptake and growth, forming a coordinated loop of C and nutrient flow in the maize and legume intercropping systems. Maize intercropped with LGMs is a sustainable practice that improves soil fertility and promotes maize growth by augmenting biological C and N input.

Enzyme Activity Stoichiometry Suggests That Fertilization, Especially Nitrogen Fertilization, Alleviates Nutrient Limitation of Soil Microorganisms in Moso Bamboo Forests

Rational application of N fertilizer is essential for maintaining the long-term productivity of Moso bamboo forests. Microbial activity is a crucial indicator of soil quality. Changes in soil nutrient resources due to N addition can lead to microbial nutrient limitations, thereby impeding the maintenance of soil quality. Currently, there is limited research on the effects of N application on microbial nutrient limitations in Moso bamboo forest soils. To examine the changes in extracellular enzyme activity and microbial nutrient limitations in Moso bamboo forest soils following N application, we conducted an N application experiment in northern Guizhou. The findings revealed that the N3 treatment (726 kg·N·hm−2·yr−1) significantly reduced β-glucosidase (BG) activity by 27.61% compared to the control group (no fertilization). The N1 (242 kg·N·hm−2·yr−1), N2 (484 kg·N·hm−2·yr−1), and N3 treatments notably increased the activities of leucine aminopeptidase (LAP) and N-acetyl-β-D-glucosidase (NAG) by 11.45% to 15.79%. Acid phosphatase (ACP) activity remained unaffected by fertilization. N application treatments significantly decreased the C:Ne and C:Pe ratios, while the N:Pe ratio was less influenced by N fertilizer application. Scatter plots and vector characteristics of enzyme activity stoichiometry suggested that microorganisms in the study area were limited by C and N, and N fertilizer application reduced the vector length and increased the vector angle, indicating that N application alleviated the C and N limitation of microorganisms in Moso bamboo forests. Redundancy Analysis (RDA) demonstrated that microbial biomass phosphorus (MBP) was the most critical factor affecting extracellular enzyme activity and stoichiometry. Furthermore, Random Forest Regression analysis identified MBP and the N:Pm ratio as the most significant factors influencing microbial C and N limitation, respectively. The study demonstrated that N application modulates the microbial nutrient acquisition strategy by altering soil nutrient resources in Moso bamboo forests. Formulating fertilizer application strategies based on microbial nutrient requirements is more beneficial for maintaining soil quality and sustainably managing Moso bamboo forests. Additionally, our study offers a theoretical reference for understanding carbon cycling in bamboo forest ecosystems in the context of substantial N inputs.

Optimizing Nitrogen Application for Enhanced Yield and Quality of Strong-Gluten Wheat: A Case Study of Zhongmai 578 in the North China Plain

This study was designed to determine the optimal nitrogen application rate for strong-gluten wheat cultivation in the North China Plain. Employing Zhongmai 578, a strong-gluten wheat variety, a field experiment was conducted with the following four nitrogen levels: 0 kg/ha (N0), 150 kg/ha (N1), 210 kg/ha (N2), and 270 kg/ha (N3). The research focused on examining the impact of nitrogen application on the photosynthesis, yield, and quality of strong-gluten wheat. The findings revealed that the N2 treatment (210 kg/ha) yielded the highest results compared to the N0 treatment. Photosynthetic parameters, including chlorophyll content in wheat flag leaves, generally exhibited an increase followed by a decrease, peaking at 7 days after anthesis (except for the transpiration rate, which peaked at 14 days post-anthesis). In the first year, quality indices such as water absorption, capacity, sedimentation value, ductility, protein, and wet gluten initially increased and then decreased with rising nitrogen levels. Conversely, in the second year, these quality indices, including hardness, showed a progressive increase with elevated nitrogen application. These results indicate that enhanced nitrogen application can significantly improve the photosynthetic characteristics of strong-gluten wheat, thereby augmenting both yield and quality. Within the parameters of this experiment, an application of 210 kg/ha of nitrogen emerged as the optimal rate, promoting the superior yield and quality of strong-gluten wheat in the North China Plain.

Nitrogen Fixation and Growth of Potted Olive Plants through Foliar Application of a Nitrogen-Fixing Microorganism

Given the importance of biological nitrogen (N) fixation in agroecosystems, using inoculants with phyllosphere N fixers effective across various crops would revolutionize agriculture. In this study, the application of an inoculant prepared from Methylobacterium symbioticum was tested on young olive trees. The pot experiment was arranged in a factorial design, with inoculant (Yes and No) and mineral N applied to the soil [0 (N0), 25 (N25), 50 (N50), and 100 (N100) kg ha−1], and four replicates. The inoculant application did not increase plant dry matter yield (DMY), whereas the application of mineral N had a significant and pronounced effect. The inoculant also did not significantly increase N concentration in tissues, unlike the strong increase observed with N applied to the soil. The inoculant significantly increased plant N recovery, a cumulative effect resulting from small increases in DMY and N concentration in tissues. This increase represented 5.2% more N in plants receiving the inoculant compared to untreated ones. However, only treatments receiving mineral N recorded positive values of fixed N, with the highest value observed in the N50 treatment (12.4%), whereas a negative value (−7.7%) was observed in the N0 treatment. Overall, these low values of fixed N question the economic rationale of using this inoculant by farmers and especially render it unsuitable for organic farming systems, where plants tend to have lower N levels in tissues.

The Effects of Nitrogen Fertilizer on the Aroma of Fresh Tea Leaves from Camellia sinensis cv. Jin Xuan in Summer and Autumn.

Nitrogen fertilization level and harvesting season significantly impact tea aroma quality. In this study, we analyzed the volatile organic compounds of fresh Jin Xuan (JX) tea leaves under different nitrogen application levels (N0, N150, N300, N450) during summer and autumn. A total of 49 volatile components were identified by gas chromatography-mass spectrometry (GC-MS). Notably, (E)-2-hexenal, linalool, and geraniol were the main contributors to the aroma of fresh JX leaves. The no-nitrogen treatment (N0) presented the greatest quantity and variety of volatiles in both seasons. A greater difference in volatile compounds was observed between nitrogen treatments in summer vs. autumn. The N0 treatment had a greater total volatile concentration in summer, while the opposite was observed in the nitrogen application treatments (N150, N300, N450). Summer treatments appeared best suited to black tea production. The concentration of herbaceous aroma-type volatiles was higher in summer, while the concentration of floral volatiles was higher in autumn. Volatile concentrations were highest in the N0 and N450 treatments in autumn and appeared suitable for making black tea and oolong tea. Overall, this research provides valuable insights into how variations in N application rates across different harvesting seasons impact the aroma characteristics of tea leaves.

Effects of Maize/Peanut Intercropping on Yield and Nitrogen Uptake and Utilization under Different Nitrogen Application Rates

The effects of maize/peanut intercropping on crop yields, peanut nodulation, biological nitrogen (N) fixation in peanuts, crop N uptake, and N use efficiency under different N application rates were studied. A long-term maize/peanut intercropping micro-plot experiment was started in 2015. The experiment included the following three planting patterns: maize sole crop (SM), peanut sole crop (SP), and maize and peanut intercropping (intercropping maize: IM; intercropping peanut: IP). Additionally, three N application rates were tested as follows: 0 kg·ha−1 (N0), 150 kg·ha−1 (N150), and 300 kg·ha−1 (N300). The results indicated that N fertilization significantly increased maize yield. Intercropping increased maize yield while decreasing peanut yield across different N application rates. Both N fertilization and intercropping significantly increased the maize harvest index (HI), whereas intercropping decreased the peanut HI under N300. The number and fresh weight of peanut nodules decreased with the increasing N application rate with reductions ranging from 31.15% to 45.23% and 39.60% to 46.67%, respectively. Intercropping increased the number of peanut nodules by an average of 62.56% under the N0 treatment. Intercropping significantly improved the N absorption capacity of the whole intercropping system, and the contribution of maize was higher than that of peanuts. Maize demonstrated a stronger competitive ability for N uptake compared with peanuts in the intercropping system. Intercropping significantly increased the N use efficiency for both maize and peanuts. However, the N use efficiency of maize increased with N application rates, while that of peanut decreased. Compared with sole crops, intercropping increased the partial factor productivity of maize by 55.2% but decreased that of peanuts by 56.3%. In conclusion, at an N application rate of 150 kg·ha−1, maize/peanut intercropping increased overall crop yield and improved the N absorption and use capacity of maize

Enhancing yield, mineral composition, and energy fractions through intercropping and nutrient management in oats and berseem

Inadequate green fodder of subpar quality poses a significant risk to livestock productivity, underscoring the pivotal role of intercropping and integrated nutrient management to effectively address the dual challenge of meeting both quantity and quality requirements in fodder. In this study, employing factorial randomized block design the experiment incorporated intercropping treatments S1- sole oats, S2- sole berseem, S3- 2 rows of oats + 1 row of berseem, and S4 −1 row of oats + 2 rows of berseem) alongside four nutrient management treatments N1- Control (100 % Recommended dose of fertilizer (RDF)), N2 − 50 % RDF + Plant growth promoting rhizobacteria (PGPR) + 2 spray of seaweed extract, N3 − 75 % RDF + PGPR + 2 spray of seaweed extract, N4 − 100 % RDF + PGPR + 2 spray of seaweed extract with each treatment replicated thrice. Results revealed that the significantly highest green fodder yield of oats (24.73 and 12.81 t ha−1) and berseem (13.35 and 13.79 t ha−1) in S1 and S2 crops recorded at both the cuts, respectively followed by intercropping of oats: berseem in 2:1 (S3) and 1:2 (S4) row ratio. Application of 100 % RDF + PGPR + 2 spray of seaweed extract recorded the highest green fodder yield of oats (21.80 and 9.79 t ha−1) and berseem (8.09 and 11.46 t ha−1). Oats and berseem recorded varying trends in nutrient concentration (1.72–18.9 %), nutrient uptake (35.5 kg ha−1 to 251.4 kg ha−1), energy fractions (0.33 MJ kg−1 to 10.2 MJ kg−1) due to intercropping and nutrient management. Therefore, we recommend adopting a combination of oats: berseem intercropping in a 2:1 row ratio, coupled with the application of 100 % RDF + PGPR + 2 sprays of seaweed extract to optimize yield, improve nutritional quality, and increase energy content. This approach ensures efficient utilization of available resources and can be beneficial for the farming community.

Experimental investigation into coal wettability changes caused by reactions with scCO2-H2O

Geological CO2 sequestration (GCS) can help mitigate global warming and enhance methane recovery from coal beds. However, few studies have linked the effects of CO2 to surface chemistry changes controlling wetting behavior in deep coal beds. Contact angles (CAs) of CO2/N2-high volatile bituminous coal-water systems were measured under different temperatures and pressures. The surface chemistry and physical structure of coals were characterized to investigate changes in physicochemical properties and their relations with wettability after reactions. For N2 treatment, the time-dependence of static and dynamic CAs were insignificant, ranging within 4°. For gaseous CO2 treatment, the static CAs and the average advancing angles increased slightly. With supercritical (sc) CO2, both the static and dynamic CAs increased significantly, and θadv changed to intermediate-wet (92°). Reactions with minerals exposed to scCO2 resulted in greater surface roughness and heterogeneity, greater contact angle hysteresis and more surface sites occupied by scCO2 rather than H2O. Increases in hydrophobic functional groups and decreases in hydrophilicity were shown by FTIR spectra, reflecting the shedding of polar oxygen-containing functional groups, reduction of hydrogen bonds, and increasing percentage of hydrocarbons. XRD patterns obtained following scCO2-treatment showed that crystallite growth and molecular polymerization were higher toward graphite-like. The calculated structural parameters of functional groups and crystallites both showed elevated coal rank. Changes in crystallite structure, notably higher carbon content and decreased negative surface charge, are unfavorable for water-wetting. This study contributes to understanding surface chemistry changes responsible for decreased wettability during CO2-enhanced coal bed methane recovery and GCS in coal reservoirs.

Methylobacterium symbioticum Applied as a Foliar Inoculant Was Little Effective in Enhancing Nitrogen Fixation and Lettuce Dry Matter Yield

Nitrogen (N) is a limiting ecological factor for plant growth in most agroecosystems. Biological N fixation, especially from nodulated legumes, has been promoted in recent decades as an alternative or complement to industrially synthesized N fertilizers. The possibility of utilizing N-fixing organisms from the phyllosphere that demonstrate effectiveness across a wide range of crops is particularly exciting. In this study, we examined the N-fixing capacity and the impact on lettuce growth of an inoculant recently introduced to the market, which contains the microorganism Methylobacterium symbioticum and is recommended for various cultivated species. A pot experiment was conducted using a factorial design, which included the inoculant (No and Yes) and four N rates (0 (N0), 25 (N25), 50 (N50), and 100 (N100) kg ha−1 of N), with four replicates, over four lettuce growing cycles. The inoculant had a significant effect on dry matter yield (DMY) only during the second of the four growing cycles. The mean values of the four growing cycles ranged from 9.9 to 13.7 g pot−1 and 9.9 to 12.6 g kg−1 in pots that received and did not receive the inoculant, respectively. On the other hand, plants exhibited a robust response to N applied to the soil, showing significant increases in both DMY and tissue N concentration across all growing cycles. Mean values of DMY in the treatments N0 and N100 ranged from 5.6 to 8.9 g pot−1 and 12.5 to 16.1 g pot−1, respectively. N concentration in tissues varied inversely with DMY, indicating a concentration/dilution effect. The difference in N concentration between treated and untreated plants, used as an estimate of fixed N, was very low for each of the soils’ applied N rates, assuming average values for the four growing cycles of −1.5, −0.9, 2.4, and 6.3 kg ha−1 for N0, N25, N50, and N100, respectively. This study emphasized the low amount of N supplied to lettuce by the inoculant and its limited effect on DMY. Generally, in biological systems with N-fixing microorganisms, achieving high fixation rates requires a high level of specificity between the microorganism and host plant, a condition that seems not to have been met with lettuce. Considering the importance of the subject, is imperative that further studies be conducted to determine more precisely in which crops and under what growing conditions the inoculant proves to be a valuable input for farmers and an effective method for reducing N mineral fertilization.

Optimization of N Fertilizer and Synergistic Intercropping to Enhance the Productivity Advantage of Faba Bean and Effective Control of Chocolate Spot Epidemics.

Intercropping of wheat/faba bean is a common practice within the legume-cereal family. However, the benefits of nitrogen (N) fertilizer-optimized synergistic intercropping in improving faba bean productivity while controlling the prevalence of chocolate spot disease have not been established. This study conducted continuous field experiments spanning two planting seasons to investigate two key findings: (i) Optimizing N fertilizer application can enhance the productivity of intercropped faba bean. (ii) The percentage severity index (PSI) during the period of maximum prevalence rate (Rmax) of faba bean chocolate spot disease poses a substantial challenge to faba bean yield. The results indicated that the land equivalent ratio and transgressive overyielding index for each intercropping treatment increased with higher N fertilizer application, exceeding a value of 1, and the land saving proportion also exceeded 0. Intercropping primarily enhances productivity, as measured by the harvest index (HI), by amplifying the complementary effect rather than the selection effect, thus improving the net benefit of intercropping. The HI of single and intercropped faba bean increased with the N1 and N2 treatments in both planting seasons. However, the HI of single and intercropped faba bean at the N3 level decreased significantly, ranging from 17.85 to 29.62%. Furthermore, a notable negative correlation was established between the PSI during critical epidemic (initial epidemic, maximum epidemic rate, and late epidemic) periods and observed and expected faba bean yields. As the PSI increased, faba bean yields decreased, and the PSI of intercropping at different periods was lower than that observed in the single cropping. Additionally, intercropping with the optimized N fertilizer treatment (N2 treatment) exhibited an enhanced relative control effect on chocolate spot disease in faba bean, ranging from 35.21 to 52.36%. This finding confirmed the productivity advantage of intercropping faba bean. In conclusion, this study suggested that optimizing N fertilizer application can enhance the productivity of intercropped faba bean. Wheat/faba bean intercropping effectively controlled the PSI during the period of Rmax, which would otherwise threaten faba bean yield. Consequently, this practice ensured sustained advantages of wheat/faba bean intercropping.

Effects of Nitrogen Fertilizer Management on Dry Matter Accumulation and Yield of Drip-Irrigated Sugar Beet in Arid Areas

Clarifying the optimal combination of N fertilizer application rate and application method can maximize the yield of drip-irrigated sugar beet in arid areas, which is of great significance for reducing farmland N pollution and achieving sustainable agricultural development. In this three-year field experiment in Xinjiang, China, the effects of three N application rates [75 kg ha−1 (N1), 150 kg ha−1 (N2), and 225 kg ha−1 (N3)] and three N application methods [the proportion of N applied at canopy rapid growth stage, taproot expansion stage, and sugar accumulation stage were (M1) 100%: 0%: 0%, (M2) 70%: 30%: 0%, and (M3) 50%: 30%: 20%] on the dry matter accumulation (DMA) and distribution, leaf senescence, yield, and agronomic N use efficiency (aNUE) of drip-irrigated sugar beet were explored. The results showed that N application (N1, N2, and N3 treatments) increased the shoot DMA by 27.7% (three-year average), 52.6%, and 83.1%, and the taproot DMA by 28.3%, 43.2%, and 61.6%, respectively (p < 0.05), compared with CK (no N supply) treatment. The N application methods M2 and M3 increased the shoot DMA by 5.6% (three-year average) and 1.0% (p > 0.05), respectively, and the taproot DMA by 7.2% and 3.6% (p < 0.05), respectively, compared with M1. In addition, M2 could delay the end of shoot and taproot growth (te) and the occurrence of maximum growth rate (tm). In particular, the N3M2 treatment increased the leaf area index (LAI) by 20.4–75.9% (p < 0.05) compared with other treatments by increasing the leaf area duration (LAD) and decreasing the leaf senescence rate (LSR). The taproot yield and sugar yield of N3M2 treatment reached the maximum at harvest time, but there was no significant difference in taproot yield and sugar yield between N3M2 treatment and N2M2 treatment. The aNUE in N2M2 treatment was the highest (p < 0.05), which was 1.29–7.85 times higher than that of other treatments. Therefore, reducing the N application rate from 225 kg·ha−1 to 150 kg·ha−1 and applying 70% and 30% of 150 kg N ha−1 at the canopy rapid growth stage and the taproot expansion stage, respectively, could achieve the goal of increasing sugar beet yield and N use efficiency. This study will provide an important reference for the sustainable production of sugar beet under drip irrigation in Xinjiang, China.