Addition Of Nitrogen Fertilizer Research Articles

Response of Elymus sibiricus (Siberian Wildryegrass) to Combined Application of Nitrogen and Phosphorus during Aging on the Qinghai–Tibetan Plateau

Elymus sibiricus plays a crucial role in ecological protection and animal husbandry. However, after many years of growth, the biomass of E. sibiricus decreases, and the plants degrade. Moreover, there is no good solution to the problem of degradation of Elymus sibiricus; the addition of nitrogen (N) and phosphorus (P) fertilizers is the primary measure of cultivation management to improve yield, so it is crucial to find the appropriate level of fertilization. This study performed a two-factor split-plot experiment, including four levels of N (0, 45, 60, and 75 kg·hm−2) and four levels of P (0, 60, 75, and 90 kg·hm−2), to investigate the effect of N and P fertilizers on yield, yield components, and photosynthesis characteristics of E. sibiricus. The results showed that the forage yield in 2017 was higher than in 2018. The forage yield in 2017 was highest at N75P0 with a value of 29,926 kg·hm−2, and in 2018 it was highest at N45P0 and N75P0 with a value of 12,266 kg·hm−2 and 12,233 kg·hm−2, respectively, which demonstrates the large impact of year effects on the forage yield. All traits increased with the increase in N and P fertilizer application, but with excess fertilizer application, the photosynthesis was limited, leading to a slowdown in growth and a decrease in yield. In addition, under adequate N fertilization, the role of P fertilization was not significant (p > 0.05). N, P, and N × P can significantly (p < 0.05) affect the yield traits and forage yield of E. sibiricus. According to the PCA, it is clear that N fertilizer has the largest effect, and the growth capacity of degraded E. sibiricus grassland can be restored by adding 75 kg·hm−2 of nitrogen fertilizer.

Soybean Response to Seed Inoculation with Bradyrhizobium japonicum and/or Nitrogen Fertilization

Seed inoculation with symbiotic bacteria is a commonly employed practice in soybean cultivation. As a result, nodulation proceeds properly and plants self-supply atmospheric nitrogen, requiring either minimal or no additional nitrogen fertilization. The aim of the study was to investigate the response of soybeans to the application of the recommended or double dose of commercial inoculants (HiStick® Soy or TURBOSOY®) and/or mineral nitrogen fertilization compared to the untreated control. It was demonstrated that a double dose of the tested preparations had the most favorable effect on nodulation. However, the impact of weather conditions modified their effectiveness during the study years, which was especially visible in 2022. Sowing seeds without inoculation (control) resulted in the formation of sparse root nodules and consequently the lowest leaf area index (LAI) and soil plant analysis development (SPAD) measurements. In addition, the values of SPAD and LAI indices varied across the years of the study, indicating that weather conditions modified nitrogen uptake by plants. Overall, seed inoculation and/or nitrogen fertilization positively influenced the chemical composition of seeds compared to the control. The only decrease observed was in the oil content, while the double dose of HiStick® Soy preparation reduced the polyphenol content. The double dose of the tested inoculants had the most favorable impact on yield components and seed yield. However, applying inoculation at the recommended dose or in combination with nitrogen fertilization yielded similar or slightly worse results, depending on the year. Therefore, soybean seed inoculation should be recommended, although the effectiveness of the procedure will depend on various factors, including the type of inoculant, dosage, nitrogen fertilization, and weather conditions.

Phytoremediation Potential of Flax Grown on Multimetal Contaminated Soils: A Field Experiment.

The aim of this study was to assess the phytoremediation potential of fiber flax (Linum usitatissimatum L., var. Calista) cultivated in a soil contaminated with multiple metals, under real field conditions. A two-year (2022 and 2023) field experiment was conducted in a site contaminated with elevated concentrations of Cd, Ni, Cu, Pb, and Zn due to mining and metallurgical activities. Three different nitrogen fertilization levels were tested (N0: 0 kg N ha-1, N1: 30 kg N ha-1, N2: 60 kg N ha-1), and both spring and winter sowings were conducted. At full maturity, growth parameters and yields were measured. The phytoremediation potential of flax was assessed in terms of the metal concentrations in the above-ground biomass and of the metal uptake (i.e., the potential removal of the soil metals in g ha-1 and per year). Flax demonstrated a shorter growth cycle, with shorter and thicker plants and higher yields when sown in spring compared to winter sowing. Plant growth and productivity were not evidently influenced by additional nitrogen fertilization during plant growth. The cadmium bioaccumulation factor was 1.06, indicating that flax accumulates this metal. For Ni, Cu, Pb, and Zn, the corresponding values were 0.0, 0.04, 0.004, and 0.02, suggesting that this crop excludes these metals. The order of the higher uptake in plant tissues was as follows: Zn > Pb > Cd > Cu > Ni. In conclusion, flax demonstrated tolerance to heavy metals in the soil, effectively supporting soil restoration through cultivation. Additionally, flax showed potential as a cadmium accumulator while excluding nickel, copper, lead, and zinc.

5-ALA, DTA-6, and Nitrogen Mitigate NaCl Stress by Promoting Photosynthesis and Carbon Metabolism in Rice Seedlings.

A large number of dead seedlings can occur in saline soils, which seriously affects the large-scale cultivation of rice. This study investigated the effects of plant growth regulators (PGRs) and nitrogen application on seedling growth and salt tolerance (Oryza sativa L.), which is of great significance for agricultural production practices. A conventional rice variety, "Huang Huazhan", was selected for this study. Non-salt stress treatments included 0% NaCl (CK treatment), CK + 0.05 g N/pot (N treatment), CK + 40 mg·L-1 5-aminolevulinic acid (5-ALA) (A treatment), and CK + 30 mg·L-1 diethylaminoethyl acetate (DTA-6) (D treatment). Salt stress treatments included 0.3% NaCl (S treatment), N + 0.3% NaCl (NS treatment), A + 0.3% NaCl (AS treatment), and D + 0.3% NaCl (DS treatment). When 3 leaves and 1 heart emerged from the soil, plants were sprayed with DTA-6 and 5-ALA, followed by the application of 0.3% NaCl (w/w) to the soil after 24 h. Seedling morphology and photosynthetic indices, as well as carbohydrate metabolism and key enzyme activities, were determined for each treatment. Our results showed that N, A, and D treatments promoted seedling growth, photosynthesis, carbohydrate levels, and the activities of key enzymes involved in carbon metabolism when compared to the CK treatment. The A treatment had the most significant effect, with increases in aboveground dry weight and net photosynthetic rates (Pn) ranging from 17.74% to 41.02% and 3.61% to 32.60%, respectively. Stomatal limiting values (Ls) significantly decreased from 19.17% to 43.02%. Salt stress significantly inhibited seedling growth. NS, AS, and DS treatments alleviated the morphological and physiological damage of salt stress on seedlings when compared to the S treatment. The AS treatment was the most effective in improving seedling morphology, promoting photosynthesis, increasing carbohydrate levels, and key enzyme activities. After AS treatment, increases in aboveground dry weight, net photosynthetic rate, soluble sugar content, total sucrose synthase, and amylase activities were 17.50% to 50.79%, 11.39% to 98.10%, 20.20% to 80.85%, 21.21% to 33.53%, and 22.17% to 34.19%, respectively, when compared to the S treatment. In summary, foliar sprays of 5-ALA, DTA-6, and additional nitrogen fertilizer enhanced rice seedling growth, increased photosynthesis, lowered Ls values, and improved seedling salt tolerance. Spraying two regulators, 5-ALA and DTA-6, quantitatively increased the effect of nitrogen fertilizer, with comparable effects on NaCl stress regulation. This study provides the basis for efficient agricultural production.

Nitrogen-fertilizer addition to an agricultural soil enhances biogenic non-extractable residue formation from 2-13C,15N-glyphosate

Glyphosate and nitrogen (N) or (P) phosphorus fertilizers are often applied in combination to agricultural fields. The additional P or N supply to microorganisms might drive glyphosate degradation towards sarcosine/glycine or aminomethylphosphonic acid (AMPA), and consequently determine the speciation of non-extractable residues (NERs): harmless biogenic NERs (bioNERs) or potentially hazardous xenobiotic NERs (xenoNERs). We therefore investigated the effect of P or N-fertilizers on microbial degradation of glyphosate and bioNER formation in an agricultural soil. Four different treatments were incubated at 20 °C for 75 days as follows; I: no fertilizer (2-13C,15N-glyphosate only, control), II: P-fertilizer (superphosphate + 2-13C,15N-glyphosate, effect of P-supply), III: N-fertilizer (ammonium nitrate + 2-13C,15N-glyphosate, effect of N-supply) and IV: 15N-fertilizer (15N-ammonium nitrate + 2-13C-glyphosate, differentiation between microbial assimilations of 15N: 15N-fertilizer versus 15N-glyphosate). We quantified 13C or 15N in mineralization, extractable residues, NERs and in amino acids (AAs). At the end, mineralization (36–41 % of the 13C), extractable 2-13C,15N-glyphosate/2-13C-glyphosate (0.42–0.49 %) &15N-AMPA (1.2 %), and 13C/15N-NERs (40–43 % of the 13C, 40–50 % of the 15N) were comparable among treatments. Contrastingly, the 15N-NERs from 15N-fertlizer amounted to only 6.6 % of the 15N. Notably, N-fertilizer promoted an incorporation of 13C/15N from 2-13C,15N-glyphosate into AAs and thus the formation of 13C/15N-bioNERs. The 13C/15N-AAs were as follows: 16–21 % (N-fertilizer) > 11–13 % (control) > 7.2–7.3 % (P-fertilizer) of the initially added isotope. 2-13C,15N-glyphosate was degraded via the sarcosine/glycine and AMPA simultaneously in all treatments, regardless of the treatment type. The percentage share of bioNERs within the NERs in the N-fertilized soil was highest (13C: 80–82 %, 15N: 100 %) compared to 53 % (13C &15N, control) and to only 30 % (13C &15N, P-fertilizer). We thus concluded simultaneous N & glyphosate addition to soils could be beneficial for the environment due to the enhanced bioNER formation, while P & glyphosate application disadvantageous since it promoted xenoNER formation.

Biomass partitioning reveals the adaptability of tiger nut (Cyperus esculentus L.) in an arid ecosystem in Inner Mongolia, China

AbstractTiger nuts (Cyperus esculentus L.) have been widely cultivated as a bioenergy crop in northern China. The value of tubers is receiving special attention, but the lack of information on how organs of tiger nuts coordinate resources to adapt to arid environments has limited the potential tuber production and diverse use. To address this knowledge gap, we experimented in the Ulan Buh Desert, Inner Mongolia (106° 33′ 28″ E, 40° 27′ 32″ N). Three fertilizer treatments were applied: zero fertilizer (N:P = 0:0), traditional fertilizer (N:P = 15:15), and additional nitrogen fertilizer (N:P = 60:15). Investigations were conducted at seedling, rhizome production, tuber formation, and tuber maturation stages. The results showed that under zero fertilizer, tiger nuts allocated biomass predominantly to propagative organs, namely rhizomes and tubers. However, an increase in leaf area or root surface area would necessitate more investment in leaf or root dry mass, resulting in diminishing returns. For biomass allocation, tiger nut responded the same way to traditional fertilizer treatment and zero fertilizer treatment, but the tuber number and yield increase under traditional fertilizer application. Additional nitrogen fertilizer stimulated shoot production through accelerated rhizome production aided by leaf area increasing. Fertilizer application can significantly increase both the number of tiger nuts and tuber yield. Nitrogen addition positively influenced aboveground biomass and enhanced rhizome tillering. Strong adaptability of tiger nuts makes the plant a suitable pioneer crop for developing marginal lands. The robust aboveground growth after nitrogen application enhances suitability for pasture utilization.

Maize residue input rather than cover cropping influenced N2O emissions and soil–crop N dynamics during the intercrop and cash crop periods

The well-known benefits of cover cropping for mitigating climate change and improving soil quality could be threatened by increased greenhouse gas emissions. Therefore, such practices could have negative consequences in the context of global climate change. The present year-long field experiment, carried out under irrigated semiarid conditions, evaluated the effect of returning maize crop residues at two topsoil input levels in combination with bare fallow, a cereal (barley, Hordeum vulgare L.) and a legume (vetch, Vicia sativa L.) as cover crops as part of an annual cover crop–cash crop (maize, Zea mays L.) rotation. In addition, control plots, without the addition of nitrogen fertilizer (either in the previous cropping season or during the experiment), were established following the same experimental design in order to assess the carry-over impact of residual nitrogen from prior crops. Nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) fluxes were measured together with soil mineral nitrogen and crop yields and nitrogen use efficiency. The significant effect of maize residue input on N2O emissions during the cover crop phase (this was 43% greater for the lower maize residue input than for the higher) was offset after subsequent maize fertilization (there was a 170% increase following the higher maize residue input compared to the lower). Although no differences in soil mineral nitrogen content were reported between treatments before maize fertilization, N2O emissions were 72% higher on the fertilized plots than on the control plots. Before maize fertilization, N2O emissions were increased by the incorporation of cover crop residues and soil rewetting after irrigation, with the highest N2O fluxes being reported for the cereal crop. Cumulative CO2 fluxes were higher in the plots with cover crops (cereal and legume) than in bare fallow plots, while CH4 sink was not affected by cover cropping or maize residue input. The grain yield penalty for maize production (a 7% decrease) with the legume cover crop on the nitrogen fertilized plots (the opposite of what was observed in the control area) highlights the need for an accurate estimation of the nitrogen supply from the mineralization of legume residues. Overall, cover crop and maize residue input did not have any significant effect on annual cumulative N2O emissions, so the positive effects of these practices should be considered to recommend them under semiarid conditions for climate change mitigation and adaptation.

Impact of different levels of foamed sulfur and Nitrogen fertilizer (Urea) on soil reaction (pH) and yield of wheat (Triticum aestivum L.) cultivar (IBAA 99)

An experiment was conducted in one of the agricultural lands of Al-Muthanna Governorate for the agricultural season 2018_2019, to find out the effect of adding one of the soil conditioners represented by foamed sulfure by three levels (0, 1000 and 2000) kg S ha-1 , addition of nitrogen fertilizer (Urea) CO(NH2)2 at three levels (200, 400 and 600) kg N ha-1 to the soil in the degree of soil reaction (pH) and the yield of wheat cultivar (IPAA 99). The treatments within the experimental units were arranged according to the Randomized Complete Block Design (RCBD) with four replicates, so the total experimental units were 36 experimental units, where the level of addition of 2000 kg N ha-1 of foamed sulfur and the level of 600 kg N ha-1 of nitrogen fertilizer (Urea) were significantly higher, to give them the lowest averages for the soil reaction (pH) of 7.13 and 7.38 at germination and 7.19 and 7.29 at the flowering stage for each of the sulfur and nitrogen fertilizers, respectively, compared to the comparison treatment. Both levels were significantly superior in giving them the highest averages for some growth characteristics, and the yield amounted to(343 and 304 spikes m-2 , 65 and 62 grains of spike-2 , 43.58 and 42.20 gm, and 4.88 and 478 tons ha-1 and 25.60 and 24.32%, for the characteristics spikes numbers, the grains spike number, 1000 grain weights, grains yield and the protein content percentage in grains, respectively, for both levels. Keywords: foamed sulfur, Nitrogen fertilizer (Urea), soil reaction (pH), yield, wheat (Triticum aestivum L.), IBAA 99cultivar.

Influence of Nitrogen Supply on Growth, Antioxidant Capacity and Cadmium Absorption of Kenaf (Hibiscus cannabinus L.) Seedlings

Kenaf (Hibiscus cannabinus L.) is considered suitable for the remediation of cadmium (Cd)-contaminated farmlands, because of its large biomass and resistance to Cd stress. The addition of nitrogen (N) fertilizer is an important measure used to increase crop yields, and it may also affect Cd accumulation in plants. To clarify the effects of different forms and concentrations of N on plant growth and Cd absorption in kenaf, a hydroponic experiment was conducted using three N forms (NH4+–N, NO3−–N and urea–N) at four concentrations (0, 2, 4 and 8 mM, 0 mM as control) under Cd stress (30 μM). The plant growth, the antioxidant enzyme activity and the Cd contents of various parts of the kenaf seedlings were measured. The results showed that the N form had the greatest impact on the growth of the kenaf and the absorption and transport of the Cd, followed by the interaction effect between the N type and the concentration. Compared to the control, the addition of N fertilizer promoted the growth of kenaf to varying degrees. Among all the treatments, the use of 2 mM of NO3−–N enhanced the biomass and Cd accumulation to the greatest extent compared to CK from 2.02 g to 4.35 g and 341.30 μg to 809.22 μg per plant, respectively. The NH4+–N significantly reduced the Cd contents of different parts but enhanced the translocation factors of Cd stem to root (TF S/R) and leaf to stem (TF L/S) by 34.29~78.57% and 45.10~72.55%, respectively. The peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT) enzyme activities of the kenaf increased with the N treatments, especially with NH4+–N. Overall, applying low concentrations of NO3−–N can better promote the extraction of Cd by kenaf.

Potential of Reinoculation Using R. tropici Applied under Cover to Increase Bean Yield

The common bean is known to require nitrogen, with mineral fertilizer being the main form of supply to the plants. However, more efficient inoculants containing strains of Rhizobium tropici that are potentially more efficient in fixing atmospheric N2 could replace the use of nitrogen fertilizers as long as some of the existing challenges in the application methodology are overcome (for example, ensuring the existence of active nodules in the most demanding crop phases: flowering and grain filling). This study aimed to verify the responses of common bean plants subjected to reinoculation using Rhizobium tropici in topdressing applied at different stages in a greenhouse and in a field between March and April 2020 and in the spring–summer harvest of 2020/2021, respectively. A randomized block design was used, along with four replications: T1 = uninoculated control; T2 = inoculation via seed (VS); T3 = VS + reinoculation at the V4 stage; T4 = VS + reinoculation at the R5 stage; T5 = VS + reinoculation at the R6 stage; T6 = VS + reinoculation at the V4 and R5 stages; T7 = VS + reinoculation at the V4 and R6 stages; T8 = VS + reinoculation at the R5 and R6 stages; T9 = VS + reinoculation at the V4, R5, and R6 stages; and T10 = mineral nitrogen fertilization. Nodulation and morphological variables were evaluated at the R7 stage, and agronomic variables were evaluated at the R9 stage at harvest. The use of reinoculation, in addition to inoculation, positively influenced the bean nodulation process. The morphological characteristics of the plants showed good development with the supply of N (carried out via inoculation and reinoculation), equivalent to the development that could be achieved via the addition of a mineral nitrogen fertilizer. Reinoculation from the R5 to R7 stages proved ineffective in supplying N to the common bean crop. Inoculation in the seed associated with reinoculation in coverage at the V4 stage provided higher yields (3.271 kg ha−1), reinforcing the potential for mineral nitrogen fertilizers to be replaced. The use of the seed inoculation technique with subsequent reinoculation under cover can completely replace the use of nitrogenous mineral fertilizers in fertilizing bean plants, making the cultivation of this fabacea more sustainable in terms of the associated costs and environmental problems.

Response of Organic Carbon Mineralization to Nitrogen Addition in Micro-aerobic and Anaerobic Layers of Paddy Soil

In field conditions, a micro-aerobic layer with 1 cm thickness exists on the surface layer of paddy soil owing to the diffusion of dissolved oxygen via flooding water. However, the particularity of carbon and nitrogen transformation in this specific soil layer is not clear. A typical subtropical paddy soil was collected and incubated with13C-labelled rice straw for 100 days. The responses of exogenous fresh organic carbon(13C-rice straw) and original soil organic carbon mineralization to nitrogen fertilizer addition[(NH4)2SO4]in the micro-aerobic layer(0-1 cm) and anaerobic layer(1-5 cm) of paddy soil and their microbial processes were analyzed based on the analysis of 13C incorporation into phospholipid fatty acid(13C-PLFAs). Nitrogen addition promoted the total CO2 and 13C-CO2 emission from paddy soil by 11.4% and 12.3%, respectively. At the end of incubation, with the addition of nitrogen, the total soil organic carbon (SOC) and13C-recovery rate from rice straw in the anaerobic layer were 2.4% and 9.2% lower than those in the corresponding micro-aerobic layer, respectively. At the early stage(5 days), nitrogen addition increased the total microbial PLFAs in the anaerobic layer with a consistent response of bacterial and fungal PLFAs. However, there was no significant effect from nitrogen on microbial abundance in the micro-aerobic layer. Nitrogen addition had no significant impact on the abundance of total 13C-PLFAs in the micro-aerobic and anaerobic layers, but the abundance of 13C-PLFAs for bacteria and fungi in the micro-aerobic layer was decreased dramatically. At the late stage(100 days), the effect of nitrogen addition on microbial PLFAs was consistent with that at the early stage. The abundances of total, bacterial, and fungal 13C-PLFAs were remarkably increased in the anaerobic layer. However, the abundance of 13C-PLFAs in the micro-aerobic layer showed no significant response to nitrogen addition. During the incubation, the content of NH4+-N in the anaerobic soil layer was higher than that in the micro-aerobic soil layer. This indicates that nitrogen addition increased microbial activity in the anaerobic soil layer caused by the higher NH4+-N concentration, as majority of microorganisms preferred to use NH4+-N. Consequently, the microbial utilization and decomposition of organic carbon in the anaerobic soil layer were accelerated. By contrast, richer available N existed in the form of NO3--N in the micro-aerobic soil layer owing to the ammoxidation process. Thus, the shortage of NO3--N preference microorganisms in the paddy soil environment prohibited the microbial metabolism of organic carbon in the micro-aerobic layer. As a whole, nitrogen fertilization enhanced organic carbon loss via microbial mineralization in paddy soil with a weaker effect in the micro-aerobic layer than that in the anaerobic layer, indicating the limited microbial metabolic activity in the surface micro-aerobic layer could protect the organic carbon stabilization in paddy soil. This study emphasizes the heterogeneity of paddy soil and its significant particularity of carbon and nitrogen transformation in micro-aerobic layers. Consequently, this study has implications for optimizing the forms and method for the application of nitrogen fertilizer in paddy cropping systems.

Response of Irrigation and Nitrogen Fertilization on Uptake of Primary Nutrients by Maize

A field experiment was accomplished from November 2018 to April 2019 at the site for agricultural research of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh to assess the effect of irrigation and nitrogen application on uptaking of primary nutrients by maize plant. A Randomized Complete Block Design (RCBD) with two factors and three replications was used to execute the experiment. Four irrigation treatments (I1, I2, I3 and I4: irrigation concerning 20%, 40%, 60% and 80% of soil available water, respectively) as factor A and three nitrogen doses [N1, N2 and N3: Nitrogen application at 75%, 100% and 125% of prescribed dose (PD) as per fertilizer recommendation guide (FRG)] as factor B was implemented. The crop responded significantly in uptaking N, P, K to different levels of irrigation and nitrogen. The uptake of N at its highest level (141.66 Kg ha-1) was observed in treatment I3N3 but the maximum uptake of P (49.17 Kg ha-1) and K (159.39 Kg ha-1) were found under the treatment I4N2. The addition of irrigation and nitrogenous fertilizer also enhanced the N (0.08%), P (8.75 ppm) and K (0.18 meq/ 100g) content of post-harvest soils. The maximum total consumptive use of water of the crop was found to be 446 mm in I4 treatment regardless N levels. Irrigation at 80% of soil available water using 100% N on prescribed dose (I4N2), appeared to be the most acceptable combination for optimal nutrient absorption by maize in the specified region.

Biobased residues sustain crop productivity and soil health in a maize–soybean rotation

AbstractBiobased residues are local and cost‐effective sources of soil amendments that can efficiently provide nutrients to crops, enhance soil health and serve as alternatives to mineral fertilizers. The objective of our study was to comprehensively evaluate the soil health and crop productivity of temperate agroecosystems amended with different types of organic residues (biobased residues), including composted food waste (compost), biosolid slurry (biosolids) and liquid anaerobic digestate (digestate), compared with nitrogen fertilizer. The experiment was conducted on a silt loam soil under maize–soybean rotation in Canada, where a wide range of physical, chemical and biological indicators were measured and integrated into a soil health score. Biobased residues resulted in about 50%–60% increase in soil‐exchangeable potassium and 10% soil‐exchangeable sodium over levels found in nitrogen fertilizer. Soil microbial biomass and the capacity of soil microbes to utilize carbon substrates differed among growing seasons but not among amendment types (p > .05). Crop productivity was similar among amendment types (p > .05). We found that the soil health score of biosolids was positively correlated with shoot and root biomass and negatively correlated with shoot nitrogen (p < .05), while that of nitrogen fertilizer was positively correlated with shoot carbon (p < .05). This was likely because of a variation in the availability of labile carbon and nitrogen among amendment types. Our research also suggests that temperate silt loam soil amended with biobased residues, especially biosolids, supplied sufficient nitrogen without the need for additional nitrogen fertilizer.

Effect of different levels of pruning and nitrogen fertilizer on vegetative traits and chemical content of Rosmarinus officinalis L.

The experiment was performed in a greenhouse belonging to the Department of Horticulture and Landscaping gardening, College of Agriculture, Tikrit University for the period from November 2021 - May 2022. The experiment included two factors: the level of pruning (without pruning, moderate pruning, and severe pruning); the addition of nitrogen fertilizer at two levels (73.4 and 146.7 g N.L-1 in the form of urea (46% N) according to the randomized complete block design (RCBD), with three replicates and three plants for each experimental unit. The results showed that the treatment of severe pruning (H2) and moderate pruning (H1) were significantly superior in the trait of the branches number (26.65 and 24.61 plants.branches-1), respectively. The treatment without pruning (H0)) was significantly superior in the leaves content of chlorophyll of (0.36 mg.g-1). The nitrogen fertilization treatment of the first concentration (F1) had a significant effect on the trait of plant height, which amounted to 37.28 cm. As for the nitrogen fertilization treatment of the second concentration (F2), it was significantly superior in the percentage of nitrogen 1.31%, phosphorous 0.24%, and potassium 1.43%. As for the interaction, the treatment (S1H0) was significantly superior in the leaves content of chlorophyll, and the treatments (H0F1) and (H0F2) also gave a significant superiority in the leaves content of chlorophyll. The interference treatment (H2F2) also led to a significant superiority in the leaves content of phosphorous. As for potassium

Electrical signal of pepper during cropping period affected by different amount of fertilizer

Precision agriculture requires supply of adequate amount of fertilizer application to increase crop yield and prevent environmental contamination. Objective of the study was to evaluate response of pepper under different fertigation method and amount using plant induced electrical signal (PIES) for precision agriculture. Pepper was fertigated 10 times with recommended additional nitrogen fertilizer and set as a control. Low fertilizer treatment did not receive additional urea and high fertilizer received three times higher amount of nitrogen fertilizer. Conventional treatment was fertigated as basal fertilizer and once with additional fertilizer. The PIES decreased during vegetative stage and remained constant at reproductive stage because of reduced nutrient and water uptake. The PIES showed positive relationship with soil NH4+, NO3−, stem NO3− and leaf N, which resulted in highest PIES value during reproductive stage in high fertilizer treated pepper. Plant growth parameters were also related with the PIES although yield was not affected by different fertilizer treatment.

Improvement of Active Organic Carbon Distribution and Soil Quality with the Combination of Deep Tillage and No-Tillage Straw Returning Mode

During the initial period of straw return, a suitable straw return technology can lay the foundation for long-term soil fertility improvement. This study focused on the issues of backward straw return technology and blind fertilizer application in the southern part of the maize-producing area in the Northeast Plain of China. In this study, two straw return modes (2-year no-tillage straw cover + 1-year deep loosening and burying straw returning mode, NPT; 3-year rotary tillage and burying straw returning mode, RT), with RT mode as a control, were combined with different N fertilizer application rates (0, 192, 240 kg/ha). The changes in soil organic carbon (SOC) and its active components (MBC, DOC, and LOC) in the 0–40 cm soil layer were analyzed, and the carbon stratification rate, carbon pool index (CPI), SOC storages of each component, and maize yield were calculated to evaluate the short-term (3-year) differences in soil organic carbon quantity and quality in order to find suitable straw return methods and nitrogen application rate combinations. The results showed that the NPT mode increased the SOC and MBC content in the 20–30 cm soil layer, with an increase of 16.2% to 37.8% and 23.0% to 50.3%, respectively, compared with the RT mode. Under the NPT mode, the carbon pool stability was higher after nitrogen fertilizer addition, with a CPI value of 10.2% to 37.8% higher in the 20–40 cm soil layer compared with the RT mode. The differences in maize yield were not significant (p < 0.05) between the nitrogen application rates of 192 kg/ha and 240 kg/ha, but the SOC storages did not show significant changes. The MBC storage had the highest value under the nitrogen application rate of 192 kg/ha. Therefore, we thought that, in the early stage of straw return, the organic carbon priming effect caused by increased microbial activity was higher under the nitrogen application rate of 192 kg/ha. Considering the aspects of not affecting maize yield and improving SOC stability, it is recommended to use the NPT mode with the application of a 240 kg/ha nitrogen fertilizer rate for straw return.

Response of Soil Aggregate Stability to Phosphorus, Nitrogen, and Organic Fertilizer Addition: A Meta-Analysis

Soil is a highly significant resource for human survival, and agglomerates, as the basic unit of the soil structure, not only enhance the soil fertility and control the biological validity of nutrients but also strengthen the soil’s erosion resistance. The mass application of fertilizers may significantly affect crop growth and the soil structure, and the rational application and dispensing of fertilizers will be an urgent issue to be addressed. Therefore, the effect of fertilizer application on the stability of water-stable soil aggregates needs to be studied under different meteorological and soil conditions to draw more general and feasible conclusions. Our meta-analysis of data from 220 independent observations from 56 published studies found that fertilizer application increased the mean weight diameter (MWD) by an average of 18% compared to the no-fertilizer treatment. Among the nitrogen (N), phosphate (P), and organic (OM) fertilizer treatments, the organic fertilizer treatment had a more significant stimulatory effect on the MWD (26%). Among the different fertilizer levels, a low level of phosphorus (<40 kg·ha−1 yr−1), a high level of N (>120 kg·ha−1·yr−1), and a low level of organic fertilizer (<5000 kg·ha−1·yr−1) increased the MWD by 19%, 14%, and 41%, respectively. Across the soil types and land use types, the response to the MWD was positive for red soils and paddy fields, and the organic fertilizer’s stimulatory effect was more significant than that of the chemical fertilizer. The correlation analysis showed that the response rate of the MWD was negatively correlated with the response rate of the soil pH and bulk density (BD) and positively correlated with the response rate of the soil organic carbon (SOC) and microbial mass carbon (MBC). Meanwhile, the partial least square structural equation model (PLS-SEM) showed that the meteorological factors were the main factors affecting the stability of the soil aggregates, while the secondary factors were the soil’s physical and chemical properties. Therefore, this study found that the long-term use of organic fertilizer instead of partial fertilizer is better than the use of chemical fertilizer alone, while more attention should be paid to the influence of temperature and rainfall on the stability of fertilizer in aggregate soil in the future.

Response of Fertilization of Nitrogen on Agronomical Attributes of Soybean

Soybean also known golden bean is a dual purpose crop grown to meet the requirement of both high protein and oil content. Fertilizers are one of the important components of farming system due to their requirement to provide essential nutrients to crop. The current research work was done to study the effect of the different rates of nitrogen fertilization on the growth and yield of soybean were studied. Field experiments were conducted at Instructional Research Farm, Krishi Nagar, Jabalpur, Madhya Pradesh, India during kharif season in the month of July to October in the year 2019‒2020. This research has been conducted in order to examine the beneficial effects of additional application of nitrogen at grain development stage on yield attributes and yield of soybean. The experimental material was early maturing variety of soybean JS 20-34. Treatments were given in 12 combinations in the split plot design. Plant samples were collected at R1 and R3 for dry matter yield and nitrogen determination. Grain yields were determined and grain samples were collected at harvest. A positive grain yield in response to nitrogen fertilizer was observed in different treatments. These imply that additional nitrogen applications are important for getting higher yields. In the current research we came to the conclusion that additional nitrogen fertilizer application to soybean crop has positive impact on several agronomical attributes of the crop.

Effect of Nitrogenous, Organic and Biological Fertilizers on some Vegetative and Qualitative Characteristics of Spinach Plant Spinacea oleracea L.

The experiment was conducted in the fields of the Department of Horticulture and Landscape / College of Agriculture / University of Karbala in Al-Hussainiya district of Karbala governorate during the autumn season 2021-2022 to study the response of some chemical and qualitative characteristics of spinach variety Viroflay, with 2 factors, the levels of nitrogen fertilizer (urea) represent the main plots and the sub plots the fertilization treatments of the secondary panels (Sub plot) and the experiment included 54 experimental units, and the differences were compared using the least significant difference test (L.S.D) at a probability level of 0.05. The results of the fertilizer addition (biological fertilizer + poultry manure) to the T6 treatment showed a significant superiority in the characteristics of vegetative growth, as it gave the highest rates and reached in plant height (23.71 cm. plant -1) And the average number of leaves (11.77 leaves. Plant-1) and the dry weight of the shoot (8.97 g. plant-1). The addition of nitrogen fertilizer (urea) when treated with N100% resulted in a significant superiority in the characteristics of vegetative growth, and the highest rates were in plant height (22.71 cm. Plant- 1) And the average number of leaves (10.89 leaves. Plant-1), and the dry weight of the shoot (10.23 g. plant-1), The same treatment had a significant effect on the chemical indicators, as it recorded a clear decrease in the content of nitrates and oxalates, which amounted to (110.0 mg g-1 and 81.20 mg g.100 ml) Plant respectively.

Effect of Different Levels of Pruning and Nitrogen Fertilizer on the Quality and Quantity of the Volatile Oil of Rosmarinus officinalis L.

The experiment was performed in a greenhouse belonging to the Department of Horticulture and Landscaping gardening, College of Agriculture, Tikrit University from November 2021 - May 2022. The experiment included two factors: the level of pruning (without pruning, moderate pruning, and severe pruning); the addition of nitrogen fertilizer at two levels (73.4 and 146.7 g N.L-1 in the form of urea (46% N) according to the randomized complete block design (RCBD). The results showed that the nitrogen fertilization treatment (F2) significantly excelled in the quantity of oil (2.505 g. 50 g plant-1) and the specific weight of the oil (0.907 g.ml-1) and an increase in the active substances (Cinol, Limonene, and α-Pinene), which amounted to (32.701, 4.476, and 8.407 mg. g plant-1).