Nitrogen Placement Research Articles

Pharmacological Evaluation of Bioisosterically Replaced and TriazoleTethered Derivatives for Anticancer Therapy

Cancer has been the cause of the highest number of deaths in the human population despite the development and advancement in treatment therapies. The toxicity, drug resistance, and side effects of the current medicaments and therapies have left the void for more research and development. One of the possibilities to fill this void is by incorporating Triazole moieties within existing anticancer pharmacophores to develop new hybrid drugs with less toxicity and more potency. The placement of nitrogen in the triazole ring has endowed its characterization of being integrated with anticancer pharmacophores via bioisosteric replacement, click chemistry and organocatalyzed approaches. This review paper emphasizes the discussions from articles published from the early 2000s to the current 2020s about the triazole-based derivatives used in anticancer therapy, elaborating more on their chemical structures, target receptors or enzymes, mechanism of action, structure-activity relationships, different triazole-derived hybrid drugs under clinical and nonclinical trials, and recent advancements toward developing more potent and less toxic anticancer agents.

Short-term effects of irrigation and nitrogen management on paddy soil carbon pools under deep placement of basal fertilizer nitrogen

Active soil organic carbon (SOC) fractions are major driving factors of soil fertility. Understanding the effects of water and fertilizer management on changes in active SOC fractions helps improve soil quality and maintain high agricultural productivity. We conducted a 3-year field experiment in Northeast China. In this experiment, natural soil (CKT) was used as a blank, and two irrigation regimes were established: conventional flooded irrigation (FI) and controlled irrigation (CI). Four nitrogen application levels were set for both irrigation regimes under deep placement of basal fertilizer N: Nd0 (0 kg ha–1), Nd (110 kg ha–1), Nd1 (99 kg ha–1), and Nd2 (88 kg ha–1). After 3 years, at similar N fertilizer application rate, the rice yield, total organic carbon (TOC), and active SOC fraction content of CI were higher under CI than FI. The growth rate of rice yield was 3.8% − 8.63% under CI than FI. Under CI, the rice yield, active SOC fractions contents and carbon pool management index (CPMI) did not decrease with decreasing N application rate but instead reached the highest level in the CNd1 treatment. Overall, CI with Nd1 treatment appears to be the best practice for improving soil fertility and crop productivity in Northeast China.

Advanced piperazine-containing inhibitors target microbial β-glucuronidases linked to gut toxicity.

The gut microbiome plays critical roles in human homeostasis, disease progression, and pharmacological efficacy through diverse metabolic pathways. Gut bacterial β-glucuronidase (GUS) enzymes reverse host phase 2 metabolism, in turn releasing active hormones and drugs that can be reabsorbed into systemic circulation to affect homeostasis and promote toxic side effects. The FMN-binding and loop 1 gut microbial GUS proteins have been shown to drive drug and toxin reactivation. Here we report the structure-activity relationships of two selective piperazine-containing bacterial GUS inhibitors. We explore the potency and mechanism of action of novel compounds using purified GUS enzymes and co-crystal structures. Our results establish the importance of the piperazine nitrogen placement and nucleophilicity as well as the presence of a cyclohexyl moiety appended to the aromatic core. Using these insights, we synthesized an improved microbial GUS inhibitor, UNC10206581, that potently inhibits both the FMN-binding and loop 1 GUS enzymes in the human gut microbiome, does not inhibit bovine GUS, and is non-toxic within a relevant dosing range. Kinetic analyses demonstrate that UNC10206581 undergoes a slow-binding and substrate-dependent mechanism of inhibition similar to that of the parent scaffolds. Finally, we show that UNC10206581 displays potent activity within the physiologically relevant systems of microbial cultures and human fecal protein lysates examined by metagenomic and metaproteomic methods. Together, these results highlight the discovery of more effective bacterial GUS inhibitors for the alleviation of microbe-mediated homeostatic dysregulation and drug toxicities and potential therapeutic development.

Nitrogen dose and placement in conservation agriculture for augmenting cropgrowth, productivity and profitability of Indian mustard (<i>Brassica juncea</i>)

Optimization of nitrogen (N) fertilization is vital for minimizing losses and realizing the yield potential of Indian mustard [Brassica juncea (L.) Czern.] under different tillage and residue management options. Hence, a field experiment was conducted during winter (rabi) seasons of 2021–22 and 2022–23 at research farm of ICAR-Indian Agricultural Research Institute, New Delhi to study the effect of nitrogen placement methods under conservation agriculture (CA) for augmenting crop growth, productivity and profitability of Indian mustard. Experiment consisted a split-plot design with three crop establishment practices (CEP) [ZT-R, Zero tillage without residue retention; ZT+R, Zero tillage with residue; CT, Conventional tillage] in main-plots and nitrogen placement methods (NPM) [control (no N); recommended dose of N (RDN)-conventional; RDN-SSB (subsurface band placement of second N split along the crop rows); 80% RDN-SSB] in sub-plots. The ZT+R enhanced crop growth rate by 6.0–36.1% over CT at various crop stages. The ZT+R reported higher soil moisture by 9–20.7% over CT and ZT-R. Significantly superior seed yield (14.3–28.5%), net return (20.5–53.9%) and benefit cost ratio (21.8–79.0%) was obtained with ZT+R over ZT-R and CT while RDN-SSB recorded 7.3–9.1% higher seed yield over other treatments. Statistically at par results were obtained under RDN-conventional and 80% RDN-SSB for yield attributing characters and seed yield delineating that a saving of 20% N in mustard production is possible without compromising yield and this can reduce environmental footprint as well. Therefore, this study concluded that the residue retention under ZT along with subsurface N placement in mustard crop gives better vegetative growth, yield attributes and yield with a potential to save 20% N and can be opted in semi-arid Indo-Gangetic plains and similar agro-ecologies.

Placement and nitrogen source effects on N2O emissions for canola production in Manitoba

AbstractThis study examined fertilizer nitrous oxide (N2O) emissions and canola (Brassica napus L.) grain yield for two granular urea sources (conventional and a dual urease and nitrification inhibitor [SuperU]) and three at‐planting placement methods (broadcast‐incorporated, shallow banded, and deep banded) on commercial fields in Manitoba. Nitrogen (N) rates were 100% and 70% of what was recommended based on soil test and target yield, with the 100% treatments having N2O emissions monitored. SuperU fertilizer consistently reduced N2O emissions (area‐, N‐applied‐, and yield‐based) compared to urea. Significant reductions in N2O emissions with SuperU occurred in four of six site‐years and coincided with delayed nitrification. Compared to broadcast‐incorporated, subsurface banding of conventional urea reduced N2O emissions in drier site‐years but increased emissions when rainfall was higher (especially in shallow banded urea). Across all six site‐years, shallow banding of urea resulted in significantly higher emission intensities than all other treatments. Nitrogen placement did not affect the emission reduction benefit of SuperU. N source or placement did not greatly affect canola yield within either 100% or 70% N rates. Fertilizer N recovery efficiency was also not greatly impacted by either N source or placement. The results demonstrate that dual inhibited granular urea fairly consistently reduces N2O emissions in canola production in southern Manitoba, whereas nitrogen placement had variable effects depending on growing season rainfall. However, with little agronomic benefit, the added cost of enhanced efficiency fertilizers must be overcome for widespread adoption and to achieve greenhouse gas reduction targets for the Canadian agriculture sector.

Sustainable nitrogen placement depth under different rainfall levels can enhance crop productivity and maintain the nitrogen balance in winter wheat fields

The deep placement of nitrogen (N) fertilizer is considered as an effective strategy for crop growth and yield formation. However, it is unclear how deep N fertilizer placement under different rainfall levels might affect the nitrogen balance of winter wheat fields. Thus, we conducted a two-year field experiment in a semi-humid region to assess the effects of different N fertilizer placement depths of 5 cm (D5), 15 cm (D15), 25 cm (D25), and 35 cm (D35) under three rainfall levels during winter wheat growth period (dry year = 125 mm, T1; normal year = 200 mm, T2; wet year = 275 mm, T3) on the N balance and crop productivity in winter wheat fields. Our results indicated that compared to D5, deeper N placement treatments increased the crop yield by 0.1–1.1 t ha–1 and N uptake by 3.0–18.0%, and reduced gaseous N losses by 0.2–1.1 kg N ha–1 under T1 and T2 (p < 0.05). T3D15 decreased the gaseous N losses by 1.2 kg N ha–1 compared with T3D5, and increased the yield and crop N uptake by 0.7–0.9 t ha–1 and 10.0–20.1 kg N ha–1 compared with T3D25 and T3D35, respectively (p < 0.05). T1 and T2 helped to maintain the N balance under deeper N placement (p < 0.05). Although T3 significantly increased NO3–-N concentration in the 60–100 cm soil layer and decreased the crop N uptake under D25 and D35, which was not conducive to maintaining the N balance, while D15 was beneficial in maintaining N balance (p < 0.05). Placement of N fertilizer at depths of 13.5 cm, 17.5 cm, and 21.6 cm in the wet year (T3), normal year (T2), and dry year (T1), respectively, could maintain the N balance in winter wheat fields through increasing crop N uptake, reducing gaseous N losses, and preserving the soil N pool.

A deep placement of lime nitrogen reduces the nitrate leaching and promotes soybean growth and seed yield

Deep placement of coated urea, lime nitrogen (Lime N), or urea with a nitrification inhibitor, 3,4-dimethylpyrazole phosphate (DMPP-U) did not inhibit N fixation activity, and it promoted soybean growth and seed yield. However, the effect of deep placement on the N budget including N leaching has not been evaluated. In this research, soybean plants were cultivated with a basal deep placement of urea, Lime N, or DMPP-U, and the control without deep placement of N fertilizer in lysimeters filled with Andosols. The nitrate was the principal N leachate and most of them leached until the flowering stage. The total amount of leached nitrate was the highest in urea deep placement, and it was reduced by the deep placement of Lime N or DMPP-U. In 2020, the total amount of nitrate in the leachate during the cultivation was 0.95, 1.83, and 2.78 ​g ​N m−2 in control, Lime N, and urea, respectively. The seed yield was higher in Lime N (424 ​g ​m−2) and urea (399 ​g ​m−2) than in the control (267 ​g ​m−2). The total amount of N accumulated in the shoots was higher in Lime N (32.1 ​g ​N m−2) than in the control (26.5 ​g ​N m−2) and urea (24.2 ​g ​N m−2) treatments. These results indicated that soybean plants with Lime N might assimilate more N both from N fertilizer and N2 fixation compared with control plants. Soil incubation test confirmed that the Lime N or DMPP-U retarded nitrification than urea.

Site-specific nutrient management in rice (Oryza sativa): Status and prospect–A review

Site-specific nutrient management (SSNM) plays a vital role in increasing crop profitability, maintaining soil health and reducing environmental pollution. Field experiments and demonstrations conducted across southeast (SE) Asia were conducted during 2020–21 at ICAR-Indian Agricultural Research Institute, New Delhi and observed that SSNM includes various nutrient management practices and each practice have a positive impact on fulfilling its vital role. After a thorough study, this review reflects that fertilizer recommendations based on targeted yield concept were more balanced, profitable and helpful in controlling soil nutrient mining and essential for sustainable crop production. Establishment of an attainable yield target, based on location, season, climate, rice cultivar and crop management ensures effective use of existing indigenous nutrients such as from soil, organic amendments, crop residue, manure and irrigation water and application of fertilizer to dynamically fill the deficit between crop needs and indigenous supply and to maintain soil fertility. Moreover, use of nitrification inhibitor, deep placement of nitrogen (N) and NPK fertilizers reduces the loss of N fertilizers up to 20% and increases rice yield up to 10%. The leaf colour charts (LCC), chlorophyll meter or SPAD are inexpensive need based tools for fertilizer N management that can reduce the excessive application of N (10–50%). Optical sensor-based nitrogen management is an alternative to LCC and SPAD that can quickly and reliably monitor N requirements of rice. On the other hand, the dissemination of SSNM through LCC, SPAD, QUEFT models, optical sensor etc., requires training of researchers, local extension workers, fertilizer retailers, and farmer leaders on techniques and guidelines for enabling rice farmers. Therefore, a simple nutrient decision support tool, Nutrient Expert® (NE) is useful to develop strategies to manage fertilizer N, P and K tailored to farmer’s field or growing environment. However, comparative evaluation of different SSNM approach is essential for location wise fertilizer prescription for increasing crop profitability, soil health and environmental safety.

Point placement of late vegetative stage nitrogen splits increase the productivity, N-use efficiency and profitability of tropical maize under decade long conservation agriculture

The rising economic and environmental costs of mineral fertilizers associated with lower nutrient use efficiency, and the need to respond the limitations of N fertilization under residue retained condition of conservation agriculture (CA) motivate the research for alternative N placement methods. The third principle of CA, i.e., residue retention on the soil surface hinders the right placement of split applied nitrogen (N). To address this issue, we assessed the impact of three N placement methods, i.e., NPM1: both the N splits were surface band placed, NPM2: the first split of N was sub-surface point placed and second N split (late vegetative stage) was surface band applied, and NPM3: both the N splits were sub-surface point placed, under 4-long-term tillage and residue management (+R) options, i.e., permanent raised bed (PB+R), zero-till flat (ZT+R) conventional till flat (CT+R) and first time zero till flat sowing of the crop on last 10-year fallow land (FZT+R), in an on-going long-term study (since 2008) in maize for three consecutive years (2018–2020). Results showed that sub-surface point placement of both the N splits (NPM3) increased maize grain yield by 4.7, 7.0 and 6.0% (3-years mean basis) compared to NPM2, under CA-based PB, ZT, and FZT plots, respectively. The peak growth rate in the CA-based PB+R plot was advanced by 4-days with a 9.2% higher growth rate compared to CT+R. Similarly, the peak growth rate in NPM3 was 20% higher than NPM1 plots. The changes in soil properties under CA altered the crop growth behavior, while sub-surface point placement of split applied nitrogen (N) increased the grain N content and altered the peak growth rate of maize. The variability in maize grain yield was best described by cob length and number of cobs in long-term tillage and by cob length in N management plots. The cob length and grains per cob were increased by 4.8–8.7 and 8.6–12.8% under CA-based plots compared to CT+R, respectively. The amount of vegetative stage accumulated N remobilized to maize grain was 21.2% higher under PB+R compared to CT+R plots, while the N remobilization in NPM3 was 22.9% higher compared to NPM1 plots. Similarly, the contribution of reproductive stage N uptake to grain was 9–12% higher in CA-NPM3 compared to CT-NPM1 plots. Further, the early and vigorous growth of maize resulted in a higher accumulation of N and its remobilization to the grains in CA-based and N point placed plots. The sub-surface point placement of N (NPM3) resulted in a 12.8, 14.5 and 9.2% higher benefit-cost ratio compared to NPM1 plots in 11th (2018), 12th (2019) and 13th (2020) years of experimentation, respectively. Therefore, the present study visualizes the impact of a decade-long CA and efficient N management on crop growth behavior, N uptake and remobilization and crop productivity and water use efficiency. This study provides evidence to popularize this technology in the CA-systems of Indo-Gangetic Plains and other similar agro-ecologies.

Effects of side deep placement of nitrogen on rice yield and nitrogen use efficiency

<p indent=0mm>Lateral deep fertilization is an efficient, high-quality, and safe cultivation technology of rice mechanical transplanting. In order to improve the technical system of lateral deep fertilization, we investigated the effects of different fertilization methods on rice yield and nitrogen use efficiency under the condition of lateral deep fertilization. In this study, Nanjing 9108 and Nanjing 5718, the representative varieties of quality and delicious rice of Jiangsu, were used as materials. Four different lateral deep fertilization methods were arranged, including 100% base fertilizer side deep application FM1 (fertilization method 1), 70% base fertilizer side deep application + 30% tillering fertilizer FM2 (fertilization method 2), 70% base fertilizer side deep application + 30% panicle fertilizer FM3 (fertilization method 3), and 35% base fertilizer side deep application + 35% tillering fertilizer + 30% panicle fertilizer FM4 (fertilization method 4). In addition, the conventional fertilization method and no nitrogen treatment were added. The effects of different treatments on rice yield, leaf area index, photosynthetic potential, dry matter accumulation, population growth rate, and nitrogen use efficiency were compared. The results revealed that the yield of FM3 and FM4 were higher than those of other treatments. The main reason was that the spikelet number of the population was significantly higher than that of other treatments on the basis of stable panicle number. The leaf area index and dry matter accumulation of FM3 treatment were higher in the middle and late growth stages, especially from heading to maturity stage. Nitrogen accumulation of FM3 was less before jointing stage, but nitrogen accumulation after jointing stage and the total nitrogen uptake during the whole growth period were significantly higher than those of other treatments. Moreover, the nitrogen agronomic utilization rate, nitrogen physiological utilization rate, nitrogen absorption utilization rate, and nitrogen partial productivity of FM3 were significantly higher than those of the other treatments. At the same time, compared with CFM and FM4, FM3 can reduce fertilization times by 1–2 times, save labor and cost, and is conducive to large-scale production. It is a high-yield, simple and efficient fertilization method for rice.

Suppressive effect of the deep placement of lime nitrogen on N2O emissions in a soybean field

Deep placement of slow-release nitrogen (N) fertilizers improves the growth and yield of soybean with a high N use efficiency. This study examined the effectiveness of deep placement of lime nitrogen (LN) in reducing N2O emissions in a soybean field and compared it with conventional fertilization. Before sowing soybeans, the starter N fertilizer (16 kg-N ha−1 ammonium sulfate) was mixed in the surface soil and the following four treatments were installed: the control with only the starter N (CT), conventional top-dressing of 60 kg-N ha−1 coated urea (CV), deep placement (20 cm depth) of 100 kg-N ha−1 urea (DU), and deep placement (20 cm depth) of 100 kg-N ha−1 LN (DL). The seasonal patterns of N2O emission rates measured using the closed chamber method differed among the treatments: in CT, N2O emissions were relatively low; in CV, N2O emissions derived from the top-dressed coated urea were observed from 91 days after sowing; in DU and DL, deeply-placed N was converted to N2O in the early growth stages. The cumulative N2O emissions in DL (1.8 kg-N ha−1) during the soybean cultivation period were significantly lower than those in DU (3.1 kg-N ha−1) and CV (2.8 kg-N ha−1), and slightly higher than CT (1.2 kg-N ha−1). The magnitude of N2O emissions was significantly lower in DL than DU, indicating that the choice of N fertilizer is important to reduce N2O emissions. Focusing on N2O emissions per unit coarse grain yield of soybeans, the value in DL was 0.45 g-N kg−1, which was significantly lower than 0.74 g-N kg−1 in CV. In conclusion, the deep placement of LN has the potential to be a sustainable farming method that can promote yields and reduce N2O emissions in soybean cultivation for high yield with N fertilization.

Effect of side deep placement of nitrogen on yield and nitrogen use efficiency of single season late japonica rice

Side deep placement of nitrogen plays an important role in improving rice yield and nitrogen use efficiency. Few studies have examined the effects of reducing the times of nitrogen (RTN) application and reducing the nitrogen rate (RNR) of application on rice yield and nitrogen use efficiency under side deep placement of nitrogen in paddy fields. Therefore, a field experiment of RNT and RNR treatments was conducted with nine fertilization modes during the 2018–2019 rice growing seasons in a rice–wheat cropping system of the lower reaches of the Yangtze River, China. Rice yield and nitrogen use efficiency were investigated under side deep placement of nitrogen. We found that under the same nitrogen application rate, the yield of RTN3 increased by 9.64 and 10.18% in rice varieties NJ9108 and NJ5718, respectively, compared with the farmers’ fertilizer practices (FFP). The nitrogen accumulation of RTN3 was the highest at heading stage, at 11.30 t ha−1 across 2018 and 2019. Under the same nitrogen application rate, the N agronomic use efficiency (NAE), N physiological efficiency (NPE) and N recovery efficiency (NRE) of RTN3 were 8.1–21.28%, 8.51–41.76% and 0.28–14.52% higher than those of the other fertilization modes, respectively. RNR led to decreases in SPAD value, leaf area index (LAI), dry matter accumulation, nitrogen accumulation, and nitrogen use efficiency. These results suggest that RTN3 increased rice yield and nitrogen use efficiency under the side deep placement of nitrogen, and RNR1 could achieve the goals of saving cost and increasing resource use efficiency. Two fertilization modes RTN3 and RNR1 both could achieve the dual goals of increasing grain yield and resource use efficiency and thus are worth further application and investigation.

Plummeting anthropogenic environmental degradation by amending nutrient-N input method in saffron growing soils of north-west Himalayas

Nitrous-oxide emission and nitrate addition from agriculture to earth’s environment are two main agriculture related anthropogenic causes of environmental degradation that needs greater attention. For addressing the aforesaid issue, new techniques/practices need to be developed and implemented. The present investigation, which was focused on this issue, resulted in developing a new mode of nitrogen (N) placement, i.e. ‘mid rib placement upper to corms in two splits (MRPU-2S)’, that could reduce nitrous oxide N emission by around 70.11% and, nitrate N leaching and runoff by around 68.26 and 67.09%, respectively, over conventional method, in saffron growing soils of northwest Himalayas. Besides plummeting environmental degradation, MRPU-2S further resulted in enhancing saffron yield by 33.33% over conventional method. The findings of the present investigation were used to develop new empirical models for predicting saffron yield, nitrate N leaching and nitrous-oxide N emission. The threshold limits of nitrate N leaching and nitrous oxide N emission have also been reported exclusively in the present study.

Nitrogen placement at sowing affects root growth, grain yield formation, N use efficiency in maize

Grain yields of summer maize are significantly affected by different nitrogen (N) rates and depths through regulating root growth and distribution in soil. Understanding of effects of the deep placement of N on the root and shoot growth, grain yield and N use efficiency in summer maize are limited. In this study, four N rates: 225, 191.25, 157.5 and 0 kg ha−1 applied at four depths: 5, 10, 15, and 20 cm were studied. Soil N content, root dry weight, root length density, biomass, grain yield and N use efficiency of maize were measured. Compared to 225 kg N ha−1 applied at a depth of 5 cm, a 15% reduction in the N application rate at a depth of 15 cm induced a larger root length density in the subsoil, as well as a larger rooting depth. It also facilitated maintaining a higher level of biomass and N accumulation during the later growth period, which increased the N assimilation of grain and enhanced grain yield by 3.9%, N recovery efficiency by 66.7%, N agronomic efficiency by 38.5%, and partial factor productivity of N by 22.1%. Overall, this study demonstrates that reducing the recommended N application rate of 225 kg ha−1 by 15% but applying it at a depth of 15 cm might be considered an efficient fertilization method that increases agricultural productivity and N use efficiency.

Assessing Effects of Agronomic Nitrogen Management on Crop Nitrogen Use and Nitrogen Losses in the Western Canadian Prairies

Effective agronomic nitrogen management strategies ensure optimum productivity, reduce nitrogen losses, and enhance economic profitability and environmental quality. Farmers in western Canada make key decisions on formulation, rate, timing and placement of fertilizer nitrogen that are suitable for soils, weather, and farming operations within which they operate. Suitability of agronomic nitrogen management options are assessed by estimates from linear interpolations and extrapolations of temporally and spatially discrete field-plot measurements of nitrogen responses. Such estimates do not account for non-linear and offsetting biogeochemical feedbacks of nitrogen cycles and cannot provide comprehensive nitrogen budgets for alternative nitrogen management options. These limitations can be overcome by using process-based agro-ecosystem models that adequately simulate basic processes of nitrogen biogeochemical cycles and are rigorously tested against site observations. Ecosys is a process-based ecosystem model, which successfully simulated the biogeochemical feedbacks among nitrogen, carbon, and phosphorus cycles across different agro-ecosystems. This study deployed ecosys to generate spatially and temporally continuous estimates to assess crop nitrogen use and agronomic nitrogen losses from the crop fields across Alberta for alternative nitrogen fertilizer management scenarios. The study simulated effects of four nitrogen management scenarios: fall banded urea, fall banded ESN (Environmentally Smart Nitrogen), spring banded urea, and spring banded ESN on nitrogen recovery and losses from barley fields on mid-slope landforms. These simulations were done at township grids of ~10km x 10km over 2011-2015 utilizing provincial soil and climate datasets. Modelled annual N2O, N2 and NH3 emissions, and nitrogen losses in surface runoff and sub-surface discharge were lower by about 25%, 30%, 70%, and 40% respectively with spring banding than in fall banding across Alberta. Modelled barley yields and grain nitrogen uptake were similar in spring and fall banding indicating agro-economic and environmental sustainability advantage of spring banding in Alberta. These modelled estimates were consistent with estimates based on plot and laboratory research for Alberta and similar prairie conditions. This study pioneered a methodology of process-based agroecosystem modelling, which is replicable and scalable to assess cumulative impacts of alternative agronomic nitrogen management options on crop production and the environment on provincial, regional, federal, continental and global scales.

Effect of Phosphate Fertilizer Type and Nitrogen Application Method on Tuber Yield and Growth Indices of Three Potato (Solanum tuberosum L.) Cultivars

Nitrogen and phosphorus are essential nutrients in growth of plants. In addition, the type and method of fertilizer application play an important role in the efficient absorption of nutrients and reduce fertilizer use. Therefore, an experiment was conducted in a randomized complete block design with three replications in the Bahar city in 2017: phosphorus fertilizer was three levels (no application, triple superphosphate and diammonium phosphate), nitrogen fertilizer with two levels (placement and no-placement) and potato cultivar with three levels (Agria, Banba and Sante). The highest leaf area index (5.27), crop growth rate (13.22 g.m-2) and total dry matter (582.86 g.m-2) were obtained from diammonium phosphate along with nitrogen placement in by using Agria cultivar. The results also showed that under conditions phosphorus deficiency, nitrogen application method did not affect leaf area index, crop growth rate and total dry matter: However, tuber yield of Agria under phosphorus deficiency increased by nitrogen placement treatment. In this study, the use of diammonium phosphate, compared to triple superphosphate, increased leaf area index, crop growth rate, relative growth rate and total dry matter. The effect of nitrogen placement along with triple superphosphate was higher than that of nitrogen with diammonium phosphate. Chlorophyll index was not affected by nitrogen placement when using diammonium phosphate, whereas, nitrogen placement increased chlorophyll index by 6.5% with triple superphosphate. The results also showed that the tuber yield increased by 25.4% when nitrogen used by placement combined with triple superphosphate fertilizer. As a whole, highest tuber yields of all three cultivars, especially in Agria and Banba, were increased under nitrogen placement treatment along with diammonium phosphate.

Ammonia volatilization, nitrous oxide emissions, and corn yields as influenced by nitrogen placement and enhanced efficiency fertilizers

AbstractEnsuring sufficient fertilizer nitrogen (N) for crops while minimizing N losses requires best management practices optimized for climate, crop, soil, and root zone hydrology. In Ontario, pre‐plant N fertilization of corn (Zea mays L.) is common; however, this practice extends the time between application and significant root interception of N by the plant, potentially increasing the risk of N loss through soil nitrous oxide emissions, ammonia (NH3) volatilization, and nitrate leaching. These losses contribute to greenhouse gas emissions, affect air quality (NH3), and are a substantial financial loss. This study compared three N placement methods (broadcast urea [BrUrea], broadcast incorporated urea [BrIncUrea], and injected urea ammonium nitrate [InjUAN]) and the presence or absence of N metabolite inhibitors (urease inhibitor [UI], urease plus nitrification inhibitor [UI+NI]). Fertilizer N was applied immediately before planting (150 kg N ha−1) to all treatments except for the control. Averaged over 3 yr (2015–2017), NH3 losses were reduced by 34% from BrIncUrea, by 42–55% from BrUrea+UI+NI and BrIncUrea+UI+NI, and by 99% from InjUAN relative to BrUrea (21 kg N ha−1). On average, N application increased corn grain yields by 83% relative to the control (6 t ha−1). There were no annual yield differences among N placement methods. It was concluded that incorporation or injection of N in soil and use of urease and nitrification inhibitors reduced NH3 emissions when N fertilizer was applied pre‐plant.

Deep Placement of Nitrogen Fertilizer Affects Grain Yield, Nitrogen Recovery Efficiency, and Root Characteristics in Direct-Seeded Rice in South China

Deep placement of nitrogen (N) fertilizer has become one of the effective management practices for increasing crop yield and improving N recovery efficiency (NRE). However, it is unclear how different N fertilization depths affect grain yield, nitrogen use efficiency, and root characteristics in direct-seeded rice (DSR) in South China. Here, we conducted stainless steel-box experiment to evaluate the effects of different N fertilization depths at four fertilization depths (0, 4, 8, and 12 cm, written as D0, D4, D8, and D12, respectively) with a conventional ammonium bicarbonate fertilizer (TN???=???17.7%) (150 kg N ha???1) and a control (no N fertilizer applied, CK) on grain yield, NRE, and root characteristics of DSR. The results indicated that both D8 and D12 significantly increased grain yields by 72.91 and 81.84%, respectively, compared with CK. The highest nitrogen agronomic efficiency (NAE) and NRE were found under D12 treatment, which were increased by 165.42 and 129.45% compared to D0, respectively. We also found that deep placement of N fertilizer (both D8 and D12) could also promote rice root growth such as larger root length, root superficial area, and thicker root diameter. Furthermore, nitrate reductase (NR), glutamine synthetase (GOGAT), and glutamine synthetase (GS) activities of flag leaves at the heading stage were also increased. The result shows that both 8 and 12 cm are relatively reasonable fertilization depths depended on adopted rice varieties when ammonia bicarbonate fertilizer is used in DSR production.

Canola is injured by in‐row nitrogen placement associated with disc openers, but not by tine openers

AbstractSeed drills are used in no‐tillage systems to place seed directly in soil. Various furrow openers exist, each with unique seed and fertilizer placement characteristics, particularly positioning of fertilizer in relation to the position of the seed. Seedling damage may occur if seed and fertilizer placement is not appropriate for the particular crop. Canola (Brassica napus L.) seed is small, resulting in seedlings susceptible to injury by fertilizers. A study was conducted to evaluate the effect of in‐row N placement with a seed drill fitted with single‐ and double‐chute tine openers, and disc openers. The study was performed in a Mediterranean‐type climate region in South Africa over 2 yr. Plant establishment was reduced by 48% when canola was established with disc openers with no separation between N and the seed (P &lt; .05). Tine openers were most successful in establishing an acceptable plant population, as well as ensuring high biomass production throughout the season, leading to a high leaf area index. Although no yield differences (P &gt; .05) were observed between openers, it was concluded that the application of N in the band at the same position as the seed is a risk. Tine openers, either with a single or double seed chute, that separate seed and fertilizer resulted in the best canola performance.

Effect of nitrogen point placement on energetic and soil enzymatic activities on long-term conservation agriculture based maize (Zea mays) - wheat (Triticum aestivum) system of western Indo-Gangetic plains

A field experiment was done in the long term conservation agriculture (CA)-based plots at ICAR-Indian Agricultural Research Institute (IARI) during 2018–19 with the treatments of nitrogen (N) point/line placement to compute the energy budgeting and soil enzymatic activity. There were four land management practices in main plots and in sub plots there were three nitrogen placement methods. Results of present study showed that the energy use efficiency was higher in the CA-based PB plots by 7.14% and 9.4% than CT plots in maize and wheat respectively. The energy output from the CA-based maize (Zea mays L.) and wheat (Triticum aestivum L.) plots was significantly higher by 9.1–11.2% and 8.8–14.4% than CT plots. However, N point placement treatments i.e. NPM3 and NPM2 had 14.8% and 8.8% higher energy output than NPM1 plots in maize respectively. Similarly in wheat, NPM2 and NPM3 plots had 4.2% and 7.0% higher energy output than NPM1. The CA-based plots recorded an increase in soil microbial biomass carbon (SMBC) by 8.7–15.6% in maize and 10.1–17.2% in wheat. The SMBC content remained statistically similar across N placement methods at flowering of maize and wheat crops. In maize and wheat, at the surface soil layer urease activity was found higher than CT by 11.7–20.2% and 13.2–22.4% in the CA-based plots. However, the urease activity was not affected by subsurface point or line placement of nitrogen at both the soil layers in both the crops. Therefore, the findings of present study suggest that the adoption of CA-based practices with point/line placement of split applied N in maize-wheat system of western Indo-Gangetic plains is favourable for improving the energy use efficiency and soil enzymatic activity.