Use Of Nitrogen Fertilizers Research Articles

Feasibility of Biofilm Biofertilizer in Halving Nitrogen Waste in Paddy Cultivation

In an attempt to achieve the target of the Colombo Declaration in 2019, we, the Centre for Advanced Research on Nitrogen Management in Agriculture (CARNMA) at the National Institute of Fundamental Studies (NIFS) conducted 112 field trials in 13 districts of Sri Lanka. Here, two practices being used extensively by the farmers were compared for the Nitrogen (N) fertilizer use efficiency in paddy; (a) chemical fertilizer (CF) practice [340 kg CF/ha (Urea 225, TSP 55 and MOP 60 kg/ha) and, as recommended by the Department of Agriculture] (b) Biofilm biofertilizer (BFBF) practice [2.5 L of BFBF/ha split into two applications, at two and six weeks after sowing, together with 225 kg CF/ha (Urea 150, TSP 40 and MOP 35 kg/ha), a reduction of CF by 34% because of the ability of the BFBF in increasing fertilizer use efficacy via microbial turnover]. Results showed that the BFBF application cut down N-fertilizer use by 33%, and hence the waste is also by the same amount with a simultaneous increase in grain yield by 23% (i.e., the average of all the 112 trials: the BFBF practice 5,860 kg/ha, and the CF practice 4,748 kg/ha). Moreover, the N fertilizer use efficiency by paddy crop increased by 6% in the BFBF practice indicating a higher N uptake, and hence lower N waste compared to the CF practice. The fertilizer cut down and the increased N uptake collectively reduced N waste by over 50%. In conclusion, the BFBF practice can be considered as a promising approach to meet the target of the Colombo Declaration in 2019 i.e., halving N waste in agriculture by 2030.
 
 Keywords: Biofilm biofertilizer, Colombo declaration, N-waste, Paddy

Effect of conjoint application schedules of organic and inorganic sources of nutrients on growth, yield and economics of rice

A field experiment was conducted during (kharif) summer season of 2019 and 2020 at Crop Research Centre, Sardar Vallabh Bhai Patel University of Agriculture and Technology, Modipuram, Meerut, Uttar Pradesh to study the effect of integrated use of chemical nitrogen fertilizer and green manure on performance of rice (Oryza sativa L.). The experiment consists of fourteen treatment combinations of conjoint application of organic and inorganic sources of nutrients was laid-out in randomized block design with three replications. The results showed that the significant highest dry matter accumulation (1,205.90 g/m2 ) at harvest stage, leaf-area index (4.18), crop growth rate (16.34 g/m2 /day), relative growth rate (7.09 mg/g/day), grain yield (3.88 t/ha) and straw yield (6.64 t/ha) recorded in the 25% recommended N through dhaincha incorporated + 75% N through chemical fertilizer was found at par with RDF (120N : 60P : 50K) and 25% recommended N through vermicompost incorporated 10 days before transplanting + 75% N through chemical fertilizer and it was significantly superior over rest of the treatment combinations. The substitution of 25% N through incorporated dhaincha at planting was found most promising in terms of productivity, profitability and performed better than other treatments and may be recommended for farmers of Uttar Pradesh and similar agro-eco regions.

Effect of a QTL on wheat chromosome 5B associated with enhanced root dry mass on transpiration and nitrogen uptake under contrasting drought scenarios in wheat.

A sufficient nitrogen supply is crucial for high-quality wheat yields. However, the use of nitrogen fertilization can also negatively influence ecosystems due to leaching or volatile atmospheric emissions. Drought events, increasingly prevalent in many crop production areas, significantly impact nitrogen uptake. Breeding more efficient wheat varieties is necessary to achieve acceptable yields with limited nitrogen and water. Crop root systems play a crucial role as the primary organ for absorbing water and nutrients. To investigate the impact of an enhanced root system on nitrogen and water use efficiency in wheat under various irrigation conditions, this study conducted two experiments using precision phenotyping platforms for controlled drought stress treatment. Experiment 1 involved four contrasting winter wheat genotypes. It included the Chinese variety Ning0604, carrying a quantitative trait locus (QTL) on chromosome 5B associated with a higher root dry biomass, and three elite German varieties, Elixer, Genius, and Leandrus. Experiment 2 compared near-isogenic lines (NIL) of the three elite varieties, each containing introgressions of the QTL on chromosome 5B linked to root dry mass. In both experiments, nitrogen partitioning was tracked via isotope discrimination after fertilization with 5 Atom % 15N-labeled KNO3-. In experiment 1 the quantification by 15N isotope discrimination revealed significantly (p < 0.05) higher nitrogen derived from fertilizer in the root organ for Ning0604 than those of the three German varieties. In experiment 2, two out of three NILs showed a significantly (p < 0.05) higher uptake of N derived from fertilizer than their respective recipient line under well-watered conditions. Furthermore, significantly lower transpiration rates (p < 0.1) were observed in one NIL compared to its respective recipient. The combination of the DroughtSpotter facility coupled with 15N tracer-based tracking of N uptake and remobilization extends the insight into the impact of genetically altered root biomass on wheat NUE and WUE under different water availability scenarios. The study shows the potential for how a modified genetic constitution of the locus on wheat chromosome 5B can reduce transpiration and enhance N uptake. The dependence of the observations on the recipient and water availability suggests a need for further research to investigate the interaction with genetic background traits.

A Warmer and Wetter World Would Aggravate GHG Emissions Intensity in China's Cropland

AbstractMany agricultural regions in China are likely to become appreciably wetter or drier as the global climate warming increases. However, the impact of these climate change patterns on the intensity of soil greenhouse gas (GHG) emissions (GHGI, GHG emissions per unit of crop yield) has not yet been rigorously assessed. By integrating an improved agricultural ecosystem model and a meta‐analysis of multiple field studies, we found that climate change is expected to cause a 20.0% crop yield loss, while stimulating soil GHG emissions by 12.2% between 2061 and 2090 in China's agricultural regions. A wetter‐warmer (WW) climate would adversely impact crop yield on an equal basis and lead to a 1.8‐fold‐ increase in GHG emissions relative to those in a drier‐warmer (DW) climate. Without water limitation/excess, extreme heat (an increase of more than 1.5°C in average temperature) during the growing season would amplify 15.7% more yield while simultaneously elevating GHG emissions by 42.5% compared to an increase of below 1.5°C. However, when coupled with extreme drought, it would aggravate crop yield loss by 61.8% without reducing the corresponding GHG emissions. Furthermore, the emission intensity in an extreme WW climate would increase by 22.6% compared to an extreme DW climate. Under this intense WW climate, the use of nitrogen fertilizer would lead to a 37.9% increase in soil GHG emissions without necessarily gaining a corresponding yield advantage compared to a DW climate. These findings suggest that the threat of a wetter‐warmer world to efforts to reduce GHG emissions intensity may be as great as or even greater than that of a drier‐warmer world.

Role of cotyledons in aluminium accumulation as a tolerance strategy in Fagopyrum esculentum Moench (Polygonaceae) seedlings.

Acidic soils have increased due to agricultural practices, climate factors, and the excessive use of nitrogen fertilizers to meet food demand. In these soils, aluminium (Al) is soluble and can be taken up by roots, but it is toxic to most plant species. Fagopyrum esculentum is able to adapt to acidic toxic aluminium conditions. Anatomical studies identifying novel potential cellular structures as sites of Al accumulation are currently lacking. This study provides an anatomical description of the cotyledons, revealing the presence of papillae and glandular trichomes at their margins. In seedlings treated with 100 μM Al, energy-dispersive x-ray spectroscopy (ESEM-EDS) analysis of the cotyledons revealed that the margin has the highest concentration of Al. The margin containing the epidermal papillae was subjected to laser microdissection, and Al was quantified using mass spectrometry with an inductively coupled plasma source ICP-MS and compared with the Al in the remaining leaf blades. The concentration of Al in the microdissected papillae was 3,460 mg Al kg-1 Dry Weight (DW), whereas the blades contained only 1,390 mg Al kg-1 DW. Moreover, histochemical tests for Al and total phenols in the epidermal papillae revealed that Al may be bound to phenolic compounds. Thus, this study demonstrated that the cotyledons of F. esculentum have epidermal papillae that can accumulate Al.

Nitrogen Cycling Dynamics: Investigating Volatilization and its Interplay with N2 Fixation

The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems, the conversion of nitrogen can be carried out through both biological and physical processes. Important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification. The majority of Earth's atmosphere (78%) is atmospheric nitrogen, making it the largest source of nitrogen. However, atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems. The nitrogen cycle is of particular interest to ecologists because nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition. Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the global nitrogen cycle. Human modification of the global nitrogen cycle can negatively affect the natural environment system and also human health. Volatilization and its Relationship to N2 fascination in Nitrogen Cycle in agriculture field is discuss in this paper.

Implications of Vegetal Protein Hydrolysates for Improving Nitrogen Use Efficiency in Leafy Vegetables

Climate change and the degradation of ecosystems is an urgent issue to which the agricultural sector contributes through the overuse of productive inputs such as chemical fertilizers. A disproportionate use of nitrogenous fertilizers combined with low efficiency inevitably results in worsening environmental problems (greenhouse gas emissions, soil degradation, water eutrophication, and groundwater pollution). Nevertheless, increasing population growth puts additional pressure on the already struggling agricultural world. Awareness of these problems has pushed the world of research towards the development of more sustainable but equally efficient strategies in terms of production. The use of biostimulant substances and/or micro-organisms promoting yield, resilience to abiotic stresses in plants, and increasing the functional quality of products have been indicated as a valid strategy to improve the sustainability of agricultural practices. In modern horticulture, the use of vegetable–protein hydrolysates (V-PHs) is gaining more and more interest. These biostimulants could influence plants directly by stimulating carbon and nitrogen metabolism and interfering with hormonal activity, but also indirectly as V-PHs could improve nutrient availability in plant growth substrates and increase nutrient uptake and utilization efficiency. By exploiting this aspect, it would be possible to reduce the use of chemical fertilizers without affecting potential yields. After a brief introduction to the issues related to the intensive use of nitrogen fertilizers, this review focuses on the use of V-PHs as a strategy to increase nitrogen use efficiency (NUE). Starting with their heterogeneous origins and compositions, their effects on nitrogen metabolism, as well as the physiological and biochemical processes involved in these products, this review concludes with an in-depth discussion of the effects of V-PHs on major leafy vegetables.

Effects of Funneliformis mosseae on Growth and Photosynthetic Characteristics of Camellia oleifera under Different Nitrogen Forms

Nitrogen fertilizer increases agricultural yields but increases economic costs and causes a series of environmental problems. Arbuscular mycorrhizal fungi (AMF) have the potential to be used as biological fertilizer. However, the influence of nitrogen form on plant growth responsiveness to AMF inoculation is poorly understood. In this study, we investigated the effects of Funneliformis mosseae on growth, root morphology and photosynthetic characteristics of Camellia oleifera under different nitrogen forms during three harvest periods and clarified the most suitable nitrogen form for C. oleifera–AMF symbiosis. The results showed that urea, ammonium and nitrate nitrogen promoted plant growth and photosynthetic capacity, among which urea treatment had the highest value in all three harvests. No significant difference in plant growth parameters was observed between ammonium and nitrate nitrogen treatments in the first two harvests, while the plant height was significantly lower under ammonium nitrogen treatment than nitrate nitrogen treatment in the third harvest. Inoculation with F. mosseae in the presence of indigenous AMF could promote AMF colonization and plant growth at all three harvest times. Inoculation with F. mosseae significantly increased gas exchange parameters, the maximum photochemical efficiency (Fv/Fm) and the actual photochemical efficiency (ΦPSII). Inoculation with AMF increased the photochemical quenching coefficient (qP) better under urea treatment and improved the non-photochemical quenching coefficient (qN) better under ammonium nitrogen treatment. Principal component analysis showed that urea is the most beneficial nitrogen fertilizer for C. oleifera–AMF symbiosis. The results of this study provide a theoretical basis for the combination use of AMF and nitrogen fertilizer in agroforestry.

Genome-Resolved Metagenomics and Denitrifying Strain Isolation Reveal New Insights into Microbial Denitrification in the Deep Vadose Zone.

The heavy use of nitrogen fertilizer in intensive agricultural areas often leads to nitrate accumulation in subsurface soil and nitrate contamination in groundwater, which poses a serious risk to public health. Denitrifying microorganisms in the subsoil convert nitrate to gaseous forms of nitrogen, thereby mitigating the leaching of nitrate into groundwater. Here, we investigated denitrifying microorganisms in the deep vadose zone of a typical intensive agricultural area in China through microcosm enrichment, genome-resolved metagenomic analysis, and denitrifying bacteria isolation. A total of 1000 metagenome-assembled genomes (MAGs) were reconstructed, resulting in 98 high-quality, dereplicated MAGs that contained denitrification genes. Among them, 32 MAGs could not be taxonomically classified at the genus or species level, indicating that a broader spectrum of taxonomic groups is involved in subsoil denitrification than previously recognized. A denitrifier isolate library was constructed by using a strategy combining high-throughput and conventional cultivation techniques. Assessment of the denitrification characteristics of both the MAGs and isolates demonstrated the dominance of truncated denitrification. Functional screening revealed the highest denitrification activity in two complete denitrifiers belonging to the genus Pseudomonas. These findings greatly expand the current knowledge of the composition and function of denitrifying microorganisms in subsoils. The constructed isolate library provided the first pool of subsoil-denitrifying microorganisms that could facilitate the development of microbe-based technologies for nitrate attenuation in groundwater.

Distribution and Origins of Hardness in Shallow and Deep Groundwaters of the Hebei Plain, China

Elevated hardness concentrations in groundwater have become a noteworthy concern in recent decades because long-term drinking of groundwater with high levels of hardness is an important factor resulting in chronic kidney diseases. In this study, the distribution and origins of groundwater total hardness (TH) in various sub-plains and different land-use areas of the Hebei Plain (HBP) were investigated. A total of 445 groundwater samples in the HBP were collected once in 2021, and twelve chemical parameters, including TH in groundwater, were analyzed. Results showed that TH-rich (&gt;450 mg/L) shallow groundwater in both the central and littoral plains was more than twice that in the Piedmont plain. Similarly, TH-rich deep groundwater accounted for about 18% in the central plain but was negligible in the Piedmont plain. In the Piedmont plain, TH-rich shallow groundwater in urban areas was twice or more than in other land use types. By contrast, both TH-rich shallow and deep groundwaters in agricultural areas in the central plain were higher than those in rural areas. This was opposite to TH-rich shallow groundwater in the littoral plain. In the Piedmont plain, TH-rich shallow groundwater was mainly attributed to water-rock interaction, groundwater over-extraction, and the infiltration of domestic sewage and animal waste. In the central plain, both TH-rich shallow and deep groundwaters likely ascribed to the evaporite dissolution and seawater intrusion. By contrast, the leaching of agricultural fertilizers resulting in the dissolution of Ca-rich and Mg-rich minerals in the vadose zone was mainly responsible for the occurrence of TH-rich shallow groundwater in the littoral plain. Therefore, in order to limit elevated hardness concentrations in groundwater in the HBP, limiting shallow groundwater extraction and strengthening the supervision of the domestic sewage and animal waste in the Piedmont plain are recommended. Besides, restricting the use of nitrogenous fertilizers in the littoral plain is also recommended.

High leaching potential combined with a low leaching amount of fertilizer-derived nitrate in conservation tillage cropland of Northeast China

Stover mulching in no-tillage farming has been widely proposed as an optimized agricultural management practice to increase soil carbon storage and improve fertilizer nitrogen (N) use efficiency in current agroecosystems. However, the regulation of soil internal gross N transformation dynamics on NO3−-N leaching potential in response to long-term conservation tillage practices is still lacking. Here, based on a combination of 15N-tracing incubation and in situ monitoring experiments, we investigated the effect of 9-year no-tillage and maize stover mulching on the vertical migration of fertilizer-derived NO3−-N into a deeper soil profile and the associated gross NO3−-N transformation dynamics in the Mollisol of Northeast China. The net positive NO3−-N production rates (varied from 3.14 to 6.22 mg N kg−1 d−1) were observed across all management practices in the studied Mollisol, indicating a relatively high NO3−-N leaching potential in the cropland of Northeast China, which was further confirmed by an average of 7.4 % fertilizer-derived NO3−-N being vertically transferred to the 80–100 cm soil layer after a complete maize growing period. Compared with traditional ridge tillage, long-term stover mulching in no-tillage farming significantly reduced total NO3−-N production by decreasing autotrophic nitrification while simultaneously enhancing total NO3−-N consumption by stimulating nitrate reduction and microbial NO3−-N immobilization, revealing a markedly reduction of net NO3−-N production in the no-tillage agroecosystem. Therefore, converting traditional ridge tillage toward no-tillage with maize stover mulching can effectively decrease fertilizer-derived NO3−-N leaching amounts and thus formulate targeted mitigation strategies for sustainable agriculture in Mollisols of Northeast China.

Improving maize carbon and nitrogen metabolic pathways and yield with nitrogen application rate and nitrogen forms.

Reduced fertilizer efficiency caused by excessive use of nitrogen (N) fertilizer is a major problem in agriculture and a hot topic of research. Most studies have focused on the effect of N application rate on N efficiency, whereas there are limited studies on changing the N form to improve N yield and efficiency. Here, the effects of different N application rates and nitrate-to-ammonium N ratios on post-anthesis carbon (C) and N metabolism and maize yield under shallow-buried drip irrigation were investigated. Two rates of N application (210 kg·ha-1 (NA1) and 300 kg·ha-1 (NA2)) and three nitrate-to-ammonium N ratios (2:1 (NF1), 3:1 (NF2), and 4:1 (NF3)) were utilized. Post-anthesis photosynthetic characteristics, activities of key enzymes in photosynthetic C and N metabolism, nonstructural carbohydrate content, post-anthesis N accumulation and transportation, yield, and N-use efficiency were determined. At both N application rates, NF2 treatment enhanced photosynthetic activity in the ear-leaf at silking stage and promoted key enzyme activities of C and N metabolic pathways, compared with NF1 and NF3. Furthermore, NF2 significantly increased nonstructural carbohydrate accumulation (4.00-64.71%), post-anthesis N accumulation and transportation (11.00-38.00%), and grain yield (2.60-13.08%). No significant differences between NA1 and NA2 were observed under NF2 in most of the measured variables; however, NA1 had higher N-use efficiency. Thus, the optimal treatment under shallow-buried drip irrigation was a N application rate of 210 kg ha-1 and a nitrate-to-ammonium N ratio of 3:1. These findings provide theoretical guidance on appropriate N applications for high-yield maize production.

Electrocatalysis of nitrogen pollution: transforming nitrogen waste into high-value chemicals.

On 16 June 2023, the United Nations Environment Programme highlighted the severity of nitrogen pollution faced by humans and called for joint action for sustainable nitrogen use. Excess nitrogenous waste (NW: NO, NO2, NO2-, NO3-, etc.) mainly arises from the use of synthetic fertilisers, wastewater discharge, and fossil fuel combustion. Although the amount of NW produced can be minimised by reducing the use of nitrogen fertilisers and fossil fuels, the necessity to feed seven billion people on Earth limits the utility of this approach. Compared to current industrial processes, electrocatalytic NW reduction or CO2-NW co-reduction offers a potentially greener alternative for recycling NW and producing high-value chemicals. However, upgrading this technology to connect upstream and downstream industrial chains is challenging. This viewpoint focuses on electrocatalytic NW reduction, a cutting-edge technology, and highlights the challenges in its practical application. It also discusses future directions to meet the requirements of upstream and downstream industries by optimising production processes, including the pretreatment and supply of nitrogenous raw materials (e.g. flue gas and sewage), design and macroscopic preparation of electrocatalysts, and upscaling of reactors and other auxiliary equipment.

The effectiveness of technologies with autumn tillage

The article shows the yield of spring soft wheat in 16 different technologies, differing in its place in the crop rotation, the type of basic tillage and the use of nitrogen fertilizer. When plowing with the removal of sowing from fallow, the yield decreased from 2,24 t/ha by 1,4-1,5 times – to 1,63 and 1,52 t/ha, and with permanent cultivation, grain harvest in relation to wheat by fallow decreased by 1,6 times to 1,38 t/ha. On a fertilized background, on the 2nd and 3rd wheat, the decrease occurred by 1,2-1,4 times: from 2,33 t/ha per fallow to 1,86 and 1,88 t/ha. The permanent crop provided grain harvest in t/ha of 1,38 in the control and 1,60 against the background of N40. During surface autumn tillage, the place of wheat in the crop rotation was also of great importance, since the yield without fertilizer decreased from 1,89 t/ha for a couple to 1,42-1,22 in the following fields and to 1,16 t/ha for permanent cultivation. When applying fertilizer, the yield dropped from 2,13 t/ha per fallow to 1,60-1,73 in the following crops and to 1,45 in permanently grown wheat. The preservation of the number of productive stems at the level of 362 pieces per 1 m2 contributed to the formation of a high yield of wheat by fallow during plowing. The number of grains in the ear was of great importance, which equaled 18,7-19,5 pieces in fallow with 13-17 in other technologies.

Problems of fertilizer application in developed agriculture and their solution

One of the important ways to obtain heavy and high-quality crops is to increase soil fertility by fertilizing to a level that fully meets the needs of crops in nutrients. According to the results of the research, the function and role of fertilizers in increasing crop yields were revealed. The data on the production and use of nitrogen, phosphorus and potash mineral fertilizers in Uzbekistan and worldwide were summarized. The ways of increasing soil fertility and crop yields through the use of fertilizers are outlined.

Optimizing wheat prosperity: innovative drip irrigation and nitrogen management strategies for enhanced yield and quality of winter wheat in the Huang-Huai-Hai region.

To examine the impacts of varied water and nitroge combinations on wheat yield and quality under drip irrigation in the Huang-Huai-Hai area, a field experiment was conducted over two growing seasons of winter wheat from 2019 to 2021. Traditional irrigation and fertilization methods served as the control (CK), with two nitrogen application rates set: N1 (180 kg/ha) and N2 (210 kg/ha). The irrigation schedules were differentiated by growth stages: jointing, anthesis (S2); jointing, anthesis, and filling (S3); and jointing, booting, anthesis, and filling (S4), at soil depths of 0-10 cm (M1) and 0-20 cm (M2). Results indicated that compared to CK, the 3 and 4 times irrigation treatments comprehensively improved grain yield (GY) by 8.0% and 13.6% respectively, increased the average plant partial factor productivity of nitrogen fertilizer (PFPN) and irrigation use efficiency (IUE) by 57.5% and 38.2%, and 62.2% and 35.8%, respectively. The gluten content (GC) of 3 irrigations was 1.6% higher than CK, and other metrics such as dough tenacity (DT), softness (ST), water absorption (WAS), and gluten hardness (GH) also showed improvements. Furthermore, the contents of amylose, amylopectin, and total starch under 3 irrigations significantly increased by 9.4%, 11.4%, and 9.8%, respectively, with higher than 4 irrigations. The crude protein content and soluble sugar content in 3 irrigations rose by 6.5% and 9.8% respectively over two years. These irrigation treatments also optimized gelatinization characteristics of grains, such as breakdown viscosity (BDV), consistency peak viscosity (CPV), consistency setback viscosity (CSV), pasting temperature (PeT), and pasting time (PaT). The study demonstrated that appropriate drip irrigation can effectively synchronize water and nitrogen supply during critical growth stages in winter wheat, ensuring robust late-stage development and efficient transfer of photosynthetic products into the grains, thus enhancing grain mass and yield. This also led to improved utilization of water and fertilizer and enhanced the nutritional and processing quality of the grain. However, excessive irrigation did not further improve grain quality. In conclusion, given the goals of saving water and fertilizer, achieving excellent yield, and ensuring high quality, the N1S3M1 treatment is recommended as an effective production management strategy in the Huang-Huai Hai area; N1S3M2 could be considered in years of water scarcity.

Carbon Footprint and Life-cycle Cost of Maize (zea mays l.) Production at Conventional and Regenerative Agricultural Practices.

This research aimed to evaluate the carbon footprint and life-cycle costs of grain maize production between conventional and regenerative agriculture practices. The material for the analyses was data from 2022–23 collected on Al-Rehman Dairy farms located in the Dunyapur region and growing maize for grain in two ways: conventional, and Regenerative (No-Till). The life-cycle assessment and life-cycle costing methodologies were applied to assess the GHG emissions and costs associated with the grain maize production in the stages from “cradle-to-farm gate”, i.e., from obtaining raw materials and producing means for agricultural production, through the processes of maize cultivation to grain harvesting. The SOC concentrations under NTS in the 0–15 cm soil layer and under NT in the 15–30 cm layer were significantly greater compared with those under CT. In the 15–30 cm soil layer, the SOC concentration under NT was higher than under CT. The difference in SOC content for the different soil depths between CT and NT was similar to the trend observed in the SOC concentration. NT produced a significantly higher SOC content in the 15–30 cm soil layer than the CT system and compared with CT in the 15–30 cm soil layer. The largest source of GHG emissions was the use of nitrogen fertilizers. Non-inversion tillage with rice straw mulch and leaving a large amount of crop residues in the field increased the sequestration of organic carbon and contributed to a significant reduction of the carbon footprint in maize production. The conventional tillage system demonstrated the highest overall life-cycle costs per hectare.

Net greenhouse gas balance in U.S. croplands: How can soils be part of the climate solution?

Agricultural soils play a dual role in regulating the Earth's climate by releasing or sequestering carbon dioxide (CO2 ) in soil organic carbon (SOC) and emitting non-CO2 greenhouse gases (GHGs) such as nitrous oxide (N2 O) and methane (CH4 ). To understand how agricultural soils can play a role in climate solutions requires a comprehensive assessment of net soil GHG balance (i.e., sum of SOC-sequestered CO2 and non-CO2 GHG emissions) and the underlying controls. Herein, we used a model-data integration approach to understand and quantify how natural and anthropogenic factors have affected the magnitude and spatiotemporal variations of the net soil GHG balance in U.S. croplands during 1960-2018. Specifically, we used the dynamic land ecosystem model for regional simulations and used field observations of SOC sequestration rates and N2 O and CH4 emissions to calibrate, validate, and corroborate model simulations. Results show that U.S. agricultural soils sequestered Tg CO2 -C year-1 in SOC (at a depth of 3.5 m) during 1960-2018 and emitted Tg N2 O-N year-1 and Tg CH4 -C year-1 , respectively. Based on the GWP100 metric (global warming potential on a 100-year time horizon), the estimated national net GHG emission rate from agricultural soils was Tg CO2 -eq year-1 , with the largest contribution from N2 O emissions. The sequestered SOC offset ~28% of the climate-warming effects resulting from non-CO2 GHG emissions, and this offsetting effect increased over time. Increased nitrogen fertilizer use was the dominant factor contributing to the increase in net GHG emissions during 1960-2018, explaining ~47% of total changes. In contrast, reduced cropland area, the adoption of agricultural conservation practices (e.g., reduced tillage), and rising atmospheric CO2 levels attenuated net GHG emissions from U.S. croplands. Improving management practices to mitigate N2 O emissions represents the biggest opportunity for achieving net-zero emissions in U.S. croplands. Our study highlights the importance of concurrently quantifying SOC-sequestered CO2 and non-CO2 GHG emissions for developing effective agricultural climate change mitigation measures.

Irrigation and nitrogen fertiliser optimisation in protected vegetable fields of northern China: Achieving environmental and agronomic sustainability

Globally, sub-optimal use of nitrogen (N) fertiliser and elevated N irrigation groundwater have led to high leached nitrate (NO3−) losses from protected vegetable field systems. Optimising fertiliser and irrigation management in different soil types is crucial to reduce future N loads from such systems. The present 4-year study examined leached N loads from lysimeter monitoring arrays set up across 18 protected vegetable system sites encompassing the dominant soil types of northern China. The treatments applied at each field site were: 1) a high N and high irrigation input treatment (HNHI); 2) a low N but high irrigation input treatment (LNHI) and 3) a low N with low irrigation input treatment (LNLI). Results showed that the mean annual leached total nitrogen loads from the HNHI, LNHI and LNLI treatments were 325, 294 and 257 kg N ha−1 in the fluvo-aquic soil, 114, 100 and 78 kg N ha−1 in the cinnamon soil and 79, 68 and 57 kg N ha−1 in the black soil, respectively. The N dissolved in irrigation water in the fluvo-aquic soil areas was 8.26-fold higher than in the cinnamon areas. A structural equation model showed that N fertiliser inputs and leaching water amounts explained 14.7 and 81.8% of the variation of leached N loads, respectively. Correspondingly, reducing irrigation water by 21.5% decreased leached N loads by 20.9%, while reducing manure N and chemical N inputs by 22 and 25% decreased leached N loads by only 9.5%. This study highlights that protected vegetable fields dominated by fluvo-aquic soil need management to curtail leached N losses in northern China.

NITROGEN USE EFFICIENCY IN SUNFLOWER (HELIANTHUS ANNUUS L.) INFLUENCED BY VARIOUS FERTIGATION AND BED PLANTING TECHNIQUES

Low nitrogen fertilizer use efficiency and high losses of nitrogen are the critical challenges being faced by sunflower grower. To address these concerns, an experiment was carried out during spring 2021 at the Agronomic research area of the Agriculture University, Faisalabad. The randomized complete block design experiment was used with three replications under split plot arrangement. The 5m x 3m net plot size was kept with sowing procedures retained in the main plot and nitrogen application techniques kept in the sub plot. The experiment was planted on 20-02-2021. The matured crop was reaped on 18 June, 2021 manually. The single row hand drill was used to sow sunflower crop. The 75 cm line to line and 25 cm plant to plant distance was maintained. The results indicated that plant population ranged from 73 to 74 with maximum plant height of 174.33 cm, stem diameter (3.70 cm), head diameter (23.13 cm), number of achenes per head (1237.6), 1000-achene weight (68.17 g), highest biological yield (10.92 t ha-1), achene yield (3.22 t ha-1), harvest index (29.48 %) and protein contents (29.03 %) was observed in treatment where nitrogen was applied by fertigation method and sunflower was sown on beds. But maximum oil contents (41.78 %) were observed where nitrogen was side dressed and flat sowing technique was adopted for crop sowing. It is found that use of fertigation method of nitrogen application and bed planting techniques proved to be the best combination for improving growth, yield &amp; yield relating attributes and improve fertilizer use efficiency with lower nitrogen losses for sunflower (Hybrid-33) under agro-climatic conditions of Faisalabad.