Inorganic Nitrogen Fertilizer Research Articles

Coupling of reduced inorganic fertilizer with plant-based organic fertilizer as a promising fertilizer management strategy for colored rice in tropical regions

Colored rice is a type of high-quality, high-added-value rice that has attracted increasing attention in recent years. The use of large amounts of inorganic nitrogen fertilizer in rice fields results in low fertilizer use efficiency and high environmental pollution. Organic fertilizer is a promising way to improve soil quality and sustain high yields. However, most studies focus on the effect of animal-based organic fertilizers. The effects of different ratios of plant-based organic fertilizer and inorganic fertilizer on the grain yield and quality of colored rice have rarely been reported. Therefore, a two-year field experiment was conducted in 2020 and 2021 to study the effects of replacing inorganic N fertilizers with plant-based organic fertilizers on the yield, nitrogen use efficiency (NUE), and anthocyanin content of two colored rice varieties in a tropical region in China. The experimental treatments included no nitrogen fertilization (T1), 100% inorganic nitrogen fertilizer (T2), 30% inorganic nitrogen fertilizer substitution with plant-based organic fertilizer (T3), 60% inorganic nitrogen fertilizer substitution with plant-based organic fertilizer (T4), and 100% plant-based organic fertilizer (T5). The total nitrogen provided to all the treatments except T1 was the same at 120 kg ha–1. Our results showed that the T3 treatment enhanced the grain yield and anthocyanin content of colored rice by increasing nitrogen use efficiency compared with T2. On average, grain yields were increased by 9 and 8%, while the anthocyanin content increased by 16 and 10% in the two colored rice varieties under T3 across the two years, respectively, as compared with T2. Further study of the residual effect of partial substitution of inorganic fertilizers showed that the substitution of inorganic fertilizer with plant-based organic fertilizer improved the soil physio-chemical properties, and thus increased the rice grain yield, in the subsequent seasons. The highest grain yield of the subsequent rice crop was observed under the T5 treatment. Our results suggested that the application of plant-based organic fertilizers can sustain the production of colored rice with high anthocyanin content in tropical regions, which is beneficial in reconciling the relationship between rice production and environmental protection.

Soil characteristics controlling nitrous oxide emissions of tropical peatlands

Emission of nitrous oxide (N2O) from peatlands contributes very significantly to the world global warming, although the factors controlling N2O emissions from peatlands are not yet clear. This study aimed to determine peat characteristics controlling N2O emissions in peatlands. N2O emissions and several soil characteristics (pH, electrical conductivity, height of water table, water-filled pore space, decomposition degree of peats, bulk density, organic carbon, total nitrogen, and concentrations of ammonium and nitrate) were observed in peatlands with different crops and land-uses: lettuce, spring-onion, albizia, shrubs-peat, and burned-peats. Correlation-regression analyses were employed to quantify peat properties influencing the rates of N2O emission from peatlands. The results of the study showed that N2O emissions varied based on the type of crops/land-uses, in which peats used for crop cultivation had higher N2O emissions than others. The results of the analysis also revealed that N2O emissions of peat were controlled by variables related to water contents and the contents of NH4 + and NO3 −. In peats with relatively similar NH4 + and NO3 − contents, N2O emissions were determined by variables related to water contents (height of water table and volumetric water contents). The result of this study shows the need for water and peat fertility management for the mitigation of N2O emission from peatlands. Thus, managing the availability of nitrogen by using biological fertilizers to reduce the amounts of inorganic nitrogen fertilizers is required to reduce N2O emissions without decreasing crop yields in peatlands.

Gross nitrogen mineralization and nitrification at an optimal phosphorus input level in southern Chinese red soil with long-term fertilization

In China, phosphorus (P) is recognized as a “key limiting nutrient” for crop production, and its overuse results in underground leaching, ecosystem alterations and risks to humans, such as degraded surface water quality. The coupling of nitrogen (N) and P implies that soil N dynamics are largely affected by P availability. However, how the addition of P affects soil N transformations remains less understood. To determine the optimal P-input level, we performed an incubation experiment on an upland soil from Jinxian in China after long-term mineral fertilizer application and P addition. The two treatments without N addition T1 (no fertilizer) and T2 (inorganic potassium fertilizer) and the two treatments with N addition T3 (inorganic nitrogen fertilizer) and T4 (inorganic nitrogen and potassium fertilizer) were selected from the long-term experiment that involved scientific management at five P-input levels (0, 25, 50, 75, and 100 kg P2O5 ha−1) with three replications. The results showed that soil organic matter (SOM) increased in the T3 and T4 treatments compared with the T1 and T2 treatments. The T4 treatment resulted in the maximum N concentration of 1.28 g kg−1, followed by that in the T3 treatment (1.25 g kg−1), T2 (0.16 g kg−1) and that in the T1 treatment (0.10 g kg−1), in the soil. Among the different treatments, soil microbial biomass carbon (SMBC) and nitrogen (SMBN) were significantly higher (492.69 mg kg−1 and 73.36 mg kg−1, respectively) in the T3 treatment than in the other treatments, while soil microbial biomass phosphorus (SMBP) was higher in the T4 treatment (17.55 mg kg−1). With the addition of P, the gross N mineralization rate was substantially enhanced when N and K were applied. After the 90-day incubation period, with higher concentrations of NO3--N and NH4+-N in the T4 treatment than in the other treatments, the concentrations were significantly increased by P addition, specifically T4P4 by 11.27% and 37.37%, T4P3 by 12.64% and 30.29%, T4P2 by 22.94% and 64.53%, and T4P1 by 3.93% and 11.09%, compared with those of T4P0, respectively; these results indicated a maximum N mineralization potential (No) and mineralization rate constant, k (NMR). As a result of the increased gross nitrogen mineralization rates and associated NH4+ substrate availability, the gross nitrification rate was also increased by P addition. Based on the polynomial regression analysis, the inclusion of P at the rate of 60 kg P2O5 ha−1 can be used effectively to obtain maximum gross N mineralization rates in soil. Additionally, to fully understand why P addition is more effective under specific soil and environmental conditions, more research is necessary to determine the underlying mechanisms.

Yield response of accessions of Bambara groundnut (Vigna subterranea (L) Verdc) inoculated with Bradyrhizobium japonicum strains

Field experiments were conducted in two different agroecological locations of Ibadan and Ikenne in Nigeria from August through December during the 2019 and 2020 cropping seasons. The studies were set up to reduce reliance on inorganic nitrogen fertilizer and to embrace the use of nitrogen-fixing bacteria to improve legume production to increase farmers' output and profitability. Ten accessions of the Bambara groundnut (BGN) were used in the trials. Seeds of each BGN accession were coated with each of the following Bradyrhizobium japonicum strains (B. japonicum): FA3, RACA6, USDA110, and IRJ2180A before planting. Furthermore, Nitrogen (N) fertilizer (20 kg/ha, urea) was applied to seedlings without inoculation, and uninoculated seedlings (without inoculation and without fertilization) served as control. The experiment was, therefore, a factorial arrangement (10 BGN accessions, 4 B. japonicum strains, N fertilizer application, and an uninoculated control). The yield and yield components of the inoculated BGN accessions were significantly enhanced at both agroecological locations and seasons. Among the B. japonicum strains used for inoculation, RACA6 strains significantly enhanced the yield and yield component of TVSu-1698 than other inoculated BGN accessions with a mean value of 6,234 ± 87 kg ha−1 recorded in both locations and seasons, compared to the result obtained in the combination of TVSu-1698 with N fertilizer with a mean value of 3,264 ± 943 kg ha−1. By using TVSu-1698 with RACA6 strain, farmers can get 85% more yield than on average with other genotypes/strains combination, while an average yield of 60% could be obtained by farmers using N fertilizer application.

Effects of Different Tillage Practices and Nitrogen Fertiliser Application Rates on Soil-Available Nitrogen

The dynamics of nitrogen availability in soil result from the net amount of organic and inorganic inputs undergoing decomposition, mineralization, and immobilization. This varies with soil type, climate, and cropping system management practices. Hence, the interaction of these factors in a specific environment is important for nitrogen management and availability in any cropping system. This study evaluated the concentration of nitrate (NO3−) and ammonium (NH4+) in a maize monocropping system in a long-term trial under different tillage practices, i.e., no-till (NT), conventional tillage (CT), and rotational tillage (RT), and with different nitrogen (Urea) fertiliser application rates (0, 100, and 200 kg/ha N). The experimental area was a split plot with randomized tillage strips as the main plots, with the nitrogen fertiliser application rates forming the subplots. The results found the highest concentration of NO3− (7.728 mg/kg) and NH4+ (0.762 mg/kg) under the NT (p < 0.05) compared to the other treatments. CT recorded the lowest amount of NH4+ (0.648 mg/kg) (p < 0.05) compared to RT (0.758 mg/kg), while the concentration of NO3− (6.755 mg/kg) under the CT was relatively higher than under the RT (4.720 mg/kg). The results also showed that the 0–10 cm depth had a significantly (p < 0.05) higher concentration of NO3− (6.787 mg/kg) and NH4+ (0.851 mg/kg), followed at the 20–30 cm depth with 6.229 mg/kg NO3− and 0.832 mg/kg NH4+. Soil samples taken at 10–20 cm depth recorded the lowest NO3− (6.188 mg/kg) and NH4+ (0.485 mg/kg). The study also found the highest NO3− concentration (0.452 mg/kg) with 200 kg/ha N (p < 0.05), while the highest concentration of NH4+ (0.954 mg/kg) was found with 0 kg/ha N. The lowest concentrations of both NO3− (6.333 mg/kg) and NH4+ (0.561 mg/kg) were found with 100 kg/ha N. the no-till also had a significantly (p < 0.05) higher NO3− (8.518 mg/kg) concentration with 200 kg/ha N compared to the CT (6.005 mg/kg) and RT (4.833 mg/kg). On the other hand, more NH4+ (1.478 mg/kg) was found with 0 kg/ha N under the NT compared to the CT (0.717 mg/kg) and the RT (0.669 mg/kg). The concentration of NH4+ was relatively low with 200 kg/ha N in the NT (0.545 mg/kg) and CT (0.598 mg/kg) but higher in the RT (0.813 mg/kg). In conclusion, the NT favoured the availability of NO3− and NH4+ in the studied cropping system; however, the concentration of these was affected by fertiliser application rate and depth. This suggested that each tillage system should be compatible with the type and the rate of inorganic nitrogen fertiliser for better crop production.

Findings on agricultural cleaner production in the three Gorges Reservoir Area

The ‘rural revitalization strategy’ is important to achieve sustainable development in the Three Gorges Reservoir Area (TGRA), the largest reservoir in China, located in the poverty alleviation region of the Qinling-Daba mountains, and characterized as mountainous and hilly dominated by backwards resettlements. Pig farming around the reservoir area is a key industry, accounting for 0.90% of the arable land area in the country, while the annual pig market represents a 1.37% share of the national figure. Here, 12 study sites were investigated on-site for understanding agricultural green development in the TGRA. We found two main prevailing models: one of ecological circulation (EC), based on animal husbandry and recycling. Of the 12 site, six cases of the ecological circulation model relied on pig husbandry, combined with cropping (grains/fruits/vegetables) by eco-industrial chains, such as pig-biogas-fruit (grain/vegetables), to prevent environmental pollution, while promoting agricultural economic growth by recycling fecal residues and wastewater (FSW) from pig-husbandry facilities to the fields. Our analysis predicted that a farm holding 10,000 pigs may save inorganic nitrogen and phosphorus fertilizers by as much as 74.36 and 11.15 ton·a−1, respectively. On the other hand, five cases of ecological models oriented towards agritourism provided tourists with high-quality ecological products while coordinating environment protection with economic development. In addition, 11 research points applied water and fertilizer integration system for the purpose of saving water. However, lack of sufficient supporting arable land made intensive pig farming a risk of ecological degradation. Green control technologies are rarely used leading to an increase in the type and amount of pesticides. Our study has theoretical and practical significance for decision-makers to promote agricultural cleaner production (ACP).

Effect of Different Organic Amendments on Actual and Achievable Yields in a Cereal-Based Cropping System

Soil fertility is at risk in intensive cropping systems when using an exclusive regime of inorganic fertilisers without returning sufficient organic matter to the soil. Our objective was to evaluate the long-term effects of commonly used organic amendments interacting with different rates of inorganic nitrogen fertiliser on crop yields of winter wheat. Yield data from winter wheat were collected for five seasons between 2013 and 2019 from a continuous field trial based at Rothamsted Research, SE England. Organic amendments (anaerobic digestate, compost, farmyard manure, and straw at a rate of 0 and 2.5 ton C per hectare) and five rates of inorganic nitrogen fertiliser (NH4NO3 at 0, 80, 150, 190, 220 kg N ha−1) were applied to winter wheat grown in an arable rotation. At the same inorganic N rate, grain yields for the different organic amendment treatments (excluding the straw treatment) were statistically similar but significantly greater than the unamended control treatment. The nitrogen rate required for optimum yields tended to be lower in plots receiving a combination of organic amendments and mineral fertiliser. Based on the observed and modelled response functions, organic amendments excluding straw increased maximum achievable yields compared to non-amended controls. The size of the effect varied between seasons and amendments (+4.6 to +19.0% of the control yield), increasing the mean maximum achievable yield by 8.8% across four seasons. We conclude that the application of organic amendments can increase the yield potential in winter wheat substantially over what is achievable with inorganic fertiliser only.

Biochar with Inorganic Nitrogen Fertilizer Reduces Direct Greenhouse Gas Emission Flux from Soil.

Agricultural waste can have a catastrophic impact on climate change, as it contributes significantly to greenhouse gas (GHG) emissions if not managed sustainably. Swine-digestate-manure-derived biochar may be one sustainable way to manage waste and tackle GHG emissions in temperate climatic conditions. The purpose of this study was to ascertain how such biochar could be used to reduce soil GHG emissions. Spring barley (Hordeum vulgare L.) and pea crops in 2020 and 2021, respectively, were treated with 25 t ha-1 of swine-digestate-manure-derived biochar (B1) and 120 kg ha-1 (N1) and 160 kg ha-1 (N2) of synthetic nitrogen fertilizer (ammonium nitrate). Biochar with or without nitrogen fertilizer substantially lowered GHG emissions compared to the control treatment (without any treatment) or treatments without biochar application. Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions were directly measured using static chamber technology. Cumulative emissions and global warming potential (GWP) followed the same trend and were significantly lowered in biochar-treated soils. The influences of soil and environmental parameters on GHG emissions were, therefore, investigated. A positive correlation was found between both moisture and temperature and GHG emissions. Thus, biochar made from swine digestate manure may be an effective organic amendment to reduce GHG emissions and address climate change challenges.

Effects of organic and inorganic fertilizers on soil properties related to the regeneration of ecosystem services in peat grasslands

Worldwide, agricultural grasslands on drained peat contribute to CO2 emission but provide also provisioning and supporting ecosystem services that are managed by farmers. This paper evaluates the performance of organic and inorganic fertilizers in relation to soil biotic and abiotic properties linked to soil ecosystem services of peat grasslands with biodiversity goals. Effects of cattle slurry, compost, farmyard manure, solid fraction of cattle slurry and inorganic nitrogen (N) fertilizer with and without added sawdust were compared to those of an unfertilized control in a three-year field experiment. Total N input was targeted at 120 kg N ha−1 year−1; total carbon (C) input was variable due to different C:N ratios of source materials. The abundance of earthworms in spring was increased with solid fraction (+35 % as compared to the control), which had the largest C input, and was reduced with inorganic N (−24 %). Combining inorganic N with sawdust did not affect earthworm abundance. Bacteria (determined by phospholipid fatty acid analysis) were increased following inorganic N fertilizer application with (+65 %) or without (+52 %) sawdust. Arbuscular mycorrhizal fungi were reduced by all fertilizers (−40 to −88 %), but less so by those with large C input (solid fraction) or with lignin-rich C input (sawdust + inorganic N fertilizer). Physical and chemical soil properties related to water infiltration and soil organic matter (SOM) decomposition were marginally influenced by fertilizers. The measured changes in soil pH, P availability and (micro)biology may affect SOM dynamics in the longer term. Grass dry matter yield was similarly increased by all fertilizers (+7 to 11 %) whereas grass N yield was increased by fertilizers only when the applied N was in mineral form (+16 to 20 %). From our results, we propose that the moderate use of organic fertilizers with a high and non-humified organic matter content such as solid fraction of cattle slurry can be part of a regeneration strategy in peat grasslands with biodiversity goals.

Optimally combined application of organic and chemical fertilizers increases grain yield and improves rhizosphere microecological properties in rice ratooning

AbstractField tests were conducted at experimental station of Chongluo, Nanping city, Fujian province, China in 2018–2019 to explore the action and physiological mechanism of organic nitrogen in rice ratooning under the configurations with different proportions of organic and inorganic nitrogen. The results showed that sole chemical fertilizer (CF) led to a significant decrease in soil nutrient availability, especially at late growth stage, and reduced grain yield of the main and ratooning crops compared with the optimal fertilizer configuration (GM2) in 30% organic nitrogen with 70% chemical nitrogen fertilizer in the premise of total application rate at 225 kg N/ha. Further studies have revealed that GM2 relative to CF treatment promoted to produce more productive panicles of the main crop and had carryover effect on the regeneration rate of ratooning rice due to national C13‐assimilates partitioning in rice–rhizosphere systems, which resulted in increased soil microbial diversity and soil fertility, thereby enhanced yields of the main and ratooning rice crops. These findings help to better understand the action and mechanism of the proper combined application of organic and inorganic nitrogen fertilizer via improving remobilization of 13C assimilates in rice–rhizosphere system, and ultimately increasing grain yield in rice ratooning.

Hydroponic Common-Bean Performance under Reduced N-Supply Level and Rhizobia Application.

This study aims to explore the possibility of a reduced application of inorganic nitrogen (N) fertiliser on the yield, yield qualities, and biological nitrogen fixation (BNF) of the hydroponic common bean (Phaseolus vulgaris L.), without compromising plant performance, by utilizing the inherent ability of this plant to symbiotically fix N2. Until the flowering stage, plants were supplied with a nutrient solution containing N-concentrations of either a, 100%, conventional standard-practice, 13.8 mM; b, 75% of the standard, 10.35 mM; or c, 50% of the standard, 6.9 mM. During the subsequent reproductive stage, inorganic-N treatments b and c were decreased to 25% of the standard, and the standard (100% level) N-application was not altered. The three different inorganic-N supply treatments were combined with two different rhizobia strains, and a control (no-inoculation) treatment, in a two-factorial experiment. The rhizobia strains applied were either the indigenous strain Rhizobium sophoriradicis PVTN21 or the commercially supplied Rhizobium tropici CIAT 899. Results showed that the 50-25% mineral-N application regime led to significant increases in nodulation, BNF, and fresh-pod yield, compared to the other treatment, with a reduced inorganic-N supply. On the other hand, the 75-25% mineral-N regime applied during the vegetative stage restricted nodulation and BNF, thus incurring significant yield losses. Both rhizobia strains stimulated nodulation and BNF. However, the BNF capacity they facilitated was suppressed as the inorganic-N input increased. In addition, strain PVTN21 was superior to CIAT 899-as 50-25% N-treated plants inoculated with the former showed a yield loss of 11%, compared to the 100%-N-treated plants. In conclusion, N-use efficiency optimises BNF, reduces mineral-N-input dependency, and therefore may reduce any consequential negative environmental consequences of mineral-N over-application.

The Soil Seed Bank Role in Mountainous Heathland Ecosystems after Fire and Inorganic Nitrogen Fertilization

Calluna vulgaris-dominated heathlands are a priority habitat type in Annex I of the Habitats Directive (92/43/ECC, habitat code 4060). In the Iberian Peninsula, the landscape of the Cantabrian Mountain range has great heterogeneity due to human management during the last 10,000 years. Another factor that can affect these communities is the increase in human-induced atmospheric nitrogen (N) deposition. During the last century, there has been a dramatic increase in N deposition rates. For all these reasons, it is important to know the regeneration dynamics of the heathlands in the context of the disturbances that these communities currently face (i.e., N deposition, fire, and decrease in sheep grazing) in the Cantabrian Mountain range. In this study, we characterized the plant species composition and soil seed bank after prescribed burning in three heathlands on their southern distribution limit in Spain, to gain insights into regenerative capacity and conservation of these communities. The results obtained suggest that the post-burn soil seed bank could restore Calluna-dominated vegetation in these habitats, indicating that the restoration potential from the soil seed bank after wildfires of these habitats is high. Our results also suggest that, in the short term after burning, the main characteristic species such as Calluna and Erica are recovered, which is fundamental to maintain the heathland community structure.

Long-term manure application improves soil health and stabilizes carbon in continuous maize production system

Soil health lies at the core of a sustainable food production system. A comprehensive evaluation of different agronomic practices and their effect on soil health is essential to determine the best practices that support soil ecosystem services. However, it may take years or decades to observe measurable changes in soil health under varying management practices. The objective of this experiment was to evaluate the effects of long-term (>77 years) manure and inorganic nitrogen (N) fertilizer on soil health and determine the interrelationship among the measured soil bio-physicochemical indicators. The study also aims to understand the sustainability of the monocropping maize production system under long-term manure and inorganic N fertilizer management. The experiment site is the historic Knorr–Holden Plot, established in 1910 and continued till today. Over the years, the treatments were constant, with manure as the main factor and N rates as the sub-plot factor. Aligning with advancements in agronomic management, the rates of fertilizer and manure have been revised from time to time. Analysis of soil health indicators showed a significant effect of manure on different labile carbon (C) & N fractions, soil enzymes, and soil organic matter (SOM). Manure treatment improved C stabilization and reached a C equilibrium for management. Water holding capacity was significantly improved at wilting point and field capacity for manure treatment. Nitrogen treatments only affected soil pH, cationic exchange capacity (CEC), and phosphorus. Analysis of the interrelationship among soil health indicators showed SOM was determinative for C & N fractions and CEC. Soil organic carbon can be used as a proxy for soil total N (R2 = 0.98). Water extractable fractions of C and N were interrelated and can be used as determinative factors for each other. The results inform that a sustainable monocropping system can be maintained using long-term manure application, where soil health and organic carbon improve over time. The results also indicate that soil health measurement can be minimized to a few key indicators based on the functional interrelationship, which can broaden the adoption of soil health monitoring and measurement.

Emissions from Managed Agricultural Soils in Context of Consumption of Inorganic Nitrogen Fertilisers in Selected EU Countries

In addition to industry, transport, and waste management, the agricultural sector is also a major emitter of CO2 emissions. This article focuses on CO2 equivalent emissions from soil in the context of mineral nitrogen fertiliser management. The methodology itself consists of several successive phases, the first of which is to determine basic statistical characteristics for all EU countries, primarily in terms of mineral nitrogen fertiliser consumption, but also in terms of the area of crops grown. EU countries with similar cropping patterns were selected for comparison so that the results could be compared. The results show that there are quite significant differences in CO2 equivalent emissions between countries under similar conditions. At the same time, the values of the marginal increment of CO2 emissions as a function of mineral nitrogen fertiliser consumption were calculated. On the basis of the results of the selected countries, an upper limit in terms of CO2 emissions per hectare of arable land was also determined, and recommendations were made from a national perspective. The emissions themselves can be seen as a negative production externality that is not accounted for in the market mechanism and can thus also distort the price of agricultural production. The methodology used in this paper can be used to set an upper limit on CO2 emissions from soil due to the use of mineral nitrogen fertilisers and can then be used as an indicator for regulating and defining future agricultural policy instruments within the EU, where the objective is to reduce the level of CO2 emissions.

Ammonia emissions from nitrogen fertilised agricultural soils: controlling factors and solutions for emission reduction

Environmental context Ammonia emissions from inorganic nitrogen fertilisers used in agriculture can impact air quality, human health and ecology. This study quantifies such emissions and their controlling factors from UK and Ireland agricultural soils. Emissions are variable and, from non-urea fertilisers, substantially exceed maximum emission factors used by the UK Department for Environment, Food and Rural Affairs. This suggests that UK emission factors need to be refined further, with consideration of inter alia land-use, fertiliser type, soil pH and chemical inhibitors. Rationale Ammonia (NH3) emissions from inorganic nitrogen (N) fertilisers applied to agricultural soils have negative implications for environmental quality and human health. Despite this, efforts to reduce NH3 emissions in the UK have achieved limited success. This study aims to provide an overview of NH3 emissions from UK and Ireland agricultural soils receiving N fertilisers, their regulating factors and the potential role of inhibitors in reducing current NH3 losses. Methodology A systematic literature search was performed to identify relevant experimental data and studies, and the extracted data (total of 298 field fertilisation events) were categorised and analysed systematically. Results NH3 emissions ranged from −4.00 to 77.00% of applied fertiliser-N lost as NH3. In addition to fertiliser type, NH3 losses were also significantly affected by land-use type and soil pH. Urease and combined urease and nitrification inhibitors significantly reduced emissions by 74.50 and 70.00% compared to uninhibited-urea respectively. Discussion In addition to fertiliser types, land-use and soil pH were found as factors for consideration as modifiers to the maximum NH3 emission factor (EFmax) values currently used in the UK, in order to improve estimations of NH3 emissions, particularly from non-urea fertilisers. This is imperative as NH3 losses exceeded current EFmax limits, particularly in the case of non-urea fertilisers, by ~34%, implying that NH3 emissions estimated from UK synthetic fertiliser require further refinements. NH3 losses are not completely inhibited, inhibitors cannot be solely relied upon for tackling NH3 emissions from UK and Ireland fertiliser usage and further research is needed into alternative mitigation methods to further reduce NH3 losses.

Effects of the configurations with different organic and inorganic fertilizers on grain yield and its related physiological traits of the main and its ratoon rice crops

The determination for properly combined application rate of organic and inorganic fertilizers is the key to coordinating soil nutrient supplies and rice growth demands, thereby obtaining improved economic and ecological returns in rice ratooning. A complete randomized block design (RCBD) trial with different configurations of organic and inorganic nitrogen fertilizers was conducted to determine the optimal substitution rate of organic nitrogen for inorganic nitrogen and its effect on the related physiological attributes and yield performance of the main and ratoon rice crops in 2018−2019. The results showed that 30% organic and 70% inorganic nitrogen in the mixture fertilizer (GM2) could produce the best effect on root activity, nitrogen nutrient uptake and its utilization, as well as the dry matter accumulation and its partitioning. This in turn resulted in improved productive panicles and harvest index, and hence increased grain yield by 10.36% and 15.48% in GM2 regime relative to that in CF treatment. Moreover, the uptake and utilization efficiency, agronomic utilization efficiency and partial productivity of nitrogen fertilizer were 44.37%, 23.82 kg/kg and 48.97 kg/kg, respectively under the optimal GM2 treatment, which were much higher than those in CF treatment by 12.66%, 5.05% and 13.4%, respectively. The results suggested that properly combined application of organic and chemical nitrogen fertilizer could improve soil nutrient supply to guarantee an efficient plant growth and rational dry matter allocation, thereby increasing the harvest index and grain yield in rice ratooning.

Growth and Yield of Maize by Nitrogen and Potassium Inorganic Fertilizers Application to Fluventic Eutrudepts

Maize production requires nutrients so that the soil becomes fertile and makes it easier for plants to grow well. It has been known that potassium nutrient enhances the carbon cycle in plant to maintain the development of plant and so on the yield quantity. This test was carried out from November 2022 to March 2023 on Fluventic Eutrudepts Located in Jatinangor. This test was carried out using a Randomized Block Design (RBD), which consisted of seven combinations of inorganic compound fertilizer nitrogen and potassium (NK) dose treatments. Each treatment was repeated three times. The test results showed that a dose of 1 ¾ NK accompanied by 1 dose of single nitrogen and phosphor (NP) could significantly increase maize yields compared to the control or without the addition of solid inorganic fertilizer NK inorganic fertilizer. The effect of giving solid inorganic fertilizer NK 1 ¾ dose of inorganic fertilizer significantly increase the yield of corn plants compared to the control treatment (without NK).

Multispecies forages in the Australian dairy feedbase: is there a biological business case?

This review considers the potential role of multispecies swards in de-risking Australian dairy systems that currently rely heavily on monocultures of perennial ryegrass and high rates of inorganic nitrogen application to be productive. Recent trends in increasing inorganic nitrogen fertiliser prices, societal pressure for increased environmental sustainability of farming practices, coupled with variable and extreme weather events have renewed interest for functionally diverse pasture mixtures. Evidence from the latest international studies either for or against the purported benefits of multispecies swards (e.g. productive, resilient, and environmentally positive) is examined. There is an ever-growing body of evidence confirming that species richness can promote high levels of productivity at low or zero rates of nitrogen fertiliser application, often with increasingly positive effects as species richness increases. However, results within and between different levels of species richness are not always consistent, suggesting that not all multispecies swards will perform alike, even at a constant level of functional diversity. A multitude of other factors is presented that interact to determine the success of one multispecies sward over another. These include soil type and fertility, species choice, functional group proportions, sward management under either grazing or cutting, fertiliser regimes, and grazing management practices. It was concluded that this complexity gives rise to a need for further research into the biological mechanisms behind multispecies mixtures to determine the factors, other than simply species richness, that will guarantee success as more farmers inevitably search for alternatives to perennial ryegrass pasture in the Australian dairy farming industry.

Optimization of chemical fertilizer application for blueberry vegetative growth, fruit quality and soil condition

Commercial cultivation of blueberry has rapidly expanded in China in recent years. However, suboptimal fertilization results in poor growth and management practices in blueberry orchards. The present study studied fertilization of southern highbush blueberry in southwest of China. We evaluated the effects of inorganic nitrogen, phosphorus, and potassium fertilizers at different doses. Plant vegetative growth, leaf photosynthesis parameters, fruit quality and soil nutrient contents were analyzed. Application of ammonium sulfate enhanced fruit weight, sweetness, and nutrient content, including vitamin C and anthocyanin contents. Comparison of P and K fertilizer treatments revealed that 30 g P/plant in combination with 30 g K/plant conferred superior plant growth and improved fruit sweetness and nutrient content. Using ammonium sulfate as the N source and monopotassium phosphate as the P and K source contributed to maintenance of soil acidity

Influence of Organic and Inorganic Nitrogen on the Growth and Yield of Wheat

To assess the effects of organic and inorganic N fertilizers regarding wheat yield and growth a field experiment was carried out from November 2019 to March 2020 at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh. There were three replications of the experiment, which was set up using a randomized full block design. The experiment comprises four varieties viz. BARI Gom-28, BARI Gom-30, BARI Gom-31, BARI Gom-32 and five levels of N viz. Control, 90 kg N ha-1 from prilled urea (PU), 57 kg N ha-1 from prilled urea (PU) + 3 t ha-1 poultry manure (PM) as organic N source, 62 kg N ha-1 from PU + 5 t ha-1 cowdung as organic N source, 29 Kg N ha-1 from PU + 4 t ha-1 vermicompost as organic N source. The outcome of the experiment revealed that there were substantial differences in the growth and yield of wheat due to different varietal effects and application of organic and inorganic nitrogen fertilizers, although some of the attributes were not found significant. At growth, BARI Gom-32 produced the highest number of total tillers hill-1 and leaf area index, while the highest number of total tillers hill-1 and leaf area index were obtained from 57 kg N ha-1 from PU and 3 t ha-1 PM at 20, 40, 60 and 80 DAS. At harvest, the highest number of effective tillers plant-1 (2.82), filled grain spike-1 (32.06), 1000-grain weight (61.07 g), grain yield (3.94 t ha-1), straw yield (5.85 t ha-1) and harvest index (40.11%) were obtained from BARI Gom-32. While, application of 57 kg N ha-1 from PU and 3 t ha-1 PM produced the tallest plant (95.49 cm), number of total tillers plant-1 (3.96), number of effective tillers plant-1 (3.20), filled grain spike-1 (36.61), 1000-grain weight (60.18 g from T5), grain yield (4.34 t ha-1), straw yield (6.23 t ha-1) and harvest index (41.07%). Again, the maximum number of total tillers plant-1 (4.06), number of effective tillers plant-1 (3.46), filled grain spike-1 (39.13), 1000-grain weight (64.62 g), grain yield (4.38 t ha-1), straw yield (6.27 t ha-1 ) and harvest index (41.16%) were found from BARI Gom-32 in combination with 57 kg N ha-1 from prilled urea and 3 t ha-1 poultry manure. Therefore, it can be concluded that BARI Gom-32 in combination with 57 kg N ha-1 from prilled urea and 3 t ha-1 poultry manure was more potential in terms of yield and would be suggested for the cultivation of wheat.