Mineral Nitrogen Fertilizer Research Articles

Effects of chicken manure substitution for mineral nitrogen fertilizer on crop yield and soil fertility in a reduced nitrogen input regime of North-Central China.

Organic manure has been proposed to substitute part of the chemical fertilizers. However, past research was usually conducted in regimes with excessive nitrogen (N) fertilization, which was not conducive to the current national goal of green and sustainable development. Therefore, exploring the potential of organic fertilizer substitution for mineral N fertilizer under regimes with reduced N inputs is important to further utilize organic fertilizer resources and establish sustainable nutrient management recommendations in the winter wheat (Triticum aestivum L.) - summer maize (Zea mays L.) rotation system in North-central China. In this study, a 4-year field experiment was conducted to investigate the effects of different chicken manure substitution ratios on crop yield, N recovery efficiency (REN), soil N and soil organic matter contents, to clarify the optimal organic substitution ratio of N fertilizer under reduced N application (from 540kg N ha-1 year-1 to 400kg N ha-1 year-1). Six substitution ratios were assessed: 0%, 20%, 40%, 60%, 80% and 100% under 200kg N ha-1 per crop season, respectively, plus a control with no N application from chemical fertilizer or chicken manure. Results showed that the highest yield was achieved under the 20% substitution ratio treatment, with 1.1% and 2.3% higher yield than chemical N alone in wheat season and maize seasons, respectively. At the chicken manure substitution ratios of 20% in wheat season and 20%-40% in maize season, the highest REN reached to 31.2% and 26.1%, respectively. Chicken manure application reduced soil residual inorganic N with increasing substitution ratio. All organic substitution treatments increased soil organic matter and total N content. Implementing 20% organic substitution in wheat season and 20%-40% in maize season under the reduced N application regime in the North-central China is therefore recommended in order to achieve high crop yields and REN, improve soil fertility and enhance livestock manure resource utilization.

Effects of Organic and Inorganic Fertilization on Soil Organic Carbon and Enzymatic Activities

The overapplication of mineral nitrogen (N) fertilizer has become a scientific problem to be solved in the North China Plain; meanwhile, most organic manure cannot be recycled into the soil. To make full use of organic manure and decrease the applied rate of mineral N fertilizer, a four-year fertilization experiment was carried out to assess the effects of substituting mineral fertilizer with organic manure on soil organic carbon (SOC), labile organic carbon (LOC), stable organic carbon (UOC), microbial biomass carbon (MBC), and soil enzymatic activity. There were six treatments including unfertilized control (CK); mineral fertilizer without organic manure (FR); and mineral nitrogen substituted by organic manure at 20%, 40%, 60%, and 80% (FM1, FM2, FM3, and FM4), respectively. The results showed that SOC, UOC, and LOC were significantly increased by 13.30~40.56%, 41.10~121.92%, and 4.91~15.57% with increasing amounts of organic manure, respectively. Adding organic manure also enhanced urease, catalase, sucrase, and cellulase activities as well as MBC in surface soil (0–20 cm). The present study revealed the activities of urease, catalase, sucrase, and cellulase were closely related to SOC and its components. Following organic manure application, MBC and enzymatic activities had active effects in enhancing LOC and UOC sequestration based on path analyses. Additionally, organic manure increased SOC by direct and indirect enhancement of UOC and LOC, respectively, and improved SOC sequestration as compared to FR treatment. Finally, the study revealed that SOC quantity and quality were both significantly improved by combined application of mineral fertilizer and organic manure, and this effect was enhanced with the increase of organic manure application. Considering the improvements in soil properties and grain yields, substituting mineral fertilizer with organic manure might be a promising alternative in the North China Plain.

Evaluation of the fertilizer potential of Chlorella vulgaris and Scenedesmus obliquus grown in agricultural drainage water from maize fields

Producing microalgae with agricultural drainage water (ADW) allows recycling water and nutrients, with the production of a biofertilizer, avoiding receiving waters' contamination. Chlorella vulgaris and Scenedesmus obliquus were cultivated using ADW and standard media supplementation and presented higher productivities, relatively to the control industrial growth medium (using freshwater). Selected strains were grown outdoors in pilot flat panel photobioreactors, reaching 2.20 g L−1 for S. obliquus and 1.15 g L−1 for C. vulgaris, and degrading herbicides in the ADW to non-quantifiable concentrations. The potential of the C. vulgaris and S. obliquus suspensions to replace 50% of nitrogen (N) mineral fertilization of lettuce (0.5 g pot−1) was evaluated through a pot trial, also using a 2-times (1.0 g pot−1) and 5-times (2.5 g pot−1) higher dose, applied 31 days before lettuce transplanting. Even the lower dose of N, applied via C. vulgaris or S. obliquus suspensions, was able to provide significantly higher lettuce fresh matter yield, relatively to the mineral fertilized control. Soil enzymatic activities were improved, with significantly higher dehydrogenase, β-glucosidase, and acid phosphatase activities for the 2.5 g pot−1 dose, more marked for S. obliquus, which was also able to increase soil organic matter content. Both the non-fertilized control and microalgae fertilized pots led to similar soil electrical conductivities, 3-fold lower than in the N-mineral fertilized pots, evidencing the capacity of microalgae fertilizers to avoid soil secondary salinization. Results suggest benefits from using ADW from maize cultivation to produce C. vulgaris or S. obliquus suspensions, that can be further used as liquid organic slow-release fertilizer.

Manure Application Is the Key to Improving Soil Quality of New Terraces

Building level terraces is a crucial strategy for agriculture development in mountainous areas. There have been many studies on improving the soil quality of terraces, but the main factors involved are still unclear. We conducted an 18-year long-term experiment on a newly built terrace with four fertilization treatments: applied mineral nitrogen and phosphorus fertilizer (NP), applied sheep manure (M), applied sheep manure combined with mineral nitrogen and phosphorus fertilizer (MNP), and an unfertilized control (CK). A soil quality index (SQI) was used to evaluate the dynamic evolution of soil quality in the terrace for these fertilization treatments, and the relationship between soil quality and crop yield was investigated. A total data set (TDS) and a minimum data set (MDS) were used to calculate the SQIs according to the linear scoring method and the nonlinear scoring method of soil indicators, respectively. The results showed that the SQI for all treatments increased over time, and both the SQI and crop yield were significantly increased by fertilization treatments. The SQI of all three fertilized treatments in the sixth rotation cycle increased by 38–313% compared to the control in the first rotation cycle (3 years). There was no significant difference in the SQI between the M and MNP, but it was significantly higher than for both the NP and CK. During the 18 year experimental period, the SQI for the M and MNP treatments showed an upward trend, while it tended to be stable after initially increasing for the NP and CK treatments. For each treatment, the SQI calculated by the linear and nonlinear scoring methods using the MDS and TDS were all significantly positively correlated, and were also significantly positively correlated with crop yield. Overall, the soil quality in the terrace was increased by fertilization; however, the application of manure was the key to a rapid increase in soil quality, and the SQI measurements demonstrated a clear link between the soil quality of the terrace and crop yield.

The impact of the long-term application of mineral nitrogen and sewage sludge fertilizers on the quality of soil organic matter

BackgroundSoil fertility is substantially influenced by soil organic matter quality and quantity. Much attention has also been given to glomalin content as one of the qualitative parameters of soil fertility. Glomalin content is considered an indicator of soil fertility due to its positive correlation with soil organic carbon.AimThis study aim to (i) determine the influence of different fertilization systems on maize yield and soil organic matter quality parameters, (ii) ensure that changes in total glomalin content (TG) and easily extractable glomalin (EEG) content are sensitive enough to reflect changes in the SOM quality resulting from long-term fertilization, and (iii) determine whether both forms of glomalin must be determined or if the easily extractable glomalin (EEG) content is sufficient, even for a fertile chernozem.Materials and methodsLong-term field experiments with silage maize monocultures were used to study relationships under different rates of mineral nitrogen and sewage sludge fertilization. The trials comprised 5 treatments: (i) no fertilization control (Con), (ii) and (iii) two different calcium ammonium nitrate rates (N120 and N240 at doses of 120 and 240 kg N ha−1 year−1, respectively), and iv) and v) two different sewage sludge rates (S120 and S240 corresponding to mineral N doses). Topsoil (0–30 cm) analysis was performed 28 years after the onset of the experiment to determine soil organic carbon, the fractions of humic substances, potentially mineralizable carbon and dissolved organic carbon, the potential wettability index, soil aggregate stability, EEG, and total glomalin (TG).ResultsThe control treatment, which did not include fertilization, showed significantly lower average yields (9.76 t DM ha−1 year−1) than the fertilization treatments (on average 12.3 DM ha−1 year−1). Significant differences in yields were not found between the fertilization treatments. A positive correlation between glomalin (EEG, TG) content and soil organic matter carbon content was observed. A periodic application of sewage sludge increased the content of glomalin. However, the highest quality of SOM was found in the control treatment (nonfertilized). This treatment had the highest values for the humic/fulvic acid ratio and the highest contents of humic acids and potentially mineralizable carbon. Furthermore, the Con treatment showed the highest soil aggregate stability and potential wettability index. Mineral N fertilization significantly reduced soil aggregate stability values.ConclusionsThe unfertilized control showed the highest SOM quality but the lowest yields. The data on glomalin content can be used to study soil organic matter quality. Because the EEG extraction method is easy to apply, uses lower quantities of chemicals and consumes less time, it presents a better option than TG extraction. The sensitivity of the methods for SOM quality determination decreases with increasing SOM content.Graphical

The Use of Organic Waste in Sustainable Water Management Under the Conditions of Dry Areas: Field and Modeling Study

Organic waste poses a threat to the environment in the event of its repeated use; however, in this study, we converted it into a useful and environmentally safe source of fertilization. In addition to its fertilization ability, it exhibited a good ability to reduce water stress in cultivated plants in area in which irrigation is lacking and are suffering the impact of climate change. Two field experiments were conducted during the 2019/2020 and 2020/2021 seasons to study the effect of the regulated deficit irrigation strategy and organic N-fertilization ratio during wheat cultivation. The majority of the studied characteristics were slightly higher when irrigation was 75% FI as compared to 100% FI. When using organic nitrogen fertilization in addition to mineral nitrogen fertilization, at 50% organic to 50% mineral, it was possible to irrigate at 75% FI. In this scenario, productivity increased by 28.5% in 2019/2020, and 56% in 2020/2021. The model simulated the studied characteristics of the two seasons relatively well. In summary, the field and modeling results indicate that the use of organic waste in sustainable water management in dry areas has various benefits, including a higher yield and reduced use of chemical fertilizers by up to 50%. This was replaced with 50% organic nitrogen fertilizer produced from the compost from agricultural waste, which is abundant on all farms. These additional benefits increase the income for farmers, and reduce environmental pollution.

Comparative Evaluation of Mineral and Organo-Mineral Nitrogen Fertilization and the Role of Amino Acids as Plant Growth Promoters in Maize Cultivation

The challenge to increase nitrogen uptake efficiency in intensively cultivated soils without runoffs and atmospheric release has been difficult to handle and usually leads to the excess application of mineral fertilizers. In the present study, four combinations of two different N fertilizers and a control were used in maize cultivation to evaluate the use of different types of N fertilization in the case of agronomic and plant physiology characteristics, as well as the quantity and quality characteristics of maize’s yield. The results show that, when the full rate of mineral fertilization with the addition of half rate of organo-mineral fertilizer with amino acids (MF+OMAA/2) was used, maize presented a 16% yield increase in comparison with the control, followed by mineral fertilization (MF) with a 10% increase. Protein content was increased in all treatments by 3–6% compared to the control, with the conventional fertilization and the alternates with lower rates of mineral fertilization not differing significantly. The nitrogen content in the leaves of maize increased in both measurements (11–23% and 19–40% at 70 and 107 days after sowing, respectively) of the different fertilizer treatments compared to the control. The results of this study confirm that the organo-mineral fertilizer containing amino acids can be used as an alternative or additive N fertilization that can decrease the use of conventional mineral fertilizers or can result in improved seed productivity and protein content in maize farms.

Effects of dairy processing sludge and derived biochar on greenhouse gas emissions from Danish and Irish soils

Globally, to ensure food security bio-based fertilizers must replace a percentage of chemical fertilizers. Such replacement must be deemed sustainable from agronomic and greenhouse gas (GHG) emission perspectives. For agronomic performance several controlled protocols are in place but not for testing GHG emissions. Herein, a pre-screening tool is presented to examine GHG emissions from bio-waste as fertilizers. The various treatments examined are as follows: soil with added mineral nitrogen (N, 140 kg N ha−1) fertilizer (MF), the same amount of MF combined with dairy processing sludge (DS), sludge-derived biochar produced at 450 °C (BC450) and 700 °C (BC700) and untreated control (CK). These treatments were combined with Danish (sandy loam) or Irish (clay loam) soils, with carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions and soil inorganic-N contents measured on selected days. During the incubation, biochar mitigated N2O emissions by regulating denitrification. BC450 reduced N2O emissions from Danish soil by 95.5% and BC700 by 97.7% compared to emissions with the sludge application, and for Irish soil, the N2O reductions were 93.6% and 32.3%, respectively. For both soils, biochar reduced CO2 emissions by 50% as compared to the sludge. The lower N2O reduction potential of BC700 for Irish soil could be due to the high soil organic carbon and clay content and pyrolysis temperature. For the same reasons emissions of N2O and CO2 from Irish soil were significantly higher than from Danish soil. The temporal variation in N2O emissions was correlated with soil inorganic-N contents. The CH4 emissions across treatments were not significantly different. This study developed a simple and cost-effective pre-screening method to evaluate the GHG emission potential of new bio-waste before its field application and guide the development of national emission inventories, towards achieving the goals of circular economy and the European Green Deal.

Effect of nitrogen fertilizers on agronomic, essential and enzymatic properties of marigold (Calendula officinalis L.) under normal and drought conditions

To investigate the effect of mineral and organic nitrogen fertilizers on some of the quantitative and qualitative reactions of marigold under normal and drought stress, a study was conducted in a split-plot factorial and based on a completely randomized block design with three replications. The first factor included irrigation (normal and water deficit) in the main plot and sub-factor included foliar application of nitrogen fertilizer (control, nitrogen (N), nano-chelate nitrogen (NC) and nitrogen fertilizer+ nano-nitrogen fertilizer (N+NC)) and biofertilizer (control, Azotobacter and Azospirillum) as factorial was placed in sub-plots. Although water deficit stress reduced plant height, flower dry weight, number of seeds per head, 1000-grain weight, biological yield, grain yield and essential oil yield, N + NC foliar application could moderate the adverse effect of water stress on the grain yield, biological yield and essential oil yield. In addition, inoculation of seeds with Azospirillum under water stress conditions could increase the number of seeds per head, 1000-grain weight and essential oil yield compared to the control treatment. NC foliar application and Azotobacter inoculation showed a synergistic effect on the content of proline enzymes and antioxidant activity. Also, simultaneous application of nitrogen + nano-chelate nitrogen foliar application along with seed inoculation with Azospirillum could have a positive effect on increasing flower dry weight, the number of seeds per head, 1000-seed weight, biological yield, grain yield, essential oil yield and proline content.

The Composition of the Organic Matter Fractions of Loamy Sand after Long-Term FYM Application without Liming

The key to soil organic matter management is understanding the transformation processes of fresh organic matter to permanent humus that control soil organic carbon dynamics. This paper presents the results of the effect of long-term soil fertilization with increasing doses of (manure) FYM and ammonium nitrate on the composition of humus compounds not limed of loamy sand. The study showed that both crop rotation and manure fertilization significantly affected organic matter fractions and humus humification index. The soil in crop rotation B (with enriching effect) accumulated significantly larger amounts of soil organic carbon in 0–30 cm layer despite a lower soil pH, but had lower soil organic quality compared to the soil in crop rotation A (with depleting effect). In both rotations, FYM was applied once per 4-year rotation at a dose of 40 t·ha−1 which improved the soil organic carbon content. Depleting crop rotation (A) showed no increase in soil accumulation of humins fractions (H), while the “enriching” crop rotation (B) had such a tendency. Mineral nitrogen fertilization significantly affected the composition of the humic acids fraction. The soil in crop rotation B was characterized by a significantly higher content of fulvic acid (FA) and lower of humins (H) carbon fraction. The large input of organic matter into the soil under lower content pH conditions may hinder its transformation into permanent humus. Changes in the humification index were the consequence of changes in the carbon content of humic and fulvic acids, under the influence of plant selection in crop rotation and manure fertilization. According to the criterion of this parameter, soil in crop rotation A and soil fertilized with manure had lower loss of the more labile FA fraction (lower value of humification index—1.48).

Nitrogen flow in livestock waste system towards an efficient circular economy in agriculture.

The race is on to achieve an important level of efficiency in the attainment of a circular economy in agriculture especially with the aim of sustainable nitrogen management. This cycle in the agricultural sector cuts across livestock farming, agriculture-induced waste generation, recycling and utilization, energy generation, crop production, ecosystem protection and environmental management through the mitigation of climate changes. In this work, we assess the process and functionalities of livestock waste generated from the piggery farm and their combinations with other by-products such as biochar and ash in comparison with mineral fertilization as sources of nitrogen applied in agricultural soil. The experiment was performed in a controlled environment with wheat (Triticum aestivum L.) grown in a neutral and an acidic soil. Pig manure was used as the primary feedstock, fed and processed to biogas and nutrient-rich digestate by the anaerobic digestion process. The results revealed that the co-amendments of pig manure digestate with biochar and ash had complimentary positive effect on measured indices such as mobile potassium, phosphorus, biomass yield and nitrogen use efficiency. The mineral nitrogen fertilizer significantly induced carbon dioxide emissions from day 35 when compared to emissions from the organic amendments. In contrast, the organic amendments influenced nitrous oxide emissions from the onset till day 30 before flattening out. The individual combination of pig manure digestate with biochar and ash had a negative influence on enzymatic activity (dehydrogenase). Soil microbial biomass carbon was induced across all treatments in both soil types. Pig manure digestate + ash and pig manure digestate had 32.1 and 48.8% soil microbial biomass increase in neutral soil and acidic soil, respectively. Overall, the processing and application of single-use amendment or in combination with biochar and ash holds huge potential in the optimization of nitrogen and carbon efficiency towards sustainable soil management via improving soil quality, carbon sequestration and climate change.

Effect of Mineral Nitrogen Fertilizer and Foliar Application of Yeast Extract on Some Flax Cultivars

Effect of Mineral Nitrogen Fertilizer and Foliar Application of Yeast Extract on Some Flax Cultivars

Integrated biofertilization using yeast with cyanobacteria on growth and productivity of wheat

BackgroundThe heavy use of conventional mineral fertilization considerably increased wheat growth and yield components. However, the excessive nitrogen fertilization accounts for large expenses on farmers’ budget and has negative environmental drawbacks to soil and water ecosystems. Recently, establishing wheat plants associations with a variety of N2-fixing cyanobacteria and/or growth promoting microorganisms in farming systems as nutrients source is seen as ecofriendly and economically feasible solution.ResultsIn this work, the influence of different nitrogen (N) levels (100% N, 75% N, and 50% N as urea) and cyanobacteria (Cy) and/or yeast (Y) inoculation each alone or both in combination with different nitrogen levels were assessed on two different wheat (Triticumae stivum L.) genotypes (Sids-14 and Giza-171) through field experiments over two consecutive seasons (2019/2020 and 2020/2021). Although, the full recommended dose (FRD) (100% N) showed the highest chlorophyll (Chl) a, b content during tillering stage, grains quality (NPK-uptake, protein%), and wheat yield components in both genotypes. The integrated inoculation of cyanobacteria and yeast with 50% N, 75% N-fertilization enhanced wheat growth characteristic (Chl a,b) and upgraded soil microbial community (nitrogenase activity and CO2 evolution) in Sids-14 and Giza-171. Cy combined with Y and partial N-fertilization levels enhanced NPK-uptake Kg/fed and protein% in wheat grains in the two wheat genotypes. Moreover, this combination recorded a wheat yield components (plant height, number of spikes/m2, number of grains/spike, 1000 grains wt (gm) and grains yield (tonne/fed) insignificantly different from those obtained by FRD in wheat cultivation.ConclusionThe integrated application of cyanobacteria with yeast and 50% N or 75% N-fertilization improved soil fertility index and promoted NPK- uptake, protein% and wheat yield components, showing comparable values to conventional chemical fertilization. Cyanobacteria combined with yeast inoculation had socio-economic benefits as it can save about 25–50% of the required mineral nitrogen fertilizers for wheat crop production.

Impact of Green Chitosan Nanoparticles Fabricated from Shrimp Processing Waste as a Source of Nano Nitrogen Fertilizers on the Yield Quantity and Quality of Wheat (Triticum aestivum L.) Cultivars.

Waste from crustaceans has adverse effects on the environment. In this respect, shrimp waste was valorized for producing chitosan nanoparticles as a source for eco-friendly nano-nitrogen fertilizer. The application of nano-nitrogen fertilizers is a valuable alternative approach in agriculture due to its potential for reducing the application of mineral nitrogen fertilizers and increasing yield quality and quantity, thereby helping to reduce the worldwide food shortage. Chitosan nanoparticles were foliar sprayed at three volumes (0, 7, and 14 L/ha) and compared with mineral nitrogen fertilizer (M-N) sprayed at three volumes (0, 120, and 240 kg N/ha) and their combination on two wheat cultivars (Misr-1 and Gemaiza-11) during two consecutive seasons (2019/2020 and 2020/2021) in order to evaluate the agronomic response. The synthesized chitosan nanoparticles displayed characteristic bands of both Nan-N and urea/chitosan from 500–4000 cm−1. They are stable and have a huge surface area of 73.21 m2 g−1. The results revealed significant differences among wheat cultivars, fertilization applications, individual or combined, and their interactions for yield-contributing traits. Foliar application of nano-nitrogen fertilizer at 14 L/ha combined with mineral fertilizer at 240 kg/ha significantly increased total chlorophyll content by 41 and 31% compared to control; concerning plant height, the two cultivars recorded the tallest plants (86.2 and 86.5 cm) compared to control. On the other hand, the heaviest 1000-grain weight (55.8 and 57.4 g) was recorded with treatment of 120 kg Mn-N and 14 L Nan-N/ha compared to the control (47.6 and 45.5 g). The Misr-1 cultivar achieved the highest values for grain yield and nitrogen (1.30 and 1.91 mg/L) and potassium (9.87 and 9.81 mg/L) in the two studied seasons when foliarly sprayed with the combination of 120 kg Mn-N/ha + 14 L Nan-N/ha compared to the Gemaiza-11 cultivar. It can be concluded that Misr-1 exhibited higher levels of total chlorophyll content, spike length, 100-grain weight, grain yield in kg/ha, and nitrogen and potassium. However, Gemaiza-11 displayed higher biomass and straw yield values, plant height, and sodium concentration values. It could be economically recommended to use the application of 120 kg Mn-N/ha + 14 L Nan-N/ha on the Misr-1 cultivar to achieve the highest crop yield.

Model-based evaluation of rainfed lowland rice responses to N fertiliser in variable hydro-edaphic wetlands of East Africa

In East Africa, rainfed lowland rice is primarily produced by smallholders in alluvial floodplain and inland valley wetlands. These wetlands differ in their dominant soil types and water regimes that vary seasonally, inter-annually and between field positions. Yield responses to mineral nitrogen (N) fertiliser thus likely vary between and within wetlands and years, modulating the profitability of N fertiliser use. Therefore, the locally-validated APSIM model was used to study yield responses to N fertiliser rates (0, 30, 60, 90, 120, and 150 kg ha -1 ) and supplemental irrigation at different field positions in a floodplain in Tanzania (fringe and middle positions) and an inland valley in Uganda (valley-fringe, mid-valley and valley-bottom positions) over 30-years. Average rainfed yield gains with mineral N and N use efficiencies were high, ranging between 1.7 and 4.5 Mg ha -1 and 27–70 kg kg -1 in the floodplain and between 1.0 and 3.2 Mg ha -1 and 18–34 kg kg -1 in the inland valley, depending on field position, N rate and year. Consequently, N fertiliser use was generally profitable in both wetlands, with value/cost ratios ≥ 4 and marginal rates of returns > 150%. Profitable N rates in all years were 30–120 kg ha -1 in the fringe and 30–90 kg ha -1 in the middle positions of the floodplain, and 60–150 kg ha -1 in the mid-valley and 90–150 kg ha -1 in the valley-bottom positions of the inland valley. In the valley-fringe position, N fertiliser use was comparatively riskier and profitable only in 77–90% of years at N rates of 60–150 kg ha -1 . Supplemental irrigation may help boost N fertiliser use efficiencies and use profitability with average yield gains of > 1.5 and > 0.4 Mg ha -1 in the floodplain and inland valley, respectively, while simulated spatial-temporal water stress pattern may help guide efficient irrigation scheduling. • Yield responses to N fertiliser in East African lowlands were studied using APSIM. • NUE a was 27–70 kg kg -1 in the floodplain and 18–34 kg kg -1 in the inland valley. • Hydro-edaphic condition and N rate affected yield and fertiliser use profitability. • N fertiliser use was largely profitable but somewhat riskier in the inland valley. • Supplemental irrigation boosted N fertiliser use efficiency and use profitability.

Responses of Soil Carbon Pools and Carbon Management Index to Nitrogen Substitution Treatments in a Sweet Maize Farmland in South China.

In China, excessive nitrogen fertilizer application in sweet maize fields contributes to greenhouse gas emissions. This study used maize straw (MS), cow dung (CD), biogas residue (BR), and straw-based biochar (CB) to substitute the mineral nitrogen fertilizer at 20% and 50% ratios in the Pearl River Delta in China. In comparison with a conventional amount of mineral nitrogen fertilizer (CK), the soil organic carbon (SOC) storages of the different treatments increased by 6.5–183.0%. The CB treatment significantly improved the inert organic carbon pool in the soil, while other types of organic materials promoted the formation of activated carbon pools. The treatments increased the soil carbon pool management index by 21.1–111.0% compared to the CK. Moreover, the CB treatments increased the soil carbon sequestration index by 78.3% and 155.8% compared to the CK. In general, substituting the mineral N fertilizer with BR, CB, and CD could improve the SOC accumulation in sweet maize farmland in South China. The CB at the high substitution level was the best measure for stabilizing carbon sequestration in the sweet maize cropping system. This experiment provides valuable information for ensuring the clean production of sweet maize in a typical subtropical area in East Asia.

EFECTOS DE LAS FUENTES NITROGENADAS EN LA MORFOFISIOLOGÍA, PRODUCCIÓN Y CALIDAD DE CACAO (Theobroma cacao L.) CCN-51 EN EL SUR DE LA AMAZONIA ECUATORIANA

<p><strong>Background</strong>. In the new global economy, cocoa is an important crop. However, far too little attention has been paid to the nutritional aspects. On the other hand, nitrogen is the most important nutrient in crop production, and mineral nitrogen fertilizers are the most widely used by farmers. Improving the efficiency of nitrogen uptake and utilization could potentially increase crop yields and quality, as well as reduce nitrogen fertilization and environmental pollution. <strong>Objective.</strong> Therefore, the objective of this study was to evaluate the effect of three nitrogen sources on morphological characteristics, yield and quality of CCN-51 cocoa, and soil chemical characteristics in the Ecuadorian Amazon. <strong>Methodology.</strong> A randomized design was established with 4 treatments with the same N dose, but varying the source (amide: urea, calcium nitrate, NC, and ammonium sulfate, SA), plus a control without N application. The investigated variables are soil chemical characteristics, shoot growth, fruit morphology, seed chemical characteristics, production and yield estimates, and agronomic efficiency of the sources. <strong>Results.</strong> NC maintained soil pH at 5.29 points compared to SA and urea, which acidified at a higher rate (4.32 and 3.96), leading to an increase of N and a decrease Ca in the soil. SA increased the fat content in the cocoa seed (54.1 %), with a higher number of fruits per plant (16.7) and, therefore, a better yield (0.799 t/ha). <strong>Implications.</strong> These results provide basic information on the nitrogen source effects and cocoa nutrition to be considered for future research. <strong>Conclusion.</strong> The findings suggested that NC conserves soil pH better than the other sources. SA increases production and fat content, so it can be considered the most efficient. </p>

Responses of crop productivity and reactive nitrogen losses to the application of animal manure to China's main crops: A meta-analysis

The effective utilization of manure in cropland systems is essential to sustain yields and reduce reactive nitrogen (Nr) losses. However, there are still uncertainties regarding the substitution of mineral nitrogen (N) fertilizer with manure in terms of its effects on crop yield and Nr losses. We conducted a comprehensive meta-analysis of wheat, maize, and rice applications in China and discovered that substituting mineral N fertilizer with manure increased wheat and maize yields by 4.9 and 5.5 %, respectively, but decreased rice yield by 1.7 %. The increase of yield is larger at low N application and low mineral N substitution rates ((SR) ≤30 %) for silt soils, warm regions, and acidic soils. High SR (>70 %) decreased rice yield as well as the N use efficiency of wheat and maize. Substitution of mineral N fertilizer with manure resulted in lower NH3 volatilization for wheat (48.7 %), lower N2O and NH3 emissions, and N runoff for maize (12.8, 49.6, and 66.7 %, respectively), and lower total Nr losses for rice (11.3–26.5 %). The loss of Nr was significantly and negatively correlated with soil organic carbon content. The rate of N application, soil properties, and climate were critical factors influencing N2O and NH3 emissions and N leaching, whereas climate or soil properties were the dominant factors influencing response in N runoff. We concluded that in silt soils, warm regions, and neutral soils, a ≤ 50 % substitution of mineral N fertilizer with manure can sustain crop yields while mitigating Nr losses.

Application of Molasses as an Eco-Innovative Approach Substitutes Mineral Nitrogen Fertilization and Enhances Sugar Beet Productivity

Application of Molasses as an Eco-Innovative Approach Substitutes Mineral Nitrogen Fertilization and Enhances Sugar Beet Productivity

IMPROVE WHEAT PRODUCTIVITY BY USING A COMBINATION OF MINERAL NITROGEN, ORGANIC AND BIOLOGICAL FERTILIZERS UNDER NEW SANDY SOIL CONDITIONS

Two experiment were conducted among two successive winter seasons (2019/2020 and 2020/2021) at Ismailia Research Station, Ismailia Governorate. The experiments were designed to improve wheat productivity by using a combination of mineral nitrogen, organic and biological fertilizers under new sandy soils conditions. A number of sixteen treatments designed by using recommended dose of nitrogen (Ammonium nitrate) or its half, organic fertilizer (Farm yard manure), grain inoculated with SWERI inoculum asbiofertilizer (Azotobacter chroococcum, B. megatheriumand B. circulant), and Streptomyces luteogriseus. The experimental results showed that the cultivated soil was belongs to sandy soil type and was poor in each of NPK elements, with low rate of each of microbial counts and dehydrogenase activity before planting. These parameters were improved after cultivation of wheat inoculated with biofertilizers and organic fertilizer compared to before planting. This was obvious when plant heights and weights of each of plant sample, straw, grains, ears and hundred wheat grains were estimated. It was also noted that nitrogen content and protein percentages in wheat grains as well as straw were improved. Treatment No. 16 consists of SWERI, and actinomycetes inoculums, as biofertilizers, and organic fertilizer combined with 50% of recommended dose of mineral nitrogen was the most effective ones compared to each of blank (unfertilized soil cultivated with un-inoculated grains, T01)or control (soil fertilized with the recommended of mineral nitrogen and cultivated with un-inoculated grains, T02). This was reflected by increasing the expected wheat yield obtained among treatment No. 16. This treatment was also gave the highest yield amounted of grains and straw which approximately an average of 19.1 Ardab per Feddan, while each of blank and control gave 7.25 and 12.8 Ardab per Feddan respectively. As a conclusion, treatment contained the SWERI and actinomycetes inoculums, organic fertilizer and 50% of recommended dose of mineral nitrogen has led to stimulate the growth of wheat plants in sandy soils, which promises the possibility of expanding the cultivation of such soils with wheat. Therefore, one can recommend with these experimental findings, which may contribute in a large and effective way to bridge the food gap, especially with the continuous increase in population numbers