Mineral NPK Fertilizer Research Articles

Microbial Activity of a Plinthosol With Application of Thiamethoxam Insecticide and Biochar

Although thiamethoxam is an insecticide widely used in agriculture, its high mobility and persistence in the soil can result in contamination of groundwater and alteration in biogeochemical cycles. The objective of this study was to verify the effect of biochar, NPK fertilizer and thiamethoxam insecticide on soil microbial properties. The experiment was conducted in a randomized block design composed of the doses combination of mineral fertilizer NPK (0 and 300 kg ha-1 of the formulated 05-25-15), and biochar (0, 8, 16 and 32 t ha-1) in the absence and presence of thiamethoxam. Deformed soil samples were collected in all plots in the 0 to 0.10 m layer to determine the activity of the enzymes: acid and alkaline phosphatase, beta glucosidase and urease, beyond the microbial biomass carbon (MBC), basal respiration rate (C-CO2) and metabolic quotient (qCO2). To compare soil microbiology before and after the application of thiamethoxam, multivariate statistical techniques were used. The application of biochar resulted in increased enzymatic activity of urease, acid phosphatase, increase of qCO2 and basal respiration and reduction of MBC. In contrast, the application of the thiamethoxam insecticide suppressed the enzymatic activity of urease, acid phosphatase, resulting, however, in the elevation of alkaline phosphatase and basal respiration of the soil. Biochar application at doses greater than or equal to 16 t ha-1 resulted in elevation of qCO2 and reduction of MBC, regardless of the absence or presence of NPK chemical fertilization. Biochar effect on soil microbiological attributes is less significant than the effect of thiamethoxam application.

Effect of Mineral -Biofertilizer on Physiological Parameters and Yield of Three Varieties of Oat (Avena sativa L.)

To study the effect of biofertilizers on physiological parameters and yield of three varieties of Oat (Avena sativa L.), field experiments were conducted during winter seasons 2016-2017 and 2017-2018 at Al- Zubair district (20 km. West of Basrah province) in sandy loam soils. A split plot arrangement, using RCBD with three replicates, the main plots contained varieties: V1 (Genzania), V2 (Shaffaa), V3 (Carloup), Biofertilizer, treatments were at the sub plots: B0 (control), B1 (NPK mineral fertilizer as recommended), B2 (biofertilizers NPK), B3 (mineral fertilizer PK+ biofertilizers N), B4 (mineral fertilizer K+ biofertilizers NP), B5 (mineral fertilizer P + biofertilizers NK), B6 (mineral fertilizer N + biofertilizers PK). Data were collected on Flag leaf area FLA, Leaf area duration LAD, Leaf area index LAI, Crop growth rate CGR, Relative growth rate RGR, Net assimilation rate NAR, Plant high Tillers number m2 and grain yield t ha-1. The results showed that the adding of biofertilizers NPK (B2) led to a significant increase in the studied traits (FLA, LAD, LAI, CGR, RGR, NAR, and grain yield). The grain yield were increased about 189.96 and 197.3% as compared with control in each seasons respectively. Cultivar Genzania resulted in highest grain yield among studied varieties in the first season (5.774 t ha-1), while cultivar Shaffa gave the highest grain yield in the second season (8.691 t ha-1). The interaction between Ganzania and B2 treatment recorded the highest seed yield (8.429 tan ha-1) in the first season. While, in the second season all varieties that interacted with B2 treatment produced the highest seed yield.

Nutrient contents and growth of corn fertigated with human urine and cassava wastewater

ABSTRACT This study aimed to evaluate the contents of macronutrients (NPK and S) and the growth of ‘Potiguar’ corn fertigated with human urine, cassava wastewater and their associations with NPK. The experiment was set up in greenhouse located on Campus I of Universidade Federal de Campina Grande. A completely randomized experimental design was used, consisting of eight treatments, corresponding to fertigation with mineral fertilizer NPK formula; organic, composed of yellow water, cassava wastewater and human urine associated with cassava wastewater; organomineral, composed of human urine associated with phosphorus and potassium, cassava wastewater associated with nitrogen and phosphorus and human urine associated with cassava wastewater and phosphorus, with five repetitions. At 50 days after sowing (DAS), plants were evaluated for the leaf NPK and S concentrations and growth variables: number of leaves, plant height, stem diameter, leaf area, fresh and dry mass of leaves, mass of stem and shoots. Nitrogen and phosphorus concentrations and the growth variables number of leaves, plant height, fresh and dry mass of leaves, mass of stem and of shoot were influenced by fertigation with human urine, cassava wastewater concentrations and their associations with NPK. In the leaves of corn cultivar Potiguar the accumulated concentrations of N, P and K, at 50 DAS, varied in the sequence N > K > P. Human urine has potential as source of N in fertigation of corn and cassava wastewater can be used if associated with other sources of nutrients.

Effect of long-term fertilization on decomposition of crop residues and their incorporation into microbial communities of 6-year stored soils

To investigate the effects of long-term fertilization on microbial decomposition of residues and priming effect (PE), 13C-labeled maize (Zea mays L.) residues were supplied to arable soils with a 20-year application of compost (COM), mineral NPK fertilizer (NPK), or without any treatments, the no-fertilizer control (NF). The soils that had been stored for 6 years were used in the present incubation experiment. The release of CO2–C and the microbial incorporation of residue-derived C determined by phospholipid fatty acids (PLFAs) analysis were monitored over a 90-day incubation period. Residue additions significantly increased cumulative CO2–C emission and induced positive PE. Cumulative residue-derived CO2-C emission and PE mainly occurred within the first 15 days. The COM soil had significantly higher cumulative residue-derived CO2–C emission but lower PE than the NF and NPK soils. Residue additions significantly increased microbial abundance and changed the composition of main microbial groups. The COM soil showed a significantly lower relative fungal abundance (mol%) but a higher relative actinomycetes abundance than the NF and NPK soils. The incorporation of residue-derived C within fungi was the highest among all the main microbial groups and decreased from 15 to 45 days, while the incorporation of residue-derived C within actinomycetes increased with time in three soils. The incorporation of residue-derived C within fungi was the highest in the COM soil over the course of incubation. The long-term compost input promoted fungal use of residue C and stimulated residue decomposition.

Sowing of Lupinus albescens Hook. e Arn. in arenization degraded area: Sowing of L. albescens in sandstone área

Lupinus albescens is an species frequent in the locals under arenization in Rio Grande do Sul (RS), with high rusticity and rapid land cover, showing potentialities for recomposition of degraded areas. The objective was to evaluate the emergence and development of L. albescens, with and without mineral fertilizer application intercropped with Butia lallemantii. Seeds were collected in three populations and submitted to the scarification for 40 seconds. Sowing was done between nine rows (2 x 1 m) of B. lallemantii by applying 0 and 30 g/hole of the mineral fertilizer NPK (5-20-20). The evaluation were: number of plants per hole (NPH), height (cm) and stem diameter (mm), in the periods of 30 and 60 days, as well as the percentage of emergence of plants/m2 (PEP) and the total emergence of plants (TEP) over 240 days, using randomized block design. The results showed a considerable PEP and height at 30 days for the plants in block 2. The 0g/hole dose of the NPK fertilizer provided higher NPH. Therefore, sowing of L. albescens intercropped with B. lallemantii presented higher PEP, NPH without the use of fertilization (30 days) and higher height of the plants among the diameter seedlings of the medium stipe.

Drivers of soil carbon stabilization in oil palm plantations

AbstractIncreasing soil organic carbon (SOC) in agroecosystems is necessary to mitigate climate change and soil degradation. Management practices designed to reach this goal call for a deeper understanding of the processes and drivers of soil carbon input stabilization. We identified main drivers of SOC stabilization in oil palm plantations using the well‐defined spatial patterns of nutrients and litter application resulting from the usual management scheme. The stabilization of oil palm‐derived SOC (OP‐SOC) was quantified by δ13C from a shift of C4 (savanna) to C3 (oil palm) vegetations. Soil organic carbon stocks under frond piles were 20% and 22% higher compared with harvest paths and interzones, respectively. Fertilization and frond stacking did not influence the decomposition of savanna‐derived SOC. Depending on management zones, net OP‐SOC stabilization equalled 16–27% of the fine root biomass accumulated for 9 years. This fraction was similar between frond piles and litter‐free interzones, where mineral NPK fertilization is identical, indicating that carbon inputs from dead fronds did not stabilize in SOC. A path analysis confirmed that the OP‐SOC distribution was largely explained by the distribution of oil palm fine roots, which itself depended on management practices. SOC mineralization was proportional to SOC content and was independent on phosphorus availability. We conclude that SOC stabilization was driven by C inputs from fine roots and was independent of alteration of SOC mineralization due to management. Practices favouring root growth of oil palms would increase carbon sequestration in soils without necessarily relying on the limited supply of organic residues.

Characterization of fluvo-aquic soil phosphorus affected by long-term fertilization using solution 31P NMR spectroscopy.

Reducing the applications of mineral phosphorus (P) fertilizers and supplementing them by organic fertilizers is becoming a necessary practice in the North China Plain due to overuse of mineral P fertilizers and improper disposal of organic wastes. Knowledge is needed about how the long-term substitution of mineral fertilizers by organic fertilizers affects soil P forms in order to understand soil P transformation and crop P uptake. In this study, we used solution 31P nuclear magnetic resonance (NMR) spectroscopy to characterize P forms in fluvo-aquic soil after 26 years of different fertilization management strategies, organic compost (OM), half compost in combination with half mineral fertilizer NPK (1/2 OM), mineral fertilizer NPK (NPK), mineral fertilizer NK (NK), and an unfertilized control (CK). Results showed that the P extraction efficiency using NaOH-EDTA varied from 13.0 to 27.7% for the soils of the treatments. 31P NMR spectra indicated that the majority of P was in the form of orthophosphate for all the treatments, which constituted 64.3-83.5% of the total extracted P. The application of P fertilizers significantly increased the concentrations of orthophosphate, monoesters and diesters regardless of the P fertilization method, although the proportions of monoesters and diesters were higher in CK. The proportions and concentrations of orthophosphate significantly decreased when all mineral fertilizers were replaced by compost. There was no significant difference in the proportions and concentrations of total organic P, corrected monoesters and diesters in NaOH-EDTA extracts of soils among NPK, 1/2OM and OM treatments. Decreasing mineral P fertilizers and partly replacing them by organic fertilizer in fluvo-aquic soil might increase soil test (Olsen) P and crop P uptake through the degradation of applied organic P forms.

The Performance of Cucumber Plants (Cucumis sativus L.) as Affected by Organic and NPK Mineral Fertilization under Plastic Houses Conditions at Arid Region

Two plastic house experiments were conducted during 2016/ 2017 and 2017/2018 seasons in the Experimental Farm, Faculty of Agriculture and Natural Resources, Aswan University, Egypt on a sandy textured soil under unheated plastic houses. The target of fertilization program seeks to achieve the best combination of various organic and NPK mineral fertilization that lead to the highest yield and quality of cucumber plant 'Merage F1 hybrid'' especially during the winter season. Therefore, 12 treatments were arranged in a split plot layout in complete randomize block design with three replicates. Chicken manure at the rates of (10, 15 and 20m3/fed.) were randomly arranged in the main plots, while NPK mineral fertilization at rates of (0:0:0, 50:30:50, 100:40:80, and 150:50:110 Kg N:P2O5: K2O/fed., respectively, were randomly distributed in the sub-plots. The obtained results demonstrated that the treatment combination of chicken manure at 20 m3/ fed. plus 150:50:110 kg. NPK/fed. exhibited the highest significant mean values of most studied characters as vegetative growth characters (i.e. number of leaves/plant, the number of branches /plant, plant fresh weight and chlorophyll index); yield characters {i.e. no. fruits /plant, average fruit weight (g), total yield/m2 (kg) and early yield/m2 (kg)}; fruit quality (i.e. TSS %, vitamin C, and reducing, non-reducing and total sugars); fruits chemical analysis characters (viz, N, P, K contents in fruits ) during both seasons of the study as compared to the other treatments. Based upon, the reported results, it is possible to conclude that, the combination among 20 m3/fed. of chicken manure plus 150:50:110 Kg. NPK/fed. considered as the optimal combination treatment whereas it gave the highest mean values of vegetative growth characters, yield and its components and fruit quality of cucumber plants grown under plastic houses conditions at Aswan governorate and similar regions.

Responses of soil fungal diversity and community composition to long-term fertilization: Field experiment in an acidic Ultisol and literature synthesis

Fungal communities play a critical role in regulating soil nutrient cycling and plant growth. However, the effects of long-term mineral and organic fertilization on fungal communities in Ultisols remain largely unknown. Soil samples from a 27-year fertilization experiment were used to investigate fungal communities through high-throughput sequencing along with literature data. The study involved seven treatments: no fertilization (Control), mineral NPK fertilizer (NPK), NPK fertilizer plus lime (NPK + Lime), NPK fertilizer plus peanut straw (NPK + PeanStraw), NPK fertilizer plus rice straw (NPK + RiceStraw), NPK fertilizer plus radish residue (NPK + RadResidue), and NPK fertilizer plus pig manure (NPK + PigManure). Long-term amendment of mineral and organic fertilizers did not alter fungal diversity in strong acidic Ultisols (original soil pH = 4.96). Meta-analysis of 60 global measurements in literature showed that fertilizer-induced decreases in fungal diversity (Hedge's d = −0.36; p < 0.05) occurred mainly in soils with initial pH >6 rather than <6, potentially due to the decrease in soil pH in fertilized soils, with mineral fertilizers having stronger effects than organic amendments. Ascomycota was the dominant phylum in all treatments, accounting for 75–90% of the total sequences, followed by Basidiomycota (5.9–11%), which are consistent with data from literature. Application of NPK + Lime and NPK + PigManure shifted fungal community structure by increasing relative abundance of Hypocreales and Pezizales, respectively, compared with the Control, while amendment with NPK alone or in combination with crop residues did not. Soil organic carbon, effective diffusion coefficient of oxygen, and pH were the three most critical determinants of fungal community structure. Overall, our results suggest that fungal community structure rather than fungal diversity responded to the application of NPK + Lime or NPK + PigManure but not NPK+ plant residues in test Ultisols, and lack of response in fungal diversity to fertilization was potentially due to the particularly low soil pH in test soils.

EFFECT OF NATURAL AMORPHOUS SILICA - MULTIMINERAL FERTILIZER FLO-RAL MICROSIL ON SOME MORPHOLOGICAL AND YIELD COMPONENTS IN RICE (ORYZA SATIVA L.)

The effect of natural multimineral fertilizer Floral microsil (FM) (50 % bio-available amorphous SiO2 + macro-nutrients and trace elements) was investigated on some morphological and productive properties in rice at the environ-mental conditions of Republic of Macedonia, on cultivar San Andrea. Two treatments were studied: control (standard fertilization) with 450 kg/ha complex mineral fertilizers NPK (16:16:16) as basic fertilizer + two splits with Urea 46 % N (200 + 100 kg/ha), and FM treatment: 20 kg/ha FM before sowing, seed treatment with 20 kg/ha FM + three splits of FM + Urea (30 + 100; 20 + 60 and 20 + 60 kg/ha respectively). The field trials were set up in Zade design during 2014 and 2015. Results were analyzed with ANOVA and LSD test.The FM treatment significantly affected plant and stem height (2014), producing shorter plant (103.02 cm) and stem (87.47 cm) compared to the control (111.81 cm and 95.91 cm). Significantly lower biological (20958.34 kg/ha) and straw yield (10769.67 kg/ha) were determined in the FM treatment compared to the control (24852.00 kg/ha and 15101.34 kg/ha). The FM treatment significantly increased the 1000 grains weight (39.97 g against 38.28 g control av-erage). The paddy and white rice yield (9839.99 kg/ha; 5856.75 kg/ha) in FM treatment were statistically on par with the control (9368.60 kg/ha and 5907.91 kg/ha), as well as the panicle length, number of productive and non-productive tillers per m2, the head rice yield (whole grains and broken grains) and the hectoliter weight.The application of FM significantly increased the nitrogen use efficiency estimated thru the partial factor produc-tivity (97.24 kg paddy rice/kg N and 57.88 kg white rice/kg N), as compared to the control average (44.61 kg paddy rice/kg N and 28.14 kg white rice/kg N). Therefore, paddy and white rice yield statistically on par with the standard fertilization were produced with a lower amount of applied nitrogen fertilizer. These findings are of ecological signifi-cance for the rice production in the Republic of Macedonia.

Sewage sludge biochar alters root colonization of mycorrhizal fungi in a soil cultivated with corn

Sewage sludge biochar (SSB) has demonstrated a large potential to improve soil quality, availability of nutrients, particularly phosphorus (P), and increase crop productivity. There is a lack of information on the effect of P from SSB on the soil microbiota, especially on arbuscular mycorrhizal fungi. Six treatments were arranged in randomized blocks, with four replicates: 1) Control - without any amendments; 2) Mineral fertilization with NPK; 3) Biochar prepared at 300 °C (BC300); 4) Biochar prepared at 500 °C (BC500); 5) BC300 + NPK; 6) BC500 + NPK. Amendments were applied in two consecutive harvests. Microbial biomass carbon (MBC), percentage of mycorrhizal colonization (MC) and easily extractable glomalin-related soil protein (EEG) of soil mycorrhizal fungi were evaluated in all treatments. Amendment with BC300 resulted in an increase in MBC, while all treatments resulted in an increase in the colonization of corn roots by AMF. Consequently, SSB stimulated the synthesis and excretion of EEG from the soil. Biochar, NPK mineral fertilizer and their combinations increased MC in corn compared to the control. However, no additive effects of SSB and NPK addition were observed.

Does fertilization impact production risk and yield stability across an entire crop rotation? Insights from a long-term experiment

The objective of our analysis was to demonstrate a novel application of production risk (probability of a yield falling below a certain level) and yield stability analysis based on the totalized yield across a `sugar beet–winter wheat–spring barley´ crop rotation. We evaluated a long-term experiment spanning more than 60 years regarding the effect of mineral NPK fertilization and the additional supply of manure on the production risk, the risk development over time (trend), and the stability of biomass yields. We found that positive impacts such as reduced production risk and enhanced yield stability were the highest for the mineral N supply, were intermediate for the K supply, and were the lowest for the P supply. The full amount of the mineral nutrient fertilization, particularly in combination with an additional manure supply, resulted in lower production risk and more stabilized crop rotational yields compared to one-half the amount of nutrient supply. The mineral fertilization of NPK (at one-half and a full amount) led to a decreasing risk trend, particularly with the additional manure supply. The risk trend of the variants with P and K (but without N) or even no mineral nutrient fertilization only decreased over time with the manure supply. The lowest production risk and the best combination of high and stable yields of the crop rotation were found at full mineral NPK fertilization in addition to manure. In contrast, the highest production risk and the worst combination of the lowest and most unstable yields were obtained under a fertilization regime without N or even under nonfertilized management. The production risk and yield stability of this fertilization regime could be reduced via regular manure application carried out once per three-year rotation during the experimental period.

Maize Productivity using Soil Amendments, Mineral and Bio- fertilization

: Two field experiments were conducted at the private farm at El- Nubaria, El- Behria, Egypt, during the summer seasons of 2017 and 2018 to study the response of the maize hybrid TWC 310 to soil amendments and mineral + biofertilization. Split plot design with three replications was used, where the main plots occupied by soil amendments (soil application of Sulfur (S) at the rate of 100 kg/fed, Humic acid with irrigation water (3 kg/fed) and soil application of Fluvic acid (2 kg/fed) and soil application of compost at the rate of 5 t/fed), meanwhile the sub plots contained mineral NPK fertilizers with bio- fertilizers of NPK (100% mineral NPK, 75 % mineral NPK + bio- fertilizers, and bio- fertilizers of NPK) in both seasons. The obtained results indicated that using compost, fulvic acid, and humic acid with mineral NPK (75% of recommended dose) with biofertilizer fertilizers increased yield and its components of maize under El- Nubaria Region.

COMPARATIVE INVESTIGATIONS WITH SOME DOMESTIC AND INTRODUCED SMALL LEAVE TOBACCO VARIETIES PRODUCED IN PELAGONIJA REGION

Field experiments were carried out on two localities, in Prilep, exactly on experimental field of the Institute and in v. Dobrushevo. The influence of different nitrogen rates upon quantitative and qualitative characteristics of the four oriental tobacco types: Prilep P-23, Prilep P-79-94 (domestic varieties), and Basma1 and Elenski 817 (introduced varieties) was investigated. Investigation included four varieties, three nitrogen rates (0, 20, and 30 kg/ha) and constant amount of phosphorus (60 kg/ha) and potassium (40 kg/ha). Soil preparation was performed with one autumn (30 cm depth) and two spring plowings (8-20 cm depth). Before the trial was set up, the soil was tested to determine its agrochemical and physical properties. Fertilization was done using inorganic mineral fertilizer NPK and 27% KAN. 50% of the nitrogen amount was applied in the last plowing, prior to planting, together with phoshorus and potassium, and the rest 50 % were applied on the first hoeing. All necessary agro-technical and plant protection practices were applied during the vegetation period of tobacco. From the results, it can be noted that yield increase correlates with the increase of nitrogen quantities, in the both localities. In the Prilep locality, fertilized varieties with the 30 kg N/ha had yield increase of 24.50% and 27.23% respectively, as opposed to the control. The highest yield is noted to the P-23 variety (3443 kg/ha), and the lowest to the Basma 1 variety (2567 kg/ha). The same legality is noted in the Dobrushevo locality, where yield increases of 24.14%, 26.75%, 23.57% and 24.29 % respectively, as opposed to the nonfertilized variant. The variety Prilep P23 as standard, fertilized with the 30 kg N/ha achieved the highest average yield per unit area (3573 kg/ha), while the Basma 1 variety have significantly lower average yield than the standard variety, 2676 kg/ha. The fertilization has a positive effect and statistical significance on the average yield and gross income, per unit area. The average purchase price of tobacco, expressed in % of quality classes, has a slight decrease with increasing nitrogen rates, in all investigated varieties. In the both localities, in all investigated varieties was observed increasing content of nicotine, total nitrogen, proteins and mineral matter, and decreasing content of the soluble sugar with increasing nitrogen quantities. To evaluate the fertilization effect on investigated varieties all results were statistically processed by analysis of variance and LSD test. Based on the obtained results it can be concluded that due lower yield and gross income per ha, the introduced varieties Basma 1 and Elenski 817 are not perspective varieties for wider production in the Pelagonija region.

Manure over crop residues increases soil organic matter but decreases microbial necromass relative contribution in upland Ultisols: Results of a 27-year field experiment

Organic fertilizers increase soil organic matter (SOM) stocks, but the underlying processes depend on the fertilizer type and remain largely unknown. To evaluate the predominant C stabilization mechanisms, upland Ultisols subjected to 27 years of mineral and organic fertilization were analyzed for SOM content, aggregate size classes, and amino sugar composition. The long-term field experiment had seven treatments: no fertilization (Control), mineral NPK fertilizers (NPK), NPK plus lime (NPK + Lime), NPK plus peanut straw (NPK + PeanutStraw), NPK plus rice straw (NPK + RiceStraw), NPK plus radish residue (NPK + RadishResidue), and NPK plus pig manure (NPK + PigManure). The 27-year application of mineral fertilizers (NPK and NPK + Lime), NPK + crop residues, and NPK + PigManure increased SOM content by 11.0–13.2%, 16.3–25.3%, and 44.3%, respectively, compared with the Control. The aliphaticity and recalcitrance indices based on 13C nuclear magnetic resonance spectra of organic fertilizers were higher for pig manure than for crop residues. Both indices were closely correlated with SOM content after 27 years, so higher proportions of recalcitrant C in manure facilitated SOM accumulation. NPK + PigManure increased the mass proportion of large macroaggregates 2.9-fold compared with the Control, and reduced the effective diffusion coefficient of oxygen in the soil. Consequently, NPK + PigManure limited the activity and abundance of aerobes and the accessibility of SOM to microorganisms, in turn facilitating SOM accumulation. The application of mineral fertilizers, NPK + crop residues, and NPK + PigManure increased microbial necromass to 2.85–3.03, 3.21–3.45, and 3.62 g C kg−1, respectively, from 2.63 g C kg−1 in the Control. Compared with crop residues, pig manure did not affect bacterial necromass but increased fungal necromass from 2.19 to 2.39 g C kg−1 to 2.58 g C kg−1, which might associate with increased SOM stability. However, the relative contribution of microbial necromass to SOM was lower under NPK + PigManure than under NPK + crop residues, since more added C was protected in the NPK + PigManure soil. Our results suggest that manure may contribute to SOM accumulation and stabilization in three ways: directly through the input of recalcitrant organic C, indirectly through the stabilization of aggregates and physical protection of C, and to a lesser extent through increasing fungal necromass.

Climate change impact on water- and nitrogen-use efficiencies and yields of maize and sorghum in the northern Benin dry savanna, West Africa

Climate change and variability challenge crop productivity and resource use efficiency in West Africa. Despite abundant research on climate change impact on crop yields and food security, little is known about climate change effects on the resource use efficiencies of the main staple crops in the dry savanna agro-ecological zone of northern Benin, West Africa. This study assessed the impact of climate change on water- and N-use efficiencies, and yields of maize and sorghum in the dry savanna of northern Benin considering three soil fertility management options (return of crop residues, mineral NPK fertilizer application, and combinations of both) and three bias-corrected ensemble mean predictions (BNU-ESM, CanESM2, and MPI-ESM-MR models) of future climate (2080–2099) under Representative Concentration Pathways (RCPs) of 2.6, 4.5, and 8.5. Seasonal rainfall is projected to decrease by 2% under RCP 2.6 and by 4% under RCP 4.5, and to increase by 1% under RCP 8.5 relative to the baseline mean (1986–2005). Increasing trends in minimum temperature of +1.0 °C (RCP 2.6), +2.0 °C (RCP 4.5), +4.7 °C (RCP 8.5) and maximum temperature of +1.1 °C (RCP 2.6), +2.0 °C (RCP 4.5), +4.6 °C (RCP 8.5) are also predicted. Solar radiation was projected to decrease by about 0.4 MJ m−2 d-1. Under these projected climate scenarios, both CERES-Maize and CERES-Sorghum simulated positive responses in aboveground biomass accumulation during the vegetative growth stages. The predicted increase in aboveground biomass growth will be largest under RCP8.5 and smallest under RCP 2.6. This impact can be enhanced by improved soil fertility management, albeit with a crop-specific magnitude. Across the soil fertility management options, CERES-Maize predicted decreases in water-use efficiency by 17–53%, partial factor productivity of nitrogen (N) by 10–47%, and internal N-use efficiency by 5–33% for maize. Similarly, CERES-Sorghum simulated decreases in water-use efficiency (23–51%), partial factor productivity of N (22–49%), and internal N-use efficiency (13–47%) for sorghum. The largest overall loss in resource efficiency and yield were predicted for the RCP 8.5 scenario. The projected climate change for the dry savanna in northern Benin will likely reduce water- and N-use efficiencies as well as grain yields of maize and sorghum considerably but these results should be treated with caution due to shortcomings in the models structure for dealing with effects of enhanced CO2. For reliable assessments of climate change impact on WUE, it is critically important to update parameterization and code of the CERES crop models in DSSAT to have a sufficiently strong effect of CO2 on stomatal conductance and on transpiration.

Tree vigor, yield, fruit quality, and antioxidant capacity of apple (Malus × domestica Borkh.) influenced by different fertilization regimes: preliminary results

Tree growth, productivity, fruit quality attributes, and antioxidant activity were tested in apple cultivar Idared under different fertilization treatments from the 22nd to the 23rd year after planting in a heavy acidic soil under western Serbian conditions. Treatments included the use of aged cattle manure, compound NPK (15:15:15) mineral fertilizer, a multinutrient fertilizer commercially named Italpolina (ITP) (NPK + organic carbon + humic acids), two types of N mineral fertilizers (calcium ammonium nitrate [CAN] and urea), and control (no fertilization). Results showed that Idared trees were more vigorous when fertilized with the two N fertilizers than when treated with another mineral, organic, or multinutrient fertilizer. Urea promoted the highest yield per tree and unit area, while yield efficiency was the highest in the control and those under treatment with urea, compound NPK, and manure. Fertilizer regimes had a significant effect on fruit weight and flesh firmness, but their effects on fruit size and dimension ratio were not significant. Compound NPK resulted in the greatest fruit weight, whereas firmness and soluble solids content were the highest in manure treatment. Titratable acidity (TA) was the highest in control trees and after CAN application, while urea induced the highest ripening index. Fertilizer treatments had no significant effect on the contents of invert sugars, sucrose, and total sugars (TS). The TS/TA ratio was highest under urea treatment and lowest in the control and under CAN application. ITP led to the highest values for total phenolics, total nonflavonoids, and total antioxidant capacity, while the highest total flavonoid content was obtained with compound NPK.

Is the long-term application of sewage sludge turning soil into a sink for organic pollutants?: evidence from field studies in the Czech Republic

Long-term microscale field experiments established at four sites in the Czech Republic (since 1996) were used for an assessment of the severity of the wide-scale contamination of treated soils by persistent organic pollutants (POPs) and pharmaceuticals and personal care products (PPCPs) as a result of the long-term regular pollutant load via sewage sludge and farmyard manure applications and for an estimation of the potential environmental risk caused by long-term pollutant inputs to agricultural soils. The experimental plots were treated as follows: (i) NPK mineral fertilization (NPK); (ii) sewage sludge (SS1); (iii) sewage sludge applied at three times the rate compared to SS1 (SS2); (iv) farmyard manure (FYM); and (v) untreated control. Except for antibiotics, which showed results for all analyses below the detection limit, all groups of the analyzed compounds showed measurable contents in the treated soils. Among the POPs, the levels of organochlorine pesticides (OCPs) were detected at two locations at levels exceeding the Czech preventive values for their contents in agricultural soils (7.5 μg/kg for dichlorodiphenyl trichloroethane family, 20 μg/kg for hexachlorbenzene, and 10 μg/kg for α-hexachlorocyclohexane), regardless of the treatment. Similarly, elevated contents of polycyclic aromatic hydrocarbons (PAHs) were occasionally observed without any substantial relationship to the fertilizer application scenario. Thus, these contaminants are connected with atmospheric deposition in the given areas (PAHs) and their long-term stability (OCPs) even several decades after their ban; the role of the fertilizer composition was negligible. The levels of per- and polyfluoroalkylated substances, brominated flame retardants, and synthetic musk compounds tended to increase in the sewage sludge–treated plots, indicating that sewage sludge can contribute to the abundance of these compounds in soil, although the contaminant levels determined do not represent a direct environmental risk. The levels of these contaminants in sewage sludge and sludge-treated soils should be regularly monitored in further research.

Response of Some Egyptian and Iraqi Wheat Cultivars to Mineral and NanFertilization

Twofield experiments were conducted at the Experimental Farm of Faculty ofAgriculture (Saba- Basha), Abess Region, Alexandria University, Egypt, duringtwo seasons of 2016/2017 and 2017/2018 to study the response of some wheatcultivars to mineral and nano- fertilization. The experimental design wassplit- split plot system with three replicates. The main plots were occupied bythe three soil mineral fertilizer NPK treatments at therate of “100, 75, and 50%”. While,sub-plots contain three foliar application of nanofertilizer NPK fertilizertreatments “100, 75 and 50%”. Meanwhile, the four wheat cultivars “Sakha 93,Gemmeiza 11, AL-Rasheed and Abu Ghareb” are distributed at random in sub-subplots. plant height, spike length (cm), number of spikes/m2,number of spikelets /spike, number of grains/spike, 1000-grains weight (g),grain yield, straw yield (t/ha.), harvest index (HI %) and protein content wererecorded in both seasons. The obtained results revealed that fertilized wheatcultivar Sakha 93 by 75 % soil application of mineral fertilization by NPK withfoliar application of Nano- fertilizers (NPK) increased yield and itscomponents of the wheatcrop under theenvironmental conditions of Alexandria Governorate.

Soil carbon transformation in long-term field experiments with different fertilization treatments

Soil carbon transformation was observed in long-term stationary field experiments (longer than 20 years) at two sites with different soil-climatic conditions (Luvisol, Chernozem). The following crops were rotated within the trial: row crops (potatoes or maize)-winter wheat-spring barley. All three crops were grown each year. Four different fertilization treatments were used: (a) no fertilizer (control); (b) sewage sludge (9.383 t dry matter/ha/3 years); (c) farmyard manure (15.818 t dry matter/ha/3 years); (d) mineral NPK fertilization (330 kg N, 90 kg P, 300 kg K/ha/3 years). At the Luvisol site, the control treatment showed a tendency to decrease organic carbon (C&lt;sub&gt;org&lt;/sub&gt;) in topsoil. At organic fertilization treatments the content of C&lt;sub&gt;org&lt;/sub&gt; increased: sewage sludge – +15.0% (Luvisol) and +21.8% (Chernozem), farmyard manure – +19.0% (Luvisol) and +15.9% (Chernozem). At the NPK fertilization, the increase was +4.8% (Luvisol) and +4.7% (Chernozem). The increased C&lt;sub&gt;org&lt;/sub&gt; content was also associated with an increase of microbial biomass carbon (C&lt;sub&gt;mic&lt;/sub&gt;) and extractable organic carbon (0.01 mol/L CaCl&lt;sub&gt;2&lt;/sub&gt; and hot water extraction). The ratio of C&lt;sub&gt;mic&lt;/sub&gt; in C&lt;sub&gt;org&lt;/sub&gt; was within the range 0.93–1.37%.