Levels Of Mineral Fertilization Research Articles

FORMATION OF THE PHOTOSYNTHETIC PRODUCTIVITY OF SOYBEAN CROPS UNDER A BIOLOGIZED FOOD SYSTEM

The process of photosynthesis and the intensity of its work are the basis of the formation of productivity and the level of productivity of agrophytocenoses of agricultural crops, including soybeans. One of the main tasks of modern intensive cultivation technologies is the creation of optimal conditions for the development of the assimilation surface, its long-term operation and the maximum accumulation of organic matter by plants. This scientific article presents the results of field research on the impact of biological preparations of different mechanisms of action created on the basis of phosphorus and potassium mobilizing and mycorrhizal forming bacteria on the photosynthetic productivity of soybean crops at different levels of mineral fertilization, namely on the dynamics of the leaf surface area, the formation of the photosynthetic potential of crops and net productivity of photosynthesis. Field research was conducted on gray forest medium-loamy soils at the experimental field of the Agronomic Research Field of VNAU during 2017-2021. According to the results of the research and the processing of the obtained data, it was established that the use of Groundfix soil biofertilizer at the rate of 5 l/ha during the pre-sowing cultivation period and the pre-sowing treatment of seeds with the biological preparation Micofrend at the rate of 1,5 l/t against the background of complete mineral fertilization ensured the formation of the maximum in the experiment the area of the assimilation surface was 40,4 thousand m2/ha, which exceeded the control by 11,6 thousand m2/ha. In addition, based on the calculations, it was found that this version of fertilizer provided the formation of the highest photosynthetic potential in the experiment at the level of 3,153 million m2 days/ha, and the net productivity of photosynthesis, which, depending on the interphase period, was 5,44, 2,16, 1,76, 2,53 and 1,34 g/m2 per day. The article also provides the results of correlation calculations of the closeness of the connection between the area of the leaf surface, the amount of accumulated dry matter and the level of productivity.

Long-Term Application of Manure and Different Mineral Fertilization in Relation to the Soil Organic Matter Quality of Luvisols

Long-term field experiments were conducted on luvisol at five sites in the Czech Republic (42–48-year duration). The average total organic carbon content in the soil varied between 9.0 and 14.0 g kg−1. In these trials, seven crops were rotated in the following order: clover, winter wheat, early potato, winter wheat, spring barley, potato, and spring barley with interseeded clover. Five treatments were studied: unfertilized treatment (Con), farmyard manure (F), and combinations of farmyard manure with three mineral fertilization levels (F+M1, F+M2, F+M3). Plant residues were not incorporated into the soil. An amount of 40 t ha−1 of farmyard manure fresh matter was applied twice during crop rotation. Intensive mineral fertilizer (F+M3) increased the average value of the carbon sequestration efficiency (CSE) by 12.9% and up to 26.3%. Combining organic and mineral fertilizers at moderate and higher intensities increased the soil organic matter quantity and quality compared to the unfertilized or manure treatment. Data on the glomalin content can be used to study the organic matter quality. We determined a strong correlation between the total glomalin content and the soil organic matter carbon, fulvic acid content, humic acid content, extractable carbon content, and dissolved organic carbon content, as well as the potential wettability index and aromaticity index.

Effect of Adding Levels of Palm Fronds Compost and Mineral Fertilizer on Fertile Soil Characteristics, Quality, and Productivity of Maize Yield (Zea Mays L.)

An experiment was carried out in one of the fields of the Soil Research Department - Agricultural Research Department/Ministry of Agriculture in the Abu Ghraib district at latitude 33° 17" 31 N and longitude 44° 03" 56 E and 35 m above sea level. This field study was conducted in the autumn season 2021-2022 for the cultivation of yellow maize ( Maha cultivar) in sedimentary soil with silty clay loam texture, with a Split Plot Design. The treatments were distributed using the RCBD for three replicates with two factors. The first factor represents the main plots that include the addition of mineral fertilizer 120, 80, and 320 kg.ha-1 for each of (N, P, and K), respectively, at three levels (0, 50, and 100%) of the fertilizer recommendation. On the other hand, the second factor was a subplot of organic fertilizer (palm frond compost) at three levels (0, 5, and 10) μg.ha-1 . Soil samples were taken to estimate the availability of nitrogen, phosphorous, and potassium, where the total yield and percentage of protein for yellow maize were estimated. The results showed that adding organic fertilizers (palm fronds) with the levels of mineral fertilizers increased the availability of nutrients and the yield of maize. Accordingly, the treatment O2M2 achieved the highest values of nutrient availability, quantity, and quality of yield, reaching (59.167, 33.407, and 257.967) mg.kg-1 soil and (10,096) μg.ha-1 and (9.435%) for each of nitrogen, phosphorous, potassium, yield, and protein percentage, respectively. Moreover, there were no significant differences between the treatments of O1M2 and O2M1 in the amount of yield and the percentage of protein, which gave the values of 8.403 and 8.134 μg.ha-1, respectively, and the protein percentage of 8.630 and 8.915% respectively. It can be concluded that organic fertilizers can be added to compensate for mineral fertilizers, reduce environmental pollution, and reduce the economic cost and soil preservation because organic fertilizers are considered safe and environmentally friendly. Keywords: yellow maize, mineral fertilizer, palm fronds compost.

Cannabis Hunger Games: nutrient stress induction in flowering stage - impact of organic and mineral fertilizer levels on biomass, cannabidiol (CBD) yield and nutrient use efficiency.

Indoor medicinal cannabis cultivation systems enable year-round cultivation and better control of growing factors, however, such systems are energy and resource intensive. Nutrient deprivation during flowering can trigger nutrient translocation and modulate the production of cannabinoids, which might increase agronomic nutrient use efficiency, and thus, a more sustainable use of fertilizers. This experiment compares two fertilizer types (mineral and organic) applied in three dilutions (80, 160 and 240 mg N L-1) to evaluate the effect of nutrient deprivation during flowering on biomass, Cannabidiol (CBD) yield and nutrient use efficiency of N, P and K. This is the first study showing the potential to reduce fertilizer input while maintaining CBD yield of medicinal cannabis. Under nutrient stress, inflorescence yield was significantly lower at the final harvest, however, this was compensated by a higher CBD concentration, resulting in 95% of CBD yield using one-third less fertilizer. The higher nutrient use efficiency of N, P, and K in nutrient-deprived plants was achieved by a larger mobilization and translocation of nutrients increasing the utilization efficiency of acquired nutrients. The agronomic nutrient use efficiency of CBD yield - for N and K - increased 34% for the organic fertilizers and 72% for the mineral fertilizers comparing the dilution with one-third less nutrients (160) with the highest nutrient concentration (240). Differences in CBD yield between fertilizer types occurred only at the final harvest indicating limitations in nutrient uptake due to nutrient forms in the organic fertilizer. Our results showed a lower acquisition and utilization efficiency for the organic fertilizer, proposing the necessity to improve either the timing of bio-availability of organic fertilizers or the use of soil amendments.

Effect of water quality, mineral fertilizer levels and methods of adding seaweed extracts on reducing salt stress, growth and yield of cauliflower.

A field experiment was conducted at one of the research stations of the College of Agricultural Engineering Sciences / University of Baghdad in Al-Jadiriyah region for the autumn season 2021-2022, located within 33.27 north latitude and 44.39 east longitude, in Clay soil with a Split Plot Design design and with three replicates to study the effect of Irrigation water quality, mineral fertilizer and methods of adding marine extracts to reduce salt stress and cauliflower growth and yield. The experiment included three factors: irrigation with two types of water, regular irrigation water (tap water) with an electrical conductivity of 0.9 dSm-1, and the second is saline water (wastewater) with an electrical conductivity of 4.8 dSm-1 and two levels of mineral fertilizer 50% and 100% of Fertilizer Recommendation and Extracts with six different levels of supplementation (S0, S1, S2, S3, S4 and S5). Cauliflower seedlings, Prassica oleracea, and cultivar Megha were transferred to the field on 9-15-2021. Nitrogen was added by 300 kg. N ha-1 in urea (46% N) and phosphate in 100 kg. P ha-1as triple superphosphate (20% p)and potassium by 150 kg. K ha-1 is in the form of potassium sulfate (42% K). Soil samples were taken over the length of the experiment and periods (30, 45, 60 and 75 days) to estimate the electrical conductivity in the soil. At the end of the season, the yield of cauliflower was estimated. The results showed the significant effect of irrigation water quality, mineral fertilizer, and methods of adding marine extracts in reducing the electrical conductivity of the soil and increasing the cauliflower yield and treatment (W1M2S5) achieved the highest significant increase in cauliflower yield, with an increased average of 47.97%, followed by treatment (W2M2S5), with an increased average of 42.63%. Keywords: water quality, seaweed extracts

MAIZE SEED INOCULATION WITH BIOAGENT AND ITS EFFECTS ON THE GROWTH AND YIELD TRAITS

The presented study sought to use the plant growth-promoting microorganism (PGPM) as a biofertilizer in maize (Zea mays L.) seeds and determine its effects on the growth and productivity of maize, with two levels of mineral fertilizer (25% and 50% of chemical fertilizer) under Iraqi conditions. Laboratory studies confirmed no antagonism between Azotobacter chroococcum and other microorganisms used in this study. Field experiments carried out during crop season 2021 were in two different regions, Mosul (36°20′6″N, 43°7′8″E) and Kirkuk (35°28′5.02″N, 44°23′31.99″E) in the north of Iraq. The result showed biofertilizer superiority when combined with 25% and 50% doses of the recommended mineral fertilizer for maize growth and yield traits in the experiments in both locations. In Kirkuk city, the biofertilizer combined with 25% chemical fertilizer recorded superiority without significant difference from the biofertilizer combined with 50% mineral fertilizer. However, in Mosul city, the biofertilizer combined with 50% chemical fertilizer expressed a more superior and significant difference than other treatments for growth and yield traits in maize. The difference between the two regions might be due to chemical fertilizer residues in the soil.

Arbuscular Mycorrhizal Fungus Funneliformis mosseae Improves Soybean Growth Even in Soils with Good Nutrition

Arbuscular mycorrhizal fungi (AMF) improve plant growth and may be useful in maintaining and even restoring soil. However, data on the latter function are sparse and only indirect, which is especially true for conventional management conditions with adequate nutrient availability. Our study focused on utilizing the prevalent AMF species, Funneliformis mosseae, to enhance Glycine max production, while also exploring its partly explored impact on soil aggregation. Working in greenhouse conditions, we examined whether, in a nutrient-sufficient environment, AMF would improve crop biomass accumulation and nutrition, as well as the stability of soil aggregates (SAS). We also looked for a synergistic effect of dual inoculation using AMF and symbiotic rhizobium. Plants were or were not inoculated with AMF or Bradyrhizobium japonicum in a two-factorial design. AMF inoculation increased soybean biomass, but AMF inoculation had no impact on P and N input to the shoots. Mycorrhiza did not affect either glomalin abundance or SAS. All the impacts were, however, independent from rhizobial inoculation, which was ineffective in this nutrient-available environment. Our assay suggests that arbuscular mycorrhiza may have a positive effect on soybean growth even under conventional management with adequate nutrition. The positive effects of AMF on soybean growth, together with the fact that AMF generally do not thrive in good nutrient availability, should be taken into account when planning mineral fertilization levels.

FORMATION OF BUSHINESS OF SPRING TRITICALE VARIETIES DEPENDING ON THE PREDECESSOR AND FERTILIZER

The article highlights the influence of precursors and levels of mineral fertilization on the formation of productive bushiness of spring triticale of different varieties. Depending on the influence of meteorological factors and weather, the influence of the studied elements of winter triticale cultivation technology, the indicators of the level of bushiness changed. The highest productive bushiness was formed by plants in the variants in which the best conditions were created for this. Triticale is an artificially bred crop that has not been studied enough in the global economy and requires research, but in Ukraine it is a well-known crop that takes its share in the overall crop structure. For example, the use of different norms of nitrogen fertilizers on the background of P60К60 contributed to an increase in the number of productive stems per unit area, and, accordingly, in the productive bushiness in general. When applying phosphorus and potassium fertilizers (P60К60), the number of productive stems did not exceed 585-591 pcs./m2, and the productive bushiness was 1.58-1.59, respectively. Triticale consumes a lot of nutrients from the soil to form a crop, which requires additional fertilization. It is not customary to apply organic fertilizers to this crop. only under its predecessors. Depending on the soil fertility, 60 to 90 kg of nitrogen, phosphorus and potassium are applied. Phosphorus and potash fertilizers are scattered under the main cultivation. And nitrogen fertilizers are divided into three fertilizing sessions during the phases of active plant growth. Experts also advise to apply superphosphate 10-15 kilograms per hectare during sowing with seeds. Triticale is very sensitive to sowing dates, which roughly coincide with the middle of the optimal sowing period for winter wheat. For sowing, it is necessary to select seeds with a germination rate of at least 92% and a purity of at least 98%. Treatment with compositions designed for winter wheat has a good effect on the yield. In most farms, the crop is sown using intensive technology in a row with the skipping of technological paths. Some farms use a cross-row or narrow-row sowing method. The seeding rate is usually between 1.5 and 5.5 million germinating grains per hectare. The recommended sowing depth is 4-6 cm, reduced on heavy soils and increased by 1-2 cm on light soils. By selecting the best predecessors, namely soybeans, sunflower and corn, we created optimal conditions for the productivity of this crop. In addition, mineral fertilizers had a positive effect on the formation of bushiness of spring triticale.

Immobilization of Cr3+, Cd2+, and Pb2+ added to calcareous soil amended with composted agro-industrial residues

The bioavailability of trace metals in soils poses a major threat to the environment, especially with massive mineral fertilizers added to increase plant yield. A plot experiment was conducted for the effectiveness evaluation of compost and vermicompost, recycled from agro-industrial wastes, in immobilizing chromium, cadmium, and lead added to calcareous soil (artificially contaminated). Moreover, immobilization efficiency was compared to the natural occurrence of these metals in the soil without metal addition (uncontaminated soil). In both soils, amendments and mineral fertilizers were applied at three different levels alone and combined to each other. The experimental design was arranged in factorial complete randomized blocks using contamination, organic and mineral fertilizer levels, and their combination as categorical factors. The distribution of metal fractions and their bioavailability in soils and bioaccumulation in wheat grains were evaluated. Soil alkalinity, the contents of soil organic carbon and nitrogen, available phosphorus, and soil micronutrients were significantly improved under vermicompost and compost compared to mineral fertilizer and control. Vermicompost was more effective than compost in reducing metals bioavailability in contaminated soils by increasing the immobilized organic fractions, but it regressed when combined with mineral fertilizers. The bioavailability of the naturally occurring metal levels in uncontaminated soil did not change significantly compared to contaminated soil. Likewise, wheat yield, plant biomass, and nutrient enrichment in wheat grains improved due to enhanced soil nutrient availability. These composted agro-industrial residues, by-products from food industries, can be classified as environmentally-friendly soil amendments for their great potential to enrich soil nutrients, reduce mineral fertilizer addition, enhance plant growth, and stabilize Cr, Cd, and Pb in contaminated calcareous soils under wheat plants.

An acid-base buffering model to describe pH buffering capacity of an acid albic stagnic luvisol under long-term agricultural land use and management

Aim. To study acid-base buffering capacity depending on the intensity of different fertilization systems, including lim- ing, with different doses of CaCO3 in a long-term (55 years) stationary experiment on Albic Stagnic Luvisol (light grey forest surface-gleyed soil). This study should serve as a basis for the restoration and protection of fertility and yield and preservation of ecological restorative functions of this soil type. Methods. Field stationary experiment, using monitoring, laboratory-analytical and statistical-mathematical methods. Results. It was found that after 35 years of a seven-field crop rotation the exclusion of the intensive crops of sugar beet, potato and one winter wheat, in combina- tion with low (2.5 time less) mineral fertilization levels, contributed to an increase in resistance to acidification over the next 20 years from 5.53 to 7.48 points (using a 100-point scale) with a simultaneous increase in soil рНКСl from 3.77 to 4.12. Organo-mineral fertilization (N65P68K68 + 10 t manure/ha of crop rotation area) and periodic application of CaCO3 by hydrolytic acidity (6.0 t/ha) and an optimal dose of lime (2.5 t/ha CaCO3) increased pH buffering over these 20 years in a four-field rotation. The general evaluation index of buffering was 21.8–21.9 points, exceeding the virgin soil by 1.9 to 2 points. In the control variants without the use of fertilizers the general evaluation index of buffering was 14.3 ± 0.3, and the coefficient of buffer asymmetry was the highest – 0.646 ± 0.013, which under these conditions indicated the danger of soil losing its ability for self-regulation and self-healing. Conclusions. The resis- tance of Albic Stagnic Luvisol to acidification increased most in the combined application of N65P68K68 and 10 t/ha manure, together with an optimum calculated dose of lime in a 4-year crop rotation. An optimal dose of CaCO3 (2.5 t/ha) and organo-mineral fertilizing system in a 4-year crop rotation improved the soil buffering capacity of the acid shoulder by 2.45 points compared to the mineral fertilization system. To support a determination of acid-buffering effects graphic charts representing pH buffering capacity proved to be useful and could be instrumental in diagnostics and optimization of the acid-base regime for acid forest soils in general.

The Role of Bio-Fertilizer EM1 in the Evolution in Addition to the Production of the Wheat Bora Cultivar

A field experience was conducted in Al-Jarallah region, 11 km south of Governorate center through the winter agricultural time 2021-2022, to know the role of bio-fertilizer EM1 in the growth and production of the Italian Bora cultivar. The experience was carried out according to a split-plot design and using the RCBD design with three replication. The first agent referred to the levels of mineral fertilizer (M) for N, P (0 (M1), 50% (M2), 100% (M3) of the metal fertilizer refreence for N, P) (in main plots). Second factor included the levels of bio-fertilizer EM1 (B) (1 ml\\L (B1), 2 ml/L (B2), 3 ml/L (B3)) (in sub plots). The results were that referred the level of mineral fertilization (M3) is superior by showing a high mean in the whole of the thoughtful characteristic. (plant height 93.67 cm, area of flag leaf 59.96 cm2, number of tillers 484.67 tiller.m2, spike length 22.33 cm, number of grains per spike 66.67 grains. spike, weight of 1000 grains 44.099 g, total grain yield 1.7657 t.h-1). The standard of bio-fertilizer (B3) is also superior by showing the highest averages in all the studied characteristics (plant height 88.89 cm, flag leaf area 54.78 cm2, number of tillers 425.56 tiller.m2, spike length 19.67 cm, number of grains per spike 64.67 grains. spike, weight of 1000 grains 42,583 g, the total grain yield is 1.5304 t.h-1). The study showed the superiority of the (M3B3) Interaction treatment in the values of all the studied traits than the values of the study factors individually, especially the total grain yield, which amounted to 1.8540 t.h-1.

Effect of Trichoderma Harzianum and Algae Chara sp and Levels of Mineral Fertilizer on Plant NPK Concentration and Wheat Yield Triticum aestivum L.

A factorial experiment was conducted in alluvial mixture soil using the design (RCBD in research) Agricultural Research and Experiment Station - in the Al Bandar area located on the banks of the Euphrates River, affiliated to the College of Agriculture / University of Al-Muthanna for the winter agricultural season (2021-2022), with the aim of studying the effect of adding Trichoderma fungus harzianum and alga Chara sp and chemical fertilizers (0, 25, 50, 75) and the interaction between them in the concentration of NPK in the plant and the yield of the plant, and the results indicated the moral superiority of the double addition of the fungus T.harzianum and the alga Chara sp in all the studied traits of nitrogen concentration in the plant. (2.04%) the concentration of phosphorous in the plant (0.632), the concentration of potassium in the plant (2.235%), the number of grains of a spike (62.17 grains of a spike-1), and the weight of 1000 grains (52.36 g) of an enzyme, as significant differences were recorded. As a result of adding mineral fertilizer at different levels, level 75 recorded the highest values in nitrogen concentration in the plant (1.82%), phosphorous concentration in the plant (0.534%), potassium concentration in the plant (1.865%), the number of grains spike (56.94 grains of a spike-1) and weight 1000 tablets (51.39 g).

Effect of Adding Phosphate-Dissolving Bacteria on the Activity of Phosphatase Enzyme and some Soil Characteristics and the Yield of Solanum melongena L. under Protected Cultivation Conditions

A field experiment was carried out in the agricultural season 2021-2022 at the second agricultural research station of the College of Agriculture - University of Al-Muthanna in Al Bandar area, southeast of Al-Muthanna Governorate, 3 km from the center of Samawa city / Al-Muthanna Governorate. The yield of eggplant (Solanum melongena L) under protected cultivation conditions. The study was carried out in two stages. The first was a laboratory study that included the isolation of Pseudomonas putida and Pseudomonas fluorescens. 10 bacterial isolates were isolated from soil samples taken from 0-30 cm depth of the rhizosphere soil from fields planted with different crops. The isolates were diagnosed The study of its cultivar, morphological, biochemical and microscopic characteristics, and the experiment was applied according to the Randomized Complete Block Design (RCBD). And I took the symbol B1, B2, B3 in addition to the I have the comparison treatment and got the symbol B0. As for the second factor, it included three levels of phosphorous mineral fertilization of 25%, 50% and 75% of the fertilizer recommendation, in addition to the comparison treatment that took the symbol F0, F1, F2, F3 sequentially. The results of the study showed the following: (1)Inoculation with phosphorous-dissolving bacterial isolates led to a significant increase in the number of phosphorous-dissolving bacteria, with a higher average of 106.6×Cfu 106.gm soil-1 compared to treatment B0 (without addition) by the effect of treatment B3 (mixing the two species Pseudomonas putida and pseudomonas fluorescens). (2) Bio-inoculation led to a significant increase in the ready phosphorous in the soil, and the highest average effect of treatment B3 was (40.10,17.88) mg/kg soil-1 for the control treatment B0 sequentially.

Формування сіяних лучних фітоценозів Передкарпаття залежно від удобрення

Goal. To reveal the peculiarities of the formation of elements of the productivity of perennial grasses in hay-type grass mixtures depending on the level of mineral fertilization. Methods. Field — to establish the level of productivity of the grass stand; visual and weight — to establish phenological changes in the growth, development, and productivity of the grass stand; statistical methods, dispersion, and factorial — to determine the probability of data. Results. The reaction of leguminous grass mixtures to the complex action of phosphoric-potassium and nitrogen fertilizers and complex microelements in the chelated form of microfol combi, which was used for foliar feeding of grasses was determined. For sowing, mixtures of perennial grasses were used, consisting of meadow timothy (6 kg/ha) and clover (16 kg/ha), meadow timothy (4 kg/ha), ryegrass (6 kg/ha), fenugreek (6 kg/ha). kg/ha), meadow clover (3 kg/ha), and horned lotus (3 kg/ha). Conclusions. The highest yield of dry matter (9.08 t/ha) was formed by sowing meadow clover, horned lotus, and a mixture of grasses (meadow timothy, perennial fenugreek). In the case of sowing meadow timothy with meadow clover on a similar agricultural background, the yield of dry matter was 8.56 t/ha. In the timothy-clover grass mixture, the share of meadow clover in the crop remained on average over the years of use of the grass stand at the level of 28.5; 28.6; 23.2; 22.7, and 17.0% in green mass. In a five-component mixture (meadow timothy, ryegrass, perennial fenugreek, meadow clover, lotus), the share of meadow clover in the formation of the grass stand was only 13.8–15.4%. The content of the lotus on average over four years of use was 11.3–22.8% in green mass.

The usage of different fertilizer type in same soil character ization improvements in Tikrit

This study included the effected of using different types of organic fertilizer in some soil chemical characterization productivity of okra plant. The experiment were designed according (R.C.B.D), with three replicates by using fertilizers remnants of cows and poultry, sludge were used. Three levels(10,20,40) ton/hectare were used in comparison with different levels of mineral fertilizer (150+115+115), (230+230+300), (460+460+600) Kg/hectare .This treatment resulted in reduction of soil organic materials, which approached 2.53% as compared with organic fertilizers and increased, phosphorus and potassium levels. While the sludge treatment increased organic material ,phosphorus and potassium over 40 ton/hectare, as well as in an increase in the plant chlorophil contents. This increase was approximately 3.52mg/g. In overall comparison between the various fertilizers, the sludge produced equal effect with the different mineral fertilizers levels.

Влияние основных приемов и способов возделывания ярового ячменя на площадь ассимиляционной поверхности и индекс листовой поверхности посевов в почвенно-климатических условиях Курской области

Purpose: to determine the influence of the cultivar, seeding rate and application of mineral fertilizers when cultivating spring barley on the assimilation surface area of one plant and the leaf surface index of crops according to the crop growth phases in the soil and climatic conditions of Kursk region. Materials and methods. The studies were conducted in 2022 and 2023 in the field experience at Federal Agricultural Kursk Research Center in grain-fallow crop rotation. The experimental scheme includes the study of three cultivars – Suzdalets, Prometheus, Despina. The second factor is seeding rates: 3, 4, 5, 6 million units of viable seeds per 1 ha. The third factor is the levels of mineral fertilization: control without fertilizers and N₃₀P₃₀K₃₀. Results. It was found that the assimilation surface area of one spring barley plant in the seedling stage depended to a greater extent on the cultivar (by 40 %), and it also increased under the influence of mineral fertilization (by 16 %). The leaf area index of spring barley in the seedling stage depended by 89 % on the seeding rate. During the tillering stage, the leaf area depended by 72 % on the year conditions. Research during the crop blooming stage revealed that the main factor influencing the assimilation surface area and leaf area index was the year of study (31 and 44 %, respectively), the cultivar factor provided 23 and 27 % of the indicator variation, respectively, and the mineral fertilization – 20 and 30 %, respectively. During the milk-ripe stage, due to the leaves dying off, a decrease in the photosynthetic parameters of spring barley is observed. Conclusion. It has been determined that the assimilation surface area of one plant and the leaf area index are very dynamic indicators and largely depend on the year of research, the cultivar and the mineral fertilization. During the initial period of crop growth, the leaf area index is affected by the seed application rate.

Response of Different Physiochemical Parameters of Wheat Genotypes (Triticum aestivum L. & Triticum durum L.) in Nutrient Stress Condition

Nitrogen management strategies during plant growth period are based on chlorophyll content of plant photosynthesis efficiency. This study is aimed to determine the impact of different nitrogen and phosphorus fertilizer rates on the dynamics of chlorophyll content in winter wheat varieties during vegetative and flowering stage to determine the relationship between nitrogen and phosphorus on chlorophyll content in different winter wheat varieties. Field trial involving nine winter wheat (TriticumaestivumL.) varieties. The treatments were T1=Control, T2=100% (N+P+K) T3= 50% N+ 100% (P+K), T4 =50%P+100%N+K.The results of the trial shown that the maximum chlorophyll content in different wheat varieties was observed at the end of flowering stage. The chlorophyll content depended on the level of mineral fertilization. The highest chlorophyll content in leaves, stem and ears was obtained by using normal recommended doses. By using chlorophyll meter Yara N-tester recorded the highest chlorophyll content in all analyzed plant parts in one year trial. Nitrogen and phosphorus fertilization significantly affected chlorophyll content, SPAD value and photosynthesis rates in leaves. Nitrogen and phosphorus fertilization had an important effect on chlorophyll content, SPAD and leaf photosynthesis rates.
 Aims: The genotypes with high photosynthetic rate and chlorophyll content characteristics identified in this study could be applied to conventional breeding efforts to more effectively exploit the constrained ecosystem whichminimize environmental impacts.
 Place and Duration of Study: This experiment was carried out during 2019-20 at subtropical region of India.
 Methodology: In this experimentPhotosynthetic rate was measured by Photosynthesis system (LICOR 6400) at 55 and 85 DAS. The measurement was taken in the morning hours (8 to 11 AM) in the leaf of wheat crop. The results were expressed inμmol m−2 s−1.SPAD meter reading was measured at 90 DAS. SPAD reading was taken in the morning and evening hours on the leaf of wheat varieties in each plot.A method described by Richardson et al. [1] was used for measuring leaf chlorophyll content at 65 and 85 DAS. Leaf samples were collected and washed with distilled water to eliminate dust. The leaf samples (0.25 g) were pulverised and centrifuged with 3 ML of DMSO. The absorbance of the supernatant was measured at 645 and 663 nm by the help of spectrophotometer to compute the total chlorophyll content.
 Results: Among the nine wheat varietiesAt 55 DAS, G 366 had highest photosynthetic rate (33.50μmol m−2 s−1) followed by NARMADA14 (33.45 μmol m−2 s−1) and at 85 DAS, HI1531had highest Ps rate (32.60 μmol m−2 s−1). Under normal dose of N, SPAD readings were higher in variety NARMADA14 (48.40), followed by HI8713 (47.70).
 Conclusion: Among all the wheat varieties tested, the variety HI 8713 had considerably higher dry weight, leaf area, biomass, grain yield, chlorophyll content, SPAD value and the maximum chlorophyll content was found in optimum dose on N and P plot.HI8737 shows optimum chlorophyll content in nutrient deficient condition.

Maize crop response to different levels of mineral and or-ganomineral fertilization associated with plant growth promoting bacteria (PGPBs)

Corn has a high nutritional requirement, especially with regard to NPK fertilization. However, the low efficiency of conventional fertilizers combined with the high cost of the input has limited the reach of high yields. The use of fertilizers with increased efficiency seeks to mitigate these limitations, reducing potential losses due to the gradual release of nutrients. The objective of this work was to compare the nutrition, growth and production of maize plants subjected to different doses and special NPK fertilizers fully applied at planting, as well as their residual effect on the soil. A randomized block design was used, in a 3 x 4 factorial scheme, with four replications. The first factor consisted of conventional mineral, polymer coated and organomineral fertilizers inoculated with PGPBs. The second factor was doses of 0, 60, 90 and 120 kg ha-¹ of NPK. Vegetative growth, foliar nutrition (N, P and K), yield growth components, productivity, profitability and P and K nutrient content remaining in the soil after cultivation were evaluated. The conventional mineral fertilizer presented higher production of dry biomass of the aerial part and profitability in relation to the special fertilizers. However, the special fertilizers presented better results in the vegetative and productive growth, in general, still showing a potential reduction of the applied doses, without compromising the grain yield, especially in the organomineral fertilization + PGPBs. The same showed greater residual effect of K in the soil, proving to be relevant longterm studies for better elucidation of these effects in the soil and subsequent culture.

Response of two soybean (Glycine max L.) cultivars to different levels of humic acid and mineral fertilization

Response of two soybean (Glycine max L.) cultivars to different levels of humic acid and mineral fertilization

Modeling sorghum-cowpea intercropping for a site in the savannah zone of Mali: Strengths and weaknesses of the Stics model

Intercropping is a key entry point for sustainable intensification of cropping systems in sub-Saharan Africa where variable rainfall conditions prevail. Crop simulation models can complement field experiments to assess the agronomic and environmental performances of intercropping systems under diverse climatic conditions, including hypothetical future climate. So far, crop models that can handle intercropping, such as STICS, have not often been extensively evaluated for tropical conditions and for species grown by farmers in sub-Saharan Africa. The objective of this study was to evaluate the performance of the calibrated STICS model to simulate sorghum-cowpea intercropping systems in rainfed conditions in West Africa. We used data from field experiments conducted at the N'Tarla Agronomic Station in Mali in 2017 and 2018. Two varieties of sorghum (local and improved) with contrasting photoperiod sensitivities were grown as sole crop and intercropped with cowpea, with additive design. Two sowing dates and two levels of mineral fertilization were also investigated. Model simulations were evaluated with observed data for phenology, leaf area index (LAI), aboveground biomass, grain yield and in-season soil moisture. Large variations in aboveground biomass of sorghum and cowpea was observed in the experiment (i.e. 3.5 – 9.6 t/ha for sorghum and 0.4–2.5 t/ha for cowpea), owing to the treatments (i.e. sole vs intercrop, early vs late sowing, no fertilizer input vs fertilizer input). Such variations were satisfactorily reproduced by the model, with EF of 0.81 in calibration and 0.58 in evaluation (with relative rRMSE of 23 % and 43 %) across crops. Sorghum AGB simulations were more accurate (rRMSE of 21 % and EF of 0.54) than cowpea AGB simulations (rRMSE of 25 % and EF of −0.09). The two main observed features of the intercropping system were well reproduced by the model. Firstly, cowpea and sorghum aboveground biomass decreased with intercropping compared with sole cropping, and the decrease in cowpea biomass was greater than the decrease in sorghum biomass. Secondly, despite a reduction in sorghum and cowpea yield, Land Equivalent Ratio of the intercropping for aboveground biomass was always above one. With regard to grain yield, observed LER was above one only in the non-fertilized treatment. The model failed at reproducing this behavior, probably because of insufficiently accurate calibration of the process leading to grain yield formation: rRMSE for grain yield was 49 % in calibration and 41 % in evaluation. Based on these findings, we discuss avenues to improve model calibration and use the model to explore options for sustainable intensification in land constrained sub-Saharan Africa. • Accurate STICS simulations of intercropped sorghum and cowpea aboveground biomass. • Inaccurate STICS simulations of intercropped sorghum and cowpea grain yield. • The model can be used to start exploring inter-annual performance of intercropping. • Experiments looking at N dynamics in intercropping needed to refine calibration.