NPK Compound Research Articles

Растеж и минерален състав на тютюн Виржиния в отговор на минерално торене и биостимуланти

The influence of mineral fertilization and two biostimulants (microbial inoculant Mycoplant® and protein hydrolysate (PH) Trainer®) on the growth and mineral composition of Virginia tobacco was studied in field and pot experiments on Rendzic Leptosol. The seedlings of the conventional technology (manure+mineral nitrogen fertilizer) had the highest weight and the highest concentration of N and Ca in the above-ground biomass. Biostimulants also had a positive effect on plant weight and the concentration of macro- and micronutrients. Microbial inoculant Mycoplant and PH Trainer increased seedling weight (fresh and dry) by 16.8% - 22.5% and 8% - 12%, respectively, compared to the manure treatment. The microbial inoculant containing AM fungi increased seedling N, P and Mg concentration by 8%, 9% and 13%, respectively, compared to manure treatment. The concentrations of Fe, Mn, Zn and Cu also increased when Mycoplant was applied. The application of a PH-based biostimulant Trainer resulted in higher concentration of N (by 11%) and Mg (by 4%) in seedlings. Leaf area and leaf weight (pot experiment) were positively affected by compound fertilizer application. Biostimulants Mycoplant and Trainer had a weaker positive effect on these indicators. The application of compound NPK fertilizer significantly increased the concentration of N, P and K in the leaves. Biostimulants also improved the uptake of essential nutrients by tobacco plants. The microbial inoculant significantly increased the concentration of Fe in the leaves - by 25.5% compared to the control. The concentration of N was increased by 14.3% when PH Trainer was applied.

Response of Carnation (Dianthus caryophyllus) to NPK Compound Fertilizer and Cormo Seaweed Extract: Effects on Vegetative and Flowering Growth, Volatile Oil Quality, and Active Compounds Analyzed by GC-MS

Response of Carnation (Dianthus caryophyllus) to NPK Compound Fertilizer and Cormo Seaweed Extract: Effects on Vegetative and Flowering Growth, Volatile Oil Quality, and Active Compounds Analyzed by GC-MS

Effect of Liquid and Single Compound NPK Fertilizer on Soil and Plant Nitrogen Content and Yield of Sweet Corn (Zea mays L. Saccharata) in Inceptisols of Jatinangor

Effect of Liquid and Single Compound NPK Fertilizer on Soil and Plant Nitrogen Content and Yield of Sweet Corn (Zea mays L. Saccharata) in Inceptisols of Jatinangor

Use of biochar and NPK fertilizer in soybean cultivation in Alfisol to improve soil physical properties and plant growth

Abstract The decrease in soil properties due to using artificial fertilizers requires finding a solution, one of which is using biochar. This research aims to assess the effect of the application of rice husk biochar and NPK compound fertilizer on the physical properties of Alfisols and soybean growth. The study was conducted from March to June 2023 on Alfisol of Kwangsan Village, Jumapolo, using a Randomized Complete Block Design (RCBD) with 10 treatments and 3 replications. The study showed that combining rice husk biochar and NPK compound fertilizer improved soil physical properties: soil C-Organic levels, field capacity, soil porosity, and soil water retention levels, and reduced soil bulk weight. The treatments also increased soybean growth: plant height, number of leaves and branches. Application of 25% NPK compound fertilizer (75kg ha-1) and 100% rice husk biochar (10 tons ha-1) is suggested to progress soil physical properties and soybean plant development in Alfisols.

Effectiveness of NPK compound (15-15-6) fertilizer to improve maize performance in inceptisol soil

Producer of fertilizer mandatory to carry out fertilizer effectiveness tests before their products were marketed, because the results of fertilizer effectiveness tests was determined by the Ministry of Agriculture to protect consumers from adverse impacts due to the use of fertilizer. The purpose of this study was to determine the effect of NPK compound (15-15-6) fertilizer to improve maize performance. The study was conducted Keling Village, Kepung Subdistrict, Kediri Regency, East Java Province, since January - April 2019. The study used RBD with 6 treatments and 4 replications, namely A = control, B = SFD, C = 300 kg Urea ha−1 + 50 kg SP-36 ha−1 + 200 kg NPK 15-15-6 ha−1, D = 300 kg Urea ha−1 + 50 kg SP-36 ha−1 + 300 kg NPK 15-15-6 ha−1, E = 250 Urea ha−1 + 400 kg NPK 15-15-6 ha−1, and F = 200 Urea ha−1 + 500 kg NPK 15-15-6 ha−1. The results showed that treatment F obtained of 8.35 t.ha−1, R/C-ratio 2,65, RAE value 137.38%, and the profite farming IDR. 21,850,000 per hectare.

The Effect of NPK fertilization on Adlay or Hanjeli (Coix lacryma-jobi L.), an alternatif forage crop

This study aims to determine the effect of compound NPK fertilizer 15-15-15 on the growth and yield of hanjeli plants as animal feed for livestock. It was conducted using polybags from October to December 2021, located at the Screenhouse of the Agrotechnology Study Program, Faculty of Agriculture, Musamus University. The study was designed in a randomized block design consisting of four fertilizer treatments with four replications. Each experimental unit contained six plant populations, and all were used as sample plants. The four applied treatments were as follows: without fertilization (P0), NPK fertilizer five g/polybag (P1), NPK fertilizer ten g/polybag (P2), and NPK fertilizer fifteen g/polybag (P3). The research results showed that fertilization affected plant height, leaf count, and stem diameter, but it did not affect germination power, tillers, and plant stove. Fertilization with a dosage of fifteen g/polybag (P3) resulted in the best growth and yield variables for all observations. The fresh harvest produced ranged from 0.73 kg to 0.96 kg per polybag.

Consequential LCA of NPK fertilizers from microbial, animal, plant, and mineral origin highlights resource constraints and environmental impacts

The production and use of mineral fertilizers lead to severe environmental impacts, therefore initiatives such as the European Green Deal promote organic farming and nutrient circularity. However, many organic fertilizers (those containing organic carbon and nutrients of exclusively biological origin) face constraints due to resource availability, and it is paramount to understand their environmental impacts to prevent unforeseen effects. This study employed a consequential life cycle assessment (LCA) to compare the environmental impact of mineral fertilizer to three types of organic fertilizers: animal-, plant-, and innovative microbe-based, considering market constraints and marginal suppliers. Organic fertilizers were complemented with mineral products to yield NPK compound fertilizers containing 1 t of nitrogen, 0.44 t of phosphorus, and 0.83 t of potassium (multi-substance functional unit). The findings reveal that 9 out of the 17 studied organic fertilizers are constained products, and that their demand is met through the supply of mineral fertilizers, soybean meal, and maize or barley grain. Consequently, for the transition to a circular and organic agrifood system, the focus should shift toward untapped resources like microbial fertilizers sourced from food and beverage industry wastewater, and sewage sludge. Constrained markets vary with time and geographical location, emphasizing the importance of context-specific decision-making. The impact of mineral fertilizers is relatively low across impact categories, but the gap between them and energy-intensive organic fertilizers narrows in an industrial symbiosis scenario where waste heat is available. An additional assessment of soil organic carbon estimated the contribution of organic fertilizers to the “4 per 1000" initiative's goal for soil carbon storage. Organic fertilizer application alone only achieves this goal in one scenario (rapeseed meal), but combining it with other management practices like crop rotation offers a promising strategy. The scenario that included fertilizer transport showed the potential for reduced environmental impacts by applying locally available by-products as organic fertilizer instead of imported mineral fertilizers. Overall, the results call for caution when transitioning from mineral to organic fertilizers as their availability and environmental impact are not self-evident.

Dampak Pemberian Green manure Dan Pupuk Phonska Terhadap Perkembangan Dan Hasil Tanaman Jagung Manis (Zea mays Saccarata L.)

This study aims to evaluate how green manure applied with Chromolaena odorata and Gliricidia sepium leaves, along with NPK compound fertilizer (phonska), affects the growth and yield of sweet corn (Zea mays saccharata L.). Conducted in Telaga Kodok, Central Maluku, from September to November 2022, the experiment utilized factorial design with varying doses of green manure (0, 10, and 20 tons per hectare) and phonska fertilizer (0%, 50%, and 100% of the recommended dose). Observed parameters included plant height, leaf count, leaf area, leaf area index, cob length, cob weight with husk, cob weight without husk, and cob diameter. The results of the ANOVA analysis indicate that both factors and their interaction significantly influence sweet corn's growth and yield parameters. It is recommended to apply 20 tons of green manure per hectare and 100% phonska dose to achieve optimal results, considering parameters such as plant height, leaf count, leaf area, cob length, cob weight with and without husk, and cob diameter. By enhancing sweet corn productivity, supporting food security, and promoting sustainable agricultural sector growth, this research significantly contributes to optimizing the use of organic and inorganic fertilizers.

Coastal Acid-Sulfate Soils of Kalimantan, Indonesia, for Food Security: Characteristics, Management, and Future Directions

Coastal acid-sulfate soils are crucial for producing crops and thus, for food security. However, over time, these soil resources experience degradation, leading to higher agro-input, lower yields, and environmental hazards that finally threaten food security. The optimal use of this fragile resource is only attained by implementing vigorous integrated water–soil–crop management technologies amid the climate change impact. This study aimed to review the distribution, properties, use, and management of acid-sulfate soils in Kalimantan, Indonesia. Acid-sulfate soils cover about 3.5 Mha of the coastal area in Kalimantan and have high acidity, high-risk iron and aluminum toxicity, and low fertility, requiring precise water management, amelioration and fertilizer application, crop variety selection, and rice cultivation technologies. Lime, biochar, organic fertilizer, compost, ash, and fly ash are ameliorants that raise pH, reduce iron and aluminum toxicity, and improve crop yield. Rice cultivation has developed from traditional to modern but needs re-designing to fit local conditions. Depending on the soil nutrient status, rice cultivation requires 80–200 kg ha−1 of urea, 50–150 kg ha−1 of SP36, 50–150 kg ha−1 of KCl, and 125–400 kg ha−1 of NPK compound fertilizer, but is affected by CH4 and CO2 emissions. Good water management impacts the effective implementation of amelioration and fertilizer application technologies. The remaining challenges and future directions for water management, amelioration, fertilizer application, crop varieties, cultivation techniques, land use optimization, climate change adaptation and mitigation, technology adoption and implementation, and resource conservation are outlined. Acid-sulfate soils remain a resource capital that supports food security regionally and nationally in Indonesia.

Compression Strength and Critical Impact Speed of Typical Fertilizer Grains

The application of fertilizer is necessary for the growth and yield of crops, especially for paddy rice. Precision application is important for the fertilizer utilization rate and sustainable development of agriculture. However, the crushing of fertilizer grains will reduce the quality of fertilization, for the decrease in the size and mass of the fertilizer particles and the degree of crushing mainly depend on the physical and mechanical properties of the fertilizer grains. In this study, the compression strength and critical impact speed of four typical commonly used fertilizer grains, a compound fertilizer of nitrogen, phosphorus, and potassium (NPK compound fertilizer), organic fertilizer, large granular urea, and small granular urea, were measured and analyzed. The static compression test was carried out using a TMS-Pro texture analyzer and the results show that the four kinds of fertilizer grains are brittle materials, and their elastic moduli are 208 MPa, 233 MPa, 140 MPa, and 107 MPa, respectively; the theoretical impact model of fertilizer granules is established based on the compression test result and Hertz elastic contact theory, the theoretical formula for the critical impact speed of fertilizer grains is derived, and the theoretical critical impact strength and speed are worked out. An image capture system for the impact process of fertilizer grains was developed, and the impact test was conducted. The results show that the critical impact speed of the four kinds of fertilizer grains decreases with the increase in granule size, while the variance analysis shows that the effect is not significant. The comparison of the experimental results with the theoretical values shows that the theoretical formula could be used to predict the trends of the critical impact speed of fertilizer grains. The model was optimized with the MATLAB 2018 function fitting tool based on the test and analysis. The goodness of fit of the formula is 0.824, which is 13.43% greater than that of the original theoretical formula, indicating that the modified formula based on the compression test data might estimate the critical impact speed of the granular fertilizer with brittle material properties more accurately. The results may provide a reference for the parameter design of a precision fertilization machine.

Minimizing Carbon Dioxide Emissions with Clinoptilolite Zeolite in Moris Pineapple Cultivation on Drained Sapric Soils

Drained tropical peat soils for agriculture emit more carbon dioxide (CO2) into the atmosphere from their stored carbon compared with their pristine state. Field and laboratory experiments were conducted to assess whether the natural zeolite of the clinoptilolite (ZeoC) species could be included in the pineapple fertilization program to decrease the CO2 emissions from tropical sapric soils. The static closed-chamber and laboratory incubation methods were used to determine the effects of ZeoC on the CO2 emitted from a drained sapric soil planted with Moris pineapple. The treatments assessed were as follows: (a) suggested ratio of ZeoC (5 g, 10 g, 14 g, and 20 g of ZeoC) and 20 g compound NPK 30:1:32 fertilizer, enumerated based on the pineapple plant requirement; (b) 20 g of compound NPK 30:1:32 fertilizer only; and (c) unfertilized sapric soils. The drained sapric soils amended with ZeoC (rate of 5 g to 20 g/plant) minimized the CO2 emissions compared with those without the ZeoC, because of the physical and chemical sorption of organic compounds and polar CO2 onto the lattices of ZeoC, which inhibited organic matter decomposition. ZeoC fertilization reduces sapric soil acidity and improves Moris pineapple fruit quality attributes and yield. Monthly pineapple fertilization with ZeoC at the vegetative and flowering phases is an alternative agronomic strategy to reduce CO2 emissions. This approach does not reduce pineapple yield on drained tropical sapric soils.

Status Hara Nitrogen, Fosfor, dan Kalium pada Lahan Sawah di Desa Savana Jaya Kecamatan Waeapo Kabupaten Buru

is research aims to study nutrients status of N, P, and K in Savana Jaya Village, District of Waeapo, Buru Regency. This research was descriptive and using survey method in the field. Soil samples were composited taken from 5 subsites with 25 m distance from sampling center point. Respondents were selected by using a purposive sampling method, and production data was collected by interviewing farmers. The results showed that the total N status in the Savana Jaya village was low (0,10-0,12%) to very low (0,09%), total P status was moderate (23-38 mg/100 g) to very high (68 mg/100 g), and total K status was low (10-13 mg/100 g) to moderate (30 mg/100 g). The proposed balanced-fertilizer management to support rice fields in the study area is site-specific nutrient management (PHSP) using NPK compound fertilizers combined with urea, Ponsta and Pelangi fertilizers based on nutrients and soil fertility status in the study area, including adding lime to increase soil pH, adding petrorganic organic matter to increase soil C-Organic and soil CEC.

Effect of Zeolite Levels and Foliar Feeding with NPK Nano Fertilizer on some Soil Chemical Properties and Grain Yield of Wheat (Triticum aestivum L.)

This study aims to demonstrate the effect of zeolite levels and foliar feeding with NPK nano fertilizer on some soil chemical properties and grain yield of wheat (Triticum aestivum L.), a field experiment was carried out during the winter agricultural season (2020-2021) in a sandy mixture of soil at the Agricultural Research and Experiments Station of the College of Agriculture, Al-Muthanna University at Al Bandar field (which is 3 km away from the city of Samawah). The study aimed at the effect of three levels of zeolite (0, 0.5 and 1) kg m 2 by volume, symbolized by Z1, Z0 and Z2, respectively, and six levels of NPK for the addition of ground and nano, spraying on the leaves in two stages at the branching and flowering, which are (0, 0.25 from the fertilizer recommendation +800 gm ha-1 nano-NPK, 0.50 from the fertilizer recommendation +800 gm h-1 nano-NPK, 0.75 from the fertilizer recommendation +800 gm h-1 NPK Nano, Recommended Ground Fertilizer Only and Recommended Nano Fertilizer Only 1600 gm ha-1), its symbols were F4, F3, F2, F1, F0 and F5 respectively in the availability of N, P and K uptake in the plant and grain of the wheat crop, the experiment was carried out by designing split plot by Randomized Complete Block Design (R.C.B.D). Wheat seeds were sown, type (Bohooth 22) on 11/11/2020. The results of the experiment showed that the addition of zeolite led to the improvement of some chemical properties of the soil, that the level Z2 achieved a significant superiority in raising the values of the concentrations of NPK elements available in the soil at the flowering and harvest stages, the compound NPK nano fertilizer had a significant effect on the chemical properties, as the levels F4 and F5 achieved the highest averages in the concentration of NPK available in the soil at. The two combinations (Z2F4) and (Z2F5) achieved significant superiority in the characteristics of nitrogen, phosphorous and potassium concentrations in the soil at flowering, and phosphorous and potassium in the soil at harvest.

Optimizing Tomato Plant Growth and Yield through Innovative Fertilizer Combinations: A Factorial Group Random Design Approach

This study employed a rigorous Factorial Group Random Design (RAK) method to investigate the synergistic effects of Liquid Complementary Fertilizer (PPC) and NPK Compound Fertilizer on the growth and yield of tomato plants. The research consisted of two key factors: PPC with four dosage levels (control, 3 g/L, 6 g/L, and 9 g/L of water) and NPK Compound Fertilizer with four levels (control, 200 kg/ha, 400 kg/ha, and 600 kg/ha) - all replicated three times. Data on critical plant parameters such as height, leaf count, flower abundance, and fruit production were meticulously gathered and analyzed. Remarkably, the combined application of PPC and NPK exhibited significant enhancements in both growth and yield, surpassing the effects observed from individual applications. Our findings highlight the immense potential of this innovative fertilizer combination in revolutionizing tomato crop production, offering a promising avenue for farmers to meet agricultural demands efficiently.
 Highlights:
 
 Utilized a robust Factorial Group Random Design (RAK) methodology to examine the impact of PPC and NPK Compound Fertilizer on tomato plant growth and yield.
 Investigated various dosage levels of PPC and NPK, each replicated three times for precise data analysis.
 The synergistic effects of the combined application outperformed individual applications, showcasing a promising approach to optimize tomato crop production.

Effect of Humic Acid and NPK Nanocomposite on the Chemical Content of Fronds of Three Cultivars of Young Palm Trees Phoenix Dactylifera L.

To investigate the impact of adding organic acid (humic acid) and spraying, the experiment was carried out in the palm grove at the Agricultural Research and Experiment Station at the Sayada site of the College of Agriculture/University of Kirkuk/Republic of Iraq from 6/15/2022 to 4/15/2023. Three different types of date palms received the NPK compound fertilizer treatment. Al-Khastawi, Al-Khaddrawy, and the yellow Shwathi. Three replications of the factorial experiment were conducted using the RCBD and split plot designs, respectively. Duncan's multiple limit test was used to assess the data at the probability level (0.05). The interaction treatment between the treatment and the treated variety T5V2 (NPK nanocomposite fertilizer and the Khestawi variety) was superior in the percentage of the wicker content of carbohydrates, nitrogen, and chlorophyll, reaching (8.19%), 2.02% 30.33 mg gm -1 fresh weight) respectively. The concentration of (1.5 g liter-1) of NPK nanocomposite fertilizer (T5) affected all the studied chemical properties. The yellow Shuwathi cultivar outperformed the Khastawi and Khadrawi cultivars in the treatment of T5V1 (nano compound fertilizer NPK). The percentage of phosphorus and potassium in the vine reached (0.97, 0.91%), respectively. Wicker's potassium content as a percentage reached 0.74%.

Moderate organic fertilizer substitution for partial chemical fertilizer improved soil microbial carbon source utilization and bacterial community composition in rain-fed wheat fields: current year.

Organic fertilizers can partially replace chemical fertilizers to improve agricultural production and reduce negative environmental impacts. To study the effect of organic fertilizer on soil microbial carbon source utilization and bacterial community composition in the field of rain-fed wheat, we conducted a field experiment from 2016 to 2017 in a completely randomized block design with four treatments: the control with 100% NPK compound fertilizer (N: P2O5: K2O = 20:10:10) of 750 kg/ha (CK), a combination of 60% NPK compound fertilizer with organic fertilizer of 150 kg/ha (FO1), 300 kg/ha (FO2), and 450 kg/ha (FO3), respectively. We investigated the yield, soil property, the utilization of 31 carbon sources by soil microbes, soil bacterial community composition, and function prediction at the maturation stage. The results showed that (1) compared with CK, organic fertilizer substitution treatments improved ear number per hectare (13%-26%), grain numbers per spike (8%-14%), 1000-grain weight (7%-9%), and yield (3%-7%). Organic fertilizer substitution treatments increased the total nitrogen, available nitrogen, available phosphorus, and soil organic matter contents by 26%, 102%, 12%, and 26%, respectively, compared with CK treatments. Organic fertilizer substitution treatments significantly advanced the partial productivity of fertilizers. (2) Carbohydrates and amino acids were found to be the most sensitive carbon sources for soil microorganisms in different treatments. Particularly for FO3 treatment, the utilization of β-Methyl D-Glucoside, L-Asparagine acid, and glycogen by soil microorganisms was higher than other treatments and positively correlated with soil nutrients and wheat yield. (3) Compared with CK, organic fertilizer substitution treatments increased the relative abundance of Proteobacteria, Acidobacteria, and Gemmatimonadetes and decreased the relative abundance of Actinobacteria and Firmicutes. Interestingly, FO3 treatment improved the relative abundance of Nitrosovibrio, Kaistobacter, Balneimonas, Skermanella, Pseudomonas, and Burkholderia belonging to Proteobacteria and significantly boosted the relative abundance of function gene K02433 [the aspartyl-tRNA (Asn)/glutamyl-tRNA (Gln)]. Based on the abovementioned findings, we suggest FO3 as the most appropriate organic substitution method in rain-fed wheat fields.

Effect of adding chemical, organic fertilizers and spraying seaweed extracts on the availability of NPK and organic material in calcareous soil

A field experiment was carried out in the agricultural season 2021-2022 in one of the farming fields in the region of Muqdadiya, Al-Harouniya district, located 40 km northeast of Baquba district of Diyala governorate. (Soil Survey Staff, 2006). It is located at a longitude of 53° 34' N and latitude of 56° 04° 45° S. The experiment aimed to study the effect of adding chemical and organic fertilizers and spraying seaweed extracts on NPKS concentrations and cauliflower yield. The investigation included three factors; the first factor was the addition of organic fertilizer (buffalo waste) at three levels (0, 5 and 10%) of the terrace size, which M1, M2 and M3 respectively symbolize. It was added at a depth of 0-30 cm a month before planting the seedlings in the field. The second factor was the addition of NPK compound chemical fertilizer (20:20:20) at two levels (0 and the full fertilizer recommendation is 300 kg H-1 when planted as a feed) and symbolized by C1 and C2, respectively. The third factor is spraying seaweed extract with three levels (0, 2 and 4) ml L-1 represented by A1, A2 and A3. The experiment results showed that adding chemical fertilizer significantly affected the availability of organic material in the soil. The 2C treatment (and the full fertilizer recommendation of 300 kg H-1) outperformed and reached 2.96 gm kg-1; nitrogen availability in the soil amounted to 2.96 %. As well as the availability of phosphorous in the soil, which amounted to 76.28 mg P kg 1-soil, and potassium availability in the soil amounted to 76.28 %. The addition of buffalo manure to calcareous soils significantly affected the readiness of the organic material. Also, treatments M2 and M3 outperformed in soil with a value of 3.34 and 23. 4 g/kg-1, and nitrogen availability in soil amounted to 29.88 and 31.25 mg N kg-1-. The M3 treatment also excelled in the availability of phosphorous in soils, which amounted to 86.98 mg P kg-1-soil mg M kg-1-soil. The availability of potassium in the soil amounted to 361.33 %. The triple interaction between the studied factors significantly affected the availability of organic material in soils. The M2×C2×A3 treatment also excelled in recording the highest value, which was 3.85 gm kg-1, nitrogen availability in soil amounted to 37.75 %, phosphorous availability in soil amounted to 94.16 mg P kg-1 and potassium availability in soil amounted to 436.42 mg kg1-soil. Keywords: chemical fertilization, organic fertilization, seaweed extracts.

Effect of adding chemical and organic fertilizers and spraying seaweed extracts on NPKS concentrations and cauliflower yield

A field experiment was carried out in the agricultural season 2021-2022 in one of the agricultural fields in the Muqdadiya, Al-Harouniya district, located 40 km northeast of the Baquba district of Diyala governorate. The agrarian soil was classified as silty clay (Soil Survey Staff, 2006). It is located at a longitude of 53° 34’ N and latitude of 56° 04° 45° S. The experiment aimed to study the effect of adding chemical and organic fertilizers and spraying seaweed extracts on NPKS concentrations and cauliflower yield. The investigation included three factors: adding organic fertilizer (buffalo waste) at three levels (0, 5 and 10)% of the terrace’s size, symbolized by M1, M2 and 3M, respectively. It was added at a depth of 0-30 cm a month before planting the seedlings in the field. The second factor was the addition of NPK compound chemical fertilizer (20:20:20) at two levels (0 and the full fertilizer recommendation is 300 kg H-1 when planted as a feed) and symbolized by 1 C and 2 C, respectively. The third factor is spraying seaweed extract with three levels (0, 2 and 4) ml L-1 illustrated by A1, A2 and according to an RCBD randomized complete block design with three replications. The experiment results showed that adding organic fertilizer (10% of the size of the terrace) led to a significant increase in the head’s weight, reaching 1.611 kg. The results of the experiment showed that the addition of organic fertilizer (10% of the size of the terrace) led to a significant increase in the weight of the head, as it reached 1.611 kg plant-1, the sulfur concentration in the fruits was 2.00 mg sulfur kg-1, the nitrogen concentration in the leaves was 4.68%. The phosphorous concentration in the leaves was 25%, and the potassium concentration in the leaves was 2.05%; chemical fertilization also increased head weight from 1.385 kg. Plant-1 to 1,108 kg Plant-1.There was an increase in each of the sulfur concentrations in fruits from 2.00% to 1.53%, in the nitrogen concentration in the leaves from 4.60% to 3.48% and an increase in the phosphorous concentration in the leaves from 0.37% to 0.26% and an increase in the potassium concentration in the leaves from 2.78% to 2.27 %, spraying seaweed extracts at a concentration of 4 mmol. L-1 led to a significant increase in head weight, which reached 1.282 kg. Plant-1, nitrogen concentration in leaves 803% and potassium concentration in leaves 2.58%.As for the triple interaction .Keywords: chemical fertilization, organic fertilization, seaweed extracts, cauliflower.

Analisis Spesifisitas Terhadap Sensor NPK

Insufficient use of fertilizers results in non-optimal plant growth, while excessive use is wasteful and results in pollution. Sensor usage is one method for measuring the nutrient content in the soil so that the fertilization process can be carried out precisely. Accuracy, precision, and error are commonly used in analyzing sensor quality. But for chemical measurements, the specificity also needs to be analyzed. This is because the soil contains various types of nutrients, so it is necessary to know whether the readings from the sensor only come from the desired nutrients or the others. In this writing, the elements measured were N, P, and K which are nutrients needed by plants in large quantities. The sensors were tested using compounds containing N, P, or/and K elements and NPK fertilizers with different NPK ratios. Results of this study prove that the sensor is not specific as the readings are known to use the electroconductivity method as proved by the regression results between the two variables which have R² ≈ 1 correlation. In addition, the sensor also produces readings for elements/compounds that should not be read and cannot distinguish the ratio of types of compound NPK fertilizer with different types.

Azotobacter and Pseudomonas Population in Rhizosphere and Yield of Choy Sum following Chemical Fertilizer and Biofertilizer application

Inoculation of beneficial microbes is a way to improve the population of rhizobacteria that has a role in nutrient cycle and hence reduce the level of chemical fertilizer. A pot experiment was performed to evaluate the effect of and consortia biofertilizer combined with various dose of NPK compound fertilizer on the population of nitrogen-fixing Azotobacter sp. and phosphate solubilizing Pseudomonas sp. in rhizosphere and yield of choy sum (Brassica juncea L.). The experimental was setup in completely randomized block design consisted of ten combinations of various biofertilizer and inorganic fertilizer dose; and three replications. The results showed that Biofertilizer inoculation with or without chemical fertilizer did not improve the population of Azotobacter and Pseudomonas in the rhizosphere but increase the shoot weight of choy sum. Higher shoot weight was showed by crops with ¾ dose of NPK combined with recommended or reduced dose of fertilizer; and recommended dose of NPK and biofertilizer. This experiment verified that the used of consortia biofertilizer composed of Nitrogen-fixing bacteria and phosphate-solubilizing microbes reduced 50-75% dose of NPK.