Doses Of Nitrogen Fertilizer Research Articles

The influence of nitrogen nutrition on the formation of the balance of nutrients in the agrocenosis of winter wheat

Аim. To study the influence of doses and methods of applying nitrogen fertilizers on the peculiarities of the use and balance of nutrients in the agrocenosis of winter wheat and to form a paradigm of an ecologically balanced fertilization system on leached chernozem. Меthods. Short-term field and analytical. Results. For the first time, under the conditions of sufficient moisture in the Forest Steppe of Ukraine, for the cultivation of winter wheat on leached chernozem, a fertilization system that forms a balanced balance of nutrients in the soil and ensures a grain yield of more than 6.5 t/ha has been substantiated. It was established that with a biological harvest, winter wheat takes the most nitrogen from the soil at the ratio N:P:K = 2.7:1:1.9. It was found that the formation of a balanced nitrogen balance in the soil depended mainly on the doses of nitrogen fertilizers and did not depend on the methods of their application. The potassium balance significantly depended on the removal of straw from the field and the doses of potash fertilizers, the phosphorus balance – on the doses of phosphorus fertilizers. Conclusions. Nitrogen was removed by plants mainly as part of grain yield, potassium – as part of by-products. In the control without fertilizers, removal of nitrogen by grain (4.77 t/ha) was 94 kg/ha, phosphorus – 33, potassium – 25, straw (5.35 t / ha) – 26, 10 and 57 kg/ha, respectively. The most ecologically stable fertilization system was that anticipated leaving winter wheat straw on the field and applying mineral fertilizers in a dose of N110Р60K60, where 60 kg / ha of nitrogen as ammonium sulfate was applied on the frozen soil surface, 30 kg/ha as ammonium nitrate on the soil surface or as urea foliarly in the phase of emergence into the tube (IVth stage of organogenesis) and 20 kg/ha as urea foliarly in the phase of milk-wax maturity (VIIIth stage of organogenesis) on the background of P60K60 applied under deep plowing. Under such conditions, an almost balanced balance of nutrients was achieved in the soil with nitrogen deficiency – 20–22 kg/ha and the accumulation of phosphorus and potassium reserves in the amount of 14–15 and 24 kg/ha, respectively. Obtaining a grain yield of more than 6.5 t/ha based on sustainability requires the application of mineral fertilizers in the dose of N130Р50K40 and under the condition that winter wheat straw remains on the field. In the case of removal of straw from the field, a deficiency of nitrogen and potassium was formed in the soil in the amount of 62–64 and 63 kg/ha with a balanced phosphorus balance, which is evidence of an ecologically unstable fertilization system.

The Effect of Different Nitrogen and Phosphorus Fertilizer Doses on the Herbage Yield and Quality Properties of Atriplex nitens Schkuhr

Alternatif yem bitkisi olarak tercih edilen Selvi sirken (Atriplex nitens Schkuhr) bitkisinde ot verim ve kalite değerleri üzerine gübreleme konusu ile ilgili öncesinde yürütülmüş bir çalışmaya rastlanılmamıştır. Mevcut çalışma ile fosfor (0, 5, 10, 15 kg da-1) ve azotlu (0, 5, 10, 15 kg da-1) gübre dozları kombinasyon halinde uygulanarak, dal sayısı, ana sap kalınlığı, bitki boyu, ham protein oranı, yaş ot ve kuru ot verimi, ham protein verimi, asit çözücülerde çözünmeyen lif (ADF) oranı, nötr çözücülerde çözünemeyen lif oranı (NDF) ve nispi yem değeri (NYD) üzerine etkisi belirlenmeye çalışılmıştır. Bu amaçla 2020 yılında Iğdır Üniversitesi Tarımsal Uygulama ve Araştırma Merkez Müdürlüğüne ait sulu deneme arazisinde tesadüf bloklarında faktöriyel düzenlemeye göre üç tekerrürlü bir çalışma planlanmıştır. Analiz sonuçları sadece fosforlu gübre dozları ve ikili interaksiyonun (ADF ve NYD) incelenen parametreler üzerine önemli bir etkisinin olduğunu göstermiştir. Araştırma sonucunda fosforlu gübre dozu arttıkça verim unsurlarının arttığı, kalite değerlerinin ise düştüğü görülmüştür. Buna göre dekara 15 kg saf fosforlu gübre uygulamalarından en yüksek yaş ot verimi (17379.6 kg da-1), kuru ot verimi (4899.3 kg da-1) ve ham protein verimlerinin (427.15 kg da-1) elde edildiği saptanmıştır. İkili interaksiyon açısından ise en düşük ADF içeriği (%38.87) ve en yüksek NYD (94.22) sırasıyla N10P5 ve N15P0 uygulamalarından elde edilmiştir. Sonuç olarak Selvi sirken bitkisinin azotlu gübrelemeye tepkisinin bulunmadığı ancak fosforlu gübrelemeye tepkisinin yüksek olduğu ortaya konmuştur.

Effect of Nitrogen Levels on Growth, Yield Attributes and Yield of Hybrid Varieties of Rice (Oryza sativa L.)

A field experiment was conducted to evaluate the effect of different Nitrogen levels on the yield performance of four rice hybrid in two consecutive Monsoon Season of 2020 and 2021. The experiment was conducted at Agronomy Research Farm, Acharya Narendra Deva University of Agriculture and Technology, Kumarganj Ayodhya (U.P.). The experiment was conducted in factorial randomized block design with three replication which comprised of 4 levels of nitrogen viz. 0% RDN, 50% RDN, 75% RDN and 100% RDN and 4 hybrid varieties viz. Arize-6444 Gold, Ankur-7576, 27P31 and Shahi-Dawat. Results revealed that significantly higher yield contributing characters and yield was obtained at 100% of RDN (150 kg N ha-1) which is at par with 75 % RDN (112 kg N ha-1) and significantly superior over 0% of RDN and 50% of RDN (75kg N ha-1). The growth parameters, yield attributes and yield were recorded significantly higher with Ankur-7576 variety except length of panicle (cm) and test weight (g). Ankur-7576 gave good response in low doses of nitrogenous fertilizer and showed good efficiency in utilization of available and applied nitrogen to the crop and best suitable for obtaining higher yield of hybrid rice.

Effect of Nitrogen Fertilization in the Sour Cherry Orchard on Soil Enzymatic Activities, Microbial Population, and Fruit Quality

Sour cherry (Prunus cerasus L.) is one of the most important fruit crops in Poland and ‘Łutówka’ is the dominant cultivar in commercial orchards. The experiment was carried out in 2007–2013 in three orchards; in each of them, three levels of fertilization were applied: 0 N kg ha−1, 60 kg N ha−1, and 120 kg N ha−1. The activity of dehydrogenase and protease in the soil was studied depending on nitrogen fertilization. The abundance of soil microorganisms was assessed: bacteria, fungi, actinomycetes, and nitrogenous bacteria (Azospirillum and Azotobacter) in the years during the experiments carried out with fertilization of 60 kg N ha−1 in all orchards. The enzyme activity of dehydrogenases increased after the use of 60 kg N ha−1 from 3.8 to 6.7 (cm3 H2 24 h−1 kg−1 DW soil), but a further increase in the dose to 120 kg N ha−1 caused a decrease in activity to 5.1 (cm3 H2 24 h−1 kg−1 DW soil). The activity of proteases was dependent on nitrogen fertilization, but to a large extent it was related to the course of climatic conditions. There is no relationship between the growth and the activity of proteases. The yield and selected quality parameters of the cherry fruits were associated with both dehydrogenases and proteases. The use of lower doses of nitrogen fertilizers allows for maintaining biological balance in the soil and a more efficient use of nutrients, contributing to less environmental pollution.

Pengaruh Intensitas Radiasi Matahari Dan Pemberian Pupuk Nitrogen Terhadap Pertumbuhan Tanaman Sawi Putih (Brassica pekinensia L. Var. Belona F1)

This study aims to determine of knowing the effect of the intensity of sun radiation and the right nitrogen fertilizer on the growth of the highest chinese cabbage. The research has been carried out in Wirogunan Village, Kec. Purworejo Pasuruan City was conducted from September to December 2021. This study used a Divided Plot Design (RPT) which was repeated three times. The intensity of sun radiation is placed as the main plot (P) which consists of three levels: : 55% sun radiation intensity, : 65% sun radiation intensity, : 75% sun radiation intensity. Nitrogen fertilizer doses were placed as subplots (J) which consisted of three levels: : Nitrogen fertilizer dose 200 kg ha-1, : Nitrogen fertilizer dose 300 kg ha-1, : Nitrogen fertilizer dose of 400 kg ha-1. From the two treatments, 9 treatment combinations were obtained and each treatment was repeated three times to obtain 27 treatment combination units. The results showed that the treatment of 65% sun radiation intensity and nitrogen fertilizer 300 kg ha-1 resulted in the highest plant growth and yield. Chinese cabbage treatment with 65% sun radiation intensity and nitrogen fertilizer 300 kg ha-1 resulted in fresh weight ha-1 of 53,61 tons.

Growth and photosynthetic pigments of passion fruit (Passiflora edulis) seedlings under foliar fertilization with nitrogen and irrigated with saline water

In the semiarid region of Brazil, salts found in water used in irrigation. The objective of was to analyze the influence of foliar fertilization with nitrogen as a mitigation of the salt stress of passion fruit seedlings. The design was randomized blocks, with the treatments generated from the Box’s Central Composite matrix, with five electrical conductivities of irrigation water (ECw) (0.50; 0.98; 2.15; 3.32; 3.80 dS m-1) and five doses of foliar nitrogen fertilization (0.0; 0.30; 1.15; 1.97; 2.30 g L-1), with four replicates. The growth and photosynthetic pigments were evaluated Application of nitrogen doses attenuated the effect of salinity on morphophysiological aspects of passion fruit seedlings. The increase in the salinity of the water caused negative effects on the characteristics the growth and photosynthetic pigments

Arbuscular mycorrhiza alters the nutritional requirements in Salvia miltiorrhiza and low nitrogen enhances the mycorrhizal efficiency

Salvia miltiorrhiza Bunge (danshen in Chinese) is one of the most important medicinal cash crops in China. Previously, we showed that arbuscular mycorrhizal fungi (AMF) can promote S. miltiorrhiza growth and the accumulation of bioactive compounds. Fertilization may affect mycorrhizal efficiency, and appropriate doses of phosphate (P) and nitrogen (N) fertilizers are key factors for obtaining mycorrhizal benefits. However, the optimal fertilization amount for mycorrhizal S. miltiorrhiza remains unclear. In this study, we studied the effects of AMF on the growth and bioactive compounds of S. miltiorrhiza under different doses (low, medium, and high) of P and N fertilizer. The results showed that the mycorrhizal growth response (MGR) and mycorrhizal response of bioactive compounds (MBC) decreased gradually with increasing P addition. Application of a low (N25) dose of N fertilizer significantly increased the MGR of mycorrhizal S. miltiorrhiza, and a medium (N50) dose of N fertilizer significantly increased the MBC of phenolic acids, but decreased the MBC of tanshinones. Our results also showed that the existence of arbuscular mycorrhiza changes nutrient requirement pattern of S. miltiorrhiza. P is the limiting nutrient of non-mycorrhizal plants whereas N is the limiting nutrient of mycorrhizal plants.

Effects of manure combined with nitrogen fertilizer on yield and quality of winter wheat and soil biological characteristics in drylands of Northwest China

We conducted an experiment with five treatments in winter wheat of the dryland of Northwest China, i.e. 30 t·hm-2 cow dung (M) plus different doses of nitrogen fertilizer (0, 75, 150, 225, and 300 kg N·hm-2), denoted by M+N0, M+N75, M+N150, M+N225, and M+N300, respectively. After three years of treatment, wheat yield, grain quality, and soil biological characteristics were measured in two consecutive years (2018 and 2019). The results showed that the combination of manure with nitrogen fertilizer significantly increased wheat yield compared with the manure-only treatment (M+N0). Compared with the manure-only treatment, the combined treatments significantly increased wheat grain protein content, wet gluten, sedimentation value, and extensibility, but not for starch content. Neither wheat yield nor grain quality had significant differences among the M+N150, M+N225, and M+N300 treatments, but both were prominently higher than those of M+N75. Soil microbial biomass carbon (MBC) and nitrogen (MBN) reached highest in M+N150 for both years, which were distinctly higher than those of M+N0, M+N225, and M+N300. In 2018, soil β-1, 4-glucosidase, cellobiohydrolase, L-leucine aminopeptidase, β-1,4-N-acetyl glucosaminidase, and alkaline phosphatase activities in M+N150 treatment were higher than those of other treatments. In 2019, soil enzyme activities (excluding L-leucine aminopeptidase) in M+N150 were higher than those of M+N0 and M+N225. MBC significantly positively correlated with MBN, and both significantly positively correlated with the activities of cellobiohydrolase, β-1, 4-N-acetyl glucosaminidase, and alkaline phosphatase. MBN significantly positively correlated with total nitrogen content and negatively correlated with NO3-. Considering winter wheat yield, grain quality, and soil biological characteristics, M+N150 was conducive to sustainable production of winter wheat in drylands of Northwest China.

Structural and production characteristics and nutritive value of two tropical grasses submitted to different levels of nitrogen

The objective of this study was to evaluate increasing levels of nitrogen on and production and nutritive value of Andropogon and Massai grasses under the edaphoclimatic conditions of the Brazil denominated Middle Nort Region. The design used was completely randomized, with sixteen replicatios. The treatments consisted of nitrogen rates: 0, 150, 300, 450 and 600 kg N ha-1 and two forages, which were evaluated independently. The grasses used were Panicum maximum cv. Massai and Andropogon gayanus cv. Kunth. For Andropogon grass, there was an effect of nitrogen fertilization on thecharacteristics: leaf elongation rate, stem elongation rate, leaf senescence rate and leaf blade final length and, in all cases, the behavior was quadratic. Nitrogen also influenced the morphogenic characteristics: leaf appearance rate, leaf elongation rate, leaf senescence rate, phyllochron, leaf blade final length, number of live leaves per tiller and It was not significant for tiller population density of Massai grass, but the behavior varied according to the characteristic, in which leaf appearance rate and number of live leaves per tiller had decreasing linear behavior, while in phyllochron it increased linearly as nitrogen doses increased. Most of the productive characteristics of the grasses had increasing linear behavior (total biomass production of forage, leaf biomass and stem biomass in Andropogon grass, while in Massai grass, only the total forage production and dead material accumulation had an increasing linear behavior with increase of N doses. Quadratic effect only for masai leaf biomass behavior and there was practically no production of stems, affecting the leaf-stem ratio ) while the highest efficiency of nitrogen utilization was achieved with the application of 150 kg N ha-1 for the two grasses. Nitrogen fertilization also favored the nutritive value of the two grasses positively, with linear increase for crude protein and mineral matter contents, only in Massai, and reduction in the contents of neutral detergent fiber, acid detergent fiber and hemicellulose of grasses. Increasing doses of nitrogen fertilization favors the production, structure and chemical composition of the two grasses. However, the highest efficiency of use is obtained with the application of 150 kg N ha-1.

Effects of nitrogen and potassium levels on growth and quality of pot-planted vicks cultivars (Plectranthus hadiensis var. tomentosu (Benth. ex E. Mey.) Codd) in Ho Chi Minh City

The study was conducted to determine the suitable dosages of nitrogen and potassium fertilizer for growth, quality and economic efficiency of Plectranthus hadiensis pot–planted. The experiment was carried out from April to June 2021 in the experiment field of faculty of Agronomy, Nong Lam University, Ho Chi Minh City. A two-factorial experiment was carried out in a completely randomized design (CRD) in three replications. The treatments consisted of 3 doses of nitrogen fertilizer (0.50; 1.00 (control) and 2.00 g N/pot) and 4 doses of potassium fertilizer (0.25; 0.50; 1.00 (control) and 2.00 g K2O/pot) in combinations. The results indicated that plants supplied with 0.50 g N/pot and 1.00 g K2O/pot gave the best results in terms of plant height (16.70 cm), stem diameter (5.45 mm), number of primary branches (10.09 branches/ plant), canopy diameter (20.37 cm), number of leaves (201.04 leaves/plant), leaf length and width (35.06 and 24.13 mm), duration on vase life (40.00 days), commercial pot ratio (94.67%). The revenue was 29,933 thousand VND per 1000 pots with the highest profit margin of 1.33 times at 60 days after planting.

The Growth and Yield of The Radishes (Raphanus Sativus L.) to doses of nitrogen fertilizer and Potassium fertilizer

The Radish (rhaphanus sativus l.) is a horticultural plant that enters into the bulbous bulbous variety. Radishproductivity has always decreased by 2.16%, although in 2016 its productivity increased by 0.11% but it was still lower inproduction (Agricultural Statistics Center, 2017). The low production of turnips is caused by highlanders and few problemsof fertilizing them. One attempt to improve the production of focused turnips on growing them at higher altitudes byexpanding areas where turnips are grown in lowland. A lowland area utilization effort to cultivate turnips by addingnitrogenous macro nutrients and potassium. Nitrogen plays a role as a chlorophyil compiler that is highly responsible for thephotosynthesis of plants and photosynthesizers secreted (Pahlevi, et. 2016). Potassium fertilizers themselves play a vital rolein sustaining turnips, durability of drought and disease pests. Aside from cultivating the use of varieties is something to takenote of in raising turnips. Superior varieties can provide the maximum yield by the growth of good plants. The experimentaims to identify the interaction of nitrogen and potassium fertilizer against the growth and horseradish yields (raphanussativus l.) The giving of the dose of nitrogen fertilizer used is N0 = 0 gr, N2 = 0.8 gr, N3 = 1 gr and potassium fertilizer doseis K0 = 0 gr, K1 = 0.2 gr, K2 = 0.4 gr, K3 = 0.6 gr. Data obtained subsequently was analyzed and tested using DuncanDMRT surplus 5%. Studies indicate that the best combination of treatment was that of a dose of n3 fertilizer treatment = 1 gr,and potassium k3 = 0,6 gr

Optimization of nitrogen nutrition in increasing the productivity of sugar beet

Purpose. Investigate the effect of doses and methods of applying nitrogen fertilizers on the productivity of sugar beets after plowing in for fertilizer of winter wheat straw.
 Methods. Short-term field and analytical.
 Results. The results of research on the effect of doses of nitrogen fertilizers applied in spring under pre-sowing cultivation over the background of straw and mineral fertilizers applied under plowing on the productivity of sugar beet are given. The yield of sugar beet, sugar content in roots and biological productivity of crop under the use of alternative organic-mineral fertilizations were determined.
 Conclusions. It was established that alternative organic-mineral fertilizations significantly increased the biological productivity of sugar beet. Application of mineral fertilizers in autumn under deep plowing in a dose of N90Р90К90 against a background of 5 t/ha of straw was determined to be less biologically productive: the yield of roots – 49.9 t/ha, sugar harvest – 8.73 t/ha, exceeding the control without fertilizers by 8.7 and 1.56 t/ha, respectively. The application of N90 in pre-sowing cultivation against the background of 5 t/ha of straw + P90K90 under plowing was determined to be the most optimal for sugar beet: root yield – 55.8 t/ha, sugar harvest – 9.71 t/ha, exceeding the control without fertilizers by 14.6 and 2.54 t/ha, respectively. Increasing the nitrogen dose in the spring by more than 90 kg/ha was not accompanied by a significant increase in yield, reduced the sugar content in roots, and therefore was ineffective.

Effect of different doses of nitrogen fertilizer on growth and yield of T. Aman rice variety (BRRI Hybrid Dhan4)

Effect of different doses of nitrogen fertilizer on growth and yield of T. Aman rice variety (BRRI Hybrid Dhan4)

Characterization and QTL identification in eggplant introgression lines under two N fertilization levels

Lowering nitrogen inputs is a major goal for sustainable agriculture. In the present study, a set of 10 Solanum melongena introgression lines (ILs) developed using Solanumincanum as the exotic donor parent were grown under two nitrogen fertilization doses supplied with the irrigation system: 1) 8.25 mmol · L−1 NH4NO3, corresponding to the high nitrogen treatment (HN), and 2) no external nitrogen supply, corresponding to the low nitrogen treatment (LN). Twenty traits, including plant growth and yield parameters, fruit size and morphology, nitrogen and carbon content in leaf and fruit, and phenolics content in fruit, were evaluated. The aim was to select of potential materials for eggplant breeding under low N inputs, as well as to identify and locate putative QTLs associated with the traits evaluated. No significant differences were observed between the soil characteristics of the HN and LN treatments, except for nitrogen and iron content, which was slightly lower in the HN, probably as a consequence of higher nutrient removal from soil by plants in the latter group. Analysis of variance showed that lowering nitrogen inputs did not significantly affect the final yield, fruit morphology, size and phenolics content. Most agronomic traits were highly and positively correlated with each other under both treatments, as well as total phenolics with chlorogenic acid content. The assessment of the differences between each IL and the recipient parent resulted in the identification of 36 QTLs associated with most of the traits—12 were specific to the HN, 17 specific to the LN, and 7 were stable across treatments. The introgressed fragment of S. incanum generally had a negative effect on the trait, except for QTLs for fruit dry matter, for fruit length on chromosome 10 under the HN, and for fruit pedicel length on chromosome 9 under the LN. The increase over AN-S-26 of the allele of S. incanum for the QTLs detected ranged between −73.98% and 26.03% in HN and −73.67% and 34.43% in LN. These findings provide useful tools for the utilization of S. incanum in eggplant breeding under lower nitrogen fertilization.

Aplikasi Pupuk Hayati Bakteri Endofitik Penambat N2 dan Pupuk N untuk Meningkatkan Pertumbuhan Tanaman Jagung (zea mays l.) Pada Ultisols Kentrong

Corn cultivation on Ultisols is limited due to low nitrogen content of the soil. Efforts to increase the N content in the soil include the use of biofertilizers by symbiotic nitrogen-fixing endophytic bacteria. This study assesed various combination of nitrogen fertilizer doses and N2-fixing endophytic biofertilizer to increase the growth of maize in Ultisols Kentrong. The experiment was conducted at the Ciparanje Experimental Greenhouse, Faculty of Agriculture, Universitas Padjadjaran, Jatinangor. A randomized block design was used which consisted of 16 treatments with 3 replications, with a combination of doses of urea fertilizer and endophytic biofertilizer applied to seeds or planting holes. The experimental results showed that the combination of urea fertilizer and biofertilizer doses had a significant effect on the population of endophytic bacteria in the roots and leaves of corn plants, plant wet weight, root dry weight and shoot dry weight, plant height, stem diameter, plant nitrogen uptake and content of plants but was not significantly affected on the number of corn leaves. Combination of 80 kg ha-1 urea fertilizer and 3.6 kg ha-1 of biofertilizer was the best combination which increased the dry weight of the corn plant and reduced the dose of urea fertilizer

THE IMPACT OF MULTIPLE DOSES OF NITROGEN FERTILIZERS ON THE GROWTH AND DEVELOPMENT OF YOUNG PLANTS OF CATALON VARIETY HAZELNUT

The article presents the results of studies, carried out in 2020–2021 in the commercial hazelnut orchard planted in 2018 by LLC “Vyazovetsky Sad”, Molodechno district, Minsk region. The purpose of the studies is to examine the impact and highlight the nitrogen fertilizer application system that optimizes the growth and development of young hazelnut plants Catalon varieties, planted according to two patterns of placement. It was revealed as a result of the study, that the additional application of nitrogen fertilizers at a dose of 60 and 120 kg a. e. had an impact on the growth rates of hazelnut plants – the area and total increase in the cross-sectional area of the bole, biometric parameters and the area of the leaf surface of plants were significantly larger compared to the control variant. In total, over 2 years of research, higher yield was noted in the variants of applying increased doses of nitrogen fertilizers, however, the highest yield was obtained in the variant of nitrogen application at a dose of 120 kg a. e.: with a planting pattern of 5.0 × 3.5 m – by 128.4 % (3.61 c/ha), with a planting pattern of 5.0 × 3.0 m – i.e. 49.2 % (3.18 c/ha) more than in the control variant.

Plant Stress and Allelotoxicity of Soils.

Stress exposures during vegetation are known to reduce the yield in crops, but the intensity and duration of stress is rather difficult to determine from the crop loss. Allelotoxins are released from plants into soil on exposure to stress factors. Soil allelotoxicity after vegetation was assumed to provide a diagnostic parameter that characterizes the total stress effect on crops. To verify the assumption, changes in soil allelotoxicity were studied after vegetation of three winter wheat cultivars fed with different amounts of nitrogen fertilizers. The cultivars Nemchinovskaya 85, Moskovskaya 39, and Lutescens 982/08 were found to differently respond to fertilizing. Nemchinovskaya 85 and Lutescens 982/08 showed lower stress responses at higher doses of nitrogen fertilizers, while their responses were appreciable when soil nitrogen was lacking. In the case of Moskovskaya 39, higher doses of nitrogen fertilizers caused an adverse reaction of increased allelotoxin release. Stepwise nitrogen fertilization was concluded to be necessary for preventing delayed plant development in the case of this cultivar. The results confirmed that soil allelotoxicity measured growing plants can serve as an indicator of stress caused by the growth conditions and use of various agricultural techniques.

Effect of nitrogen and potassium fertilizers on melon plant productivity

The objective of this investigation was to evaluate the effect of different doses of nitrogen and potassium fertilizers on some production parameters of melon plants. The experiment was carried out in San Roque, which is 24 km from the city of Concepción, Paraguay, at the coordinates 57°14´10.29´´ South and 23°19´12.05´´ West. The study design was the completely randomized block with three replications in a split plot scheme 4 x 4. The dose used in the main plot was of N (0, 50, 100 and 150 kg ha-1) and in the sub-plot, K (0, 95, 190 and 285 kg ha-1). A light harrow was carried out to prepare the soil, seedlings were produced in 1500 cm3 pots of 60-micron thickness and the transplant was carried out when the seedlings had between 4 and 6 true leaves at 30 days after planting. Urea with 45% N was used as the source of nitrogen and potassium chloride 60% was used as the source of potassium. Fertilisation was carried out in September 2017 on two occasions: at 15 and 30 days after transplanting. The spacing used was of 1.5 m between rows and 1.5 m between plants, giving a total of 4356 plants ha-1. Harvesting began 90 days after planting and was carried out three times as the fruits reached commercial ripeness. The variables that were measured were average fruit weight (AFW), total soluble solids (TSS), polar diameter (PD), equatorial diameter (ED), fruit weight per plant (FWP). The data of the evaluated variables were subjected to the analysis of variance using the Fisher test where significant differences were found in: AFW, TSS, PD, ED and FWP. Subsequently, the regression analysis was performed (AFW, TSS and PD) and response surface (ED and FWP). The dose combination that produced the best values for equatorial diameter and fruit weight per plant was 71.9495 kg ha-1 of N and 160.554 kg ha-1 of K, 77.5921 kg ha-1 of N and 147.369 kg ha-1 of K, respectively. Key words: Cucumis melo L., fertilizer application, nitrogen, potassium, dose, weight, diameter, productivity

Nutrient uptake and yield of rice (Oryza sativa) applied with mycorrhizal fungi using different doses of nitrogen and phosphorus fertilizers

Rainfed rice fields in general often lack water and nutrients that are difficult for their roots to reach. The Vesicular Arbuscular Mycorrhiza (VAM) fungus can assist in absorbing water and nutrients to increase the efficiency of nitrogen and phosphorus fertilizers. The purpose of this study was to determine the uptake of N, P, and K nutrients and the yield of rainfed lowland rice applied with VAM at different doses of N and P. This study was conducted in rainfed rice fields in Demangan, Central Java, Indonesia, during 2019. This research was laid out in completely randomized block design with two factors and three replications. The first factor was nitrogen with a dose of 0, 45, 90, and 135 kg/ha, while the second factor was phosphorus at 0, 25, 50, and 75 kg/ha. The results showed that VAM could increase the uptake of nitrogen, phosphorus, and potassium and increase yield using N and P fertilizers at 90 kg/ha and 75 kg/ha, respectively. This research shows that the use of N and P fertilizers at 90 kg/ha and 75 kg/ha, respectively, is sufficient to cultivate rainfed rice applied with mycorrhizal fungi. Based on the discussion, it can be concluded that the application of mycorrhizae is beneficial in rainfed rice cultivation because it can suppress the use of N and P fertilizers by increasing the uptake of N, P and K nutrients and increasing yields. In addition, in rice cultivation in rainfed rice fields, it is better to use mycorrhizae.

Estimating the optimum dose of nitrogen fertilizer with climatic conditions on improving Boro rice (Oryza sativa) yield using DSSAT-Rice crop model

This study was conducted at Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh using the DSSAT-Rice crop model for estimating the nitrogen fertilizer dose of the rice varieties BRRI dhan 28, BRRI dhan 29 and BR16. Three different varieties such as CL448, Basmati-515 and KS-282 were used to calibrate the model. The research used 2 years (2020–2021) weather data and soil data of different layers (0–60 cm). Four different nitrogen fertilizer treatments i.e., nitrogen (N) @ 50 kg/ha; N @ 100 kg/ha; and N @ 150 kg/ha along with control (no nitrogen) were used for running the simulation process. Result showed that BRRI dhan 29 was the best performed variety and the yield was 6000 kg/ha @ 150 kg/ha N fertilizer treatment. In addition, 1:1 graph showed highest simulated grain yield observed 6050 kg/ha with 150kg/ha N fertilizer treatment for BRRI dhan 29. RMSE, nRMSE and d stat values showed tiller number, grain weight, leaf area index and harvest index had excellent performance with the simulated data for the 150 kg N fertilizer treatments. The study revealed that DSSAT crop model could be useful to estimate optimum N dose to obtain the best variety with climate changing.