Optimum Fertilizer Rate Research Articles

Current situation of nitrogen application and its effects on yield and quality of Chinese materia medica

Nitrogen fertilizer has been the long-lasting crucial component in cultivation of Chinese materia medica(CMM) and crops for its profound effects on enhancing the productivity. In consideration of its role in better production, intensive and excessive application of N fertilizer is often found in CMM cultivation. Therefore, firstly, this review summarized various concentrations of N application with regards to different CMM and districts from the literatures published in the last two decades. The recommended concentration of nitrogen application of forty seven CMM species were covered in this review. We found that the optimum rates of nitrogen fertili-zer for different medicinal plants species were varied in the range between 0-1 035.55 kg·hm~(-2). Most of the optimum rates of nitrogen fertilizer for CMM in published researches fell between 100-199 kg·hm~(-2). The optimum rate of nitrogen fertilizer is not only related to amount of nitrogen required for different medicinal plants but also to soil fertilities of different fields. In addition, we outlined the diffe-rent effects of proper and excessive nitrogen deposition on yield of CMM. Proper nitrogen deposition benefits the yield of CMM, howe-ver, excessive nitrogen use accounts for a decrease in CMM yield. We elucidated that nutritional content, water use efficiencies, and photosynthesis capacity were major influencing factors. Researches showed that proper nitrogen fertilizer could promote the water use efficiencies of plants and boost photosynthesis. Consequently, the yield of CMM can be enhanced after nitrogen deposition. However, negative effects of nitrogen fertilizer were also found on plant including producing toxic substances to the soil and causing severe pest damages. Lastly we analyzed the impact of N fertilizer application on secondary metabolites which accounts for a large part of active pharmaceutical ingredients of CMM. It usually caused an increase in nitrogen-containing secondary metabolites content and a decrease in non-nitrogen-containing secondary metabolites content respectively. The potential underlying mechanisms are the different synthetic pathways of these metabolites and the plant nutritional status. Synthesis of non-nitrogen-containing secondary metabolites like phenols can be inhibited after nitrogen application because of the competition of the same precursor substances between metabolites synthesis and plant growth. To sum up, impacts and mechanisms of nitrogen fertilizer on yield and quality enhancement of CMM were discussed in this review. Negative effects of excessive nitrogen application on CMM should be paid special attention in CMM cultivation and prescription fertilization based on the field soil quality is strongly recommended. Overall, this review aims to provides insights on improving the proper application of N fertilizer in the cultivation of CMM.

Influence of irrigation and fertilizer rate on changing the nutritional regime of mixed crops (sorghum and pea) soil on stubble

Relevance. The article quotes questions of the influence of fertilizer rates and the number of irrigations on the change in the nutrient regime of the soil when growing mixed crops of pea and sorgho in the conditions of the Karabakh zone of Azerbaijan. In this regard, one of the main issues considered was the development on a scientific and practical basis of the nature of changes in the nutrient regime of the soil and the effect of optimal fertilizer rates and the number of irrigations on crop yields in mixed crops in long-irrigated gray meadow soils.Methods. To study the effect of irrigation and fertilizer rates in mixed crops on changes in the nutrient regime of the soil, soil samples were taken from two soil layers (0-30 and 30-60 cm) after cutting. In the soil samples taken, compounds of nitrogen, phosphorus and potassium that are readily absorbed by plants were analyzed.Results. Analysis of soil samples shows that the application of mineral and organic fertilizers against the background of different amounts of irrigation fundamentally affects the effective fertility of the soil. In general, in the phase of flowering and panicle formation under the influence of irrigation and fertilizers, effective soil fertility was observed compared to the control variant without fertilizing, which remained at a sufficient amount. And this indicates that the plant showed a high demand for this nutrient. The decrease in the number of nutrients in the panicle formation phase indicates its connection with the removal of high yields. Analysis of soil samples during the study shows that the introduction of mineral and organic fertilizers against a background of varying amounts of irrigation has fundamentally affected the effective soil fertility.

Optimization rate of empty fruit bunch and NPK compound fertilizer for 4-years-old oil palm

Indonesia is the world’s largest producer of Crude Palm Oil (CPO), followed by Malaysia as the second producing country. CPO production of Indonesia and Malaysia reaches 80% of all world production. However, fertilizing empty fruit bunches should be combined with inorganic fertilizers. Empty fruit bunches of oil palm are waste from CPO processing, and the amount is very abundant. The use of empty bunches combined with compound NPK fertilizer is intended to increase the vegetative growth and support productivity. The purpose of this study is to determine the optimum rate of empty fruit bunches and NPK compounds. The research was conducted at the Teaching Farm of IPB-University, Jonggol, Bogor, from March 2016 to March 2017. The treatment consists of two factors, the first factor is the treatment of empty bunches (0, 50, 100, and 150 kg plant−1 year−1) and the second factor is NPK compound (0, 2, 4, and 6 kg of plant−1 year−1). The results of this study determined that the optimum rate of empty fruit bunches fertilizer is 128 kg palm−1, and the optimum rate of NPK compound fertilizer is 4.61 kg palm−1 for 4-year-old oil palm.

Effect of Silicon Application on Growth, Yield and Uptake of Rice (Oryza sativa L.) in Two Different Soils

Two pot experiments were conducted to study the effect of silicon application on growth, yield and uptake of rice plant, to observe the response of silicon fertilization in relation to two different soils and to evaluate the optimum rate of silicon fertilizer for rice production in each soil during dry and wet season, 2019 at Department of Soil and Water Science, YAU. The experiment was laid out in split plot design with four replications. The main plots were soil types; Shwebo and Yezin soils and sub plots were levels of silicon with Si 0, Si 100, Si 150, Si 200 and Si 250 kg·ha-1. Urea, T-super and Potash fertilizers were applied at recommended dose of DAR (85:12:31 kg·ha-1 NPK). The calcium silicate fertilizer was used as a silicon source. In dry season, Shwebo soil provided the higher tiller numbers, grain yield, straw yield and nutrient uptake than Yezin soil. In both seasons, panicle numbers per hill were higher in Shwebo soil and panicle length and spikelets per panicle were higher in Yezin soil. The effect of silicon application on grain yield and Si uptake was found in the second season. The maximum grain yield was achieved from the application of Si 250 kg·ha-1 which was not statistically different from the application of Si 200 kg·ha-1. According to this study, the application of Si 200 kg·ha-1 in combination with the recommended dose of NPK fertilizers could be used to give the optimum grain yield in two soils. Silicon uptake of rice was significantly increased by all the silicon levels compared to control in two soils. A significant interaction was not observed in all parameters in this study.

Effect of Blended Fertilizer and Lime Application Rates on Grain Yield and Yield Component of Maize (Zea <i>mays</i> L.) in Omo Nada District, Jimma Zone South-western, Ethiopia

Maize (Zea mays L.) is one of the important food security crops and play significant role in the live hood of most Ethiopians. However, yields are low primarily because of low soil fertility and use of inappropriate fertilizer rates. This study was therefore; conducted to determine optimum rates of blended fertilizer under limed and un limed condition of acid soil on Maize in Omo Nada District, Jimma Zone Southwestern, Ethiopia during 2017 main cropping season. The amount of lime that was applied at each location was calculated on the basis of the exchangeable acidity. The experiment used seven treatments; Control, NPS, NPSB, NPSB plus Recommended rate of Lime, NPSB plus 0.75* recommended rate of Lime, NPSB plus 0.50* recommended rate of Lime and NPSB plus 0.25 * recommended rate of lime were laid out in randomized complete block design (RCBD) replicated across seven farmers’ fields in each location. Application of lime was dramatically improved soil pH from 4.5 to 5.28. yield and yield components of Maize were significantly affected by integrated use of blended fertilizer and lime. Accordingly, Plant height, Grain Yield, Biomass Yield, Harvest Index and thousand kernel weight of Maize were obtained with application of NPSB plus recommended rate of Lime. Higher net return 15914 Ethiopia birr /ha with marginal rate of return of 557% of Maize was obtained with application of NPSB plus Recommended rate of Lime. Thus, integrated use of NPSB plus Recommended Lime is recommended for Maize production in acid soil of Omo Nada district and similar agro ecologies.

Effect of Blended NPS Fertilizer Rates on Dry Fruit Yield and Yield Components of Hot Pepper (<i>Capsicum annuum </i>L.) Varieties at Arba Minch, Southern Ethiopia

Hot pepper is one of the most important crops grown by smallholder farmers of Arba Minch Zuria district mainly for income generation. The dry fruit yield of the crop is very low in the district due to several production constraints of which the low accessibility of improved varieties and soil nutrient deficiency are among the major ones. Therefore, this experiment was conducted at Chano Mille Kebele, Arba Minch Zuria district of Southern Ethiopia during 2018/2019 cropping season to assess the effect of blended NPS fertilizer rates on growth, yield and yield components of hot pepper varieties and to determine optimum rate(s) of blended NPS fertilizer for hot pepper production for the study area. Six rates of blended NPS fertilizer (0, 50, 100, 150, 200 and 250 kg ha-1) and three hot pepper varieties (Bako Local, Mareko Fana and Melka Shote) were used as experimental treatments and laid-out in 3x6 factorial arrangement in Randomized Complete Block Design in three replications. The results revealed that the main effect of variety and rates of blended NPS fertilizer had a significant effect (P<0.05) on growth, yield and yield components of hot pepper. The interaction effect of variety and rates of blended NPS fertilizer significantly affected the yield and yield components of hot pepper but not growth parameters. Melka Shote variety showed better vegetative growth. Melka Shote and Bako Local at the application of 200 kg ha-1 blended NPS fertilizer produced large number of fruits plant-1 and seeds fruit-1, maximum fruit weight plant-1 and dry fruit yield without significant variation among the two treatment combinations. Regression analysis revealed that as application of blended NPS fertilizer increased by one kg, the total dry fruit yield of Bako Local, Mareko Fana and Melka Shote increased by 7.3, 6.2 and 8.6 kg, respectively. Melka Shote variety had dry fruit yield advantage of 1.3 and 2.4 kg over Bako Local and Mareko Fana, respectively, as the rates of blended NPS fertilizer increased by one kg. Thus, application of 200 kg ha-1 blended NPS fertilizer for Melka Shote and Bako Local varieties could be optimum and recommended to improve hot pepper productivity for the current soil fertility status of the study area and vicinity with similar soil fertility status and agro-ecology.

The main technological parameters of growing highly productive fodder crops on the drained lands of the humid zone of Ukraine

The most effective use of highly-productive crop species in fodder production and obtaining of sustainable yields of agricultural products is only possible when following scientifically sound technological processes of land reclamation in combination with a set of agronomic measures for their cultivation.&#x0D; The aim of the research is to develop the main technological parameters of growing highly productive fodder crops (Japanese millet, amaranth and fodder beans) on the drained lands in the humid zone of Ukraine.&#x0D; The results of research on determining the main technological parameters of growing highly-productive fodder crops (Japanese millet, amaranth and fodder beans) on drained lands are highlighted.&#x0D; It was specified that when cultivating these crops it is necessary to adhere to the optimal sowing dates taking into account the purpose of their use (green mass, grain). When they are sown too early there is a decrease in field seed germination and increase of germination period, thinning of crop plantings, intensive spread of weeds and also the probability of crops damage by spring frosts increases. When they are sown too late, especially in case of small-seeded crops (amaranth), drying of the top layer of soil is possible, which is unacceptable in the period of germination and emergence of seedlings. The most favorable conditions for the formation of herbage when cultivating on drained peat soils are formed when the crops are sown on May 15 (by 8.1–16.7% more of herbage and by 2.1–9.6% of dry matter is formed).&#x0D; The main technological parameters of cultivating Japanese millet, amaranth and fodder beans are determined, incl. by phases of development and taking into account the critical periods of their optimal moisture supply, agronomic measures and optimal fertilizer rates.&#x0D; The admissible terms in which the reclamation system should provide drainage of excess waters and the recommended levels of ground waters and the humidity rates in a soil root layer in the vegetative period at the crop cultivation were determined.&#x0D; It was specified that during the growing season the needs of Japanese millet, amaranth and fodder beans in moisture in the soil root layer change depending on their biological needs and current meteorological conditions. Soil moisture rates were specified as following: on peat soils the optimal one is 65–75%, the lowest permissible one in the summer period is 55–60%; on mineral soils, respectively - 65-80% and 55-60% of FMHC.&#x0D; It was established that modern climate change in the Western Polissya of Ukraine (uneven distribution of precipitation during the growing season, abnormal average daily air temperature fluctuations and low night air temperatures (˂10oС in summer months) have a negative impact on the cultivation of heat-loving crops (Japanese millet). In the context of climate change, it is necessary to provide for the accumulation of sufficient water volumes in storage tanks or reservoirs to supply them for irrigation of cultivated crops during dry growing seasons and to ensure optimal water regulation parameters.&#x0D; On radioactively contaminated reclaimed lands of the Chemerne peat-bog array with a rate of 137Cs radionuclide contamination of up to 1 Ki/km2, the contamination rates in the vegetative mass of Japanese millet, amaranth and fodder beans during the research years was within acceptable limits, so it can be used freely for feeding animals.

Sweet Orange Orchard Architecture Design, Fertilizer, and Irrigation Management Strategies under Huanglongbing-endemic Conditions in the Indian River Citrus District

The prevalence of Huanglongbing (HLB) in Florida has forced growers to search for new management strategies to optimize fruit yield in young orchards and enable earlier economic returns given the likelihood of HLB-induced yield reductions during later years. There has been considerable interest in modifying orchard architecture design and fertilizer and irrigation management practices as strategies for increasing profitability. Our objectives were to evaluate how different combinations of horticultural practices including tree density, fertilization methods, and irrigation systems affect growth, foliar nutrient content, fruit yield, and fruit quality of young ‘Valencia’ sweet orange [Citrus sinensis (L.) Osbeck] trees during the early years of production under HLB-endemic conditions. The study was conducted in Fort Pierce, FL, from 2014 to 2020 on a 1- to 7-year-old orchard and evaluated the following treatments: standard tree density (358 trees/ha) and controlled-release fertilizer with microsprinkler irrigation (STD_dry_MS), high tree density (955 trees/ha) with fertigation and microsprinkler irrigation (HDS_fert_MS), and high tree density with fertigation and double-line drip irrigation (HDS_fert_DD). Annual foliar nutrient concentrations were usually within or higher than the recommended ranges throughout the study, with a tendency for decreases in several nutrients over time regardless of treatment, suggesting all fertilization strategies adequately met the tree nutrient demand. During fruit-bearing years, canopy volume, on a per-tree basis, was higher under STD_dry_MS (6.2–7.2 m3) than HDS_fert_MS (4.3–5.3 m3) or HDS_fert_DD (4.9–5.9 m3); however, high tree density resulted in greater canopy volume on an area basis, which explained the 86% to 300% increase in fruit yield per ha that resulted in moving from standard to high tree density. Although fruit yields per ha were generally greatest under HDS_fert_MS and HDS_fert_DD, they were lower than the 10-year Florida state average (26.5 Mg·ha−1) for standard tree density orchards, possibly due to the HLB incidence and the rootstock chosen. Although tree growth parameters and foliar nutrient concentrations varied in response to treatments, management practices that included high tree density and fertigation irrespective of irrigation systems produced the highest fruit yields and highest yield of solids. Soluble solids content (SSC) and titratable acidity (TA) were lower, and the SSC-to-TA ratio was highest under STD_dry_MS in 2016–17, with no treatment effects on quality parameters detected in other years. Both drip and microsprinkler fertigation methods sufficiently met tree nutrient demand at high tree density, but additional research is needed to determine optimal fertilization rates and better rootstock cultivars in young high-density sweet orange orchards under HLB-endemic conditions in the Indian River Citrus District.

Responses of Cowpea to Phosphorous Application Rates and Row Spacing in the Sudan Savanna Zone of Nigeria

Field trials were conducted to evaluate the effects of rates of Phosphorus fertilizer and intra-row spacings on growth and yield of Cowpea (Vigna unguiculata (L.) Walp) in the Sudan Savana zone of Nigeria, during 2018 cropping season at Mohammet Lawan college of Agriculture, Maiduguri (110 50’ N, 130 10’ E, altitude 354 above sea level, altitude 354 above sea level. The experiment consisted of five (5) Phosphorus rates (0, 20, 40, 50 and 60 kg Pha-1) and five (5) intra-row spacings (15, 20, 25 30 and 35cm). The treatments were arranged in a split plot design and replicated three times at each site. Phosphorus rates were assigned to the main plot and intra-row spacings in the sub-plot. The objective was to determine the optimum rate of phosphorus fertilizer that will increase yield performance of cowpea in Sudan savanna zone of Nigeria and determine the most suitable intra-row spacing that will increase yield of cowpea in Sudan Savanna of Nigeria. Data were collected on plant height, number of leaves per plant, days to 50% flowering, number of grain per pod, 100 grain weight, grain yield per hectare and fodder yield per plant respectively. Application of P fertilizer significantly influenced most of the growth and yield characters as well as the yield. Grain yield per hectare were optimum at 50kg Pha-1 Contrary to above finding, number of grain per pod and 1000-grain were all not influenced by the application of P fertilizer and intra-row spacing.

Estimating Economically Optimal Levels of Nitrogen Fertilizer in No-Tillage Continuous Corn

AbstractStochastic plateau production functions provide improved fertilizer recommendations based on multi-year agronomic experiments where weather and other stochastic variables change over time. This research assesses the profitability of no-tillage corn production in northeastern Colorado and determines economically optimal nitrogen fertilizer rates. It also proposes an alternative parameterization of the linear response stochastic plateau model which provides a robustness check against traditional parameterizations. Results show the current use of nitrogen fertilizer in the area exceeds estimated economically optimal levels. This suggests that a reduction in nitrogen use could increase expected profits and simultaneously reduce environmental costs.

Application of Mitscherlich-Bray equation to formulate fertilizer recommendations for sweetpotato in Leyte, Philippines

Until now, no studies have been conducted in the Philippines on the use of the Mitscherlich-Bray equation to formulate NPK fertilizer recommendation for sweetpotato. This study used the Mitscherlich-Bray equation to formulate NPK requirements for sweetpotato. Independent experimental set-ups of N (7 application levels), P (6 levels), and K (9 levels) arranged in RCBD with three replications were simultaneously conducted. Theoretical maximum yield, NPK constants c, and c, NPK fertilizer recommendations for sweetpotato at different soil fertility levels, and optimum fertilizer rates were calculated. Fertilizer recommendations for a common range of soil test values were developed but needed further field verification trials. Theoretical maximum yields determined by the Mitscherlich-Bray equation were 19.05, 12.66, and 14.88t ha-1 for NPK, respectively. The study showed that inherent soil fertility is vital in the development of fertilizer recommendation for sweetpotato not only to increase root yield but likewise to increase overall productivity. It showed that 30, 50, and 60 percent of the maximum possible yield was attributed to the inherent soil N, P, and K, respectively. N, P2O5, and K2O recommendations for sweetpotato were computed based on a common range of soil test values ranging from 50 to 300, 5to 40, and 200 to 700kg ha1 NPK, respectively.

Determinants of smallholder farmers’ decisions on fertilizer use for cereal crops in the Ethiopian highlands

AbstractThis study identified decision variables influencing fertilizer adoption and optimal fertilizer rates among smallholder farmers in the Ethiopian highlands. The fertilizer adoption and fertilizer use were examined in four regional states using a questionnaire survey, which was administered to 2880 farm households. A double hurdle model was used to analyze factors influencing the two independent decisions of adoption of fertilizers and use of fertilizers. The model estimates of the first hurdle revealed that the probability of fertilizer adoption increased by 1.2% as household education status improved, by 1.4% for an increased number of active family members, by 5.6% with improved access to credit, by 3.4% with cooperative membership, by 3.3% with an increase in farm size, by 4.6% when soil and water conservation practices are employed, and by 3.4% when agroecology of the farm is located in the medium to highland zone. Conversely, the probability of fertilizer adoption reduced by 0.9% for an increase in family size, 0.6% with 1 km distance from all-weather road, 1.6% for a kilometer further to farm plots, and 0.9% for an increase in number of parcels. The intensity of use of fertilizers was influenced by education status of the household head, family size, access to credit, membership to cooperatives, use of crop rotation, annual income, number of farm plots owned, use of soil and water conservation, and agroecology. Therefore, a concerted effort is needed to encourage fertilizer adoption and optimum fertilizer use intensity by improving households’ resource endowment, institutional capacity to deliver services, and infrastructure development.

Optimum nitrogen rate to maintain sustainable potato production and improve nitrogen use efficiency at a regional scale in China. A meta-analysis

The great challenges of ensuring global food security and reducing environmental risk caused by excessive fertilizer inputs require optimizing fertilizer rates to maintain crop production and environmental sustainability. Previous results regarding optimizing N-fertilizer rate for potato were mainly based on case studies and lacked regional-scale information on N-fertilizer management. We hypothesized that regional optimum N rates would increase N use efficiency without sacrificing potato yield compared with low and high N rates. We determined the optimal N-fertilization rates for Chinese potato production at a regional scale based on a dataset of 706 observations from 142 peer-reviewed publications. The linear-plus-plateau model was used to estimate regional optimum N rates, which were 115, 150, 120, and 126 kg N ha−1 for the northern, central, southwestern, and southern regions of China, respectively. The target yield could be obtained by applying less N fertilizer when the indigenous N supply was higher across the main potato production region in China. Compared with high N rates, recommended N rates increased N use efficiency and agronomic efficiency by 48.60–81.67% and 17.12–72.90%, respectively, without any yield losses. Recommended N rates also achieved 5.95–14.70% greater yield than low N rates. Here, we show for the first time that, based on a comprehensive literature review, regional optimum N-fertilizer rates result in increased yield and N use efficiency, and reduced negative environmental impacts, all of which play a vital role in maintaining sustainable potato production. The present study highlights the importance of research for achieving a reasonable trade-off between food security and N-fertilizer management for sustainable agriculture.

PENGARUH DOSIS PUPUK ORGANIK CAIR TERHADAP PERTUMBUHAN DAN HASIL TANAMAN TERUNG (Solanum melongena L.)

This research aimed to know the effect and optimum rates of liquid organic fertilizer on the growth and yield of Eggplant. The research used Randomized Block Designconsisted of 5 rates of liquid organic fertilizer;(M0 = control/without fertilizers, M1 = 1 liters ha-1, M2 = 1 ha-2 litres, M3 = 3 liters ha-1, M4 = 4 liters ha-1). The observed variable is the height of plants, number and leaf area, length of fruit, fruit diameter, number of fruit, the weight of fruit per plant, weight of fruit per hectare, fresh residues per plant, and fresh residues per hectare and harvest index. The result of experiment showed the rates of liquid organic fertilizer effect on percentage of the growth and yield of eggplant; they are; height of plants(6,22%), leaf number (28,20%), leaf area (29,58%), length of eggplant (43,11%), eggplant diameter (9,00%), number of eggplant (22,03%), weight of eggplant per plant (25,62%), weight of eggplant per hectare (16,70%), fresh residues per plant (28,58%), residues per hectare (34,93%), and harvest index (53,91%). Optimum rates of liquid organic fertilizer which effect on the growth and yield of eggplant are about 4 litre ha-1.

Application of Taxonomic Classification in Soil Fertility Management Using Maize (&lt;i&gt;Zea mays &lt;/i&gt;L&lt;i&gt;.&lt;/i&gt;) as Test Crop in Alfisols of Makurdi, Benue State

The Alfisols of Makurdi Local Government Area of Benue State was studied with the aim to characterize and classify the soils and determine the optimum fertilizer rate for maize production on the selected soil type of the study area. The soils were formed on Makurdi sand stone, deep (141 cm) and well drained. They were coarse-textured and moderately acidic in reaction (pH 6.6 – 7.0). They had low organic carbon contents ranging from 3.36 to 3.78 % and high base saturation of 58.6 % to 77.4 %. Based on the physical and chemical characteristics, the soils were classified as Eutric Ochrustalfs/Eutric Luvisols. In terms of growth parameters; plant height and number of leaves were not significantly different while leaf area, leaf area index and the stem diameter were significantly different. The highest (130.60 cm, 12.30 and 79.88 mm) plant height, number of leaves and stem diameter were observed at the rate of NPK 150:75:75 kg/ha of fertilizer. In terms of yield parameters, ear weight and grain yield were not statistically significant whereas, ear length and ear diameter were statistically significant. However, NPK 60:30:30 kg/ha showed the highest (178 g) ear weight while application of NPK 150:75:75 kg/ha gave the highest (2.82 kg) grain yield. Since there was no significant difference between the fertilizer rates, it could be concluded that the minimum application rate (NPK 60:30:30 kg/ha) should be used in cultivating maize in Alfisols of Makurdi instead of the highest or the blanket recommendation which involved higher cost.

The effect of sewage sludge fertilization on the biomass yield of giant miscanthus and the energy balance of the production process

The application of sewage sludge as fertilizer in the production of non-food crops is an environmentally sustainable approach to sewage sludge management. This article presents the results of a multidirectional analysis (agronomic and energy efficiency analysis) evaluating the effects of sewage sludge applied at rates equivalent to 100 and 160 kg N ha−1 on the production of giant miscanthus (Miscanthus × giganteus Greef and Deuter) in north-eastern Poland in 2013–2018. The optimal fertilizer rate was 160 kg N ha−1 regardless of nitrogen source (mineral fertilizers, sewage sludge), and it contributed to the achievement of the highest biomass yield (19.8 Mg ha−1 dry matter - DM) and the highest energy output (272–275 GJ ha−1). Energy demand was highest (19–24 GJ ha−1) in production technologies involving mineral fertilizers. The replacement of mineral fertilizers with sewage sludge decreased energy inputs in the production of giant miscanthus biomass by 32–34%. Energy gain was highest (259 GJ ha−1) when M. giganteus was supplied with sewage sludge at a rate equivalent to 160 kg N ha−1. The energy efficiency ratio peaked (24.7) in the production technology without fertilization. Energy efficiency was 43–52% higher when giant miscanthus plants were supplied with sewage sludge rather than mineral fertilizers.

Effects of Nitrogen and Phosphorus Fertilizer Rates on Maize (Zea mays L.) Growth and Yields in Terraced Lands of Medium and High Altitude Regions of Rwanda

Depletion of nitrogen and phosphorus in terraced hilly areas of Rwanda has lowered maize (Zea mays L.) production. Trials were carried out in 2017 and 2018 in four-year-old-terraced Lixisols and Acrisols of medium and high altitudes to determine effect of nitrogen and phosphorus fertilizer application rates on maize yields. A factorial arrangement of four levels of nitrogen (0, 60, 120 and 180 kg N ha-1) and phosphorus (0, 40, 80 and 120 kg P2O5 ha-1) in a randomized complete block design with 3 replications, was used. Results showed that combinations of 120 - 180 kg N ha-1 and 80 - 120 kg P2O5 ha-1 resulted in significantly (P less than 0.05) higher increases in plant height (45 – 60 % and 56 – 70 % over the control), stem collar diameter (63 – 74 % and 43 % over the control) and grain yields (3 times over the control; i.e. 6.40 – 6.46 t ha-1 and 6.02 - 6.12 t ha-1) in medium and high altitude sites. The optimum fertilizer rates are 176.6 kg N ha-1 and 96.2 kg P2O5 ha-1 in terraced Lixisols of medium altitude area. Land use needs to adjust fertilizer application to these optimum rates for enhanced maize yields in this area and other regions with similar agro-ecological characteristics. Further studies on integrated effects of N and P fertilizers are recommended.

Finding the optimal fertilizer type and rate to balance yield and soil GHG emissions under reclaimed water irrigation

Water and inorganic nitrogen fertilizer have a notable impact on crop yield and greenhouse gas (GHG) emissions from soil. Reclaimed water (RW) is widely used for irrigation when there are shortages of water resources. It is very important to control yield and greenhouse gas emissions by fertilization under reclaimed water irrigation (RWI). The study consisted of a continuous test that evaluated three types of fertilizer treatments (urea, amine, and slow-release fertilizer) and a no-fertilizer treatment under three-year RWI and four fertilizer levels (150, 200, 250 and 300 kg.N.ha−1) under one-year RWI to determine the best fertilizer to support maize production and reduce GHG (CO2 and N2O) emissions from soil; further, the applicability of RWI in the DNDC model was verified. For many years, GHG emissions under RWI showed an increasing trend, but the effect was not significant. A strong correlation was found between the GHG emissions flux and fertilizer amount, and a threshold fertilization amount existed between 220 and 260 kg.N.ha−1 that minimized yield-scaled N2O emissions and the ratio of GHG cumulative emission to yield (GHG/Y). The results indicated that the optimal amounts of SF and UF under RWI were 240 and 225 kg.N.ha−1 by second-order equation and the DNDC model, respectively, and the rate better balanced the yield and GHG emissions.

Optimization of turfgrass fertigation rate and frequency

The main aim of turfgrass fertilization is to maintain high turf quality and obtain proper turf colour. Fertigation has been recognized as the best fertilization method for proper turfgrass nutrition and for minimizing nitrogen leaching. The aim of this study was to determine the optimum fertilizer rate and frequency for obtaining high-quality turfgrass and minimizing nutrient losses using a fertigation system.Lysimeter experiment was conducted on perennial ryegrass and Kentucky bluegrass mixture in 2016-2018. Three different fertigation rate treatments were applied: 60, 120, and 240 kg N ha−1 (NPK). Fertigation was applied at three intervals: 2, 4 and 8 days between fertigation (DBF). A control treatment with granular fertilizers (CTR) was also applied. The following turfgrass parameters were scored: leaf texture, overall appearance, turf cover and turfgrass colour. Additionally, colour was measured using a spectrophotometer. The colour parameters were expressed using the CIELAB colour system. Leached water samples were taken every two weeks during the vegetation period. The contents of the available forms of selected macro- and microelements (N, P, K, Mg, Ca, Na, Zn, Cu, Mn and Fe) were determined.The fertigation parameters, nutrient rate and interval between fertigation, significantly affected the contents in leachate of most nutrients and metals, except those of N-NH4, Na and Zn. Fertigation resulted in significantly lower N-NO3 losses in comparison with those under CTR. Higher rates of nutrients in fertigation solution resulted in increased N-NO3 content in leachate. The same effect was observed for P, Mg, K, Ca and Cu. The fertigation interval only affected P losses. The lowest P content in leachate was observed in the 2DBF treatment, and the P content in leachate increased as the intervals increased. The fertigation interval did not affect the leaching of any other nutrient. However, a significant difference in leachate content was observed between the CTR with granular fertilizers and fertigation. This effect was observed for N-NO3, K, Ca, Mn and Cu. A significantly higher content of all these nutrients was observed in leachate from the CTR treatment than in that from the fertigation treatments.Fertigation resulted in darker grass leaves in comparison with those under CTR. Higher fertigation rates resulted in darker leaves with higher green hue content than those at lower rates. There were no differences in colour hue in turfgrass fertigated at different time intervals. Turfgrass quality was affected by the fertigation rate and interval. This effect was significant for overall appearance, turf colour and leaf texture, but not for turf cover. The highest mean quality score was obtained at 240NPK, and the lowest was obtained at 60NPK. The optimal fertigation parameters for reduced nutrient losses and high turfgrass quality were calculated to be the 60NPK fertigation level at a fertigation interval of 4.4 days.

Fertilization Methods for Organic and Conventional Potted Blueberry Plants

This study determined optimal fertilization for each of three production methods (i.e., two organic and one conventional) of potted Vaccinium corymbosum ‘Duke’ northern highbush blueberry plants. The three production methods were as follows: 1) organic granular [(OG) organic coir substrate fertilized with Bio-Fert General Purpose + bloodmeal applied at 4.4, 7.3, 10.2, 13.1, and 16.0 g/pot nitrogen (N)], 2) organic liquid [(OL) organic coir substrate fertilized with Bio-Fert General-Purpose Liquid + calcium oxide (CaO) applied at 12.2, 14.7, 18.6, 25.3, and 39.5 mmol·L–1 N), and 3) conventional (C; pine bark, coir, and peat substrate fertilized with Osmocote Plus 15N–3.9P–9.9K, 5- to 6-month-duration controlled-release fertilizer applied at 4.4, 7.3, 10.2, 13.1, and 16.0 g/pot N). Blueberry plants were grown in #5 black, squat nursery containers outdoors in the Niagara peninsula, ON, Canada for two (2015–16) growing seasons. Both of the organic and the conventional production systems produced healthy blueberry plants when fertilizer was applied appropriately. With fertilizer application at 4.4 and 7.3 g/pot N for C, 12.2 and 14.7 mmol·L–1 N for the OL, and 8.50 to 13.95 g/pot N for the OG treatments, healthy plant growth was observed in combination with low nutrient leaching. High fertilizer rates resulted in excessive root zone electrical conductivity (EC), poor plant growth, and interveinal chlorosis, which affected fruit production negatively. For C and OL treatments, fertilization at rates of 4.4, 7.3 and 10.2 g/pot N, and 12.2, 14.7, and 18.6 mmol·L–1 N, respectively, produced the greatest total fresh weight of fruit. For OG, a large total fruit fresh weight was produced by all plants with no difference among fertilizer rates. This study suggests optimal fertilizer rates from 4.4 to 7.3 g/pot N for C, 12.2 to 14.7 mmol·L–1 N for the OL treatment, and from 8.50 to 13.95 g/pot N for the OG treatment can be applied based on the methods described in this study during potted blueberry production in nurseries and home gardens.