Fertilizer Delivery Research Articles

Controlled release fertilizer delivery system derived from rice straw cellulose nanofibres: a circular economy based solution for sustainable development

ABSTRACTRecently, the development of sustainable and environmentally friendly biomaterials has gained the attention of researchers as potential alternatives to petroleum-based materials. Biomaterials are a promising candidate to mitigate sustainability issues due to their renewability, biodegradability, and cost-effectiveness. Thus, the purpose of this study is to explore a cost-effective biomaterial-based delivery system for delivering fertilizers to plants. To achieve this, rice straw (agro-waste) was selected as a raw material for the extraction of cellulose. The cellulose was extracted through alkali treatment (12% NaOH), followed by TEMPO-based oxidation. The cellulose nanofibers were characterized using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, and transmission electron microscopy. In scanning electron microscopy, a loosening of the fibrillar structure in cellulose nanofibers (CNFs) was observed with a diameter of 17 ± 4 nm. The CNFs were loaded with nitrogen-based fertilizer (ammonium chloride) in 1:1, 1:2, and 2:1 (w/w) proportions. The loading was estimated through surface charge variation; in the case of the 1:1 sample, maximum reductions in surface charge were seen from −42.0 mV to −12.8 mV due to the binding of positive ammonium ions. In the release kinetics study, a controlled release pattern was observed at 1:1, which showed a 58% cumulative release of ammonium ions within 8 days. Thus, the study paves the way for value-added uses of rice straw as an alternative to the current environmentally harmful practices.

Soil-MobiNet: A Convolutional Neural Network Model Base Soil Classification to Determine Soil Morphology and Its Geospatial Location.

Scholars have classified soil to understand its complex and diverse characteristics. The current trend of precision agricultural technology demands a change in conventional soil identification methods. For example, soil color observed using Munsell color charts is subjective and lacks consistency among observers. Soil classification is essential for soil management and sustainable land utilization, thereby facilitating communication between different groups, such as farmers and pedologists. Misclassified soil can mislead processes; for example, it can hinder fertilizer delivery, affecting crop yield. On the other hand, deep learning approaches have facilitated computer vision technology, where machine-learning algorithms trained for image recognition, comparison, and pattern identification can classify soil better than or equal to human eyes. Moreover, the learning algorithm can contrast the current observation with previously examined data. In this regard, this study implements a convolutional neural network (CNN) model called Soil-MobiNet to classify soils. The Soil-MobiNet model implements the same pointwise and depthwise convolutions of the MobileNet, except the model uses the weight of the pointwise and depthwise separable convolutions plus an additional three dense layers for feature extraction. The model classified the Vellore Institute of Technology Soil (VITSoil) dataset, which is made up of 4864 soil images belonging to nine categories. The VITSoil dataset samples for Soil-MobiNet classification were collected over the Indian states and it is made up of nine major Indian soil types prepared by experts in soil science. With a training and validation accuracy of 98.47% and an average testing accuracy of 93%, Soil-MobiNet showed outstanding performance in categorizing the VITSoil dataset. In particular, the proposed Soil-MobiNet model can be used for real-time soil classification on mobile phones since the proposed system is small and portable.

PRODUKSI TRICHOKOMPOS DARI KOTORAN SAPI

The majority of the people of Bangket Parak Village still rely on the agricultural and animal husbandry sectors as a source of economic resilience. The current constraint in the agricultural sector is the availability of fertilizers, while in the livestock sector is the management of livestock waste. To overcome these two problems, the management of livestock waste as trichocompost fertilizer can be an alternative solution. The purpose of this activity is to provide education and skills to the community in making trichocompost fertilizer with livestock manure waste. The activity method consists of surveys, socialization activities, and demonstrations as well as assistance in making trichocompost fertilizer. In this socialization activity there are three stages including preparation, implementation, and reporting. This socialization activity began with a video screening. The activity continued with the presentation of socialization material. After that, demonstrations and assistance were carried out on how to make trichocompost fertilizer from utilizing livestock manure with the help of Trichoderma sp. The activity ended with the delivery of fertilizers to continue the fermentation process and the distribution of plant seeds to the participants. All participants who attended were very enthusiastic about following and listening to the entire series of events. It is hoped that through this activity, the community will gain new understanding and useful skills in overcoming the problems that are currently occurring.

Temperature-responsive hydrogel prepared from carboxymethyl cellulose-stabilized N-vinylcaprolactam with potential for fertilizer delivery

The growth of plants is highly dependent on sufficient water and suitable fertilizer nutrients, but the soil often loses moisture and the fertilizers are low efficiency. To address this issue, the temperature-responsive hydrogels were developed using the N-vinylcaprolactam (NVCL) dispersed in water through the emulsification of carboxymethyl cellulose (CMC) and acrylamide (AM), and urea was loaded into the hydrogel as a fertilizer. The amount of CMC and monomer have an effect on the structure, mechanical properties, swelling ability, and temperature sensitivity of the hydrogel. Therefore, the maximum swelling ratio of the hydrogel can reach 2056 % with the increasing hydrophilic groups, and the hydrogel exhibits a deswelling behavior as the temperature rises to higher than LCST due to the temperature responsiveness. Moreover, the fertilizer can rapidly release when the temperature is higher than LSCT, and exhibits similar release behavior in water and soil. Thus, the temperature-responsive hydrogel shows a great potential application for the controlled release of water and fertilizer in agriculture and forestry.

Design and Test of Soil–Fertilizer Collision Mixing and Mulching Device for Manure Deep Application Machine

Aiming at the problems of low uniformity and utilization rate in the traditional deep application method of orchard manure, a soil–fertilizer collision mixing and mulching device was designed. The ditching mechanism, the structure of the soil divider, and the fertilizer delivery auger were analyzed and designed. Furthermore, with the rotational speed of the cutter and auger and the deflection angle of the soil divider as factors, as well as the uniformity of soil–fertilizer mixing and mulching as evaluation indexes, the discrete element simulation tests were conducted. The simulation results showed that when the turret speed, the stirrer speed and the soil separator deflection angle were 140 r/min, 146 r/min and 22°, the mixing uniformity and mulching uniformity were the highest, which was 88.35% and 96.86%, respectively. Based on the optimal parameters, the field test was conducted, and the soil–fertilizer mixing uniformity was 87.02%, with a relative error of 1.33% compared with the simulation test results. The relative error of 94.37% of mulch uniformity is 2.49%, which indicates that the simulation optimization results are reliable and the mixing performance of the device is good and can meet the requirements of soil–fertilizer mixing operation. The results of this study can provide an important reference for the design of the soil and fertilizer mixing machine.

Biodegradable, anti-freezing and self-healable hydrogel mulch film for weed control

Hydrogel is widely used in agriculture as water retention agent and fertilizer delivery vehicle due to its highly porous and hydrated structure. Hydrogel loses water gradually and becomes fragile, which greatly hinders its potential application as mulching film for weed control as the weeds can penetrate the weakened hydrogel film easily. Here, we report a self-healable and biodegradable hydrogel (COCu-K) mulching film composed of chitosan derivatives, copper-doped carbon dots (Cu-CDs) and KCl for weed inhibition. The dehydrated COCu-K hydrogel fragments spread on top of soil self-heal in-situ into an integrate hydrogel film by simple watering, preventing the germination and growth of weeds. SEM reveals the well-dispersed multi-hierarchical structure on the surface of COCu-K hydrogel. The effects of dosages of KCl and Cu-CDs on the hydrogel structure and consequent performances of hydrogel mulching film including self-healing, anti-freezing, weeds inhibition have been explored. The pot experiments illustrated a weed seeds inhibition ratio of 90% and strengthened growth of pepper seedlings induced by the best practice hydrogel COCu0.08-K2.5. Meanwhile, the COCu0.08-K2.5 hydrogel shows an outstanding degradability with a degradation rate of 63.61±3.26% within eight weeks, and soil containing degraded COCu0.08-K2.5 hydrogel presents no phytotoxicity. This study provides a facile and viable strategy to design and utilize hydrogel mulching for weed control.

Instream sensor results suggest soil–plant processes produce three distinct seasonal patterns of nitrate concentrations in the Ohio River Basin

AbstractThe Ohio River Basin (ORB) is responsible for 35% of total nitrate loading to the Gulf of Mexico yet controls on nitrate timing require investigation. We used a set of submersible ultraviolet nitrate analyzers located at 13 stations across the ORB to examine nitrate loading and seasonality. Observed nitrate concentrations ranged from 0.3 to 2.8 mg L−1 N in the Ohio River's mainstem. The Ohio River experiences a greater than fivefold increase in annual nitrate load from the upper basin to the river's junction with the Mississippi River (74–415 Gg year−1). The nitrate load increase corresponds with the greater drainage area, a 50% increase in average annual nitrate concentration, and a shift in land cover across the drainage area from 5% cropland in the upper basin to 19% cropland at the Ohio River's junction with the Mississippi River. Time‐series decomposition of nitrate concentration and nitrate load showed peaks centered in January and June for 85% of subbasin‐year combinations and nitrate lows in summer and fall. Seasonal patterns of the terrestrial system, including winter dormancy, spring planting, and summer and fall growing‐harvest seasons, are suggested to control nitrate timing in the Ohio River as opposed to controls by river discharge and internal cycling. The dormant season from December to March carries 51% of the ORB's nitrate load, and nitrate delivery is high across all subbasins analyzed, regardless of land cover. This season is characterized by soil nitrate leaching likely from mineralization of soil organic matter and release of legacy nitrogen. Nitrate experiences fast transit to the river owing to the ORB's mature karst geology in the south and tile drainage in the northwest. The planting season from April to June carries 26% of the ORB's nitrate and is a period of fertilizer delivery from upland corn and soybean agriculture to streams. The harvest season from July to November carries 22% of the ORB's nitrate and is a time of nitrate retention on the landscape. We discuss nutrient management in the ORB including fertilizer efficiency, cover crops, and nitrate retention using constructed measures.

Significance of biopolymer-based hydrogels and their applications in agriculture: a review in perspective of synthesis and their degree of swelling for water holding.

Hydrogels are three-dimensional polymer networks that are hydrophilic and capable of retaining a large amount of water. Hydrogels also can act as vehicles for the controlled delivery of active compounds. Bio-polymers are polymers that are derived from natural sources. Hydrogels prepared from biopolymers are considered non-toxic, biocompatible, biodegradable, and cost-effective. Therefore, bio-polymeric hydrogels are being extensively synthesized and used all over the world. Hydrogels based on biopolymers finds important applications in the agricultural field where they are used as soil conditioning agents as they can increase the water retention ability of soil and can act as a carrier of nutrients and other agrochemicals. Hydrogels are also used for the controlled delivery of fertilizer to plants. In this review, bio-polymeric hydrogels based on starch, chitosan, guar gum, gelatin, lignin, and alginate polymer have been discussed in terms of their synthesis method, swelling behavior, and possible agricultural application. The urgency to address water scarcity and the need for sustainable water management in agriculture necessitate the exploration and implementation of innovative solutions. By understanding the synthesis techniques and factors influencing the swelling behavior of these hydrogels, we can unlock their full potential in fostering sustainable agriculture and mitigating the challenges posed by an ever-changing environment.

Analysis of the current state of mineral fertilizers transportation and justification of the choice of transport and logistics delivery systems involving inland waterway transport

The article considers the current state of mineral fertilizers transportation in export-import and domestic directions when using various types of transport, including inland waterway transport. The introduction presents the results of the analysis of a number of literary sources and research works of domestic and foreign scientists in the field of transportation of mineral fertilizers. As a result of the research, it was determined that it is necessary to make optimal logistics decisions on the choice of transport and logistics systems, cargo transportation conditions, the development of rational routes with the redistribution of cargo flows from land to inland water transport, which in the future will have a positive impact on the process of organizing the delivery of mineral fertilizers to consumers. The relevance of the choice of transport and logistics systems for the delivery of mineral fertilizers by inland waterways to seaports in a promising direction is substantiated, the results of calculations based on the methodology for determining the cost of cargo delivery in comparison with alternative modes of transport and taking into account qualitative indicators are presented.

Microgreens for Home, Commercial, and Space Farming: A Comprehensive Update of the Most Recent Developments.

Microgreens are edible young plants that have recently attracted interest because of their color and flavor diversity, phytonutrient abundance, short growth cycle, and minimal space and nutrient requirements. They can be cultivated in a variety of systems from simple home gardens to sophisticated vertical farms with automated irrigation, fertilizer delivery, and lighting controls. Microgreens have also attracted attention from space agencies hoping that their sensory qualities can contribute to the diet of astronauts in microgravity and their cultivation might help maintain crew physical and psychological health on long-duration spaceflight missions. However, many technical challenges and data gaps for growing microgreensboth on and off Earth remain unaddressed. This review summarizes recent studies on multiple aspects of microgreens, including nutritional and socioeconomic benefits, cultivation systems, operative conditions, innovative treatments, autonomous facilities, and potential space applications. It also provides the authors' perspectives on the challenges to stimulating more extensive interdisciplinary research.

Availability of Metribuzin-Loaded Polymeric Nanoparticles in Different Soil Systems: An Important Study on the Development of Safe Nanoherbicides.

Nanoformulations have been used to improve the delivery of fertilizers, pesticides, and growth regulators, with a focus on more sustainable agriculture. Nanoherbicide research has focused on efficiency gains through targeted delivery and environmental risk reduction. However, research on the behavior and safety of the application of these formulations in cropping systems is still limited. Organic matter contained in cropping systems can change the dynamics of herbicide−soil interactions in the presence of nanoformulations. The aim of this study was to use classical protocols from regulatory studies to understand the retention and mobility dynamics of a metribuzin nanoformulation, compared to a conventional formulation. We used different soil systems and soil with added fresh organic material. The batch method was used for sorption−desorption studies and soil thin layer chromatography for mobility studies, both by radiometric techniques. Sorption parameters for both formulations showed that retention is a reversible process in all soil systems (H~1.0). In deep soil with added fresh organic material, nanoformulation was more sorbed (14.61 ± 1.41%) than commercial formulation (9.72 ± 1.81%) (p < 0.05). However, even with the presence of straw as a physical barrier, metribuzin in nano and conventional formulations was mobile in the soil, indicating that the straw can act as a barrier to reduce herbicide mobility but is not impeditive to herbicide availability in the soil. Our results suggest that environmental safety depends on organic material maintenance in the soil system. The availability can be essential for weed control, associated with nanoformulation efficiency, in relation to the conventional formulation.

INCREASING PERFORMANCE OF OIL PALM NPK FERTILIZATION WITH RISK MANAGEMENT AND ANALYTIC HIERARCHY PROCESS (AHP)

This research is intended to improve the performance of oil palm fertilization by examining the fertilizer procurement process. The research design that will be carried out in this study is based on the problems studied using descriptive analysis methods. Measurement of priority risk using FMEA and formulation of mitigation strategies using AHP (Analytic Hierarchy Process) by collecting data through observation, questionnaires with stakeholders who have expertise in their respective fields at the research site. One of the plantation crops that are widely cultivated by large plantation companies is oil palm. The moratorium on oil palm plantation permits for the addition of new land for 3 years encourages companies to increase crop productivity on existing plantation lands, one of which is fertilization. Constraints experienced in fertilizing on mature plants are the incompatibility of the fertilizer applied to the planned one. So that the increase in fertilization performance can be done through improvements in the procurement process. The purpose of this research is to study the risk priorities in the planning process to the acceptance of fertilizers in the procurement of fertilizers. The results showed that the priority risk of fertilizer procurement planning is that the budget availability is not in accordance with the recommendations (RPN 27), the supplier selection process is the announcement of the old tender (RPN 18), the dropping/delivery process is a late contract signed (RPN 18), the acceptance process is that the fertilizer is accepted. past the time period (RPN 18). The criteria are fertilizer procurement planning, supplier selection, fertilizer delivery and fertilizer receipts with successive values ​​of 0.575, 0.214, 0.134, 0.077. The alternatives are ensuring budget adequacy, adding fertilizer suppliers, improving communication between fertilizer providers and users, determining the timing of fertilizer application, increasing the frequency of fertilizer quality inspections and using information technology in fertilization. Improving the performance of fertilizer procurement can be done with three main strategies, namely improving the budgeting system, improving procurement documents, selecting suppliers with a multi-winner system.

The role of carbon dots in the life cycle of crops

The novel 0-dimensional quasi-spherical fluorescent carbon dots (diameter <10 nm) have the characteristics of small size, adjustable emission wavelength range, easy functional modification of surface groups, and good biocompatibility. Studies showed that it has great application potential in the entire life cycle of crops, including pre-harvest and post-harvest. Subsequently, crop waste can be used to prepare carbon dots and re-enter the crop life cycle. This review summarizes recent studies showing that carbon dots with specific chemical or optical properties can enhance crop yields in different ways. The small size and surface hydrophilic groups that can cross the plant cell barrier are beneficial to CDs to promote seed germination and absorb nutrients to promote growth. The high carbon content (>60%) endows it with potential as a nano-carbon fertilizer. CDs with positive surface charges or prepared by medium molecular weight PEI are the key to targeted delivery of fertilizers, pesticides, fungicides, DNA or RNA. The luminescence range of CDs covers the absorption range of plants and the electron donor and acceptor properties promote plant photosynthesis. The antioxidant properties of CDs are crucial for improving crop stress resistance. Photodynamic, photothermal, and UV absorption properties endow CDs with antibacterial and preservation applications. Finally, current challenges and future prospects are discussed.

Lignin-based nano-enabled agriculture: A mini-review.

Nowadays sustainable nanotechnological strategies to improve the efficiency of conventional agricultural practices are of utmost importance. As a matter of fact, the increasing use of productive factors in response to the growing food demand plays an important role in determining the environmental impact of agriculture. In this respect, low-efficiency conventional practices are becoming obsolete. On the other hand, the exploitation of nanoscaled systems for the controlled delivery of fertilizers, pesticides and herbicides shows great potential towards the development of sustainable, efficient and resilient agricultural processes, while promoting food security. In this context, lignin - especially in the form of its nanostructures - can play an important role as sustainable biomaterial for nano-enabled agricultural applications. In this review, we present and discuss the current advancements in the preparation of lignin nanoparticles for the controlled release of pesticides, herbicides, and fertilizers, as well as the latest findings in terms of plant response to their application. Special attention has been paid to the state-of-the-art literature concerning the release performance of these lignin-based nanomaterials, whose efficiency is compared with the conventional approaches. Finally, the major challenges and the future scenarios of lignin-based nano-enabled agriculture are considered.

Zeolites as Carriers of Nano-Fertilizers: From Structures and Principles to Prospects and Challenges

The world is facing immense challenges in terms of food security, due to the combined impacts of the ever-increasing population and the adversity of climate change. In an attempt to counteract these factors, smart nutrient delivery systems, including nano-fertilizers, additives, and material coatings, have been introduced to increase food productivity to meet the growing food demand. Use of nanocarriers in agro-practices for sustainable farming contributes to achieving up to 75% nutrient delivery for a prolonged period to maintain nutrient availability in soil for plants in adverse soil conditions. In this context, sieve-like zeolites and the diversity in their structural morphologies have attracted increasing interest over recent years. Engineered nano-porous zeolites, also called aluminosilicates, are defined based on the presence of micro- (&lt;2 nm), meso- (2–50 nm), and macropores (&gt;50 nm), which can be employed as carriers of fertilizers due to their enhanced ion-exchange properties and adsorption capabilities. In this study, we provide a detailed overview of the production and optimization of hierarchical zeolite structures within the size range from micro- to nanometers, as well as the various top-down and bottom-up approaches which have been used to synthesize zeolites with a large surface area, tunable pore size, and high thermal stability, which make them an excellent candidate to be used in agronomy. The delivery of pesticides, insecticides, and fertilizers by loading them into nano-zeolites to manage the crop production without disrupting the soil health is discussed, as well as future perspectives of zeolites in the perpetual maintenance of soil productivity.

PENGGUNAAN PUPUK ORGANIK CAIR DARI LIMBAH SAYURAN PADA BUDIDAYA TANAMAN CAISIM (Brassica chinensis var. parachinensis) DENGAN SISTEM HIDROPONIK

The number of vegetables that fail to harvest or are not sold in the market causes vegetable waste that can pollute the environment, so it is necessary to reprocess it into liquid organic fertilizer. The study aimed to look at the effect of liquid organic fertilizer delivery on caisim crop production and determine the best dose of liquid organic fertilizer from vegetable waste for caisim crops. The dose of liquid fertilizer used t0 = 0 mL L-1 , t1 = 10 mL L-1, t2 = 20 mL L-1, t3 = 30 mL L-1, t4 = 40 mL L-1 with the observed parameters of plant height, leaf width, wet weight and dry weight of the plant with caisim plants as research parameters. From the results of research that has been done the use of four doses of liquid organic fertilizers from vegetable waste is able to increase the growth of caisim plants in the hydroponic method of the wick system. The best dose in caisim plant growth is in the use of a dose of t2 = 20 mL L-1 with a plant height in the fourth week of 23.68 cm, a leaf width of 8.11 cm, a wet weight of a plant of 14.44 grams, and a dry weight of 1.91 grams. The study also analyzed the production costs and business income of liquid organic fertilizer vegetable waste. The result of the production cost of liquid organic fertilizer vegetable waste amounted to Rp. 85,000 rupiah. Receipt of business income for liquid organic fertilizer vegetable waste amounted to Rp. 180,000 rupiah. From the results of production costs and business income of liquid organic fertilizer vegetable waste obtained a total income of Rp. 95,000 rupiah with the efficiency of the vegetable waste liquid organic fertilizer business Rp. 2.12 rupiah.

Nanotechnology: its scope in agriculture

The growth in human population is estimated to reach 9.8 billion by mid-2050. To meet the food requirements, reducing the judicious use of fertilizers, agrochemicals and their impact on environment, soil, water, humans and the surrounding biodiversity we have to shift towards sustainable methods. Nanotechnology is one such technology that will help in crop production by improving the input use efficiency by minimizing their losses, site-specific, controlled delivery of fertilizers or agrochemical as per the requirement, increases shelf life, efficiency of the agrochemicals and reduces their recommended dosage. Nanoparticles are organic, inorganic or hybrid materials whose dimensions may range from 1 to 100 nm. Nanosensors can detect environmental stress and enhance the plant’s ability to combat diseases, used in automation of irrigation; it is a rapid and accurate tool to detect insect and pest, which helps in timely application of agrochemicals. Nano-iron fertilizer was found to improve essential oil content, nano-zinc and boron fertilizers improved fruit yield and quality, nano zeolite can sustain the nutrients in the soil for long term and it enhance germination and plant growth. As nanoparticles enhances growth, they aid in early maturity of the crop, improves the plant’s ability to tolerate stresses, hence they are effective tools in drought and flood-prone areas, they detoxify harmful pollutants especially heavy metals, pesticide residues. As nanoparticles have greater persistence, they may have long-term effect on plants, humans and also environment, but it has less impact than that of the normal agrochemicals. Advanced research is required to conclude in this aspect.

MOF Hybrid for Long-Term Pest Management and Micronutrient Supply Triggered with Protease.

Advanced intelligent systems for delivery of pesticides or fertilizers require formulations that allow for long-term efficacy. In this work, a metal-organic framework (MOF) hybrid was developed for long-term pest management and micronutrient supply. Zeolitic imidazolate framework-8 was fabricated for crop micronutrients (Zn2+) supply and insecticide dinotefuran (DNF) encapsulation. Polymethylmethacrylate was polymerized in situ to impart the MOF hybrid with sustained cargo delivery. Then, zein was introduced to facilitate protease-triggered cargo release associated with the microenvironment of pests and targeted release. The resulting MOF hybrid exhibited stimulus-responsive, slow-release behaviors. Sustained DNF delivery was achieved over a period of at least 32 days in soil. Compared with that of free DNF, the UV resistance of DNF in the MOF hybrid increased by nearly 10 times, and the insecticidal efficiency increased 33.3% with leaching treatment and 40.1% after incubating in a greenhouse for 14 days. This MOF hybrid provides a controlled, targeted, and sustained delivery formulation for long-term pest management and crop micronutrient supply and has huge application prospects in sustainable agriculture.

PVDF/KNO3 Composite Sub-Microfibers Produced by Solution Blow Spinning as a Hydrophobic Matrix for Fertilizer Delivery System.

Nutrient supplementation is a common practice in agriculture to increase crop productivity in the field. This supplementation is usually excessive, causing nutrient leaching in periods of rainfall leading to environmental problems. To overcome such issues, many studies have been devoted to developing polymeric matrices for the controlled and continuous release of nutrients, reducing losses, and keeping plants nourished for as long as possible. However, the release mechanism of these matrices is based on water diffusion. They start immediately for swellable polymeric matrices, which is not interesting and also may cause some waste, because the plant only needs nutrition only after the germination process. Here, as proof of concept, we tested a hydrophobic polymeric matrix based on sub-microfibers mats, produced by solution blow spinning, filled with potassium nitrate (KNO3) for the controlled release of nutrients to plants. In this work, we used the polyvinylidene fluoride (PVDF) polymer to produce composite nanofibers containing pure potassium nitrate in the proportion of 10% weight. PVDF/KNO sub-microfibers mats were obtained with 370 nm average diameter and high occurrence of beads. We performed a release test using PVDF/KNO3 mats in a water bath. The release kinetic tests showed an anomalous delivery mechanism, but the composite polymeric fibrous mat showed itself to be a promising alternative to delay the nutrient delivery for the plants.

Drivers of ecosystem vulnerability to Corbicula invasions in southeastern North America

Invasive species introduction is one of the major ongoing ecological global crises. Identifying factors responsible for the success of invasive species is key for the implementation of effective management actions. The invasive filter-feeding bivalve, Corbicula, is of particular interest because it has become ubiquitous in many river basins across North America and elsewhere. Here we sampled bivalve assemblages, environmental indicators, and land cover parameters in the Ouachita highlands in southeastern Oklahoma and southwestern Arkansas, and in the Gulf Coastal Plain of Alabama to test three working models (using structural equation modeling, SEM) based on a priori scientific knowledge regarding Corbicula invasions. Our models tested three competing hypotheses: (1) Native mussel declines are related to land use changes at the watershed level and subsequent Corbicula colonization is a result of an empty niche; (2) Corbicula abundance is one of the factors responsible for native mussel declines and has an interactive effect with land use change at the watershed level; (3) Native mussel declines and Corbicula success are both related to land use changes at the watershed level. We found no evidence for the first two hypotheses. However, we found that environmental indicators and land cover parameters at the watershed scale were robust predictors of Corbicula abundance. In particular, agricultural land cover was positively related with Corbicula density. These results suggest that further improvement of conventional agricultural practices including the optimization of fertilizer delivery systems may represent an opportunity to manage this species by limiting nutrient inputs to stream ecosystems. Preservation of extensive floodplain habitats may help buffer these inputs by providing key ecosystem services including sediment and nutrient retention.