Enhancement of Phosphorus Fertilization
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Soil degradation and nutrient deficiency limit crop production in drylands, while urbanization compounds the challenge by increasing municipal waste. Municipal waste compost (MWC) offers a dual solution—enhancing soil health and reducing urban waste. Israel has industrial composting facilities like Dudaim, but Jordan lacks similar infrastructure.
This project aims to enhance the value of MWC by studying its use alongside poultry and dairy manure compost to improve crop and soil health. Greenhouse and field trials will be conducted in Israel, while household composting initiatives in Jordan will be supported by women’s associations. Cross-border knowledge sharing and stakeholder workshops will promote sustainable agriculture and waste management in both countries.
Exploring Natural Polyphosphate Reserves in Soil and Novel Plant Uptake Mechanisms
Phosphorus (P) is an essential nutrient for crops, but its availability in soil is often limited due to reactions that render it immobile—leading to poor utilization and environmental concerns. Unlike plants, microorganisms store phosphorus in the form of polyphosphates (poly-P), which reduce fixation and increase potential availability to plants. Although polyphosphates have been extensively studied in aquatic environments, their role in soil remains largely unknown—mainly because standard phosphorus extraction methods do not account for them.
Traditionally, plants are believed to absorb phosphorus only in the form of orthophosphate, relying on microorganisms to break down polyphosphates. However, new findings suggest that certain plant species can degrade polyphosphates independently, even under sterile conditions—indicating that plant roots may secrete specific proteins to break down poly-P in the rhizosphere (root zone).
Our research hypothesis is that long-chain polyphosphates represent a significant phosphorus reservoir in soil, and that different plant species vary in their ability to utilize this resource. The main objective is to identify the mechanism by which plants acquire phosphorus from polyphosphates—through the activity of the enzyme polyphosphatase (PPase) in the soil and roots.
The research includes two main components:
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Assessing the polyphosphate reservoir in soils under various management regimes.
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Characterizing polyphosphatase activity in plants.
To this end, we are developing tailored protocols for extracting poly-P from soil, conducting surveys to measure its levels in different soil types and organic amendments, and simultaneously isolating, purifying, and cloning PPase enzymes from plants to understand their function and gene expression—especially under sterile conditions where poly-P is the sole phosphorus source.
Understanding the role of natural polyphosphates and PPase enzymes in the soil phosphorus cycle could significantly improve agricultural phosphorus management, enhance use efficiency, and reduce the environmental impact of excessive fertilizer use.
Algae in Wastewater – Recovering Phosphorus from Water
Phosphorus is vital for the development of agricultural crops, yet its limited availability in soil necessitates frequent fertilization in intensive farming systems. Soil reactions often render added phosphorus immobile, causing it to accumulate in the topsoil, resulting in inefficient use and increased risk of phosphorus runoff into water sources—a phenomenon that contributes to eutrophication.
This inefficiency, along with limitations in synthetic fertilizer supplies, highlights the need for sustainable phosphorus management strategies.
Our research aims to recover phosphorus from wastewater using microalgae, which can efficiently absorb and store phosphorus as polyphosphates during water purification processes, while simultaneously capturing carbon dioxide. By cultivating hyper-accumulating microalgae capable of absorbing excess phosphorus, the study seeks to maximize poly-P storage within the algae. This polyphosphate can then be used as a biologically derived fertilizer suitable for agricultural application.
Additionally, the research will examine best management practices for using these biofertilizers to evaluate their agronomic benefits and contribute to closing the sustainable phosphorus loop—while reducing reliance on chemical fertilizers.
PhoSul Project – Enhancing Phosphorus Availability via Sulfur and Organic Additives
Plants absorb phosphorus solely as orthophosphate from the soil solution. However, this form quickly becomes unavailable due to fixation—especially in alkaline soils rich in poorly soluble calcium-phosphate minerals. In such conditions, soil oxidation can enhance phosphorus solubility and make it more accessible. Microbial activity also contributes to phosphorus availability, through the secretion of organic acids, phosphatases, and other compounds that dissolve minerals and promote root uptake.
The goal of this research is to increase the availability of phosphorus from low-solubility sources such as rock phosphate and sewage sludge ash (SSA), particularly in organic farming systems where synthetic phosphate fertilizers are prohibited. The study evaluates the use of two potential additives—sulfur and organic matter—to determine whether they enhance phosphorus availability in these systems and can serve as sustainable alternatives to conventional phosphate fertilizers.
Ostara Project – Utilizing Struvite Fertilizer
The primary aim of this project is to evaluate the impact of struvite-based fertilizer blends (e.g., Crystal Green) on crop yield, plant quality, and nutrient composition in plant tissues, in comparison to traditional phosphorus fertilizers.
The experiment will be conducted on fixed plots over multiple seasons, maintaining consistent treatments each season to monitor changes in soil chemistry, soil health, and the mechanisms by which struvite influences phosphorus availability over time. The use of crop rotation will help simulate real-world commercial farming conditions.
