Speaker
Description
Introduction
Homemade dry manure tea (HMT), a widely used organic fertilizer in North Africa, is considered by local farmers as an affordable alternative to synthetic fertilizers. HMT is used to boost plant growth and health and enhance soil fertility. However, despite its widespread use, HMT remains largely understudied as for its properties and use in North African farming systems. From a survey of agricultural areas in Tunisia, our primary objective was to explore the diversity of HMT recipes utilized by farmers. We aimed to analyze their physicochemical properties and understand the various uses of teas, determining if they are linked to the preparation methods.
Methodology
To study this peasant innovation and bridge the existing knowledge gaps, we approached 60 farmers from all regions of Tunisia.
The surveyed farmers have specialized expertise in this technique and have amassed real-production experience over several years. This phase enabled us to delineate various methods of preparing and applying teas, pinpoint technical specifics (like irrigation systems, filtration, container types, etc.), and discern their variability based on crop type, soil attributes, available resources, and employed agricultural practices. The data from the interviews on HMT development underwent factorial analysis of mixed data, FAMD, followed by an ascending hierarchical classification (CAH), distinguishing four types of HMT preparation formulas:
• Category 1: Farmers produce HMTs from poultry manure under 2 months old, with a low manure/water ratio.
• Category 2: The employed manure comes from ruminants and is over 12 months old. The tea features a medium manure/water ratio.
• Category 3: The manure comprises a blend of ruminant and poultry manure, aged 2 to 6 months, with a maceration time of 10 to 25 days, and the HMT possesses the highest ratio.
• Category 4: This represents the most intricate recipe relative to the others. It pertains to farmers who engage in aeration and introduce an organic additive to the HMT. The manure's age is 2 to 6 months, maceration is the lengthiest, and the manure/water ratio is elevated.
Following the FAMD, we selected five representative recipes from each category. We evaluated the relevance of each farmer's recipe for our study and the feasibility of future collaboration. Each recipe was replicated thrice in plastic containers, mirroring the conditions utilized by farmers. After 3 days of maceration (T3), specimens were procured and dispatched to the laboratory. This period aligns with the minimum maceration adopted by some farmers for archetype recipes. At this juncture, three evaluations of each subsequent parameter were executed: pH, electrical conductivity, chloride, organic nitrogen, ammonium, nitrates, total phosphorus, orthophosphate, potassium, calcium, magnesium, and sodium. To trace the evolution of macro-elements and secondary nutrients during maceration, identical analyses were reiterated at the end of the maceration duration (Tf), complemented by measurements on suspended matter, Escherichia coli, iron, manganese, and silicon.
Results and Implications
The chemical properties of HMT were strongly influenced by various factors such as the source of manure, aeration, additives, and maceration duration. Our analysis revealed four main recipe categories, characterized by the type of manure, manure-to-water ratio, maceration duration, and other parameters.
The first category is found in the center of the country where we met farmers who sell poultry tea and others who buy it. The second category is mainly found in the center of Tunisia. The third class is somewhat scattered. 50% of the surveys of the 4th class are found in the South. Farmers in this region are more motivated and interested in their oases and believe that the teas improve the fertility of their soils and the quality of their dates.
Our results highlight significant variability in the physicochemical properties among HMT recipes. The physicochemical properties of HMT in categories 1 and 2 were relatively similar from one recipe to another, indicating low variability in physicochemical composition within these categories. In contrast, recipes in categories 3 and 4 were more complex, with varying maceration durations, aeration, and the addition of additives. Some recipes, prepared over extended maceration periods, are richer in nutrients, confirming the farmers' observations. Also, the age of the manure used for making the teas influences the physicochemical characteristics of the teas. The more mature and well-decomposed the manure, the higher its nutrient concentration.
| Keywords | Synthetic fertilizers, plant growth, field Survey, Statistical analysis, agroecological practices |
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