**Chapter 9**

**143**

**129**

Preface

Both developing and underdeveloped countries have adopted strategies to produce economically optimal agricultural products to feed the world's growing population, which is expected to reach 9 billion in the first half of this century according to the United Nations Food and Agriculture Organization (FAO). Since the main goal of these strategies was to increase the amount of production, soil productivity was prioritized, whereas the fertility factor of soil was ignored. To increase productivity, chemical fertilizers were used excessively and uncontrollably, which caused many short- and long-term problems in the fertility of the soil, continuity of biodiversity, and the sustainability of the balance in nature. Improper fertilizer applications led to an increase in soil salinity, insufficiency of nutrient elements in soil, increased diseases and pests, pollution of the environment, agricultural lands, and drinking water and rivers, and contributed to climate change, which increased the biotic and abiotic stresses on plants and harmed sustainability. As a result, the use of chemical fertilizers decreased agricultural production in the long term. This outcome triggered the efforts to develop agricultural activities involving organic inputs to regain biodiversity, maintain the ecological balance, and decrease the adverse effects of

By definition, a fertilizer is any material of natural or synthetic origin that is applied

to soil or plant tissues to provide at least one, but often more, of the nutrients required for plant growth. Most fertilizers that are currently used in commercial agriculture provide the three main nutrients: nitrogen, phosphorus, and potassium. These fertilizers are produced industrially from petroleum and petroleum-based products. On the contrary, organic fertilizers are derived from natural sources such as vegetable matter (e.g., compost and crop residues), animal manure, natural rocks, algae extracts, and so on. They are mostly richer in composition compared to chemical fertilizers and provide more nutritional elements as well as beneficial microorganisms. One of the main advantages of using organic fertilizers is that they increase the resistance of plants against biotic and abiotic stress conditions by boosting their immune systems. Moreover, they provide a slow, long, and sustained

Several natural resources, biological products (beneficial bacteria, lichens, algae, and fungi), mineralization products of plant and animal residues (leonardite, humic acid, rock phosphate, bat manure), fermentation products of waste by worms (worm manure), and products obtained from waste of slaughterhouses (amino acid products) are used in agricultural production as organic fertilizers. Although the use of these environmentally friendly products enables the regeneration of natural resources, improves the productivity and fertility parameters of soil, and contributes to carbon footprint management and sustainability, the substitution of chemical fertilizers with these organic products by producers is still slow due to lack of awareness. These products will get greater recognition only when their benefits

Besides the aforementioned natural sources, solid wastes of organic origin in the agricultural and industrial wastes can be converted into new organic products to

chemicals on human health.

release of nutritional elements for plant uptake.

are explained thoroughly and scientifically.

The Insects as a Workforce for Organic Fertilizers Production – Insect Frass *by Regina Menino and Daniel Murta*
