Answer:
Farmers use a mixture of manures and fertilizers in the field for several reasons. These reasons are primarily related to soil health, crop yield, and environmental sustainability.
Soil Health
1. Nutrient Supply: Both manure and fertilizers provide essential nutrients to the soil that are necessary for plant growth. Manure, which is organic matter derived from animal waste, is rich in nutrients such as nitrogen, phosphorus, and potassium. Fertilizers, on the other hand, are typically synthetic substances that contain specific proportions of these same nutrients. By using a combination of both manure and fertilizers, farmers can ensure that their soil has a balanced nutrient profile.
2. Soil Structure: Manure also contributes to the physical structure of the soil. It increases the soil's ability to hold water and improves its texture, making it easier for plant roots to penetrate. This is not something that synthetic fertilizers can do.
3. Microbial Activity: Manure is also beneficial because it promotes microbial activity in the soil. These microbes play a crucial role in nutrient cycling and help make nutrients more available to plants.
Crop Yield
4. Increased Productivity: The use of both manure and fertilizers can lead to increased crop yields. The nutrients provided by these substances promote healthy plant growth, leading to more productive crops.
5. Sustained Yield Over Time: Using a combination of manure and fertilizers can also help sustain high crop yields over time. This is because manure helps improve the long-term health and fertility of the soil, while fertilizers provide a quick boost of nutrients that can be immediately used by plants.
Environmental Sustainability
6. Recycling Waste: Using manure as a fertilizer allows farmers to recycle animal waste, turning it into a valuable resource.
7. Reducing Chemical Use: By using manure in addition to synthetic fertilizers, farmers can reduce their reliance on chemical inputs. This can have benefits for the environment, such as reducing runoff pollution.
8. Promoting Biodiversity: The use of organic matter like manure can also promote biodiversity in the soil, which has benefits for the overall ecosystem.