Green Manure

Green Manure

News: The Punjab agriculture department is promoting the cultivation of green manure these days.

About:
• Green manures are crops grown specifically for maintaining soil fertility and structure.
• It is done by leaving uprooted or sown crops parts, allowing them to wither onto the field and serve as mulch and soil fertilizers.
• They are normally incorporated back into the soil, either directly, or after removal and composting.
• Three main varieties of Green Manure are Dhaincha, Cowpea and Sunhemp.
• Green manure must be leguminous in nature
• They must bear maximum nodules on its roots to fix large amount of atmospheric nitrogen in the soil

Why Punjab needs Green Manure?
• Punjab’s per hectare fertilizer consumption is one of the highest in the country and is also higher than national average
• Switching to Green Manure can curtail this consumption to a large extent and can save huge input costs for farmers
• High intensity agricultural practices is prevalent in Punjab which requires lot of chemical fertilizers. This in-turn also leads to deficiencies of micronutrients like Iron and Zinc, affecting crop productivity.
• In such scenarios, Green Manure is a viable alternative which not just improves soil health but also enhances crop productivity.

How does it help soil and crop?
• Increases organic matter in the soil
• Decomposes rapidly and liberates large quantity of Carbon Dioxide and weak acids, which act on insoluble soil minerals to release nutrients for plant growth.
• They naturally suppress weed growth, hence preferred by farmers.
• Soil erosion is prevented with improved stability of the top-soil. This helps to improve the overall soil structure by providing porosity and aeration in the soil.

Limitations of Green Manure:
• Excessive use of Green manure may cause over-fixation of nitrogen and phosphorous into the land making it toxic and further leading to nutrient pollution.
• Costly for farmers
• Farmers won’t be able to plant their marketable cash crop during the manure phase as sometimes they may choose to increase land fertility rather than plant crops.
• The green manure crop may sometimes compete with the crops that will be the primary source of income.