Editorial Book

Book Title: Handbook of Organic Farming

PAID ACCESS | Published on : 11-Aug-2026 | Pages: 91-102 |

Cover Crops and Green Manures- Role of Cover Crops in Soil Fertility and Weed Suppression

• Rajender Sharma
• Department of Vegetable Science, DR YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP), India.


• Aanchal Chauhan
• Department of Vegetable Science, DR YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP), India.


• Reena Kumari
• Department of Vegetable Science, DR YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP), India.

Abstract

This chapter highlights the vital roles of cover crops and green manures in enhancing soil fertility and suppressing weeds within sustainable agro-ecosystems. Both being important ecological tools, green manures are ploughed directly into the soil to rapidly release nutrients upon decomposition, while cover crops primarily protect topsoil from erosion, improve water infiltration and minimize nutrient leaching between cash crop cycles. Categorized functionally into leguminous species (Fabaceae), grasses/cereals (Poaceae) and brassicas (Brassicaceae), these crops offer distinct agronomic benefits. Legumes supply fixed biological nitrogen (often 80-100 kg N ha^-1), making 40-60 per cent of total N progressively available to subsequent crops. Conversely, deep-rooted non-legumes act as scavenger crops, preventing nitrate leaching by up to 95 per cent, mobilizing sparingly soluble phosphorus through organic acid exudation and building soil organic matter. Weed suppression relies on physical, chemical and competitive interactions. Rapid canopy growth restricts light access, surface residues act as thermal and physical barriers post-termination, and chemical mechanisms-such as allelopathy (e.g., benzoxazinoids in rye) and biofumigation via glucosinolates (in brassicas)-actively disrupt weed germination and soil-borne pathogens. Integration into crop rotations requires balancing termination timing and species selection using mechanical incorporation, no-till crimping, or herbicides, as well as multi-species polycultures to optimize carbon-to-nitrogen (C: N) ratios. However, operational problems present significant practical challenges.

Keywords

cover crops and green manures, soil organic matter, green bridge, Crop rotation, leaching

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