Soil fertility hinges on maintaining sufficient organic matter levels. It is crucial to adopt an integrated approach that includes organic fertilizers, rather than relying solely on chemical ones. While animal-derived manures are commonly used, they are often not available in large quantities. A great alternative to boost soil fertility and organic matter is green manure. Green manures consist of annual or perennial leguminous plants, cultivated either individually or more commonly in crop mixtures.
During peak planting, farmers face seed shortages, forcing them to buy expensive seeds or skip green manure. Empowering farmers to grow their seeds is crucial. To ensure high-quality seed production for green manure crops, the following steps should be considered:
COWPEA: Recommended for Punjab's irrigated areas, cowpea thrives in well-drained, organic-rich soils. CL 367, a dual-purpose variety yielding around 4.9 quintals per acre, is commonly suggested. For fodder, sow 12 kg per acre from March to mid-July; for seed production, sow 8 kg per acre in rows 30 cm apart from late July to early August. Inoculate seeds with 100 ml liquid biofertilizer. Apply 7.5 kg N (16.5 kg urea) and 22 kg of P2O5 (140 kg single superphosphate) per acre at sowing. Skip phosphorus if the preceding wheat crop received it. Provide 4 or 5 irrigations and ensure good drainage. Harvest ripe pods by hand or cutting when half to two-thirds mature to prevent seed loss during shattering.
SUNNHEMP: A rapid-growing leguminous crop, vital for fiber and green manure. It thrives in most soils except waterlogged ones, preferring loamy sand to loamy soil in tropical and subtropical climates. Recommended varieties include PAU 1691 (maturing in 136 days) and Narendra Sanai 1 (maturing in 152 days), yielding 4.8 and 3.9 quintals per acre, respectively. For seed production, sow in June with a seed rate of 10 kg per acre, spaced 45 cm apart in rows. Soaking seeds before sowing aids emergence. Apply 16 kg of P2O5 (100 kg single superphosphate) per acre at sowing. Ensure adequate irrigation during flowering and grain development to prevent water stress. Weed control may require hoeing one month after sowing. Harvest for seed production typically occurs from mid-October to early November, depending on sowing time.
DHAINCHA: Dhaincha is a vital leguminous crop primarily used as green manure, thriving in sandy loam to loamy soils. It exhibits tolerance to salinity and sodicity, though gypsum application is advised for soils with a pH exceeding 9.3. Notably, Punjab Dhaincha 1 (7-8 q ha-1 grain yield), with bold seeds and rapid growth, is recommended by PAU. Sow 8-10 kg seeds per acre from mid-June to mid-July, spacing at 45 cm. Apply 12 kg P2O5 (75 kg single superphosphate) per acre at sowing. Ensure no water stress during flowering and grain development. A hoeing session after a month aids in effective weed management. Harvest typically spans from mid-October to early November.
Finally, seek guidance from specialists at Punjab Agricultural University's Krishi Vigyan Kendras and Farm Advisory Service Centres regarding pest problems in green manure crops. By adhering to their advice, farmers can autonomously produce superior-quality seeds for green manure crops.