India: Sustainable rotations
Paraquat enables higher sugarcane yields and provides weed control for lucerne crops in India while reducing the cost of labor and materials.
In the Indian State of Maharashtra, sugarcane and lucerne are often grown on the same farm, together with dairy cows. Sugarcane is the cash crop, while the lucerne is used for cattle feed. Paraquat is a unique component of this sustainable system. With its contact action and minimal environmental impact, paraquat provides weed control at a lower cost than the region’s scarce manual labor or any other herbicide program.
In sugarcane, paraquat is usually sprayed in tank mixture with 2,4-D 15-20 days after emergence of new cane shoots. Paraquat's contact action suppresses these shoots and stimulates more side shoots to be produced, with a consequent yield improvement. By delaying herbicide application in this way, weeds are controlled for at least 45 days until the crop canopy closes and they are no longer a problem.
In lucerne, paraquat is applied every 21 days after cutting the crop. Since the herbicide is inactivated on contact with soil and has no systemic activity, weed control is achieved without damaging the lucerne root system from which new shoots quickly emerge and the cycle begins again.
In addition to the benefits paraquat provides farmers in increased yields and weed control, sustainable benefits of this system are:
- Considerably reduced need for artificial fertilizers because the lucerne crop enriches the nitrogen content of the soil ready for the following sugarcane crop. Manure from the cattle is also returned to the fields
- Low artificial fertilizer requirement minimizes soil damage and ground water contamination
- Waste material from the sugar mills is spread on the fields, improving soil organic matter content, stimulating crop growth and increasing numbers of soil organisms.