Pasja Turnip Potential as a Cover Crop or Forage
Feature article from the Central Grasslands Forum - Fall 2014 edition
Fara Brummer, Area Extension Specialist / Livestock Systems, CGREC
Pasja (pronounced pas-jah) turnip is a brassica hybrid that has garnered interest in recent years due to its potential use as a fall cover crop for soil health application, as well as foraging benefits that can extend the livestock grazing season.
Pasja was developed in New Zealand by crossing a forage turnip with a forage rapeseed. Producing a high amount of leafy biomass, Pasja turnip has a root that is longer and more tapered than other turnips. The narrower root can penetrate soils and assist in infiltration. It is also a drought-resistant plant.
Pasja can be planted in late spring or early summer as a full-season crop, or in August for extended grazing season benefits. Most producers in North Dakota are utilizing Pasja turnip as part of of cover crop mixture that is seeded in August into fallow (prevented-planting acres) or into harvested cereal grain stubble. In Nebraska and elsewhere, producers are flying on mixes containing Pasja turnip into their corn fields so that grazing options are available after corn in harvested.
Fertilization of Pasja turnip is important. Nitrogen requirements are from 50 to 100 pounds/acre, with available phosphate at 60 pounds/acre, for establishment and production success. Pasja should be seeded as part of a cover crop mix where legumes can provide nitrogen benefits to the developing plant.
Here at CGREC, plot trials with Pasja turnip have shown a yield of up to 15 tons/acre (as fed). However, due to its high water content, actual dry-matter yields are approximately 1.5 tons/acres for a full-season crop planted in late May.
Pasja turnip contains a high level of energy and digestibility that should be balanced with other forage or cereal grain species to slow the passage of nutrients in the grazing ruminant. Also, like any brassica species, Pasja can be high in glucosinolates, which are compounds that can cause thyroid problems in cattle. These compounds will be lower in late fall as leaves turn yellow or after a hard frost. However, take care to graze cattle with Pasja turnip as part of a mix where other species are also available.
Forage quality information from CGREC has shown Pasja turnip to be high in crude protein as well as digestible energy. During three years, the turnip averaged a crude protein value of 15 percent pre-freeze and post-freeze, while dry-matter digestibility was 88 percent pre-freeze and 85 percent post-freeze.
The current price of Pasja turnip seed is about $3.25/pound. While higher than other cover crop species, the usual seeding rate in a mix is only about 1 to 2 pounds/acre. With the high grazing values and the price of cows today, Pasja has the potential to become a part of a cover crop mixture with beneficial grazing application.
For a comparison of Pasja turnip with other annual forage species, see this article by Guojie Wang and Matthew Danzl in our 2013 Annual Report.