What is the genetic yield potential of forages and vegetative crops, rather than reproductive crops such as corn and tomatoes?
These vegetative crops do not have the same genetic constraints as reproductive crops. For these crops, the limit to growth and yield is the photosynthetic capacity. When optimal CO2, water, sunlight, and nutrients are provided grasses and forages can be extraordinarily productive, as described in this cover article of Acres USA in early 1977.
Original Acres article:
Moving cows from pasture to pasture has a long and respected history, notably in Australia and arid territory where overgrazing is a capital sin. Its application to irrigated and rain belt pasture has seldom been tested on a controlled basis.
Last summer, C.J. Fenzau of Boise, Idaho divided a 31-acre field into single acre plots. He put 272 cattle into the first single acre plot when the grass was knee-high on April 5, 1976. By the next morning the first plot had been mowed down much like a city lawn. During that single day the cattle had eaten the whole plant-the rich upper part, the leafy mid-part, and the fibrous stem. This gave the animals a total ration, a well-balanced ration at that.
“If you put cattle on fresh young pasture,” Fenzau told Acres U.S.A., they eat the high protein buds the first day. The next day they get a little less value, and so on. In four or five days of milking, you see a cow on pasture give more milk than any grain would ever produce. As pastures go down, farmers put in grain. This animal is fighting her own droppings in the pasture. She is compacting the ground. When you’re stripping a plant, you’re putting it under stress each day, and you have less leaf capacity for photosynthesis. But in 30 days a plant has a chance to grow back all the leaves in their full working power for more productivity.”
On the second day, the cattle were moved to acre No. 2. The first acre was then given a shot of irrigation water. This melted away the still-soft droppings and set the stage for at least 30 days of growth. There was a second irrigation during the 30 to 35 day growth period.
The growth period was stretched to 35 days as cattle were shifted from acre No.2 to Acre No. 3, 4, 15, 20, whatever. During May, June, and July only 20 of the 31 acres were used. Cattle couldn’t mow down the grass fast enough.
“We’re looking at having 400 head of 500 to 600 pounders there next year to utilize the grazing potential of those 31 acres to the optimum,” Fenzau summarized.
What does this amount to in terms of beef production? Over the scales, Fenzau logged in 2.4 to 2.5 pounds of grain per head per day. A total of 2.25 or so on 400 head means 1,000 pounds of beef per day. This multiplied by 200 days comes to 200,000 pounds of beef off 31 acres, or in excess of 6,000 pounds of beef per acre.
Needless to say, the best fertility management has to underscore such heads-up farming. This management has only one name—scientific eco-farming.
These results were achieved in 1976. Today is 2020. 44 years. Who will follow through and test what new forage genetics are capable of when provided optimal water, CO2, sunlight and nutrients?
This is without question the most efficient protein production per acre.