- (Public Value) UCANR: Protecting California's natural resources
- Author: Margaret Gullette Lloyd
Yes, mow it! Mowing works to at least prevent seed spread and regular mowing will weaken rhizomes.
Seed establishment has the greatest potential for the establishment and spread of johnsongrass and must be prevented. Therefore, mowing works to at least prevent seed spread. An individual plant can produce 28,000-30,000 seeds and a single inflorescence can measure 1,240 seeds (Keeley and Thullen, 1979). Viable seed may be produced as early as 2 weeks after flowering begins, so timely control measures throughout the season are needed to prevent seed production. Even though the viability of johnsongrass seed in soil remains high for as long as five years, seed can remain viable in soil up to 10 years.
Regular mowing can be effective in both orchard and non-crop situations. Due to its capacity to regenerate from rhizome fragments, complete control of S. halepense by mowing alone is difficult. Nonetheless, intensive grazing and mowing can be used to reduce a stand of johnsongrass. If grazed or mowed closely for at least two years, the plants become weak and stunted and the rhizomes become concentrated near the soil surface.
Consider mowing johnsongrass stands before seeds set to weaken current stands and avoid the spread through seed dispersal.
REFERENCE
P. E. Keeley, & R. J. Thullen. (1979). Influence of Planting Date on the Growth of Johnsongrass (Sorghum halepense) from Seed. Weed Science, 27(5), 554-558. Retrieved June 30, 2020, from www.jstor.org/stable/4043118
- Author: Margaret Gullette Lloyd
Are you concerned with your plant growth or wondering how your winter and spring activities (compost, cover crops, pre-plant fertilizers) are contributing to plant-available nitrate? If so, now is a great time to consider taking leaf or soil samples.
Here are easy ways to test for plant or soil nitrate.
SOIL NITRATE TESTS will tell you about the current plant-available nitrate levels. This can help you understand how compost, cover crops, pre-plant fertilizers as well as soil organic matter are currently contributing to nitrate in the soil.
Soil nitrate can be determined by taking a soil sample and sending it to a lab or using test strips which can be done in the field for an immediate estimate.
- How to Soil Sample for Nitrate Determination can be found here.
- How to use Soil Nitrate Test Strips can be found here
- Also, here's an instructional video on how to use Soil Nitrate Test Strips in the field.
PLANT TISSUE samples are useful for understanding the status of your plant nutrition (NPK), which helps answer the questions: are you meeting the crop demand or should you supplement? This can also help answer questions about whether symptoms you are seeing are due to crop nutrition or something else. Below is a list of the optimal plant tissue to sample for nitrate analysis. Click here for more detailed information.
The timing and type of tissue is unique to each crop. Use these tables as guidelines for your crop of interest.
