Tillers, rhizomes, and stolons are three types of branches produced by grass plants. All are stems that branch at some point from the crop’s mainstem or from other stems.
The tiller is an above-ground branch on a grass plant. Tillers are an important component of the crop’s shoot system and through carbon capture and partitioning, contribute to seed yield. As a tiller grows and develops, additional tillers can form in the leaf axils of that tiller. All grasses produce tillers. Continue reading →
Grass seed crops are biologically inefficient in the production of seed. Many flowers are produced by these grasses yet relatively few of the flowers become seed, thus the potential seed yield may be many times greater than the actual seed yield harvested. Losses due to inadequate pollination and fertilization, abortion during seed development, and seed shattering all contribute to the relative low numbers of seed that are harvested compared to the crop’s yield potential.
Under certain conditions, the tiller cannot support the weight of the developing inflorescence and seed. The tiller lodges or falls to the ground, especially when there are high levels of nitrogen fertilizer and soil moisture present (Fig. 1). Both conditions are common in Oregon’s commercial grass seed production fields in the spring. But will that be the case in spring 2013?
The winter months of January through March 2013 have been the 2nd driest winter period on record at Corvallis with only 6.28 inches recorded. Can we expect more of the same dry weather during spring? No one can say for sure, but an examination of weather records for the past 124 years reveals that when precipitation is very low (50% or less of the 16.02 inch normal) in January through March, the following April through June period averages 5.78 inches or near normal rainfall (normal is 5.83 inches).
Despite the very dry weather that has been recorded to date, there may still be enough rainfall present in coming months to make lodging a problem for local seed growers.
Figure 1. Lodging in ryegrass. (T.G Chastain photo)
Why is lodging important in grass seed crops? Under certain conditions, the tiller cannot support the weight of the developing inflorescence and seed. The tiller lodges or falls to the ground, especially when there are high levels of nitrogen fertilizer and soil moisture present (Fig. 1). Both conditions are common in Oregon’s commercial grass seed production fields in the spring.
Figure 1. Lodging in ryegrass. (T.G Chastain photo)
One question that is on the minds of seed producers is how much has the cold weather set crops back? Over the 123 years of weather records at Corvallis, there has been only 15 times that the month of March has been colder than we experienced in March 2012. Cold spring weather has been a phenomenon that’s been observed here in the Willamette Valley over the past few years (Fig.1). This cold weather was accompanied by near record wet conditions (Fig. 2).
Figure 1. Monthly average temperature at Corvallis (click to enlarge)
