The fall rains caught some people by surprise last October and there was some alfalfa that did not get planted. Other people lost stands due to flooding and high water tables and are motivated by high hay prices to replace that acreage. Now that there looks to be a break in the weather, it might be possible to rush out and get some new alfalfa planted. What's the prognosis for spring planted stands?
First of all, it is never a good idea to follow alfalfa with alfalfa. At least two years of another crop is recommended before returning to the same ground with alfalfa to prevent premature stand loss. If it is desired to fill in drowned out ends of fields, consider sudangrass planted later in the spring after temperatures turn warm.
Second, fields that have had inadequate ground preparation such as ripping and leveling will seldom produce long lasting, high yielding hay. While it may be possible to get on some light ground, doing a good job of land preparation will not be possible until the ground dries out a lot more than it is now.
But even if ground preparation is adequate, there are other reasons to avoid spring plantings of alfalfa. First, because there is less time to grow, the first cutting will not be made until summer, and first year yields will be only a portion of a fall planted stand because there will be fewer cuttings. Most important, however, is the physiology of the alfalfa plant itself. While mild spring temperatures are optimum for growth of the alfalfa plant, day length determines whether the seedling plant is putting more of its energy into growing roots or growing tops. In the fall, decreasing day length favors the establishment of a good root system. In the spring, with increasing days, the plant will produce a lot of top growth, but will not put much energy into forming roots. In some planting date studies, poorer yields from spring plantings have carried over into the second year.
In a 1977 study in Yolo County, first year data showed a yield advantage of almost 4 tons the first season for the September planting compared to the March planting. A second study in 1978 showed an almost 5 ton advantage for a September planting over the March planting. Similar studies in Fresno County gave a 3 ton (1979) and 4 ton (1988) yield advantage of fall over spring plantings.
Considering the investment in ground preparation and seed, it may be more profitable to grow another crop this spring and delay planting of alfalfa until early fall, when conditions are much better for obtaining a high yielding, long lasting stand.
November 5, 1999