Weather still wins

By Mike Rankin

Farmers and ranchers have a reputation of always talking and complaining about current weather conditions in the same way that police officers get hung with the notoriety of consuming donuts like they were an official USDA food group.

Both of these associations are no doubt exaggerated, but in the case of crop production, weather is still the Holy Grail that determines where the year will end on the scale of success to disaster. Planting improved hybrids and varieties that essentially handle stresses better than their predecessors will certainly temper weather effects, but the latter, especially in extreme doses like hurricanes and droughts, always trumps genetics.

Forage crops, grasses, and legumes are perhaps more impacted by weather conditions than other annual grain crops. This revelation was driven home to me about 10 years ago as I was analyzing the results from an alfalfa yield project that I was involved with as an extension agent.

The program entailed weighing all the production off of an alfalfa field for the life of the stand beginning with the first production year. Most of these fields, about 15 to 20 per year, were located on large dairy farms that had their own drive-over weigh scales. This was a long-term project that still exists today, so there were many years of data collected.

The purpose of the project was to document on-farm alfalfa yields in Wisconsin. Most of the farm cooperators were excellent managers; they planted the best varieties, fertilized to recommended levels, controlled pests, and cut for high quality. Still, year in and year out, the average total-season dry matter yield across all these farms was usually between 4 and 4.5 tons per acre.

The alfalfa yields on these farms were certainly higher than the state average reported by USDA, but they were also well below what we knew was alfalfa’s potential based on small plot research from Midwest universities and seed companies.

So where was the disconnect?

The obvious place to start was simply the high level of care given to small plot research. Such research trials don’t deal with the complexities of soil type and geography differences found in most large fields. They also don’t have to withstand the rigors of heavy wheel traffic imposed during multiple harvests per year, which no doubt takes its toll on yields.

I’m sure all of the above factors contribute to lower farm yields relative to small plot trials, but here was my bigger revelation that affects both farm and also small plots alike. Alfalfa and other forage species that are harvested multiple times per year don’t have just one annual growing season, they have multiple growing seasons or cycles.

Let’s say, for example, there is a two- or three-week dry spell in the middle of summer that may not even show up on USDA’s Drought Monitor map. Full-season annual crops such as corn and soybeans can often fully recover once precipitation resumes, but in the case of perennial forages, one of the growth cycles or “growing seasons” is severely impacted . . . and so are yields for that harvest.

In the alfalfa trial referenced earlier, this type of phenomena occurred on almost an annual basis. We would measure tremendous first and second cutting yields, then the third cutting would be south of 1 ton of dry matter per acre. In some years, it was the first, second, or fourth cutting that was significantly down. Regardless, essentially losing that one cutting because dry weather took a major toll on harvested yields for these nonirrigated farms.

This same scenario can be applied to grazed forages, and the ramifications may even be worse because livestock producers are forced to feed stored hay or overgraze their paddocks, which further reduces productivity even after soil moisture is regenerated.

Yes, weather wins, but the prudent farmer without irrigation recognizes this fact and prepares for those times when a forage growth cycle or two is essentially lost. Planning stored forage and/or pasture inventories needs to be better than a Goldilocks (just enough) approach. There are a multitude of ways to accomplish this.