It's not to save money on inputs or provide the highest yield, but it can allow a grower to harvest a crop sooner to avoid a frost," explains Yantai Gan, a research scientist at AAFC Swift Current, Saskatchewan.
"The maturity problem with chickpeas is that they have a strong indeterminate growth habit.When conditions are favourable, the plants continue their vegetative growth, which delays maturity.But with nitrogen fertilizer, the plants develop a more vigorous vegetative growth early in the season, which depletes applied nutrients and soil water, promoting earlier maturity."Gan
conducted three years of field experiments at Swift Current and Shaunavon, Saskatchewan from 2004 to 2006, with funding from the Saskatchewan Pulse Growers Association, the Saskatchewan Agricultural Development Fund, and the AAFC Federal MII
has summarized the results of the first two years, while the final year of data is being analyzed.However, Gan
says the trends in the first two years are evident in the 2006 data as well.
...Source: Gan, AAFC Swift Current.
"As a risk management tool, using nitrogen fertilizer looks very promising," says Gan
In 2006, Gan
says differences were relatively small, because precipitation in July and August was very low, and all crops matured quickly.
says that while the inoculant treatments often produced higher yields, they had to be balanced off with the risk of delayed maturity.
To use nitrogen fertilizer as a maturity risk strategy, Gan
says producers should carefully select the field.He
explains that a field that has a low residual soil N is a good choice for chickpeas.The field that had a crop with very high yield the previous year, such as a durum, canola or barley crop, would be good for chickpeas to follow this year because this land has low soil residual nitrogen.Conversely, summerfallow fields usually have very high residual nitrogen, along with the fields that had poor crops the previous year due to poor growing conditions, or the field that shows high fertility levels in a soil test are not good candidates for chickpeas.Gan
says that fields with 50 to 60 pounds per acre of available N would not be suitable for this strategy.
, AAFC Swift Current
, from 2004 and 2005 data.
"On fields with lower residual fertility, the nitrogen fertilizer applied at seeding is picked up quickly during the early seedling stages, resulting in vigorous vegetative growth which will be the foundation for pod production later on.Later in the season, the soil will run out of nitrogen-supplying power, and the chickpeas vegetative growth will shut down and seed set will start," explains Gan
.But if there is high soil residual N, it will allow plants to continue to grow because the residual soil nitrogen will be released gradually from the soil, and it may last for the entire growing season."
Once the 2006 data is crunched, Gan
will be summarizing the research and providing more specific recommendations.