Article by Warrick Nelson, Plant and Food Research.
The Aspire Asparagus app is derived from extensive physiological analysis of the asparagus annual growth cycle. During this process, a key finding was that carbohydrate content of the root system provides information useful for making general crop management decisions about how to manage fern growth and spear harvest duration. Further, a simple root exudate test is an excellent measure of root carboydrate content that can be done on farm rather than sending samples away for analysis.
Asparagus stores carbohydrate over the dormant period from photosynthesis that occurs in the previous growing season. This carbohydrate provides the spears during harvest, but enough needs to be left to ensure enough ferns develop to capture sunlight through the growing season to supply carbohydrate for the following year.
We can think of this in terms of fuel used when driving a car. The fuel of interest is that used for our journey – like carbohydrate producing spears for harvest. However, to use the car example again, we need enough fuel left in the system to get to a fuel pump to refill the tank. This equates to the carbohydrate left in the roots that is needed to produce ferns for next season’s harvest. The carbohydrate content measure can be thought of as the fuel gauge. Experienced growers soon learn to interpret this to help make harvest decisions.
It would also be useful to know how big the fuel tank (asparagus root system) is. Estimating the size of the root system is an enormous amount of work and is certainly not practical other than for intensive research activities. Many attempts have been made to provide suitable proxies for estimating the size of the root system. However, research has shown that after about six years, the root system is generally reasonably stable in size unless severely stressed in some way. For this reason, many growers have found the carbohydrate measure used by Aspire is sufficiently useful to continue to use the concept to assist in decisions during the growing and harvest phases of their crop.
Aspire Asparagus Lite is available from the Google Play Store. Head over there on just about any relatively recent Android device and check it out.
The original research and development of Aspire was partially funded by the NZ Asparagus Council.
