2017 ASHS Annual Conference

A controlled experiment was conducted to compare the dynamics of yield and quality for the mother stalk as compared to the standard 6-week clear-cut harvesting strategies. Crowns were produced of three distinct asparagus genotypes and replanted in a uniform experimental configuration in spring 2011. The experimental design was randomized block with two factors (variety and harvesting method), four replications, and three years. The daily harvesting treatments were: 1) standard harvest (clear cut for 6 weeks from start of season); 2) Extended standard harvest (10 weeks); 3) mother stalk harvest; 4) 2 weeks standard followed by mother stalk harvests; 5) no spring harvest, remove foliage late July, then clear cut for 6+ weeks. Treatments were applied to the same plots for the duration of the experiment. The mother stalk harvesting method consisted of three shoots allowed to mature into the canopy from each crown in the plot, followed by removal of all new spears thereafter. Mother stalk treatment plots were staked, trickle-irrigated, and fertigated. Each plot was harvested at regular intervals (usually daily) and spears were accumulated for one week, then graded and weighed. Dynamics of yield were similar for all varieties and years: The standard harvest treatment resulted in high relative weekly yields during the 6-week harvesting period, while weekly yields from the mother stalk treatment were generally lower. In all cases, mother stalk treatments “caught up” with the standard harvest treatment. Full-season mother stalk total cumulative yields ranged from 116.5 to 167.9% of the corresponding standard harvest treatment. The three varieties all exhibited overall 3-season average cumulative season yield increases in the mothers stalk treatment ranging from 34.3 to 55.7% as compared to standard harvest. Spear size/girth generally declined as the mother stalk season progressed, but spear quality remained high generally until late August. Overall, acceptable spear yields and quality could be sustained for up to 22 weeks. Due to higher costs of finished goods and unstable market conditions during the June-August time frame in North America, the mother stalk method is currently recommended only for direct marketing and value-added (branded/packaged) applications.