Chile stand management for mechanical green chile harvest

Authors: HAVLIK, CHARLES - New Mexico State University; WALKER, STEPHANIE - New Mexico State University; Funk, Paul

Submitted to: New Mexico Chile Conference
Publication Type: Proceedings
Publication Acceptance Date: 2/23/2016
Publication Date: 2/23/2016
Citation: Havlik, C., Walker, S., Funk, P.A. 2016. Chile stand management for mechanical green chile harvest. 2016 New Mexico Chile Conference. Proceedings.

Interpretive Summary: Specialty crop mechanization requires changing the entire cropping system including cultivar selective breeding, production processes, harvest mechanisms, and processing plant equipment. This study looked at the response of two commonly planted cultivars to changes in the spacing between the plants. It confirmed work done with antique cultivars that indicated that crowding chile pepper plants makes them grow in a way that works better with machine harvest and does not reduce total yield, at least up to a point.

Technical Abstract: Currently the red chile crop is mechanically harvested. Because the pods will be dehydrated before consumption, breakage and bruising of red pods is not a concern. Green chile, however, is currently hand harvested because of the fragile nature of the fruit and the need to avoid pod damage. Hand harvesting green chile is labor-intensive and expensive. Converting to mechanically harvesting green chile is challenging. One aspect of the challenge is plant architecture, which might be improved by appropriate thinning treatments. Earlier studies have suggested that closer plant spacing can have a beneficial impact on machine harvested fruit quality and yield. The objective of this experiment was to determine optimal plant spacing for mechanical harvest based on fruit size, quality and marketable yield. Two New Mexico green chile cultivars, NuMex Joe E. Parker (Biad Chili Company, Las Cruces, NM) and AZ-1904 (Curry Chile and Seed Company, Pearce, AZ), were direct seeded on April 17th, 2015 at the New Mexico State University Ag Science Center in Los Lunas, NM in a randomized complete block design with five replications of three thinning treatments. The field was irrigated, fertilized and cultivated following normal production practices. On June 11th, 2015 the plots were hand thinned to the planned treatments resulting in stands with plants four, eight, and twelve inches apart. On September 1st, 2015 after taking plant measurements and cleaning ground fall from each plot the fruit was harvested using an Etgar® MOSES 1010 (Bet-Lehem-Haglilit, Isreal) inclined open double helix pull harvester. It was designed for high crop recovery and minimum damage in both green and red chile. Harvest data included weights of undamaged green fruit harvested, broken fruit, fruit left on the ground, fruit left on the plants, and extraneous matter. Ten pods from each plot were sampled for fruit dimensions weight, width, length and fruit wall thickness. Variability made it difficult to separate treatment results, but in general the NuMex Joe E. Parker yielded about 30% more marketable product than the AZ-1904, and closer plant spacing increased yield from 25 to 50%. The NuMex Joe E. Parker and the AZ-1904 had similar amounts of broken fruit. There was a statistical significance between the NuMex Joe E. Parker thinned to 12 inches apart (3.09 kg/plot) and AZ-1904 thinned to 4 inches apart (6.03 kg/plot). The NuMex Joe E. Parker and the AZ-1904 had similar amounts of fruit left on the ground and left on the plant. There was a statistical significance with fruit left on the ground between the NuMex Joe E. Parker thinned to 4 inches apart (1.79 kg/plot) and AZ-1904 thinned to 8 inches apart (5.42 kg/plot). In general the AZ-1904 had fruits that were heavier and longer, yet there was no statistical significance between the two cultivars. The fruit size results were mixed. There are more results currently being analyzed which will be forthcoming.