Sign up for email alerts of new Fluid Journal issues!
Fluid Journal : Summer 2017
16 The Fluid Journal Summer 2017 a growing plant and can be lost to the environment. This sensor arrangement allowed observation of the effects of watering intervals between drip and sprinklers. Drip irrigation appears to have the ability to control irrigation intervals with much smaller increments of water. Visual differences can also be observed by the wetting pattern that occurs with drip irrigation. Instead of irrigating just the plants, a sprinkler system irrigates the areas between plant rows which allows a greater incidence of evaporation, leading to poor water use efficiency (Figure 4). Harvest and Results Potato plants were shredded, allowed to dry, drip tape was lifted and removed carefully from the field to assure no pieces of tape would be left in the field. The two center rows from each plot were lifted with a two row harvester and total potato harvestable weights were measured. A composite sample from each treatment was collected and placed in storage at a controlled temperature and at four weeks taken to Food Group for quality evaluation based on the Simplot contract. Based on those results, graphs were developed to illustrate measured differences within each treatment and compared to the same variety of potato produced under conventional sprinkler application. Drip irrigated potato yields were all higher compared to traditional sprinkler irrigation (Figures 5 and 6). The greatest response differences were observed for Russet Burbank and Alturas varieties and the smallest response differences in Ranger and Clearwater varieties. It should also be noted that there was no advantage or disadvantage from decreasing the rate of N applied (70% of GSP). However, there were additional positive responses to NutriSphere-N applied through the drip system for both Ranger and Alturas but nothing striking for Russet Burbank or Clearwater varieties in this study. It is interesting that both ends of the variety spectrum did not respond more favorably--Russet Burbank that is difficult to grow and Clearwater whose inputs are much more reasonable and of higher nutrient use efficiency. Perhaps this is also a reflection of irrigation use efficiency. Fry color (Figure 7) is a very important part of processing potato quality parameters and dependent on agronomic factors that include nutrient management, Figure 5. Total field weight for each variety of potato tested and summarized over the three years of drip studies (2 years for RB, 3 for Ranger and Alturas and 1 for Clearwater. This comparison is a relative comparison to sprinkler irrigation and indicates the percentage of yield above sprinkler. Figure 6. Specific gravity as it relates to comparisons of sprinkler and drip irrigation to different potato varieties—Parma Idaho, 2015-16. irrigation rates and timings as well as varieties. Treasure Valley, Idaho has been notorious for high sugar ends and this has been in the past reflected in percent color changes. However, these quality issues vary from year to year. There were greater changes in 2015 in Russet Burbank where all percentages of fry color were less than the other varieties. In 2016 the percent fry color was minimal for all other varieties (Russet Burbank not included). This was also true for irrigation effects on fry color. There did not appear to be challenges with fry color percent between sprinkler irrigation and drip. Perhaps this might be