RELATING POTATO YIELD AND QUALITY TO VARIABILITY IN SOIL CHARACTERISTICS

Authors: REDULLA, C - WSU-IAREC, PROSSER, WA; DAVENPORT, J - WSU-IAREC, PROSSER, WA; Evans, Robert; HATTENDORF, M - WSU-IAREC, PROSSER, WA; Alva, Ashok; Boydston, Rick

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/1/2002
Publication Date: 6/1/2002
Citation: REDULLA, C.A., DAVENPORT, J.R., EVANS, R.G., HATTENDORF, M.J., ALVA, A.K., BOYDSTON, R.A. RELATING POTATO YIELD AND QUALITY TO VARIABILITY IN SOIL CHARACTERISTICS. AMERICAN JOURNAL OF POTATO RESEARCH. 79:317-323. 2002.

Interpretive Summary: An increasing number of growers are monitoring potato yield during harvest. However, the relationship between within field tuber yield variability and soil properties is poorly understood. These studies were conducted from 199 to 2000 on a commercial farm in southeastern Washington to better understan the causes of within field yield variability. Selected center-pivot irrigat tfields were soil-sampled on a grid prior to planting potatoes. The soil samples were analyzed for plant nutrients, organic matter, pH, texture, and other chemical properties. Potatoes were harvested using the same grid pattern. Differences in soil texture contributed to potato yield variabilit in two fields. Soil pH contributed to variability in potato tuber yield on two other fields. Soil textural class, pH, and OM all contributed to within field yield variability, but results suggest that other unmeasured soil, environmental, or pest variables contribute to the spatial variability of potato yield and quality. Growers can utilize these results to facilitate interpretation of potato yield maps and researchers can focus on additional factors that may affect the yield variability within a field.

Technical Abstract: There is a void in our understanding of the causes of within-field spatial yield variability in potato (Solanum tuberosum L.). To address this void, a study was conducted from 1998 to 2000 on a commercial farm in southeastern Washington. Selected center-pivot irrigated fields were soil-sampled on a 0.4-ha grid interval prior to potato planting. The soil samples were analyz zfor nitrate-N, ammonium-N, P, K, organic matter, pH, texture, and other chemical properties. The altitude at each grid point was also measured. Fo to five days before commercial harvest, a 3-m long potato row was harvested at each original grid point using a one-row digger. The potatoes were weighed, sorted into five different size classes by weight, and evaluated f specific gravity. Correlation and stepwise regression analyses were conduct on the data from four fields, which had been uniformly fertilized. The soil variable which had the highest r with yield differed among fields. Highest correlation coefficient with the yield variable was with sand (r = 0.33, < 0.01) and silt (r = -0.33, P < 0.01) on one field, with clay on a second field (r = 0.20, P = 0.04), and with pH on the two other fields (r = -0.22, P = 0.04 and r = -0.18, P = 0.12). Stepwise linear regression analyses with yield as the dependent variable revealed that soil textural class, pH, and contributed the largest partial R2 of the model although the highest model obtained was < 0.42 indicating other soil, environmental, or pest variables contribute to the spatial variability of potato yield and quality.