Anticrustant Effects on Vegetable Seedling Emergence (1984)

Research report from OSU's North Willamette Agricultural Research and Extension Center

Delbert Hemphill
OSU Dept of Horticulture, NWREC

The purpose of this trial was to compare the anticrustant activity of phosphoric acid, a recently produced (1983) lot of the commercial anticrustant Nalco 2190, and an older (1980) lot of Nalco 2190 which had undergone some browning of the normally colorless liquid. It was speculated that the relatively poor performance of Nalco 2190 compared ti phosphoric acid in some previous trials might have been caused by breakdown with age of the Nalco 2190.


The plot area was rototilled for seedbed preparation and 'Salad Bowl' lettuce and 'Nantes' carrot were seeded with a Planet Jr. on July 26, 1983. Seeding rate was 6/feet for carrots, 3/feet for lettuce. No pesticides or fertilizers were applied. Phosphoric acid, new and old Nalco 2190, and a water-sprayed check treatment were applied immediately after seeding with a hand-held sprayer. In each case, the spray band width was three inches. Rate of phosphoric acid was 0.3 ounce/foot of a solution derived by mixing one part concentrated acid (85% H P04) with two parts water. Rate of both Nalco 2190 lots was 0.3 ounce foot of a 10% solution. Water was applied to check plots at the same rate.

Plot size was 20 row feet for each crop and each crop x treatment combination was replicated four times in randomized block design. irrigation of 0.75 inch was applied by overhead sprinkler on July 27 and again on August 4. Stand counts were made on August 2, 4, 8, and 11. Mechanical resistance of the soil was measured on August 9 with a Technical Products Co. penetrometer.


Lettuce emergence was initially more rapid, but carrot emergence surpassed that of lettuce by August 8 and final (August 11) carrot stand were much higher than for lettuce (Table 1). On August 2 and 4, lettuce emergence was greatest with phosphoric acid, intermediate with Nalco 2190. Carrot emergence at the early date was promoted only by phosphori acid. By August 8, no treatment significantly affected stands of lettuc but the same trend existed. Carrot stands at this date were more than doubled by phosphoric acid but not significantly improved by Nalco 2190. On August 11, the final stands of carrots were doubled by phosphoric aci (5.0 vs 7.5 seedlings/foot), and increased significantly, but to a lower degree, by Nalco 2190. In no instance were stands of lettuce or carrots affected differently by the two lots of Nalco 2190.

Emergence of seedlings was approximately inversely proportional to soil mechanical resistance (crusting). Phosphoric acid reduced mechanical resistance by 50%. The two lots of Nalco 2190 reduced resistance by approximately 20% (Table 1). Again, there was no evidence for significant differences between lots of Nalco 2190. This relatively poor performance of Nalco 2190 compared to phosphoric acid as an anticrustant on Willamette silt loam confirms previous results at the North Willamette Station but differs from results reported by certain other researchers. Relative activity of these anticrustant materials may be related to soil type or other local environmental conditions.

  Table 1. Effects of phosphoric acid and two lots of Nalco 2190 on stands of   lettuce and carrot and soil mechanical resistance 14 days after seeding                                   Stand (seedlings/ft.)                                     Lettuce              Carrots       Treatment	      8/2 8/4 8/8 8/11	   8/2 8/4 8/8 8/11   Soil MR(g)      Check                 0.1 0.2 0.5 0.6      0.1 0.1 2.2 2.5       730   Phosphoric Acid       1.0 1.1 1.2 1.3      1.1 1.5 4.8 5.0       365       Nalco 2190, old       0.6 0.8 1.0 1.1      0.1 0.1 2.9 3.2       585       Nalco 2190, new       0.6 0.7 0.9 1.0      0.1 0.2 2.5 3.5	 595        LSD(0.05)       0.6 0.7 NS   NS      0.3 0.3 1.1 0.6        88