We have gotten several calls about the use of zinc (Zn) fertilizers to address potential Zn deficiencies. The price of zinc is going up, and it is prompting growers to look more carefully at the use of zinc. Use of zinc fertilizers became widespread in the late 1970s after it was discovered that the “alkali disease syndrome” was caused by zinc deficiency. The problem was widespread in the Sacramento and San Joaquin Valleys and affected young seedlings after the first true leave emerged. The syndrome consisted of yellowing of leaves from the base up, weak leaves that floated in the water, and plants eventually dying 4 to 6 weeks after seeding, resulting in thin stands. Cool temperatures during the early part of the season can exacerbate zinc deficiency problems.
Currently, we do not know how widespread zinc deficiency is. We know that zinc deficiency is more common in alkaline soils (pH higher than 7). In such soils a level below 0.5 to 0.8ppm (obtained by theDTPA method) suggests a deficiency. In soils with pH lower than 7, the threshold for zinc deficiency is 0.3ppm. Duringtillering stage, a Y-leaf Zn concentration of
Based on research out of the 70s, you can correct for Zn in a couple of ways. First by applying a Zn fertilizer. This is most often done by adding some Zn containing fertilizer (e.g. zinc sulfate, chloride, or nitrate) to the starter fertilizer blend. In most fields, no more than 8 lbs of Zn/ac was needed to correct deficiencies. Another option is to coat the seed with Zn before planting. When coating seed, 2 lb of Zn per 100 lb of seed was enough.
If you are reassessing the need to use Zn, use the pH and Zn content of your soil to decide if the investment in Zn is justified. Also, if you are using a starter fertilizer that has Zn in it, you may be supplying enough to address any deficiency.
Field with suspected zinc deficiency./table>
- Author: Whitney Brim-DeForest
2019 Annual Rice Grower Meetings
Sponsored by UC Cooperative Extension
-------------- 5 Locations --------------
WHERE & WHEN
Richvale: Thursday, Jan. 17, 8:30am, Evangelical Church, 5219 Church St., Richvale
Glenn: Thursday, Jan. 17, 1:30pm, Glenn Pheasant Hall, 1522 Hwy 45, south of Glenn
Colusa: Friday, Jan. 18, 8:30am, Colusa Casino Resort, 3770 Hwy 45, Colusa
Marysville: Friday, Jan 18, 1:30pm, Yuba County Government Center, 915 8th St. Marysville
Woodland: Tuesday, Jan. 22, 8:30am, Cracchiolo's Market, 1320 E. Main St. Woodland
TIME: Doors open at 8:00 am and meetings start at 8:30 am at Richvale, Colusa, and Woodland.
Doors open at 1:00 pm and meetings start at 1:30 pm at Glenn and Marysville.
8:00 a.m. (1:00 p.m.) Doors open, sign‐in, coffee
8:30 a.m. (1:30 p.m.) Call meeting to order
California Rice Commission Referendum – Tim Johnson, CRC
8:50 a.m. (1:50 p.m.) Rice Research Board Nominations – Dana Dickey, Rice Research Board
9:00 a.m. (2:00 p.m.) Rice Pesticide and Regulatory Update – County Ag Commissioner
9:15 a.m. (2:15 p.m.) Weedy Rice and Emerging Weed Issues – Whitney Brim‐DeForest, UCCE
9:35 a.m. (2:35 p.m.) Arthropod and Disease Update – Luis Espino, UCCE
10:05 a.m. (3:05 p.m.) Season Review and Fertility Update – Bruce Linquist, UCCE
10:35 a.m. (3:35 p.m.) Weed Control Update – Kassim Al‐Khatib, UCCE
11:05 a.m. (4:05 p.m.) — ADJOURN —
****Applied for DPR and CCA CE credits****