Don’t guess. Soil test!

Dustin Harrell, LSU AgCenter rice specialist
Dr Dustin Harrell
Extension Rice Specialist

There are several nutrients we should pay close attention to when it comes to rice production. Along with nitrogen, the most important nutrients to monitor include phosphorus, potassium, sulfur and zinc.

When I make farm visits to evaluate nutrient problems, the culprit is generally one of these five. Visual observation of nutrient deficiency symptoms is one tool used to diagnose which nutrient is the problem, but another even more powerful diagnosis tool includes the results from a recent soil test.

The truth is that a calibrated soil test is very good at providing an availability index of the important plant nutrients. Calibrated soil tests also include fertilizer recommendations needed to provide optimum yields while preventing the occurrence of yield-limiting nutrient deficiencies during the growing season.

Although soil testing is a very powerful tool that estimates nutrient availability and provides research-based fertilizer recommendations, many growers still do not use it. Low rice yields and poor economics over the past few years have many growers looking for places to save money.

Soil testing and reduced fertilizer rates are often the first line in the budget to be cut. However, are you really saving money when you are losing yield to unexpected nutrient deficiencies? Absolutely not.

In this upcoming growing season, be sure to use soil testing to determine nutrient levels and fertilizer needs. Who knows, a soil test may inform you that you have been applying a nutrient annually that is not needed. Last, but not least, the most important take home from this article is that when it comes to applying fertilizer nutrients, don’t guess. Soil test!

Weeds: What should you be aware of in 2020?

Whitney Brim-Deforest
Dr. Whitney
University of California Cooperative Extension Rice and Wild Rice Adviser

Managing weeds in California rice has always been complicated, and it seems to continue to get more so every year. Last year due to late rains, weed control was particularly troublesome.

In many cases, there was insufficient time to prepare the seedbed before planting, and excessive amounts of water in the field diluted granular herbicides. Although we do not yet know how different the weather may be this year, there are some key things to be on the lookout for this season:

1) Watergrass control: Over the past couple of years, we have become aware of a couple of watergrass species or biotypes that are increasingly difficult to control with herbicides. While we do not yet know the species, we can provide some tips:

a. Go as early as you can in your watergrass control program, either at day of seeding or pre-emergence, if possible. This particular species/biotype grows quickly and outcompetes the rice if allowed to get a head start.

b. Tankmix two grass herbicides or apply sequential applications of grass herbicides as quickly as possible. This helps to overwhelm the plants’ ability to process the herbicides if they are metabolically resistant. If they are target-site resistant, having multiple modes of action will increase the likelihood of control.

c. Keep water depth high, especially at the beginning of the season. Watergrass species can emerge through flooded conditions, but their emergence is suppressed.

2) Weedy rice: Although not a widespread problem (about 3% of California acres are infested), we want to continue to keep the populations low and stop the spread to new fields and farms. Please report any suspicious plants to your local farm adviser.

3) Drift: Many of our rice-growing counties now allow for outdoor hemp farming or will allow it for the first time in 2020. Since we do not yet know the effect of rice herbicides on hemp, it is important to continue to exercise caution when applying foliar herbicides, following label directions and county restrictions on aerial spraying, and checking for wind speed and direction.

4) Herbicide Update: RebelEX is a Corteva product that has been registered in California since 2012. It has not been marketed, however, so it is not in widespread use. RebelEX is a liquid formulation, combining Clincher (cyhalofop-butyl) and Granite SC (penoxsulam). The application timing is from one-leaf rice up until 60 days before harvest. It is an excellent grass control herbicide, but pay close attention to whether cyhalofop-resistant sprangletop and/or watergrass species are present. Presence of resistance will decrease efficacy of this product.

Weed management continues to pose new challenges every year. Growers and pest control advisers are the first line of defense to ensuring new species do not spread as well as ensuring that everyone is practicing safe and efficacious herbicide applications.

On your mark, get set, plant!

Dr. Mo Way
Dr. M.O. “Mo” Way
Rice Research Entomologist

We are at the start of the 2020 field season, but really, Texas farmers should have begun prepping for the 2020 field season back in the fall of 2019. Timely land prep prior to the 2020 field season is crucial for a successful 2020 rice crop.

I know farmers west and south of Houston have had good weather relative to being able to disk, land level and harrow fields last fall and this winter. However, rice farmers east of Houston have not been as fortunate. Seems like every seven to 10 days on the east side of the Texas Rice Belt, we get a rain that prevents field preparation.

So if you have not prepped your fields by this time due to persistent, wet weather, be poised to take advantage of any window of opportunity to get in the field and begin/continue working ground. Clearly, timely field prep allows for early planting, which helps ensure good yields on both the main and ratoon crops.

We experienced extremely wet weather at the end of the 2017 season (think Hurricane Harvey) and 2019 season (think Tropical Storm Imelda). A lot of main crop rice had not been harvested when these events occurred, demonstrating the importance of planting early.

chinch bugs
A greenhouse study highlights the amount of damage adult chinch bugs may cause to rice plants at various populations. Two adults per plant can kill a rice plant — photo by Dr. M.O. Way

One of Texas’ early season but sporadic rice pests is the chinch bug, which can reduce stands. The adults and nymphs feed above and below ground. Feeding on recently emerged rice can cause stippling and striping of foliage, stunting and stand loss. In the past, rice fields in Liberty County have been especially hard hit.

We have two seed treatments that do a good job controlling this early season pest — CruiserMaxx Rice and NipsIt Inside. Timely flushing of fields can also help drown the insects and/or move them up the plant, resulting in less damage. So be on the lookout for chinch bugs when rice emerges.

I recently participated in a meeting in San Antonio, Texas, of the National Alliance of Independent Crop Consultants. These professionals are highly trained and can make your operation run more efficiently and profitably.

I know rice farming is a highly complex and constantly evolving profession. It is difficult to keep up with government regulations and programs, new agronomic practices, changing pest management tactics, rice market fluctuations, maintenance of equipment, financing, etc.

A certified crop consultant can help you make decisions, scout your fields and provide other expertise. If you don’t employ a crop consultant, you may want to do some research on this topic. I am convinced crop consultants can help your operations while assuming some of the responsibilities you farmers shoulder every day to produce our food and protect our environment.

Use Extension seeding rates as a baseline

Jarrod Hardke, University of Arkansas
Dr. Jarrod Hardke
Asst. Professor/Rice Extension Agronomist
University of Arkansas Cooperative Extension Service

Seeding rate selection is one of the most argued points in any crop. Rice is certainly no different as we rely on drills rather than planters that currently lack some of that precision. The move toward air drills has certainly improved seed placement in rice, though it’s still a sort of controlled spill.

For rice grown on a silt loam soil, we recommend drill-seeding 30 seed/ft2 for varieties or 10 seed/ft2 for hybrids (assuming a good seed bed and optimum planting date). This equates to about 64 to 80 pounds of seed per acre for varieties and 21 to 24 pounds of seed for hybrids, depending on your specific cultivar selection. It’s generally advised to increase these seeding rates by 20% for rice grown on clay soils.

These recommendations are an excellent starting point and are built on a great deal of research supported by rice growers through the Arkansas Rice Check-Off. They provide an excellent chance at establishing a successful stand and should be used as a baseline. It is up to individual growers to deviate from the baseline recommendation based on their specific situation.

Seeding rate selection is one of the
most argued points in any crop — photo courtesy University of Arkansas

The goal with choosing your seeding rate is to achieve a final plant stand of 12-18 plants/ft2 for varieties or 5-8 plants/ft2 for hybrids to obtain maximum grain yield potential. On average across a wide range of locations, soils and conditions, we only see about 50% to 60% of the seed we plant in the final stand — which puts us in these recommended ranges and is why we recommend the seeding rates we do.

At the end of the day, if you can achieve the final plant stands mentioned above with a lower seeding rate, do it! Saving $10 to $15 per acre can really add up — just be conscious that you’re removing any room for error, and any event may reduce your stands below a level needed to achieve maximum yields.

In general, a stale seedbed, good soil conditions and an optimal planting date give us the greatest opportunity to reduce seeding rates and still achieve the minimum plant stands necessary to maximize yield. Make any adjustments small and gradually and when in doubt, keep the seeding rate up.

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