The art of irrigation begins now

The art of irrigation begins now

Associate Professor /
Rice extension specialist
University of Missouri

The time we have all been waiting for has finally come. As I write these comments on March 29, several thousand acres of rice have already been planted throughout the Missouri building. In fact, 12 days ago, on March 17, we conducted the first study of the date of planting. To no one’s surprise, the seeds still look exactly the same as when they came out of the bag. Despite this, it is nice to feel that we are making little progress with the 2022 rice harvest.

There is no better time than now to start thinking about water management. Last year, about 30 percent of Missouri’s rice fields were irrigated by furrows. If you are preparing to plant rice with irrigation along the grooves, then the size of the bed has a thin edge. We want to make sure that the furrows are enough so that we do not break through the water, but at the same time the furrows were not too deep so that the water does not flow adequately through the beds. As if none of us knew it was hard to lift water up – at least if we wanted to!

While beds need to be prepared for planting on our loamy soils, heavier clay sharks seem to work best when planted in a flat place. Shallow furrows can be created somewhere between the emergence and the first watering. It seems the later the better at this time. The reason for this is simple. Heavy clay has a lot of potential for leakage. So even if we do not get a furrow that can be overcome, and on the mud or lighter soil we do not have such a luxury.

If you have a field where it is difficult to get water for your soybeans, you will not enjoy rice irrigated by furrows. We have tried this several times. If you do not want rice 100 bu / AC, I would suggest not to try irrigation on the grooves. Rice, especially hybrids, can withstand much more stress from water shortages than most of us realize. But in the end, we still have to get water when summer comes, and these sealed soils can become real worries.

If we set ourselves up well on the front, we will be much happier with the return card without those scary red stripes. If you have any questions, feel free to ask me or your local expert. As always, eat Missouri rice!

Effective rice irrigation

Jarrod Hardke, University of Arkansas
Professor / Rice extension
University of Arkansas Cooperative
Extension Service

During floods or furrows, effective irrigation will be an important key to the profitability of rice in 2022. Given the rising cost of resources, minimizing our time and energy costs associated with irrigation should become an even higher priority than usual.

Repeated irrigation of rice at the entrance (MIRI) remains an underused practice. Many cite the cost of the pipe and the time required to install it as major constraints to practice. However, the 2022 season is a great opportunity to implement this practice and get the most out of it.

Diesel prices this year could increase irrigation costs by $ 50 per acre compared to 2021. This increase makes it easy to calculate the cost of the pipe and installation. When using electric pumps, budget figures may be closer, but electricity costs are rising.

Arkansas rice expert Dr. Jarrod Hardke said that if you don’t use sensors, the general approach to irrigation can be to water every three to five days on loamy loam or every five to seven days on clay.

Despite the fact that we have increasing installation costs, these efforts are offset by the fact that you need to install the gate of the dam only once. There is no need to “close” the fields after the first flood. When using MIRI the goal is to set the gates (rods) high for emergency tipping and be able to capture rainfall cases.

MIRI’s goal is to flood each individual rice and keep water out of the gates unless extreme rain falls. That means less control of the gates in season because we don’t want water to flow through them. Instead, we regulate the flow of water that enters each line from the political group – much easier.

According to current estimates, the use of MIRI can reduce irrigation work by 30% and pumping by 25% or more, depending on soil and situation.

To include a few remarks on the rice irrigated on the furrows – avoid transfusions. To many this may seem strange, but we are seeing more problems with pouring rice irrigated by furrows than you think, especially where cold water from a well is a source of irrigation.

Rice does not require flooding; we just need to avoid water stress. Most importantly, avoid water stress during reproductive growth from the beginning of the panicle to the filling of the grain. You can also water the last time you normally drain a flooded field – just to provide enough moisture to bring the rice to maturity.

If you use soil moisture sensors, place them about one-third down the field at the top of the bed. If you do not use sensors, the general approach to irrigation may be to water every three to five days on loamy loam or every five to seven days on clay.

Use a computer hole selection program to help set up rice irrigation using MIRI or furrow irrigation. If we can help, contact your county expansion agent or specialist.

Mistakes to look out for in 2022

Luis Espina
Dr. Luis Espina
Adviser on rice cultivation systems
Expanding collaboration with the University of California

The 2022 season will be unprecedented for rice growers in California. Drought will significantly reduce acreage and may affect yields in other ways, including arthropod control.

Given the unavailability of water and dry fields, we are set to slow flooding in the spring. This can worsen shrimp problems. Longer flood times allow shrimp to hatch and grow to a size that can damage rice.

Typically, rice can avoid injury to shrimp if it takes root (with a well-developed green thorn and a 1-inch root in the soil) before the shrimp shell reaches the length of the rice seed. If the rice is well established, even large shrimp will not damage it.

If the size of the tadpole shell is equal to the size of a germinating rice seed, rice seeds may be injured.

This year, be especially careful in fields that are flooded for a long time. If small shrimp are present before sowing or directly at sowing, treatment is required. Also, keep in mind that lambda-cyhalothrin, the main insecticide used for tadpoles, is now controlled at the same drain sites used to control thiobencarb. Growers should be careful when spraying near drains and observe water retention times.

The second pest of concern are army worms. The question I was asked several times during our winter meetings was: is there a way to predict whether army worms will be a problem this year. Unfortunately, I don’t know any way to predict whether 2022 will be an army year. The big outbreak of the military worm in 2015 occurred in a year of declining acreage and after several years of drought. In 2022, we will face a similar situation.

This year, I will re-establish a network of army worm traps and upgrade the industry when the number of moths starts to grow. Although the number of moths does not always correlate with worm populations, we learned that one to two weeks after we reach the peak of the moth, we see the peak of worm activity in the field.

The web is a great tool to determine when we need to watch for worms and defoliation so we don’t get caught unawares, as in 2015.

Rice on water

Ronnie Levy
Rice extension specialist
Louisiana State University

Most rice is sown in Louisiana – about 80% – but there is again interest in water rice to control weeds.

The most common method of water sowing in Louisiana is point flooding. After sowing the field is briefly drained. The initial period of drainage is enough only for the root to penetrate into the soil (pin) and secure the seedlings. Under normal conditions, a three- to five-day rainfall period is sufficient. The field is then constantly flooded until the rice is close to maturity (the exception is mid-season drainage to facilitate directing under certain conditions).

In this system, rice seedlings emerge through flood waters. Seedlings should be above the water surface at least at the stage of 3-4 rice leaves. By this stage the seedlings usually have enough accumulated food and available oxygen to survive. Atmospheric oxygen and other gases are necessary for a plant to grow and develop.

A rice specialist from Louisiana, Dr. Ronnie Levy, said the state has revived interest in planting water to suppress weed rice.

A precision flooding system is an excellent means of suppressing weed rice that emerges from seeds in the soil because the oxygen needed for weed rice to germinate is not available as long as the field is maintained in a flooded (or saturated) state. The Continuous Flood System, another water-seed system, is limited in Louisiana. Although it is similar to a precision flooding system, the field is never drained after sowing.

As for water crops, a continuous flooding system is usually best for suppressing red rice, but creating rice paddies is the most challenging. Even the strongest varieties may have problems with attachment to this system. Inadequate rostrum creation is a common problem in both systems.

These emerged rice seedlings are ready for a point flood.

Terms of fertilizer application are the same for precision flooding systems and for continuous flooding. Phosphorus (P), potassium (K), sulfur (S) and zinc (Zn) fertilizers are applied before planting, as in the dry crop system. After flooding the field should not allow the soil to dry out.

If the need of a particular field for nitrogen is known, all nitrogen fertilizers can be applied before flooding and sowing. Otherwise, half to two-thirds of the estimated need for nitrogen fertilizer should be made before flooding and sowing or made during a short drain period in a precision flooding system. Additional N fertilizer can be applied in the middle of the season at the beginning of reproductive growth between panicle initiation and panicle differentiation (2 mm panicles).

Previously, water crops were used to control weeds. Will water crops return to help control weeds? The art of irrigation begins now

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