Land rolling is a practice that evens out the field and prepares it for harvesting in the fall. A roller is used to push rocks into the soil and break up dirt clods or root balls, and to smooth the seed bed. Soybean rolling is usually done either before or after seeding, but in this blog, our team looks at why rolling after emergence is a good choice.
What is rolling soybeans?
Rolling soybeans is a technique that prepares and levels the field for harvest using a roller that pushes stones into the soil, breaking up root balls or dirt and smooths the seed bed. This is normally done before or after planting, but we will describe in this blog why it is done when the plant has emerged.
Roll soybeans to increase yield
A 2020 study highlights the benefits of rolling soybeans after emergence (VE) , by using a 30-inch diameter smooth roller on soybeans planted in 15-inch rows with a row unit planter1. Over the course of the study, rolling was done during 5 different growth stages. For quicker recovery, the rolling was conducted in the afternoon, during the warmest part of the day, when the plants are less turgid (stems are softer then).
Result: Rolling soybeans after emergence provided a slight yield gain compared to rolling immediately after seeding. Indeed, rolling post emergence acts as a stress factor on the plant, potentially encouraging more branching, and therefore more pods.
Increased pod set does not automatically mean increased yield. Rather, what increases is the maximum yield potential, since other conditions such as favorable moisture levels, optimal nutrient uptake, and adequate weed control are also essential.
Rolling in the 1st trifoliate stage (V1) offered the best yield gain compared to the other stages. Interestingly, the same result was observed in both till and no-till fields.
Roll soybeans to encourage node set and branching
As a corollary, soybean rolling also promotes node set and branching. Indeed, “stressing” the terminal growing point at the top of the plant helps increase the formation of soybean nodes and branches. A definitive study by the University of Minnesota found a 2-pod gain with approximately 2.5 beans per pod, which is theoretically the equivalent of 4 more bushels per acre.
A study conducted in Ontario by OMAFRA found the best yield gain to be at stage V1, namely 1.8 bushels/acre2. The cost of rolling being less than the value of a bushel of soybeans per acre, the use of this practice therefore seems beneficial and justifiable to soybean growers.
Some growers who practice soybean rolling immediately after seeding find other benefits besides yield gain, such as emergence 2 to 3 days earlier. The land rolling improves seed contact with the soil. In areas with shorter growing seasons, this can make a notable difference, especially if spring arrives late.
Roll soybeans to optimize combine harvester work
Soybean rolling offers another advantage for growers. The practice allows them to position their grain pan lower to the ground, by reducing the risk of picking up stones, dirt clods or root balls. In the end, soybean rolling prevents stones, roots and dirt from reaching and damaging machinery.
Rolling soybeans: a delicate, but beneficial operation
Soybeans can safely be rolled until the V3 stage, namely the 3rd unrolled trifoliate leaf. After V3, the damage caused to plants can cancel out all the benefits.
Soybean growers interested in this practice must consequently make sure that they intervene at the optimal time, when they can stress the plant without negative side effects. By optimal time, we mean within 3 days after seeding and, beyond that, between the unifoliolate stage and the V3 stage. It is also important to limit rolling to rocky or flat fields that present a low risk of erosion, and to roll only when field conditions are favorable.
That does it for our brief review of soybean rolling. To learn more, we invite you to contact us. You can also check out the Blog section on our website for more information on the world of soybeans.
Happy rolling!
1 https://fieldcropnews.com/2020/06/the-1st-trifoliate-is-the-best-time-to-roll-soybeans/
2 https://www.ilsoyadvisor.com/on-farm/ilsoyadvisor/agronomy-rolling-beans