Quick Tips For Inoculant Use

Remember how important this one input is to a top-yielding crop.

Inoculants are an essential input on peanuts. How often to apply an inoculant likely depends on each producers preference for making certain that fresh, viable, peanut-specific, nitrogen-fixing bacteria are in close proximity to the seed so that when germination occurs, the bacteria can readily enter the roots and begin turning atmospheric nitrogen into a form the plant can use. The following are reminders for 2015.InoculantFixed

Spend On Inoculants First

To provide nitrogen for your crop, the first money you should spend should be for a peanut inoculant. In some areas, an inoculant is needed every year because of hot, dry conditions. Conversely, waterlogged soils may also lack viable rhizobia. Whatever the conditions, providing the bacteria needed by the crop in order to fix nitrogen through applying an inoculant is much more cost effective than supplying nitrogen through fertilizer applications. Research has shown that trying to catch up nitrogen management through fertilizer applications has already cost you valuable yields.

Find That Proper Place

Placement of the inoculant is one of the most important points. Ensure that the inoculant is placed in the furrow with the seed. The stream jet, not a fan nozzle or any kind of spray nozzle, for in-furrow liquid application or the drop tube for granular application must place the inoculant directly in the furrow where the seed is placed. You do not want to be shooting at the furrow from 10 to 12 inches away, especially from the tip of a drop tube for granular inoculant.

Throughout planting, check nozzles and tubes to make sure they are neither plugged nor shooting off to the side. Planters can be outfitted with sensors that will alert the driver to a plugged tube.

Finally, ensure that the furrow is covered by soil properly. Sometimes the planter doesn’t drag enough soil back over the seed where the furrow opener is located. Planting at higher speeds may compound this. Make sure the seed is covered. If you plan to irrigate and are relying on the soil wall of the furrow to collapse over the seed, this is not sufficient because the seed and bacteria may dry out before the irrigation system comes around.

Follow Label Instructions

Inoculants are live bacteria and require special care. To maximize the effectiveness of rhizobia-containing inoculants, follow the recommended handling, storage and application directions for each inoculant product. Apply only an inoculant product specific to peanuts. Avoid storing outside or unprotected from the elements for long periods. Prevent the product from freezing. Avoid exposure to fumigants during storage and use. Know the compatibility with fungicide and insecticide products to be applied. Use and mix inoculants only with non-chlorinated water. Regularly check calibration of application equipment.

Scout For Nodulation

Use a shovel and dig, don’t pull, at least 10 plants among a couple of rows from four different sites in the field about six weeks after planting. Look for evidence of nodulation development on the tap root, which is direct evidence of inoculant use.

Slice open a few nodules and look for a pink to red inside, which is evidence of nitrogen fixation. Nodules that are white or a light shade of green may not have started fixing nitrogen.

Repeat the nodulation assessment about mid-August to see what peak nodulation may have occurred. Again, look for nodulation on the taproot. You may also notice a lot of nodules on the lateral roots. These nodules are likely from native or background rhizobia bacteria, which may or may not contribute to nitrogen fixation. Nodulation of the taproot is much more likely to fix the desired nitrogen for your peanut crop.

Adding nitrogen fertilizer at planting or in a mid-season application will curtail nodulation, especially if applied early. If mid-season nitrogen is applied, delay it for six weeks or long enough that nodulation has at least started. Consider delaying fertilization until a nodule assessment can be conducted, which may enable you to reduce mid-season nitrogen fertilizer applications.


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