Planting Peanuts with Liquid Inoculant: Top 10 Planting Tips.
Liquid inoculant is the most effective delivery for high-counts of Bradyrhizobium bacteria. Exceed® SAR for peanut is our premier liquid inoculant providing the highest benefit to your peanut crop, especially in the formative early growing stage.
Do not expose inoculant to direct sun, heat or freezing temperatures prior to planting.
Use a minimum of 5 gal of non-chlorinated water—more is better than less.
Plant at a depth of 1.5 inches or greater so the inoculant and seed land into moist soil.
Inoculant left in tanks overnight will be ineffective. Add fresh inoculant before planting.
Check your equipment. Make sure the flow hits the center of the furrow, not the dry side walls. Tips knocked out of alignment can lead to yellow peanuts and reduced yield. Be sure to clear the strip tillage rigs, debris will deflect the stream of inoculant.
On ground that has never been planted with peanuts, apply liquid inoculant at double the rate.
Apply with a steady stream - not pulsating pump or by using a fan nozzle and make sure seeds are covered with soil immediately after being placed in the furrow.
Twin Rows require a full inoculant rate in each row.
Mark your calendar to scout fields for proper nodulation and nitrogen-fixation at five-six weeks after planting. Mark your calendar again for late season scouting in mid-August to early September.
Field Scouting for proper nodulation and nitrogen-fixation.
Peanut growers should target two key times to scout for nodulation. First, scout at approximately six weeks after planting to assess early nodulation in advance of decisions about applying mid-season nitrogen. Second, checking late-season nodulation from mid-August to early September.
At the first scouting, around 45 DAP (approximately 6 weeks after planting), use a shovel and dig, lifting out at least 10 plants among a couple of rows, from four different sites in the field. Don’t pull the plant out or you could break off the taproot.
Look for evidence of nodulation development on the tap root, which is direct evidence of inoculant use. The presence of large (1/8" or larger) nodules on the taproot indicates successful inoculation. An average of 15 large nodules per taproot at 45 DAP is considered good nodulation. Less than 10 nodules per taproot is considered marginal and less than 5 indicates poor nodulation.
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. If only small nodules (1/16"), mostly on the lateral roots, are present the plant has probably only been colonized by native Bradyrhizobium bacteria, not the applied inoculant. Properly inoculated peanuts can become nitrogen deficient due to molybdenum deficiency in the nodules if the soil is too acidic (pH 5.5 or lower.)
For poorly nodulated fields, try to examine why nodulation did not occur to the amount desired and what can be done to enhance nodulation in next year’s crop. Obvious signs where the inoculant was misapplied are yellow rows or even spotty green/yellow areas throughout the field or light pea-green field color suggesting nitrogen deficiency. Common causes of minimal to no taproot nodulation, despite inoculant application, are as follows:
Poor placement of in-furrow liquid inoculant. Make sure the liquid stream is coming right in on top of the seed, not on the dry side walls of the furrow.
Shallow planting. Peanuts should not be planted less than one and a half to two inches deep. Peanuts planted at less than one inch depth, where the surface soil can become hot and dried out, can cause the rhizobia bacteria to die. Reduced nodulation may also occur when too little soil is drug back over the seed even if planted deeper.
The use of starter fertilizer, at rates beginning near 30 lbs per acre, near the seed. This will reduce nodule development. Larger applications of mid-season nitrogen can reduce peak nodulation. The easy availability of early fertilizer spurs the peanut plant to take the lazy approach and use the fertilizer before fostering nodule development.
Incompatibility with other products applied at planting. Always read and follow the label for product compatibility or consult your inoculant company representative.
Broadcast ammonium sulfate (500lb/ac of 21%=105 N units) must be applied if the inoculant totally fails, but yield will probably not equal a properly inoculated crop. Ammonium sulfate typically provides the best results. If the canopy has not closed, liquid nitrogen can be dripped in the row middle of affected rows. Foliar Nitrogen applications are not cost effective and often cause unacceptable leaf burn.