Category: Fertility/Inoc

Timing Assess soybean root nodules each year, regardless of the field history or inoculant strategy. The ideal time to assess nodulation is at the R1 (beginning bloom) stage. Root nodule assessment at this stage gives a clear picture of whether or not a crop has sufficient ability to produce its own nitrogen (N) via biological…

Identification Iron deficiency chlorosis (IDC) is most commonly observed in soybean crops, but dry beans, faba beans and field peas can also be sensitive to IDC. Symptoms of IDC include interveinal yellowing (chlorosis) of new growth, where leaf veins remain green (Figure 1). In extreme cases, interveinal browning (necrosis) can occur. Symptoms show up in…

Nodulation failure and nitrogen (N) deficiency has appeared in soybeans across Manitoba, particularly on fields without a history of soybean, in high residue production systems and on acidic soils (pH <6.0). A possible explanation for poorer than usual nodulation and/or nitrogen fixation could be the dry seeding and growing conditions encountered this spring and early…

Recommendations on phosphorus fertilization in soybeans and a calculator to assist with your annual P balance.