How to Apply Amendments

Timing of the Applications

Many farmers prefer to lime in the fall and add the other minerals in the spring. If this is not possible, all the minerals can be applied at the same time.  But nitrogen and boron and sulfur (usually as gypsum) especially should be added to the soil just before planting. They are likely to leach over the winter.

Methods of Application

For small area, like under an acre (although perhaps less than 3 acres) we apply the individual minerals separately, starting with the smallest amounts.

When applying small amounts of BioMin Copper or Copper Sulfate, Sodium Molybdate Dihydrate and Cobalt Sulfate we often use a sprayer. (These amendments are particularly difficult to handle; see the section below on cautions.)  We dissolve the minerals in warm, good water (bicarbonates are less than 70 ppm). A lot of problems can be avoided by using reverse osmosis water in the tank. We have applied these minerals separately, but it may be possible to combine them in the same tank. Do a jar test to see if the sulfates cause precipitation. Check the bottom of the tank when finished, and if there is residue, add more warm RO water, and go over the area again. The amount of water applied is not important, just the weight of the minerals.

A small amount of humic or fulvic acid is a great addition to the tank. It will help to complex or lightly chelate the minerals.

We find it easier to apply borax, manganese sulfate, gypsum, sulfur, N sources and most other minerals one at a time, just casting them by hand as evenly as we can.

If the area is large, or for other reasons you want to make just one trip through the field, all of the minerals may be blended with compost before applying. We purchased an “Odd Job” roll around concrete mixer for this – it will hold about a sack of concrete. Larger areas will require a larger mixer. Be sure to wear a dust mask and gloves for this. Mixing with compost is especially important for the sulfates which are usually applied in small quantities and are difficult to spread evenly. Check that the color of the mix is even everywhere before applying. The disadvantage of this technique is now we have to be careful with the whole mix, not just one component.

Avoid mixing calcium sources like lime and gypsum with phosphate sources in the same hopper, so we do not tie up the phosphorus. The phosphorus sources especially need a bioactive soil in order to be available to plants. If you are making serious compost, it might be best to incorporate your P sources into that process. With phosphorus, it is not so much the amounts which matter, but the availability.

No-Till Mineralization

The advantage of no-till (tarping) (which we practice here) is better biology and lower weed pressure. The disadvantage is stratification of the nutrients. At some point you will want to test the top 3″ and the 3″-6″ slice separately. Stratification can be a big issue; there are stories where nothing much would grow because of stratification.

Let’s look at this table: Here is information on what minerals will move in the soil profile, and which won’t. The table is for minerals in their elemental form; they are all mobile in their sulfate forms, especially when applied with water. So, if you need zinc (which is immobile in the soil), for example, you can dissolve it in water (as much as you can) and apply it during a rain event. It will penetrate to the depth of the water.

Phosphorus is very immobile in the soil. So, Fertoz or Calphos soft rock phosphate needs to be dug in. There is a way around this, which is to use a high P liquid fish every 7-10 days to feed the plants.

The same strategy of feed-the-plants rather than feed-the-soil will work for other nutrients. Zinc for instance, can be applied as a liquid and foliar (not just as a foliar – won’t be enough). This is lots of work compared to establishing a soil reserve for the plants to draw upon. You really need to evaluate the plants response to liquid minerals by maintaining a control area and presumably measuring the brix of the two areas.

In climates with moderate rainfall, the minerals will generally stabilize, and probably just the nitrate N, B, and S will need replenishing (for every crop). This is a great time to think about a no-till program.

The Boron, Sulfur and Nitrate-N are anions and they leach. The boron and sulfate-sulfur can be surface applied, and they will make their way down when watered in. An N source, like feathermeal, requires a biological decomposition. If you leave it dry and on the surface, it will degrade/maybe vaporize until it finally gets wet and in contact with the soil. The same goes for surface-applied compost.

If you need to raise your pH with lime, there really isn’t another way other than digging it in.

The First Time You Mineralize

If this is a first time application, consider tilling or spading the amendments in to a depth of 6 inches (15 cm) to mix them thoroughly. Although tillage has a detrimental effect on soil biology, it is helpful to correct major nutrient deficiencies before beginning a no-till program.

OrganiCalc has a place to enter the depth you will be digging your amendments into. Normally this is 6 inches (15 cm), or the depth of your soil sample.

The first time you mineralize, apply the recommended amounts of Kelp or Azomite for the trace minerals we don’t test for. If you cannot afford the recommended amount, apply what you can afford. Quantities can be reduced/eliminated in subsequent years. Or, you may substitute foliar feeding with liquid kelp, about every 2 weeks.

In many cases cobalt can wait until the second year – there are often so many issues their effects are masked by other deficiencies or excesses.

Amendments to Use With Caution

Read the MSDS for all of the organically approved sulfates. These can be found by an internet search for “safety data sheet” and the name of the amendment. In general you will want to avoid touching or breathing or ingesting any of the materials.

Cobalt is especially hard to handle safely. Be sure to wear a dust mask or respirator and gloves as required. Store it in a locked cabinet. Or, better yet, spray any excess around the orchard or other areas.

Boron has a relatively narrow range of appropriate levels in the soil. Too little means that plants won’t grow to their full potential. Too much and the result can be boron toxicity, until the boron is leached below the root zone. Until you get the hang of how much is just right, it’s a good idea to measure carefully.

Which Amendments are the Most Important?

For best results apply all the recommendations. However, for large areas it may be necessary for cost reasons to triage the mineral applications. The Kelp/Azomite application is the first to go. It is a single large application to cover minerals we don’t test for.

Next, look at the bar graph at the end of the analysis. If the micronutrients are over 50% maybe there is enough there. These small measurements are difficult for the lab to make.

If your copper is over 2 ppm it is not deficient. We strive for 5 ppm so there is plenty there.

The amendments that will remedy the largest deficiencies are generally the most important. Although all the plant-essential nutrients are essential, some are more critical than others. The big three, nitrogen, phosphorus and potassium, are the ones that plants use the most of. A critical deficiency of any of these will usually cause serious setbacks.