Monitoring soil conditions is critical for planting success, especially in no-tillage. If soil is too wet, sidewall compaction can result which causes roots to have trouble exploring the soil.
The primary roots– the radicle and the seminal roots that grow out of the seed – are most severely affected. These roots supply water and nutrients to the newborn seedling. So if you place fertilizer next to the seed (2 inches beside and 2 inches below the seed) these primary roots cannot access it if there is sidewall compaction. Or if the soil dries out, the young seedling will more readily suffer from drought stress.
To check if soil conditions are fit to plant – use the ‘ball test’. Take a handful of soil from the top 2 inches and knead it in the palm of your hand. If the soil sticks together, the soil is too wet and sidewall compaction is likely. If the soil crumbles, the soil is fit for planting.
Unfortunately, it seems that the entire field is almost never fit to plant, so companies and private innovators have come up with many new attachments such as different types of spiked closing wheels to break up the sidewall after it has been created by the double-disk openers.
It is also beneficial to use no more downpressure than required on the planter units to place the seed at the right depth. New types of depth control wheels are available that do not compress the soil right next to the double disk openers which can also help to reduce side-wall compaction. Soil that has a stable, crumb structure suffers less from sidewall compaction.
Soil structure can be improved by using continuous no-tillage, adding organic matter such as compost or manure, and maintaining living roots in the soil as much of the year as is possible. Other points to watch for when planting is to check planting depth. Again, this is especially critical in no-tillage. In tilled soil it is possible to be a bit sloppy about planter performance but in no-tillage your planter needs to be in good shape and set up right to plant the seed not too deep, not too shallow, but just right. In no-tillage, too shallow planting is the greatest threat. Shallow planting leads to more adverse soil moisture conditions so that the seedling experiences a lot of drought stress – so check downpressure and add weights if needed to make sure those units are placing the seed at the right depth.
Hairpinning is another issue to watch for – if you see crop residue or cover crop material being stuffed into the seed slot this is a good recipe for disaster. Seed-to-soil contact will be poor so the seed cannot ‘imbibe’ water to make it swell and germinate. Further, green plant material stuffed into the soil can start ‘rotting’ and releasing certain acids that hurt the young seedling. Often hairpinning is not uniform throughout the field, so you will typically end up with a non-uniform stand which is highly detrimental to yield. Make sure the coulters of disk openers cut through the mulch and cover crop so that you get good seed-to-soil contact. Use row cleaners to clear a path for the double disk openers to they don’t have to cut through excessive plant material.
By taking care of these details and checking soil conditions and planter performance you will be off to a good start for a successful growing season.
(Source – http://extension.psu.edu/plants/crops/news/2014/05/monitor-soil-conditions-and-planter-performance-for-optimal-results)