Soil compaction during sowing increases the chances of disease

The expectation of normalization of rains in the Central-West is encouraging and reminds us that we still have a lot of crops to sow and, therefore, a deadline to meet. But be careful, the rush to make up for lost time in planting crops can lead to problems. Farmers and consultants often come to laboratories and research institutions after sowing, bringing some plants with symptoms of wilting, falling over or poorly developed, trying to understand why the plants do not develop normally. And often the answer is that diseases are just opportunistic. Illnesses in plants shortly after sowing generally reveal soil management problems, mainly related to compaction, hindering the normal development of the root system and predisposing plants to all types of diseases. 

Preventing illnesses costs much less and is much more effective than trying to control them after they occur. And thinking about soil diseases, which are caused by microorganisms that naturally inhabit the soil, there is little or nothing we can do once the disease is detected. Therefore, at this sowing stage, the main thing to do to avoid diseases is to avoid soil compaction.

And how to avoid soil compaction? During sowing, it is important to avoid the operation and movement of machines in crops with very wet soil, especially clayey soils. The producer knows, but it doesn't hurt to remember: agricultural operations with very moist soil promote soil compaction, the decompression process is difficult, and compacted soil predisposes plants to diseases. Compaction can occur both due to the pressure of agricultural machinery tires on the soil, and also in the sowing furrows, through the action of the fertilizer distribution machete and/or the seeding discs, promoting the mirroring of the furrow walls and thus facilitating the accumulation of water, which favors the occurrence of diseases.

Some soil diseases favored by compaction are: soybean root and stem rot caused by Phytophthora soyae, which causes upward darkening, starting from the base of the stem, rising homogeneously up the plant to the branches of the main stem. Pre- and post-emergence damping-off caused by Rhizoctonia solani, which causes strangulation of the plant neck, with circular to elliptical reddish-brown lesions, which become elongated and depressed. And gray stem and root rot caused by Macrophomina phaseolina. This disease is observed more at the end of the cycle, due to the anticipation of maturation (forced maturation) in those affected by the disease. 

In addition to these, poorly maintained soils generally predispose plants to several other diseases, such as end-of-cycle diseases, white mold, and nematoses. Taking care of soil structure and conservation can prevent many diseases from occurring or from reaching the damage threshold. This information reinforces that much of the success in farming is related to our care of the soil.