Plow or compact?

The colonizers brought the technology of burning cultural remains, plowing and harrowing the soil, to cultivate plants of economic interest. With the development of tractors and mechanized equipment, man's work capacity and control over natural resources increased.

Plowing, scarification and harrowing are practices used in agriculture, theoretically, to loosen and prepare the soil for sowing soybeans, wheat, corn and other grains.

A curious contrast occurs with road builders, who, when preparing the base for asphalting, use the same practices to disrupt, compact and waterproof the soil.

In crops, these practices, at a minimum, cause soil compaction and reduce the infiltration of rainwater, causing erosion of fertile land and a reduction in plant root growth.

Soil losses due to erosion, in the 70s and 80s, were estimated at 24 t/hectare/year, for a production of 2,3 tons of grains (wheat and soybeans) in the same area. That is, for every ton of grain produced, 10 tons of fertile land were lost.

The habit of burning straw and preparing the soil was introduced to Brazil by European colonizers. In their countries of origin, plowing and exposing the land to the sun were necessary for heating and germination of plants.

In regions with a tropical and subtropical climate, such as Brazil, the situation is reversed. There is no need to expose the land to the sun for plant germination, and the straw decomposes quickly, being insufficient to maintain soil coverage throughout the year.

Plowing and soil harrowing are being left aside by farmers who adopt direct planting. This practice is expected to dominate the agricultural scenario in the coming years, with estimates of 80 to 90% of the area with annual crops and cultivated pastures. With this, we will be reducing soil losses due to erosion by more than 90%, fuel consumption by more than 70% and the need for tractors by 60%, in addition to allowing the recovery of water from rivers and, mainly, removing carbon dioxide from the atmosphere, fixing it in the soil in the form of carbon in straw and plant roots.

Direct planting through sowing, without soil preparation, and on the straw from the previous crop can already be recognized as the biggest revolution in agriculture in tropical regions.

Dirceu Gassen,

Co-planting