AQI estamos em mudança

Fertilization

• 03-08-2022

What is fertilization?

It is the process that consists of providing plants with nutrients that the soil cannot provide, thus ensuring their healthy development. It is necessary because the soil does not have all nutrients available for plants to absorb.

This process and the amount of compost or fertilizers to apply may vary according to the type of plants to be fertilized and the specific phase needs at the time of fertilization.

The main essential nutrients for plants are Nitrogen, Phosphorus and Potassium (which are macronutrients), however, other nutrients are also indispensable because they guarantee the maintenance and development of plants.

When some nutrient is missing, symptoms appear on the plant as shown in the image below, and the correction must be made by applying the fertilizer that helps to fill the identified deficit.

NOTE: For an appropriate fertilization, soil and plant analyses must be carried out in order to make a correct assessment of the amount needed at the time. Foundation fertilization (what it is, when it's done, product examples)

It is the fertilization done to the soil before sowing or transplantation. This fertilization can be done with organic or mineral fertilizers. It aims to ensure that the soil has nutrients for the first days of plant development.

 Regarding the origin of the fertilizer/compost components

• Organic: has its origin in organic and natural sources such as cattle and chicken manure, and plant stubbles (vegetable, animal source). Administration can be done prior to planting or during plant development (in liquid, processed form). This fertilization provides the nutrients in a slower and more durable way.

Advantage: One of the great advantages of fertilization through plant stubbles and manure incorporation in the soil is that they also help to improve the structure of the soil, thus ensuring a higher lifespan for the soil.

• Mineral: these fertilizers, also called chemicals, are more quickly absorbed, thus more immediately available to the plant than the organic ones.

Advantage: they ensure immediate availability of nutrients to plants and promote faster growth, ensuring that the results are noticed in a short time.

 Timing of application

• Foundation fertilization: this fertilization can be organic or mineral. It ensures that when the seed is placed in the soil it receives the nutrients it needs in its first days of life. In the case of organic fertilization, it is usually made 30 days before sowing to ensure that the nutrients are available, since the availability of the nutrients is slower, while mineral fertilization can be done one day before sowing since the nutrient availability is faster.
• Topdressing: this fertilization consists of maintaining the nutrients because, as the plant grows, it needs more nutrients to develop and be healthy to bear the fruits or produce the desired yield. It can be made with mineral as well as organic fertilizers in liquid or solid form.

Physical state

• Liquide
• Solid

Topdressing

Topdressing consists of filling nutrient deficiencies that were not possible to give in the foundation fertilization phase and ensuring that the plant continues to develop to bear fruit and can reach its maximum potential yield capacity.

This fertilization can be done with organic or mineral fertilizers, mainly in the solid state, and in some cases liquid, in the form of composting (fermentation process of organic products).

 IRRIGATION

Watering or Irrigation

It is the technique or set of techniques that allow the artificial application of water:
it essentially aims to replace the water consumed by plants in the process of perspiration/evaporation, commonly called evapotranspiration. Plants need a balance of soil, water, air and light.

The purpose of irrigation is to create optimum soil moisture conditions.

Advantages of irrigated agriculture

• Guaranteed production, not dependent on rain;
• Higher production per unit area.

Possible disadvantages of irrigated agriculture

• Intense cultivation may endanger soil fertility;
• Possible flood damage;
• Salinization hazard;
• The irrigation and drainage channels take up space;
• Costs involved;
• Leaching of nutrients by deep percolation.

Factors that determine the amount of irrigation water:

• Precipitation (Pr).
• Crop Water Needs (CWN) or Crop Evapotranspiration (ET).

Irrigation Methods

An irrigation system must take into account:

• the amount of water required for washing salts;
• losses in the transport of water from the source to the field and in the field;
• the water needed for the initial moisture replacement.

 The choice of one of these systems/methods/processes depends on:

• the quantity and cost of available water;
• the size and topography of the land;
• particularities of the crop to be irrigated;
• climatic conditions of the region in which the irrigation area is located.

Furrow irrigation

• main irrigation system used in our country;
• reduced irrigation efficiency (50 to 60%);
• tomato, maize, sunflower, soybean, tobacco crops, etc.
• bedside flow, adaptation of the terrain to the crop, slope and length of the furrows.

Basin irrigation

• Used in rice cultivation;
• Reduced irrigation efficiency (20 to 40%);
• It is important to consider the sizing and orientation of the basins, irrigation channels and drainage ditches.

Sprinkler irrigation

It has gained increasing importance. Each sprinkler distributes a flow of >500 l/h with a watering efficiency of 70 to 80%. The alternatives:
 • fixed or conventional sprinkler
 • center pivot
 • traveler
 • cannon

Center pivot

• preferred alternative for large areas (circular or semicircular);
• Irrigation and fertilization automation (nocturnal);
• Flexibility of operation in different situations (soils and slopes);
• Possible association between center pivot and fixed sprinkler for better use of the area.

Drip irrigation

• The drip irrigation (1 to 12 l/h) and the mini-sprinkler (20-150 l/h) systems have become particularly relevant in tomato crops;
• There is a foreseeable expansion to maize crops;
• Very high watering efficiency =90%;

Significantly improves the efficiency of water and nutrient use.