Guimarães Duque Method: Soil water harvesting

Solution type: Soil water harvesting

• Objectives: Use sloping surfaces for on-site rainwater harvesting under conditions of low rainfall. Use volumes of runoff water from pre-determined surface areas to meet crop and pasture demands.

• Description: This is a low-cost technique widely used in rainfall-dependent agriculture. It consists of a methodology that modifies the soil surface prior to planting so that the space between the crop rows acts as a water catchment area. This zone has a slope that increases surface runoff and directs the water towards the portion of the soil where the root system of the plants is located.

Location and selection of soil

The water retention capacity of the soil is a determining factor for the implementation of this technique; therefore, a soil of medium texture, with good structure and good drainage, without obstacles for agricultural tillage, with a depth greater than 0.5 m, is indispensable for its success.

The process of creating furrows for water collection involves removing the front disc of a three-disc reversible plow. It is carried out on land with slopes whose natural gradient does not exceed 5%. The furrows are constructed with a spacing of 1.5 meters. This method is applicable to most soil types and is mainly used in the cultivation of corn, termite, sorghum, castor beans, cassava, cotton and perennial crops.

Capturing and conserving water

Increases autonomy in agricultural production and allows planning according to the potential of the property. Although it is mainly applied in perennial crops, it has been adapted for annual crops through the use of equidistant furrows with two inclined planes between consecutive furrows. The first forms the edge of the furrow and serves as the planting area, while the second, wider one connects the top of the first furrow to the bottom of the second, forming the catchment area. However, it presents productive limitations in the spacing between consecutive rows.

Another alternative known as the “W” method involves the creation of alternating wide and narrow ridges in contour lines. In this system, the ridges with wide sloping planes function as catchment areas, the narrow ridges act as planting areas, and the furrows between ridges are used as storage areas. The ratio between the catchment and planting zones is 2:1, which ensures the necessary water supply for the crop per unit of planting area.

Advantages

• • • It is estimated that the implementation of the Guimarães Duque Method uses an average of 1.6 h/ha using a tractor. This represents a 50% reduction in the time spent per hectare, in relation to the traditional system of total ploughing, in addition to the benefits of storing rainwater in the soil profile, making it available for cultivation.
    • Clear demarcation between the planting area and the catchment area, allowing the latter to be compacted to increase surface runoff production;
    • Placement of two rows of plants per bed; depending on the width of the planting area, it allows a choice of layout for different types of crops;
    • The symmetrical shape of the system facilitates mechanisation by tractor or animal traction; Adaptable to any space.
    • Various technological alternatives to create the rainwater harvesting technique “in situ”.

Complexity

On-site rainwater harvesting is a simple technique that is accessible to all levels of producers, as some of them traditionally already carry out rainwater harvesting practices.

Sources:

• Barbosa, J. Teixeira, L. Captação de água de chuva para cultivos de milho e feijão caupi. Petrolina, PE; EMBRAPA, 1999.
• Porto, E.R.; Vivallo Pinare, Ag.; Wllllams Fuentes, C.O.; Silva, A De S.; Lopes, L. H. De O. Pequenos agricultores V: métodos de execução de sistemas integrados de produção agropecuária (SIP). Petrolina, PE; EMBRAPA-CPATSA, 1990.