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The RAINCATCHER

Agriculture

Raincatcher for Agriculture

The utilization data of RAINCATCHER that you will find in the different parts of this section are generic data: our specialists can direct you towards a use adapted to your horticultural or agricultural needs.

You will find in the chapter "AGRICULTURE AND IRRIGATION" a broad explanation of the possibilities of the use of the RAINCATCHER and its principle of operation.

The other chapters will show you how to use RAINCATCHER on a daily basis in the different fields of activity.

We will soon be giving access to the download of an automatic dosage , simulation tool from RAINCATCHER to apply.

General principles

To adapt the dosages of RAINCATCHER to your plants, it is necessary to take into account three important elements which constitute the terrain: the soil, the climate and the type of culture.
Each of these elements has a direct influence on the water requirements and therefore on the dosages of RAINCATCHER to be used to obtain an optimal growth yield in the plant.

Below, we present some lines of thoughts and concepts to take into account to help you optimize your horticultural and agricultural yields.

At the end, we present you the solution RAINCATCHER and the gains brought to the irrigation of your cultures. 

The soil

Soil is an important element to consider when using RAINCATCHER. 

The type of soil

Let’s consider the different types of soils:

Sandy soils

Sandy soils  

Sandy soils are mostly found near bodies of water or in desert climates and are often dry, poor in nutrients and very draining.

Their draining characteristic does not allow a satisfactory retention of water from plant roots. In the same way, they are scarcely (if at all) capable of transporting water from the deep layers by capillarity, and to retain it.

This type of soil requires increasing the amount of RAINCATCHER used to:

  • to compensate for the strong draining effect and to allow the creation of a sufficient reserve of water at the foot of the plant,
  • to allow it to partially counter the effect of evaporation.

We recommend using 2g of hydrogel per kg of soil to retain moisture twice as long as untreated soil.

Loamy soils (0 to 10% clay) 

These soils differ from sandy soils in their ability to form a crust, which is often very hard.

If they are too worked, they can become compact which reduces the infiltration capacity of the water during wet periods.

It is therefore advisable to apply RAINCATCHER during the tillage period and to water it abundantly within 15 days after plowing so that our product hydrates before the crust is formed under the action of the sun.

Clay soils

Clay soils (<25% clay)

These soils are different from the previous ones because they can be subject to a very hard crust. The crust is so hard that it becomes difficult to destroy.

With a low rate of clay and organic matter, the formation of aggregates is often poor, which is a brake on the supply to roots of essential materials for their good development.

RAINCATCHER promotes good aeration for this type of soil because of its cyclic changes of physical forms under the action of water.

Clay soils (25 to 40% clay) 

These soils have a good ability to carry water by capillarity from the deep layers, but the diffusion is slow and does not cover the entire water requirements of plants.

The color of these soils is darker and their aggregations are more distinct. Aggregation decreases the risk of crust formation.

Clay soils (> 40% clay) 

Heavy clays have a high water-retention capacity, but most of this water is tightly bound and unavailable to plants.

The humus content is often higher than that of other mineral soils. They do not form a crust.

Diagram #1: Soil types

The more clay in the soil, the more likely it is to maintain the irrigation water near the roots because it will flow less by gravity than in sandy soil for example.

In this case, the main function of the RAINCATCHER will no longer be to maintain the water around the roots, but to promote a stable water supply to avoid any water stress during a drought, for example. simply to optimize irrigation on a very greedy water culture.

Soil texture

Diagram #2: Fine earth

This is determined by the size of the soil particles and their respective proportions. Recall the dimensions of the three categories of soil constitutive particles:

  • Coarse sand: 0.2 mm to 2 mm
  • Fine sand: 0.05 to 0.2 mm
  • Coarse silt: 0.02 to 0.05 mm
  • Fine silt: 0.002 to 0.02 mm
  • Clay: (commonly called clay) 0.002 mm and less

The structure of these particles can be compact or aggregated. In the latter case, the particles are bonded together while having spaces allowing the transport of oxygen and carbon dioxide to the roots.

The water content is a function of the porosity and permeability of the soil. The maximum volume of water that a soil can hold is the "field capacity" FC, or soil holding capacity that depends on its particle size.

Agregation

The aggregation of particles by RAINCATCHER amplifies its work as a water retainer because the notion of Total Water Available increases automatically with the aeration of the soil.

Remember that good oxygen aeration also allows a better decomposition of the fresh organic matter, a better life of the anaerobic soil and a better installation and development of the plant notably via the facilitated contribution in ferrous materials.

Climate and soil moisture

Climate

Climates condition by the volumes of precipitation and by induction, the types of soils.  

The place and the type of soil of the location where RAINCATCHER will be used will be, of course, a determinant, but it will also be necessary to specify the type of climate according to the region and / or the latitude: in a country like France, one can find several types of climates that have a direct influence on the types of soils and geology they have carved for centuries.

The effects of global warming will also affect the dosage of RAINCATCHER to be used, depending on the occasional occurrence of drought events and precipitation characteristics (spacing of violent showers punctuated by significant temperature rises).

Soil moisture

In the soil, water can be divided into 3 states:

  1. The water of gravity or saturation contained in the gaps (between the aggregates) which flows by gravity towards the aquifer. The wetting point for saturated soil corresponds to the end of flow of water by gravity.
  2. The Total Water Availability (TWA) or Soil Moisture Content (SMC) is the water used by the plant which is retained in the form of rather thick films around the earth particles or in the fine capillaries. When the TWA is exhausted, we are at the point of permanent wilting.
    The TWA can be divided into 2 parts: the RAW (Ready Available Water) or hydric comfort and the MAD (Management Allowable Depletion) which generates water stress.
  3. Unusable water which is the water retained vigorously in the form of very thin films around the particles of earth and unusable by the plants. The retention capacity or Field Capacity corresponds to the TWA + unusable water. The TWA varies according to the soil types from 1/3 (in sandy soil) to 2/3 (in clay soil) of the retention capacity.

A plant that will leave the area of the TWA, either because of soil too waterlogged (or too much moisture in a greenhouse), or because of a drastic drying, will perish respectively by asphyxiation or wilting.
 

Diagram #3: Hydro Balance

Total water available TWA – soil moisture content SMC

The volume of water available to plants, expressed in millimeters per centimeter of soil depth and called the Total Water Available TWA, therefore includes the “Ready Available Water” RWA and the “Management Allowable Depletion” MAD or "Survival Reserve".

The TWA is, as its name suggests, a reserve that must be regularly replenished to prevent the plant moving into water stress.

The TWA depends on 2 parameters: the soil depth colonized by the root system (about 1 m for an annual wheat or maize crop) and the soil texture.

For a depth of 1 m, useful reserve values are obtained ranging from 70 mm of water for coarse sandy soil, to 200 mm of water for loam-clay soil.

The root volume varies according to the plants. We can divide the vegetable plants in 3 groups according to their rooting:

  • Low rooting: about 15 cm, radish, salad ...
  • Average rooting: about 20 cm, onion, potato, cabbage ...
  • Strong rooting: more than 30 cm, turnip, carrot, tomato, eggplant, zucchini, spinach ...

As an indication, the average value of the TWA is:

  • 0.9 to 1.2 mm / cm of soil for sand,
  • 1.3 to 1.6 mm / cm of soil for a clay loam,
  • 1.8 to 2 mm / cm of soil for a clay soil, silty clay, sandy clay.

The texture of the soil has a direct influence on the UK:

  • Sandy soils have low water retention capacity, which implies lower RUs.
  • Soils with a high proportion of fine particles (silts and clays) store more water; in return, a large part of these water reserves remain unavailable for plants because of horizontal circulation or by difficult capillaries.

Other important points:

  • The coarse elements (soil elements whose size is greater than 2 mm: pebbles, gravel ...) do not allow to store water. Soils with a high proportion of coarse elements therefore have a limited TWA.
  • Organic materials have higher retention capacities than clays. By contrast, they make water restoration more difficult. However, the balance of organic inputs remains positive in the TWA.
  • The TWA of a soil can be evaluated from the texture. This is determined by the granulometric analysis of the soil (distribution of particles of a soil according to their sizes). 

The Texture Triangle is used to estimate the TWA by soil type. The TWA is expressed in millimeters of water per centimeter of fine soil (particles less than 2 mm in size).

Diagram #4

From the experiments we have done, we know that RAINCATCHER increases the TWA from 30% (very clayey soil) to 70% (fine sand soil).

Ready available water (RAW)

Plants can never extract all the water from the soil because the root capacity differs according to the type of plant and the roo volume. The plants use only part of the TWA: The Ready Available Water.

The RAW of a soil is also expressed in millimeters of water per cm of fine soil. It is difficult to estimate, but can be estimated at 60% of the TWA in the absence of precise analysis and at least half of the hydrated RFU should be maintained to avoid water stress.

Diagram #5: The triangle of texture
SMC
Sand 0.7
Loamy sand 1
Sandy loam 1.45
Loam 1.8
Sandy clay loam 1.75
Sandy clay 1.7
Clay 1.7
Silty clay 1.8
Clay loam 1.95
Silty clay loam 1.8
Silty loam 1.75
Silt 1.3

Example of estimating the TWA of a soil from the texture triangle 

For a low to medium stony soil over a horizon of 80 cm deep (= depth of colonizing roots) composed of:

  • 0 to 30 cm: 90% of fine earth of which 15% of clays, 60% of silts and 15% of sands.
  • 30 to 80 cm: 50% of fine earth of which 35% of clays, 40% of silts and 25% of sands.

Calculation of the TWA and the RAW on this horizon:

According to the Texture Triangle and the associated coefficients, this horizon corresponds to a fine silt soil in the first 30 cm and a clay loam soil in the 50 cm below.

  • The fine silt TWA = 1.75 x 30 = 52.5 mm
    This soil consists of 90% fine earth (<2 mm), so the TWA is 52.5 x 0.9 = 47.25 mm.
  • The TWA of clay loam = 1.95 x 50 = 97.50 mm
    This soil consists of 50% fine soil (<2 mm), so the TWA is 97.5 x 0.5 = 48.75 mm.

On 80 cm, the total TWA is therefore 47.25 + 48.75 = 96 mm.

The RAW of the horizon is therefore = 96 X 0.60 = 57.6 mm.
 

Considering the properties of this soil, the application of RAINCATCHER increases its TWA by 55%.

The coefficient of permeability 

The permeability (k) of a soil is defined by the rate of infiltration of water into the soil; k is measured by Darcy's law:

A layer is deemed impervious for values of k of the order of 9 - 10m / s. The water that falls on the soil surface begins to moisten the upper part of the soil (for a few centimeters): part of which is evaporated directly during and after the rain.

With the warming of the climate, natural irrigations have become increasingly outdated and are often applied to dry soils and the type of soil, that holds a coefficient of permeability limiting the penetration by gravity.

The plant receiving large amounts of water in a short time is not able to take advantage of this excess of abundance.

Diagram #6: Permeability

In case of abundant rainfall and depending on the region, we also take into account the coefficient of permeability in the RAINCATCHER assay. During these showers, RAINCATCHER will rebuild its reserves with the little water that will seep into the soil and hold for several weeks this water that the plant will not be able absorb for a short time.

Cultures

The water balance 

he water balance provides elements for the calculation of irrigation dosages, it is based on the knowledge and data of ETo (Reference Evapotranspiration) and TWA (Total Water Available).

Evapotranspiration ET = sum of water evaporated by soil and plant: ET = EV + T

Evapotranspiration is the combination of two phenomena of water discharge: the evaporation of water (EV) in contact with the plant under the climatic action on the one hand, and the transpiration (T) of it on the other hand.

This phenomenon could be compared to humans, who need to drink water to live. The more effort a person makes, and depending on their growth phase, the more water they need (there is evidence that the stomata of the leaves of the plant open and close according to the wind, which is why the effect of the latter partially increases the ET).

If we took two immobile individuals, one sitting under the sun in the desert and another sitting in a humid forest, we would also understand that the perspiration of the one in the desert would be more important and that the individual sitting in the forest would have substantially more water reserves provided by the ambient humidity.

The same is true for plants: the roots of plants draw water from the soil's valuable reserve and disperse it into the atmosphere through ET evapotranspiration via their intrinsic perspiration and the evaporation of water under effect of heat. Each plant, just like every living being, has specific water needs:

Type of crop Water need* Sensibility to drought
Alfalfa 800-1600 low-medium
Banana 1200-2200 high
Barley / Oats / Wheat 450-650 low-medium
Bean 300-500 medium-high
Cabbage 350-500 medium-high
Citrus 900-1200 low-medium
Cotton 700-1300 low
But 500-800 medium-high
Melon 400-600 medium-high
Onion 350-550 medium-high
Peanut 500-700 low-medium
Peas 350-500 medium-high
Pepper 600-900 medium-high
Potato 500-700 high
Paddy field 450-700 high
Sorghum / Millet 450-650 low
Soy 450-700 low-medium
Sugar beet 550-750 low-medium
Sugar cane 1500-2500 high
Sunflower 600-1000 low-medium
Tomato 400-800 medium-high

*mm/total crop period

Water requirements by plant cycle

Plants are living creatures that consume water for their growth and it is important to help them settle after planting. We must follow the watering the first 15 days to allow them to avoid later problems such as the "black ass" for tomatoes or peppers.

The quality of the plants has an influence on the resistance to drought: old plants will emit fewer roots and therefore have a lower resistance to drought (squash, salads in particular).

It is also very important that RAINCATCHER receives a normal initial watering to build up its reserves. Subsequently, it replenishes these reserves with each irrigation to counter the losses due to evaporation which will result in a significant water saving.

It is possible to apply RAINCATCHER directly in its gel form: this process is used for special needs such as tree transplantation and allows for an exceptional transplant success rate.

Throughout the growth of the plant, the water needs will be different and they can be quantified according to:

  • ETo: Reference evapotranspiration in mm of evaporated water / day
  • ETc: Crop evapotranspiration = K x ETo,
  • K: crop coefficient varying according to the stage of the plants.

As an example, for a crop grown in a hot climate:

Specy K Initial K Max K Final
Tomato 0.2 1.4 1
Cucumber 0.2 1.2 --
Melons 0.2 1.3 1.1

Vegetables do not have the same needs according to their stage of cultivation. For example, for the tomato, the ETc reaches a maximum at the 4th bouquet in flower or at the 1st fruit maturing ie turning to red.

But beware, if you water too much at maturity, the fruits burst, hence the use of RAINCATCHER which will accompany the plant in its ETc according to its needs. Similarly, pumpkins will be supplied with water only at their request: their conservation will be better.

Diagram #7

Racinary values of the main crops

Effective Rooting Depth of Mature Crops for Irrigation System Design

Estimation of water requirements by difference between TWA and ET

Let's take an average plant with a depth of rooting of 20 cm in a soil of loams to the TWA of 1.8.

The TWA of the horizon will be (1.8 x 20) x 0.6 = 21.60 mm

With an ET= 4mm / day, the soil water reserve for the plant will then be 21.6 / 4 = 5.40 days.

We usually apply a correction of 80% in desirable water supply (excluding salad): 5.40 / 0.80 = 4.32

This results in about 4 to 5 days of reserve for a plant rooted at 20 cm.

Estimation of ET  

ET varies considerably depending on meteorological parameters such as wind, sunshine and heat. On average, we consider the values of the following table:

ET in mm according to climate:

Mean daily temperature

Climatic zone low (less than 15°C) medium (15-25°C) high (more than 25°C)
Desert/arid 4 to 6 7 to 8 9 to 10
Semi-arid 4 to 5 6 to 7 8 to 9
(Moist) Sub-humid 3 to 4 5 to 6 7 to 8
Humid 1 to 2 3 to 4 5 to 6

The values in the table above, which only take into account heat, are therefore only indicative and show that the ET can vary twice for an average ΔT of 20 °. Irrigation water evaporates very quickly on hot soil and at high temperatures, whether on the surface or in the soil. The heat increases in parallel the perspiration of the plant but in lesser proportions.

It is also necessary to increase the ET by 10 to 20% in windy regions.

By compiling all the theses that have been made on the ratio Perspiration / Evapotranspiration, we also find that the Latitude of the place of culture has an influence on the ET varying the perspiration of 30 to 70% by following the gradient of increase heat.

It is very easy to understand that the use of the RAINCATCHER, in addition to its direct effect on the increase of the TWA, will greatly reduce the ET in its "evaporation" effect because the water stored and necessary for the plant is between 5 and 10 cm underground, or even deeper with the development of roots that will bind to the gel nodules. Due to low exposure to sunlight and surface soil, RAINCATCHER will maintain its water efficiency longer than untreated soil. In addition, RAINCATCHER is in a solid state and will, by definition, require a greater amount of energy than water in the liquid state to turn into gas and thus evaporate.

With RAINCATCHER, we must separate the terms "evaporation" and "perspiration". The "evaporation" effect will only occur via the warming of the earth, which decreases with depth. It is the Perspiration of the plant which, by drawing in the available reserves, will influence mainly the value of the ET under the action of the RAINCATCHER.

From our experiences, we know that the ET and therefore the ETc, is decreased under the effect of RAINCATCHER a value of between 20% to 40% depending on the climate.

RAINCATCHER and agriculture

RAINCATCHER has an undeniable effect on crop growth.

  • The TWA of a soil is linked to the nature of the soil: RAINCATCHER changes the nature of the soil with its ability to absorb water and thus changes the TWA. More TWA means a decrease in irrigation needs.
  • In parallel, the "Evaporation" part of Evapotranspiration ET is strongly limited by the effect of RAINCATCHER, which increases the resistance of the plant in a hot climate.
  • Another important element for an optimal development of the plant and its fruits is the fact that RAINCATCHER associates with the roots via its nodules which reduces water stress. This water stress factor is significant because in the natural environment, any action causes a reaction and repeated periods of wilting have enormous consequences on a crop.
  • The aeration capacity of the soil is increased during the expansion of the RAINCATCHER crystals  and this also increases the capacity to collect water from the soil, and allows a better circulation of all the nutrients contained in the soil.
  • Fertilizer saving is also proven: the soluble fertilizer is captured by the nodules when they swell under the effect of water. It is not only the financial savings that are important but the fact that the action of the fertilizer will act for several months against a few weeks in normal times.
  • RAINCATCHER continues its crystal-powder transformation cycle between 3 and 5 years depending on where it is used, before biodegrading completely. Its application is very versatile, unlike a fertilizer which must be repeated regularly.
  • RAINCATCHER can also be of great help in the greenhouse where bacteria often grow rapidly due to high humidity and sustained heat. Feeding the plant with buried moisture via RAINCATCHER helps to deal with these problems.

Implementation of  RAINCATCHER

Recall  

1mm of precipitation corresponds to 1 liter on 1 m2. 

Basic

Take the soil:

  • 0 to 30 cm: 90% of fine earth of which 15% of clays, 60% of silts and 15% of sands.
  • 30 to 80 cm: 50% of fine earth of which 35% of clays, 40% of silts and 25% of sands.

This soil has a TWA of 57 mm over a horizon of 80 cm, so a water requirement of 570 m3 of water per hectare (1 mm = 10 m3 / ha) to be replenished.

From our proving experiments, we know that RAINCATCHER increases the TWA of this soil by 55%, which means that the TWA after application of the RAINCATCHER is raised to 88 mm.

Example

Maize requires 500 to 800 mm of water throughout its growing season, which means that it must replenish 9 to 14 times the TWA of this type of soil over the period.

At latitude 45, under a subtropical climate (hot and long summer) between April and September, it needs 500 mm of water with the following ETc (mm):

APRIL MAY JUNE JULY AUGUST SEPTEMBER
11.9 77.7 109.5 187.6 112 16.9

We estimate at -30% the influence of RAINCATCHER on the ET (and thus the ETc) under this type of climate.

We thus extrapolate this table which matches the new TWA of the ground vis-à-vis the ETc under the action of RAINCATCHER, by considering a complete TWA following a consequent watering after application of the RAINCATCHER:

RAINCATCHER APRIL MAY JUNE JULY AUGUST SEPTEMBER
ETc mm 8.3 54.4 76.6 131.3 78.4 11.83
TWA mm 88 88 88 88 88 88
BALANCE WATER mm 79.7 25.3 8.7 7.4 9 7.17
IRRIGATION mm 0 60 130 80 10 --

The total irrigation to be provided with the RAINCATCHER APPLICATION will be 280 mm, giving a saving of 54% in water.

Application 

The application of RAINCATCHER will be 15 to 100 kg per hectare depending on the terrain.

Our specialists will make a personalized study and advise you on the ideal dosage to apply according to your parameters. We will soon be providing our customers with an online simulation tool to tell you the earnings generated by using the RAINCATCHER.

Results observed with RAINCATCHER

  • In Germany, in clay soils and in an ocean-continental climate, our customers have already given us feedback on the use of RAINCATCHER for carrot cultivation, which is consistent with our calculations:
Application Sandy Soil Mud Soil Clay Soil
Beans 35 kg / ha 20 kg / ha 16 kg / ha
Carrots 30 kg / ha 18 kg / ha 12 kg / ha
  • In South Africa, under a more arid climate, significant results were observed on the size of carrots with application of RAINCATCHER between 25 and 50 kg per Ha according to the time of the year:
Carrots
Carrots
  • In France, an experiment on the cultivation of tomatoes with drip irrigation was conducted in the summer of 2019 in the region of Salon de Provence in hot weather: the weight of vegetables was more than doubled:
Tomatoes

On the left, the biggest of the tomatoes pushed with RAINCATCHER, on the right the biggest of the tomatoes pushed without:

Tomato
Tomato

To come up

A simulation tool for professionals will soon be available online to calculate the various parameters you need:

Input parameters:

  • % clay soil
  • % loam sol
  • % sand soil
  • % fine soil (particle size <2 mm)
  • Type of plant (by type for vegetables, flowers, indoor plants greedy or not in water, trees, grass etc ...)
  • Type of climate
  • Latitude of exploitation (N ° - S °)
  • Price m³ of irrigation water
  • Average outdoor temperature

Output parameters:

  • Total Water Available
  • Ready Water Available
  • ET
  • Number of mm of watering required per day
  • Watering in m³ / day / Ha
  • Quantity of RAINCATCHER per Ha to save 40% watering
  • Water savings realized by RAINCATCHER (USD)