Rice growing guide

Recommended types:

Starter Fertilization

Top dressing

1 Introduction

1.1 Importance of Rice Cultivation

Nutritional and Financial Value:

Rice is a key source of carbohydrates and energy, particularly in Asia, Africa and Latin America.
It is used both as a foodstuff and as a raw material in industrial applications (e.g. starch, spirits).

Environmental Benefits:

- Greece is a major rice producer in Europe, mainly in Macedonia (Axios-Loudias-Aliakmonas Delta).
- Rice contributes to the local economy through exports and the processing industry.

1. Environmental Importance:

It is grown in wetland systems that function as natural ecosystems and wildlife sanctuaries.
Offers protection against corrosion and improves water retention.

1.2 Categories and Uses of Rice

Rice is categorized based on:

Macroelements:

Long grain (Indica): It has a long, thin grain, ideal for salads and pilaf.
Medium seed (Japonica): Shorter and stickier, suitable for soups and risotto.
Short seed: Ideal for desserts and sweets.

Environmental Benefits:

Irrigated (Liquid): It is grown in flooded fields and covers 90% of the production.
Dry (Flood-independent): Cultivated in soils without permanent flooding, mainly in mountainous areas.( Not available in Greece )

2. Botanical and Physiological Characteristics

2.2 Radical System

Root

Type: Fibrous and extended root system.
Adaptation to Flooded Soils:
- Development of adventitious roots for oxygen uptake.
- Formation of aerenchyma to transport oxygen from the leaves to the roots.
Depth: 20-30 cm in soils with sufficient moisture.

2.1.2 Shoot

Shape: Cylindrical, articulated and concave.
Height: Ranges from 50 cm to 150 cm, depending on the variety.
Joints (Nodes): They serve the development of leaves and siblings.
Sprouting Ability: Allows the production of new shoots (siblings) from the nodes.

2.1.3 Sheets

Morphology: Linear and lanceolate with an alternating layout.
Length: 20-50 cm, depending on the variety.
Importance:
- Perform photosynthesis.
- control.
- Participation in solar energy intake for grain growth.

2.1.4 Flowers

Flower

Type: Hermaphrodites with self-fertilization.
Structure:
- Wheat (Panicule): Main reproductive organ.
- Flowers (Spikelets): Each ear bears multiple flowers that produce one grain.
Fertilization: It is mainly carried out through self-fertilization, but it is also possible to cross-fertilize in a small percentage.

2.1.5 Fruit (Grain)

Shape: Samaroid fruit enclosed by blades.
Size and Weight: Length 5-10 mm and weight 20-30 mg per grain.
Structure:
- Enclosures: They include outer bark (lepira) and bran.
- Endosperm: Rich in starch and proteins.
- Fetus: Source of enzymes and oils.

2.2.1 Germination and Root Development

Duration: 7-10 days.
Main Processes: Water
- absorption and seed swelling.
- Initiation of germination and development of primary roots.
- Development of first cards.

2.2.2 Stem Elongation and Brotherhood

Duration: 20-30 days.
Main Processes:
- Creation of side shoots (siblings) from the nodes.
- Increase leaf area for maximum photosynthesis.
- Preparing for the flowering phase.

2.2.3 Flowering and Fertilization

Duration: 5-7 days.
Main Processes: Flower
- opening and pollen release.
- Self-fertilization and embryo formation.

2.2.4 Grain Filling and Maturation

Duration: 25-35 days.
Main Processes:
- Accumulation of starch and proteins in the granules.
- Drying and hardening of the fruit.
- Full ripening and ready to harvest.

2.3.1 Climate

Temperature:
- Optimal: 25-35°C during the vegetative period.
- Minimum: 10°C for germination.
- Maximum: 40°C may cause flower infertility.
Solar Radiation:
- High sunshine is required for photosynthesis and grain growth.
Rainfall:
- Ideal: 1000-1500 mm per year.
- In arid areas, continuous irrigation is required.

2.3.2 Soil

Soil

Type:
- Loamy and loamy soils with good water retention.
- Neutral to slightly acidic pH (5.5-7.0).
Drainage:
- Necessary for alternating irrigation (AWD) and root oxygenation.
Organic Substance:
- Must be equal to or greater than 2% to improve structure and fertility.

3. Soil Preparation and Seeding

3.2 Soil Preparation

Soil preparation aims to:

The creation of a uniform surface for good root development.
Improve water retention and reduce evaporative losses.
Removal of weeds and organic residues to reduce competition.

3.1.1 Preparation Stages

1. Άροση (Βαθύ Όργωμα):

- Depth: 20-30 cm for soil structure improvement and ventilation.
- Objective: Destruction of weeds and increase of water filtration.

Disc

Machining:

- Crushing large pellets to create a thin layer of seeding.

Surface

improvement for even flooding.

Calcium (Ca):

Use of Laser Leveling to ensure uniformity.
Importance: Facilitates even water distribution during irrigation.

Calcium (Ca):

- Creating a 2-5 cm water layer to soften the soil.

Weed

suppression through suffocation and removal of weed seeds on the surface.

3.2 Sowing season

Rice sowing is planned based on climatic conditions:

Spring (April – May): Appropriate period in most areas of Greece.
Temperature: Must be >15°C to ensure uniform germination.
Climatic Conditions: Avoid sowing before periods of heavy rainfall that can cause erosion.

4. Introduction to Rice Fertilization

4.1.1 Importance of Lubrication

The growth of rice depends largely on the availability of nutrients in the soil. Proper lubrication:

Supports the growth of roots and leaves in the early stages.
Enhances photosynthesis and carbohydrate accumulation.
Improves fruit setting and grain filling.
Increases the protein and starch content.
Enhances resistance to diseases, enemies and stress (drought, salinity).

4.1.2 Lubrication Targets

Improve Initial Development:

Ensure a strong root system and dense fraternity.

Trace elements:

Support the production of carbohydrates and proteins during the filling stage of the granules.

Trace elements:

Maintaining soil fertility.
Limitation of losses due to leaching or gassing (e.g. ammonia).

Trace elements:

Reduction of overfertilization and water pollution.
Rational use of fertilizers based on soil analysis and phyllodiagnostics.

4.1.3 Factors Affecting Lubrication

The need for lubrication depends on several factors:

soil

pH:

Mullein Soils: Better water and nutrient retention capacity.
Sandy Soils: Increased fertilization needs due to nutrient leaching.
Organic Substance: Soils with low organic matter need additional nutrition.

Σύστημα Καλλιέργειας:

Flooded Fields: Limit oxygen availability and affect nitrogen dynamics (reduction).
Dry Conditions: They cause rapid depletion of nutrients due to erosion and runoff.

Στάδιο Ανάπτυξης του Ρυζιού:

Sprouting and Breeding: Nitrogen (N) and phosphorus (P) are required.
Filling: Increased requirements in potassium (K) and microelements (Zn, Fe).

Macroelements and Microelements:

Fertilizers with urease/nitrification inhibitors (CRFs): They gradually provide the nutrients.
Fertilization: Adapts nutrition to the needs of the plant in real time.

4.1.5 Integrated Nutrition Strategy

The rice fertilization strategy is based on the following principles:

soil pH:

Determination of nutrient levels before sowing.
Calculation of fertilizer doses based on production needs (target 800-1300 kg/acre).

Environmental Benefits:

Basic Lubrication (Pre-plant): Supply of phosphorus (P) and potassium (K).
Top-Dressing: Add nitrogen (N) in multiple doses.
Foliar Feeding: Provision of trace elements during flowering and filling of the grains.

4.2.1 Macronutrients (N, P, K)

1. Nitrogen (N)

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Λειτουργία:

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Promotes germination, leaf growth and sibling production.
It helps to increase the protein and amylose content in the granules.
Supports the production of chlorophyll and enzymes.

Techniques:

Supplementary (basic fertilization): 4-6 kg/acre.
During development (surface fertilization): 6-10 kg/acre in multiple applications.
In total: 10-17 kg/acre for high yields (900-1300 kg/acre).

Techniques:

Yellow leaves (chlorosis) and limited sibling development.
reduction.

Techniques:

Excessive vegetative growth, plant lying down and increased risk of disease.

2. Phosphorus (P)

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Λειτουργία:

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It promotes the development of the root system.
Improves the flowering and filling of the grains.
Supports energy transfer (ATP) and DNA synthesis.

Techniques:

Basic fertilization before sowing: 3-5 kg/acre (P₂O₂).
During brotherhood: Additional application 2-3 kg/acre.

Techniques:

Delayed growth and short shoots.
Reduced flowering and small, empty grains.

Techniques:

Inactivation of microelements (e.g. Zn, Fe) due to chemical interaction.

2. Potassium (K)

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Λειτουργία:

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Improves disease resistance and fights stress.
Controls the maintenance of water balance in cells.
Supports the transfer of sugars to the beans during ripening.

Techniques:

Basic fertilization before sowing: 6-9 kg/acre (K₂O).
Κατά την άνθηση: 3-5 κιλά/στρέμμα.

Techniques:

Peripheral burns (necrotic spots) on the leaves.
Delayed maturation and reduced resistance to stresses.

Techniques:

It is easily balanced by the plant without toxicity.

4.2.2 Secondary and Micronutrients

1. Calcium (Ca)

Role: Strengthen cell walls and increase disease resistance.
Requirements: 2-3 kg/acre.
Deficiency: Delayed growth and weakening of cell membranes.

2. Magnesium (Mg)

Role: Chlorophyll formation and phosphorus transport.
Dose: 0.5-1 kg/acre.
Lack: Yellowing of old leaves and reduced photosynthesis.

2. Sulphur (S)

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Ρόλος: Σύνθεση πρωτεϊνών και ενζύμων.
Requirements: 2-3 kg/acre.
Ellipse: Pigmented leaves with a white tint on the tops.

2. Zinc (Zn):

Role: Enhancement of enzyme reactions and root development.
Dose: 0.5-1 kg/acre.
Lack:
- Disease “Vaginal Chlorosis” with yellow stripes on the leaves.
- Reduced root development and production.
Correction: Foliar nutrition with zinc-EDTA.

2. Iron (Fe):

Role: Chlorophyll synthesis and electron transport.
Dose: 0.5-0.8 kg/acre.
Deficiency: Young leaf chlorosis (Fe-induced chlorosis).
Correction: Foliar nutrition with iron chelate (Fe-EDDHA).

2. Manganese (Mn):

Role: Enzyme processes and photosynthesis.
Dose: 0.5-0.8 kg/acre.
Ellipse: Chlorosis and spots on the leaves.

4.3 Lubrication Program

The rice fertilization program is designed based on the needs of the plant at each stage of development, taking into account the soil analyses and the intended yields. Fertilizer application must be spread over time to ensure maximum nutrient absorption and reduce losses due to leaching or gasification.

4.3.1 Basic Lubrication (Before Seeding)

Basic fertilization provides the nutrients required for the germination and planting of the plant.

Application

Rates (per acre):

Root and shoot

Nutrient	Quantity (kg/ha)	Target
Nitrogen (N)	4-5	development.
Phosphorus (P₂O)	3-5	Strong root system and early development.
Potassium (K₂O)	6-8	Resistance to disease and sugar metabolism.
Zinc (Zn)	0.5-1	Prevention of chlorosis and root development.

4.3.2 Surface Lubrication (During Growth)

Surface fertilization complements the basic nutrition and supports the basic stages of development: fraternization, flowering and grain filling.

Breakdown By Development Stage:

Development Stem Grain

Stage	Nitrogen (N)	Potassium (K₂O)	Micronutrients (Zn, Fe)
Brotherhood (20-30 days)	3-4 kg/ha.	2-3 kg/ha.	Zinc (Zn): 0.5 kg/ha.
Elongation (40-50 days)	3-4 kg/ha.	3-4 kg/ha.	Magnesium (Mg): 0.5 kg/ha.
Flowering (60-70 days)	2-3 kg/ha.	2-3 kg/ha.	Iron (Fe): 0.3-0.5 kg/ha.
Filling (80-100 days)	2-3 kg/ha.	2-3 kg/ha.	Foliar solutions of microelements.

4.3.3 Foliar nutrition (Foliar Lubrication)

Foliar nutrition is used to rapidly correct micronutrient deficiencies and enhance production at critical stages.

Critical Elements and Applications:

Solution Implementation Grain

Item	Concentration	Stage
Zinc (Zn)	0.5% – 1%	Stalking and shoot elongation.
Iron (Fe)	0.3% – 0.5%	flowering and filling.
Magnesium (Mg)	0.5%	Foliar nutrition before flowering.
Boron (B)	0.1% – 0.2%	During flowering.

Advantages of foliar nutrition:

Rapid absorption and action.
Correction of deficiencies at critical stages.
Compatibility with plant protection products (combined applications).

4.3.4 Use of Fertilizers with Urease/Nitrification Inhibitors

Πλεονεκτήματα:

Gradual nutrient supply.
Reduction of losses due to leaching or gassing.
It is indicated in areas with high rainfall or nitrogen leaching problems.

Techniques:

Basic fertilization before sowing.
Superficial application of small doses during development.

4.3.5 Lubrication Monitoring and Adaptation

soil pH:

Monitoring of nutrient levels in leaves for timely correction of deficiencies.

Calcium (Ca):

Estimation of nitrogen status in plants based on chlorophyll.

Trace elements:

Adjustment of doses according to growth conditions and yields.

4.4 Development Stages and Fertilizer Needs

The application of fertilizers to rice must be targeted and adapted to the needs of the plant at each stage of development. Each phase requires specific nutrients for optimal growth and production of high-quality grains.

4.4.1 Stage 1: Germination and Initial Root Development (0-15 days)

Description:

Water absorption and swelling of the seed.
Appearance of primary roots and first leaves.

Techniques:

Strengthening the root system and early development.
Provide phosphorus for rooting and nitrogen for growth initiation.

Suitable Nutrients:

Nitrogen (N): 3-4 kg/ha for fast growth of shoots.
Phosphorus (P₂O₂): 3-5 kg/acre for a strong root system.
Potassium (K₂O): 4-5 kg/acre for stress resistance.

Steps:

Basic fertilization with incorporation before seeding or flooding.
Application of zinc (Zn) in foliar nutrition if deficiency is found.

4.4.2 Stage 2: Brotherhood (20-40 days)

Description:

Formation of adjacent shoots (siblings).
Increase leaf area for photosynthesis.

Techniques:

Support shoot growth and sibling formation.
Maintain the availability of potassium for disease resistance.

Suitable Nutrients:

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Άζωτο (N): 4-6 κιλά/στρέμμα για ενίσχυση της ανάπτυξης.
Potassium (K₂O): 3-4 kg/acre to increase strength.
Μαγνήσιο (Mg): 0,5-1 κιλό/στρέμμα για ενίσχυση της φωτοσύνθεσης.

Steps:

Surface fertilization in wet soil or through fertigation with water.
Foliar nutrition with zinc (Zn) and iron (Fe) to enhance growth.

4.4.3 Stage 3: Stem Elongation and Preparation of Flowering (40-60 days)

Description:

Rapid increase in plant height and the growth of cinders.
Preparation for flowering and fertilization.

Techniques:

Enhancement of germination for adequate production of cinders.
supply for carbohydrate metabolism and strength enhancement.

Suitable Nutrients:

Nitrogen (N): 3-4 kg/acre for foliage development.
Κάλιο (K₂O): 4-5 κιλά/στρέμμα για ενίσχυση της αντοχής σε καταπονήσεις.
Phosphorus (P₂O₂): 2-3 kg/acre to strengthen the root.

Steps:

Water fertilization for a gradual supply of nutrients.
Foliar nutrition with magnesium (Mg) and iron (Fe) to enhance photosynthesis.

4.4.4 Stage 4: Flowering (60-75 days)

Description:

Opening of the flowers and fertilization.
formation and fruit development.

Techniques:

Maintain adequate levels of nitrogen and potassium for flowering.
Provision of microelements to improve fertilization.

Suitable Nutrients:

Nitrogen (N): 2-3 kg/acre to enhance flower fertility.
Potassium (K₂O): 3-4 kg/acre for stress protection.
Boron (B): 0.5 kg/acre to increase flower fertility.

Steps:

Foliar nutrition for the immediate absorption of micronutrients.
fertigation to maintain nutrition during flowering.

4.4.5 Stage 5: Grain Filling and Maturation (75-100 days)

Description:

Carbohydrate

transfer to the granules.
Maturation and hardening of the granules.

Techniques:

Maintenance of potassium reserves for grain quality.
Correction of microelement deficiencies for full filling.

Suitable Nutrients:

Potassium (K₂O): 2-3 kg/acre for sugar metabolism.
Calcium (Ca): 1-2 kg/acre for cell wall stability.
Magnesium (Mg): 0.5 kg/acre to improve the quality of the grain.

Steps:

Foliar nutrition with potassium and calcium to enhance maturation.
Careful control of moisture and avoidance of excessive nitrogen lubrication.

4.5 Adjustment of Lubrication with Soil Analysis

Soil analysis is a key tool for the proper management of rice fertilization. It allows the precise identification of available nutrients and helps to calculate fertilizer needs. This ensures maximum efficiency, minimization of costs and environmental protection.

3.1.1 Importance of Soil Analysis

1. Δειγματοληψία Εδάφους:

- Depth: 0-30 cm, where most of the roots are located.

Sampling

Areas: Sampling from various points for representative results.
Timing: 2-3 months before sowing for timely lubrication planning.

Environmental Benefits:

MeasurementSheetStressChlorophyll

Parameter	Goal	Ideal Levels for Rice
pH (acidity/alkalinity)	Improve nutrient availability.	5.5 – 7.0
Organic matter (%)	Support microbial activity and water storage.	>2%
Nitrogen (N)	development and yield increase.	10-15 mg/kg (nitrate NO①).
Phosphorus (P)	Strong root system and flowering.	15-20 mg/kg (Olsen-P).
Potassium (K)	resistance and sugar transport.	100-150 mg/kg (K₂O).
Zinc (Zn)	Prevention of abnormalities and enhancement of growth.	1.0-2.0 mg/kg.
Iron (Fe)	formation and chlorosis prevention.	4-6 mg/kg.

4.6.1 Pre-plant Application

Description:

Application of fertilizers before sowing, during basic soil preparation.
It usually includes phosphorus (P), potassium (K), and microelements such as zinc (Zn).

Techniques:

Creation of a nutrient substrate for the early development of the root system.
Provide a stable nutrition base for the early stages of development.

Techniques:

Incorporation into Soil:
- Incorporation of granular fertilizers by ploughing or disk harnessing before the flood.
dispersion:
- Suitable for flooded soils by applying fertilizers to water.

Techniques:

In acidic soils, phosphorus can be inactivated. It is preferable to apply at a depth of 5-7 cm.
Zinc should be applied by foliar spraying if the soil has a high pH.

4.6.2 Top-dressing

Description:

Application of fertilizers during the development of rice, mainly nitrogen (N) and potassium (K).

Techniques:

Support the development of siblings, the flowering and filling of the beans.
Address potential deficiencies identified through phyllodiagnostics.

Techniques:

Macroelements:

Application of granular fertilizers to slightly moist soil or water surface.
Avoid application to dry or saturated soil due to evaporative or flushing losses.

Trace elements:

Mixing fertilizers in irrigation water for even distribution.
Appropriate technique for fertigation.

Trace elements:

Avoid single application of nitrogen to reduce losses.
separation in 2-3 applications (fraternization, flowering, filling of granules).

4.6.4 Foliar Feeding

Description:

Applying fertilizer solutions directly to the leaves.
Useful for quickly correcting microelement deficiencies.

Pros:

Rapid absorption and action, particularly at critical stages of development.
Reduce nutrient losses from soil.
Combined with plant protection products for labour economy.

Techniques:

Zinc (Zn): 0.5% solution in fraternity and flowering.
Iron (Fe): 0.3% solution for chlorosis correction.
Boron (B): 0.1% solution during flowering.
Potassium (K): 1-2% solution to support granule filling.

Techniques:

The application should be done early in the morning or late in the afternoon to avoid evaporation.
Avoiding sprays when flowering at high temperatures (>30°C).

4.6.5 Use of Fertilizers with Urease/Nitrification Inhibitors

Description:

Granular fertilizers with special technology that release nutrients gradually.

Pros:

Reduction of leaching losses.
Reduce the need for iterative applications.
Consistent nutrient supply throughout cultivation.

Application:

Suitable for basic fertilization before sowing.
They are recommended for phosphorus and potassium, while nitrogen is usually administered superficially.

4.7.1 Lubrication Planning and Planning

1. Ανάλυση Εδάφους:

It is carried out before sowing to calculate nutrient needs.
It is based on laboratory results for pH, organic matter and N, P, K levels.

Environmental Benefits:

- Sandy soils: Small doses need to be applied more frequently due to leaching.
- Silty-clay soils: They require a lower frequency of applications, but larger doses.
- Acidic soils (pH < 5.5): Require addition of lime (CaCO ①) to improve pH.

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1. Στόχευση Ανά Στάδιο Ανάπτυξης:

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Distribution of fertilizers in basic and surface fertilization according to the needs of the plant.
Particular attention to critical stages such as fraternization, flowering and grain filling.

4.7.2 Effective Nitrogen Management (N)

Transportation:

Basic fertilization: 40-50% of the total N is applied before sowing.
Surface applications: The remaining N is applied in 2-3 doses during fraternization and flowering.

Environmental Benefits:

Application of nitrogen to wet but not saturated soil to avoid leaching.
Avoiding overfertilization leading to itching and increased susceptibility to disease.

Drainage System:

preference with urease inhibitor. ( NBPT )
Reduce ammonia release by incorporating fertilizers into the soil.

4.7.3 Phosphorus (P) and Potassium (K) Management

1. Φώσφορος (P):

- Apply the entire amount during basic fertilization, as P quickly binds to the soil.
- Placement 5-7 cm below the surface for improved uptake.

1. Κάλιο (K):

Two-phase

administration:
1. 60-70% before sowing.
2. 30-40% during flowering to enhance grain filling.
Use of potassium chloride or sulfate depending on the sulfur (S) need of the soil.

4.7.4 Dealing with Trace Element Deficiencies

1. Ψευδάργυρος (Zn):

- Common problem in flooded soils.
- Use of 0.5% Zn-EDTA spray solution during fraternization.

1. Σίδηρος (Fe):

It occurs mainly in calcareous or alkaline soils.
Correction by spraying Fe-EDDHA in 0.3-0.5% solution.

Potassium (K):

- Improve flowering and fertilization.
- Application of 0.1-0.2% solution during flowering.

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1. Μαγνήσιο (Mg):

Essential for photosynthesis and chlorophyll formation.
Spraying with 0.5-1% magnesium sulfate (MgSO) solution during shoot development.

5. Irrigation and Management

5.1 Water Needs

Growing rice requires a constant supply of water, especially in flooded farming systems. The total water height required ranges from 800 to 1500 mm depending on climate, soil type and variety.

5.1.1 Distribution of Needs by Development Stage

DevelopmentWater Stem Grain

Stage	Duration (days)	Depth (cm)	Notes
Vegetation and Initial Growth	0-15	2-3	Light coverage of the soil with water to enhance vegetation.
Brotherhood	15-40	3-5	Maintenance of moisture to enhance the growth of roots and shoots.
Elongation	40-60	5-7	Increase of water to support the increase of biomass and spikes.
Flowering and Fruit Setting	60-75	7-10	Critical stage for grain formation. Continuous water supply is required.
Filling and Maturation	75-100	3-5	Reducing the water level to stabilize plants and reduce moisture.
Before the Harvest	100-120	0	Drained soil 7-10 days before harvest to reduce grain moisture.

5.2.1 Flood Irrigation

Description:

The most widespread system for rice.
The water is kept at a depth of 5-10 cm in the field during most stages of development.

Pros:

Weed

suppression through suffocation.
Increase the availability of nutrients such as phosphorus and iron.
Improve yield in varieties adapted to flooded soils.

Techniques:

Large water losses due to evaporation and filtration.
Risk of nutrient leaching.
Requirements for irrigation and drainage infrastructure.

5.2.2 Alternate Wetting and Drying (AWD)

Description:

Toggle flooded and dry periods during development.
The water is applied when the level drops 15 cm below the ground surface.

Pros:

Reduce water consumption by 25-30%.
Enhance root growth and improve nutrient uptake.
Limitation of methane emissions due to soil oxygenation.

Techniques:

Careful control of moisture with ground sensors is required.
It can affect the uniformity of production if not implemented properly.

6. Plant protection

6.1 Herbicide

Weeds are one of the most important factors in reducing rice yield, competing with plants for light, water, and nutrients. Proper treatment starts with prevention and continues with chemical and mechanical methods of control.

6.1.1 Weed Categories

Mullet (Echinochloa crus-galli): Rapidly growing weed, it competes strongly with rice and has shown resistance to herbicides.
Red rice (Oryza sativa): Wild rice that reduces the quality and yield of the crop.
Paspalum distichum: Perennial weed that expands with rhizomes and seeds, affecting yields.
Ragazi (Scirpus maritimus): A resistant perennial weed that competes with rice, especially if the presence of other weeds is reduced.
Nutmeg (Cyperus difformis): Small weed that grows mainly in sparse rice plantings.

6.1.2 Herbicide Strategies

Transportation:

Use of clean seeds without weed seed contamination.
periods of the field for control of aquatic weeds.

Environmental Benefits:

Cultivation and Plowing: Destruction of roots before sowing.
Flooding: Flooding for asphyxiation of dry weeds.

Χημική Καταπολέμηση:

With the appropriate – approved preparations in pre- or post-emergence herbicide.

6.2 Insects

Insects pose a serious threat to rice, affecting both the above-ground and underground parts of the plant.

6.2.1 Major Enemies of Rice

Sesamia nonagrioides: The larvae of this insect, after the stage of desquamation, devour the stems of rice plants, causing significant damage to the crop.
Chilo suppressalis: The larvae of the Chilo suppressalis enter the rice stems, causing discoloration and drying of the leaves, as well as a reduction in yield.
Aphids (Rhopalosiphum maidis): These small insects suck out plant juices, leading to stunted growth and transmission of viral diseases.
Nematodes (Heterodera oryzae): Tiny worms that attack the roots of rice, causing a drop in plant vitality and a decrease in production.

6.3 Disease Management

Fungal and bacterial diseases can cause significant losses if not treated in a timely manner.

6.3.1 Main Diseases

Pyricularia oryzae: The most devastating rice disease in Greece. It causes stains on leaves, shoots and ears, leading to a significant reduction in production. It is favored by high humidity and excessive nitrogen fertilization.
Rhizoctonia solani: Appears in wet conditions and causes dark spots on leaves and shoots, which can lead to plant drying.
Helminthosporium oryzae: Causes brown spots on leaves and grains, reducing the quality and quantity of production.
Root rot (Pythium spp.): Affects young plants, causing root rot and weak growth.

7. Harvesting and Storage

7.1.1 Maturity Criteria for Harvesting

Signs of Water Stress:

85-90% of the grains in the wheat have turned golden-yellow.
The grain moisture is at 20-24%.
The granules are hard and do not deform under pressure.

Environmental Benefits:

Use of moisture meters to accurately control the moisture content.

7.1.2 Harvest Delay – Risks

Insect and Fungal infestations: Increase of infections during prolonged stay in the field.
Losses: Reduction of commercial value from dried and crushed rice.
Bird infestations: Losses due to consumption of grains from birds in mature ears of wheat.

8.3 Post-harvest Management

Post-harvest management involves the direct processing of grains to maintain quality.

7.3.1 Cleaning of Grains

Removal of straw, garbage and foreign matter.
Use of mechanical sieves and air separators.
Protection from infections and fungal growth.

7.3.2 Grain Drying

Target:

Moisture

reduction from 20-24% to 12-14% for safe storage.

Methods:

Macroelements:

Low cost but requires a lot of space and depends on weather conditions. ( not recommended )

Trace elements:

Use of hot air (50-60°C) in special drying chambers.
Faster process and accurate humidity control.

7.4 Storage of Rice

Proper storage is essential to maintain the quality of rice in the long term.

7.4.1 Warehouse Types

Transportation:

Controlled temperature and humidity conditions.
Suitable for large quantities of rice.

Shade Storage:

Suitable for smaller quantities.
Regular ventilation and moisture protection is required.

7.4.2 Temperature and Humidity Control

Temperature: Keep at 15-20°C to prevent insect growth.
Moisture: Below 14% to prevent fungal growth.
Ventilation: Regular air circulation to prevent water vapor concentration.