Lettuce & Green leaf crops

IRRIGATION OF LETTUCE AND GREENLEAF CROPS

The purpose of irrigation is to prevent water stress, especially during the formation of the part of the plant that will be harvested.

Water stress can occur in a crop when the soil moisture is excessive or when it’s deficient. When oxygen concentration levels in the soil atmosphere are lowered due to displacement by water for an extended period of time, the root system can be severely damaged.

Lettuce and green-leaf plants are especially susceptible to water stress due to their shallow root systems.

Water stress can lead to two main problems:

• Poor yields and poor product quality (in terms of firmness, head size, and color) due to damage caused to the head lettuce.
• Rot at the base of the roots.

Moisture deficiencies occurring early in the crop cycle may delay the maturity season and reduce yields.

Shortages later in the season often lower quality, as well as yields. However, irrigation surplus, especially late in the season, can reduce both the quality and the post-harvest life of the crop.

Uneven or surplus irrigation, above the amount required to replace evapotration, causes nitrate leaching below the root system and the ability of the crop to recover from the nitrogen deficiency decreases.

Efficient water use, namely irrigation scheduling, high uniformity of water distribution and light precipitation rate, will help prevent stress conditions.

IRRIGATION SCHEDULING

• To prevent water stress, aim at an irrigation threshold of 20-30% water deficit.
• With tensiometers, use 10-25 centibars to trigger irrigation, according to soil type.
• Otherwise, irrigate every 1-3 days.
• During hot weather it is preferable to pulse irrigate in order to preserve high humidity.

WATER REQUIREMENT CALCULATION:

Range of crop factor is 0.25-0.9.

The crop factor is related to canopy coverage:

Canopy coverage = Ca x Cb

Ca= coverage between plants (%)

Cb= coverage between rows (%)

Water requirement = daily ET (Evapotranspiration) x crop factor.

FERTILIZATION

Potassium and phosphorus are recommended at the start of the season. Nitrogen is recommended during the growing season. Using Nitrogen in nitrate form helps to minimize tip burn.

High investment costs are associated with producing green-leaf crops.  Selecting the most suitable irrigation system and managing it efficiently is crucial for success.

NaanDanJain offers a number of solutions:  Irristand sprinklers or drip systems are ideal for open field, while inverted micro-sprinklers are best for greenhouse irrigation.

IRRISTAND SYSTEMS

The IrriStand system for lettuce and green-leaves is a low-flow sprinkler that simulates light rain. Based on a flexible in-and-out solid-set PE system, the system successfully meets all crop requirements at all stages of development:

• Germination
• Uniform irrigation (while maintaining soil aeration conditions)
• Continuous application of nitrogen
• Micro-climate
• Prevention of soil erosion
• Frost protection

Main system advantages

• Low precipitation rate
• High efficiency and uniform water distribution
• Full control over wetted profile
• Availability of optimal moisture and nutrients for the root system
• Increase of lettuce production up to 70 tons/ha, according to species and season

High distribution uniformity and low application rate, at frequent irrigation cycles, provide maximum control and monitoring of the wetted and aerated soil profile, which is essential for the shallow root system of the lettuce.

Low application rate (3-5 mm/h): allows optimal absorption of water into the soil with no run-off, even on slopes.

Low droplet impact: preserves soil structure and prevents crust formation to allow perfect germination and development.

Short irrigation cycles: prevents stress caused by water surplus; provides optimal growing conditions with highly accessible moisture and nutrients in a controlled wetted and aerated soil profile; and ensure no nitrate leaches below the root zone and leakage into the groundwater.

ELITE SYSTEMS

Based on the IrriStand concept, ELITE is a solid-set system including 50 mm PE pipes with 10-12 meter segments. The system is flexible, portable and easy to operate.

SPRINKLERS FOR IRRISTAND AND ELITE SYSTEMS

NaanDanJain has developed a wide range of sprinklers for the irrigation of lettuce and green-leaf crops.

Characterized by their sturdy construction, corrosion resistance and extremely high water distribution uniformity, they respond to the specific field conditions.

SERIES OF 1/2” SPRINKLERS WITH LOW PRECIPITATION RATE

Characterized by excellent water distribution uniformity and reliability at low pressure conditions.

Super 10

Compact ball-driven sealed mechanism for • spacing up to 12 m Available with flow regulator

5022 SD-U

Low flow single or double nozzle for spacing up to 12 m

5022 SD

Single larger nozzle concept with unique SD hammer for spacing up to 14 m

6025 SD

Single larger nozzle concept with unique SD hammer for spacing up to 16 M. Improved wind resistance

LPD for IrriStand (IrriStand Leakage Prevention Device)

• Prevents drainage from the irrigation system
• Maintains a full irrigation system and ensures uniform irrigation in each area at a given time
• Prevents destruction of crop rows

DRIP SYSTEM

NaanDanJain has developed a special drip concept to meet the needs of lettuce and green-leaf crops. The wetted uniform strip is based on low flow rate drippers, close dripper spacing and excellent uniformity. The drip irrigation concept combines accurate water and fertilizer applications.

The Wetted Strip

The concept of a continuous wetted strip creates optimal growing conditions for densely cultivated crops with shallow roots, such as lettuce. This prevents the deep percolation of water and nutrients under the shallow root system into the ground water, which can create pollution.

Product Selection and Design

Based on the particular agro-technical needs of lettuce crops, two main products are highly recommended:

TalDrip Dripline

• Light dripline with molded and integrated Cascade drippers.
• Effective, uniform crop irrigation with low CV and high EU% standard.
• Clog resistance: self-cleaning design with a double-flow
• regime that continuously flushes out small dirt particles.
• Available at 16-23 mm diameter, 6-35 mil wall thickness
• Dripper flow rate: 0.6, 1.0, 1.7 l/h
• Dripper spacing: from 15 cm

Chapin

Economical thin walled drip tape

• Turbulent flow twin wall
• Clog resistance: unique turbulent flow path with wide cross-section
• High resistance to insect damage and field abrasion.
• Available at 16, 22 mm diameter, 6-15 mil wall thickness
• Slit outlets reduce root intrusion

Basic Design Recommendations

Drip lateral spacing: one lateral for two closed rows

Dripper spacing: 15-30 cm, depending on soil type

Dripper flow rate:

Tal Drip: 0.6, 1.0 l/h

Chapin BTF: 4.8 l/h per meter (0.96 l/h per outlet)

DOUBLE SYSTEM CONCEPT

Based on farmers’ needs and specific field conditions, NaanDanJain has developed the double system solution:

sprinklers (portable Irristand system) and drip, for maximum potential.

Stage 1: Soil preparation and bed cultivation, using over-head Irristand system

Stage 2: Pre-season application of chemicals, using Irristand

Stage 3: Germination or seedling establishment, using Irristand

Stage 4: Irrigation and fertigation throughout the season, using the drip system

Stage 5: Technical irrigation, such as cooling and dust washing, using Irristand

The Irristand system can be shifted from plot to plot, for germination purposes only.

SOLUTIONS FOR GREENHOUSE LETTUCE CROPS

Greenhouses, tunnels or net houses improve the growing conditions of lettuce and green-leaf crops.

NaanDanJain has a targeted solution for these conditions:

A range of inverted micro-sprinklers, installed under the greenhouse roof.

A wide range of flow rates to match the specific precipitation rate required, according to the optimal irrigation time. User-friendly software (the “Space”), especially adapted to greenhouse and tunnel conditions to achieve maximal uniformity (CU 88-95%) of design.

THE SINGLE LINE AND ANTI-MIST CONCEPT

NaanDanJain has developed a specific solution for tunnel conditions, taking into consideration the tunnel shape and the required needs, in order to achieve optimal effective irrigation. The single line creates a uniform strip with relatively big droplets and higher precipitation rate. It is suitable for tunnels up to 6.0 m in wide. Wider tunnels require 2-3 lines.

Recommended Inverted Micro-Sprinklers

The common guideline for all models is: height of installation is 120-200 cm above crop level, or as per the local conditions. All models are compatible with LPD (Leakage Prevention Device).

Green Spin

• Bridgeless: no dripping during operation
• Excellent uniformity
• Flow rate: 43-200 l/h
• Spacing: up to 4.0 m
• Anti-mist combination available

Aquamaster 2005

• Inverted anti-insect micro-sprinkler for extra range application
• Uniform coverage over a wide range of spacings, flow rates and pressures
• Large droplets
• Flow rate: 35-200 l/h
• Spacing: up to 6.0 m

Modular

• The traditional inverted model
• Flow rate: 35-300 l/h
• Spacing: 3-5.0 m
• Anti-mist combination available

THE SINGLE LINE AND ANTI-MIST CONCEPT

NaanDanJain has developed a specific solution for tunnel conditions, taking into consideration the tunnel

shape and the required needs, in order to achieve optimal effective irrigation.

The single line creates a uniform strip with relatively big droplets and higher precipitation rate. It is suitable for tunnels up to 6.0 m in wide. Wider tunnels require 2-3 lines.

The benefits :The side by side layout, using the anti-mist device, achieves maximum uniformity at specific wetted strip.

High precipitation rates

Allows irrigation over a shorter time scale and causes reduced humidity, resulting in plants staying dry longer.

Dry walls

NaanDanJain’s unique combination of nozzle and anti-mist provides an ideal solution to this traditional greenhouse irrigation problem.

NaanDanJain is committed to finding the ideal solution for your lettuce and green-leaf crop tailored to your local climatic conditions, soil and water properties and budget.