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MANNA SUPPORT CENTER

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Frequently Asked Question

Why Water Demand by Protocol shows zero?2018-09-24T20:47:43+00:00

This is expected when the protocol Kc is 0, i.e. between season start and irrigation start, and between irrigation end and season end. Alternatively, when the daily ET0 is 0 (cold days with massive precipitation).

Why is Water Demand by Satellite different from Water Demand by Protocol?2018-09-24T20:47:43+00:00

Water Demand by Satellite represents the ACTUAL or OBSERVED field (and even irrigation zone) evapotranspiration based on current images and meteorology. while the Water Demand by Protocol represents the THEORETICAL evapotranspiration based on a crop irrigation model (Kc tables).

Why is there an exclamation mark above VPD?2018-09-24T20:56:33+00:00

Heat wave is expected within the coming days (VPD > 3.5 kPa)

Why are there no irrigation recommendations for my field / irrigation zone?2018-09-24T20:47:43+00:00

If this is a new field created in the past 24 hours, then the system is still working on it. It will take up to 24 hours to provide the first recommendation. If it is an old field, it is probably Out of Season – check the dates for Season Start and End, Irrigation Start and End in the Field Info tab.

Who is Manna’s weather provider?2018-09-24T20:49:01+00:00

FORECA: http://corporate.foreca.com/en/

Which crops are supported for the GDD Counter?2019-06-19T07:39:40+00:00
  • Alfalfa
  • Almonds
  • Avocado
  • Broccoli
  • Citrus – Grapefruit
  • Citrus – Lemon
  • Citrus – Orange
  • Corn – Grains
  • Corn – Silage
  • Corn – Sweet
  • Cotton
  • Olive – Fruit
  • Olive – Oil
  • Potatoes
  • Tomatoes – Processing
What satellites does Manna use?2018-09-24T20:51:21+00:00

We currently use 2 constellations: the European Space Agency (ESA) Sentinel 2a/2b and NASA’s Landsat 8 for the Irrigation Recommendations and for Crop Monitoring.

What is Water Demand by Satellite?2018-09-24T20:47:43+00:00

Water Demand by Satellite represents the OBSERVED Crop Evapotranspiration based on the Manna’s model that uses current and frequent images and Hyper-local weather service. The number represents the ACTUAL amount of water (in mm or in.) that the crop demands daily and for the entire week without adjust stress.Water Demand by Satellite represents the OBSERVED Crop Evapotranspiration based on the Manna’s model that uses current and frequent images and Hyper-local weather service. The number represents the ACTUAL amount of water (in mm or in.) that the crop demands daily and for the entire week without adjust stress.

What is Water Demand by Protocol?2018-09-24T20:47:43+00:00

Crop Evapotranspiration (ETc) as CALCULATED based on Crop Coefficient (Kc) provided by the local protocol (or the FAO 56) selected for the field, and ET0 provided by the Manna Hyper-local weather service. The number represents the ESTIMATED amount of water (in mm or in.) that the crop demands daily and for the entire week.

What is VPD2018-09-24T20:56:51+00:00

Vapor-pressure deficit = the difference (deficit) between the amount of moisture in the air and how much moisture the air can hold when it is saturated. It is used to assess potential plant stress conditions – high value = high stress

What is the satellite revisit frequency?2018-09-24T20:52:38+00:00

Sentinel 2 revisit time is every 5 days, Landsat every 16 days. The two combined provide a revisit time of up to 5 days, in most cases 3-4 days.

What is the satellite image resolution?2018-09-24T20:52:16+00:00

For irrigation purposes – the resolution is like having a 100 sensors per Hectare. The actual spatial resolution is between 10-30 meter per pixel

What is the pricing model?2018-09-24T20:54:39+00:00

A paid annual subscription – price per hectare/acre with price steps according to the area size. Please see the current pricing or contact a local dealer or Manna representative to get a quote

What is the minimum size of a field?2018-09-24T21:02:09+00:00

1 Hectare = 2.47 Acre

What is the maximum size of a field?2018-09-24T21:02:26+00:00

500 Hectare = 1235.5 Acre

What is the geographic coverage of the weather service, and in what resolution?2018-09-24T20:49:22+00:00

The Manna weather service is global and provides historical, nowcast and forecast weather conditions in a grid of 5 by 5 km worldwide

What is the difference between the various Crop Monitoring layers?2019-06-19T14:07:02+00:00

There are 3 data layers in the Crop Monitoring tab:

  1. Vegetation Levels – shows the field’s vegetation levels on a scale of 0 to 1.
    As the scale of the images is always fixed, this layer is used to compare growth within the field between dates or between seasons (for the same crop).
    For easy comparison, use the ‘Slider’ tool in the crop monitoring tab.
  2. Vegetation Variability – shows the field’s vegetation level on a dynamic scale (stretched from the field’s minimum to its maximum values).
    This layer changes between each image, hence it is not suitable for comparison.
    Use this layer to scout and detect areas in the field where the vegetation is not uniform or to spot abnormal vegetation growth.
  3. Visual – a visual image of the field.
  4. Plant Wetness Variability – shows the water potential of the plants in the field. This is a Variability map, hence uses a dynamic scale which correlates to the range between the Field’s driest and wettest areas.
    Learn more about Plant Wetness Variability maps and their usage in here.
What is the difference between Season Start, Irrigation Start, Irrigation End and Season End?2018-09-24T21:07:15+00:00

These are all important dates for the setup of the crop season:
Season Start – in field crops this is date of planting or seeding. In vineyards and orchards of deciduous plants it means bud break. In other crops it will just be the same as Irrigation Start.
Irrigation Start – the planned date for beginning of routine irrigation, excluding technical irrigations such as pre-planting or germination irrigations (cannot occur before Season Start). It will be automatically selected by the system after you define a Season Start and select a Kc Protocol, but you can edit this date as needed (not if the Protocol is from the FAO).
Irrigation End – the planned date for end of routine irrigation. It will be automatically selected by the system after you define a Season Start and select a Kc Protocol
Season End – usually harvest date. it will be automatically selected by the system after you define a Season Start and select a Kc Protocol, but you can edit this date as needed.

What is kPa?2018-11-04T15:55:28+00:00

Kilo Pascal – pressure unit used for VPD

What is Irrigation Rate?2018-09-24T21:06:09+00:00

Often times referred to as Application Rate – the effective rate in which the irrigation system can provide water to the crops. Measured in mm or inches per hour

What is GDD and how to use it?2019-06-19T07:41:13+00:00

What is GDD?

The Growing Degree Day, GDD, (also referred to as Growing Degree Units, GDUs, or Heat Units) is a heat index that can be used to predict when a crop will reach maturity. Each day’s GDD is calculated by subtracting a reference temperature, which varies with plant species, from the daily mean temperature.
Unless plants are overly stressed by drought or pests, the total GDDs accumulated throughout the season can be used to predict when a crop will reach maturity. Corn, for example, requires 1360 GDD to mature.

What data is presented in the GDD counter?

Manna’s GDD counter presents the current accumulated GDD of a specific field, based on temperature observations and default thresholds which were selected for each crop by Manna’s agronomy department. The counter is displayed for selected crops and will be added to additional crops in the future.

What else should I know?

  • The GDD accumulation starts on the Season Start date (as set in the field setup form or in the Edit Growth Stages function).
  • The GDD counter is not displayed to fields which are Out of Season.
  • The counter presents the accumulated GDD until today in either degrees Celsius or degrees Fahrenheit, according to the Units selected by the user through the system’s profile settings.
What is ET0?2018-09-24T20:56:03+00:00

ET0= Reference Evapotranspiration – an environmental/weather parameters that combines solar radiation, air temperature, relative humidity and wind speed. It represents the evapotranspiration from a standardized vegetated surface of well-watered grass, meaning the amount of water (in mm) that this patch of grass would evapotranspirate in certain weather conditions (Panman-Monteith formula).

What is an irrigation protocol?2018-09-24T20:53:03+00:00

Irrigation protocol, or Kc Table is a table of weekly Kc (crop coefficient) values for specific crop and location. Usually these are published by local research organizations or government services. Manna has collected hundreds of protocols for dozens of crops, including the ones provided by the FAO (known as FAO 56), all available to use in the system. It is also possible to import private tables should you have one, please contact Manna Support.

What if the system’s effective-rain values are not accurate?2018-09-24T20:50:05+00:00

You can always update effective rain values in the Recommendation Tab by clicking EDIT.

What if my irrigation season is only a few months out of the entire year?2018-09-24T20:54:18+00:00

The Manna solution provides benefits such as crop monitoring and water budget planning tools that can be accessed year round. The subscription is therefore for a full year

What if I can’t find my Protocol in Manna’s system?2018-09-24T20:53:26+00:00

Manna has collected hundreds of protocols for dozens of crops, including the ones provided by the FAO (known as FAO 56), all available to use in the system. if you cannot find a local protocol for your crop, you can either select the ones provided by FAO or you can import private tables should you have one, please contact Manna Support.

What formats of field boundaries files are supported?2018-09-24T21:03:07+00:00

Google Earth .KML and ESRI .SHP formats are supported for upload of field’s boundaries

What data sources are used by the weather service?2018-09-24T20:50:48+00:00

The hyper local service consumes data from a wide array of sources: weather stations (public and government provided), weather satellites, radars, airport stations and more. It then operates advanced forecast models and interpolation algorithms to provide high resolution weather forecast.

What are the week numbers in the Water Budget table?2018-09-24T21:00:53+00:00

The week number in the Water Budget indicates the calendar week number in the year, same as it is presented in the Recommendation tab.

What about cloudy areas?2018-09-24T20:51:51+00:00

Clouds do present a challenge for acquiring satellite data. However, in most irrigated areas in the world, the revisit frequency of the satellites provide good chances to have enough data for irrigation recommendations and crop monitoring. The Manna model keeps track of each field’s vegetation levels by building the development curve during the season. Even if some observations are missed, the curve is still accurate so the model can predict the vegetation levels for a week in advance and provide good irrigation recommendations.

in addition, Manna is diligently working on new technologies that will allow ‘Cloud Piercing’ data capture, as well as increasing the revisit frequency by using additional sensors from other satellite constellations.

Was the Manna recommendation model tested and verified?2018-09-24T20:47:43+00:00

The Manna model is based on deep research and scientific knowledge of the evapotranspiration method for irrigation management. In addition it has been going through extensive field calibration and validation trials on various crops and different geographies and irrigation systems.

The weekly recommendation today is different than the number I saw yesterday, why?2018-11-04T16:53:44+00:00

Irrigation recommendations are dynamic! Every night, irrigation recommendations are being re-calculated based on the freshest satellite imagery and weather data (both current and forecast).

Is there a size limit to a farm?2019-05-16T12:28:45+00:00

A farm can include unlimited number of fields with combined area of no more than the area paid for by the account. In addition, all fields within a farm must be inside a radius of 100 km or 62.13 miles from the farm’s center.

Is my subscription renewed automatically?2018-09-24T20:55:22+00:00

Yes, unless you cancel it at least 30 days before the renewal date

I trust my local weather station. Can I add it as a source of information for Manna?2018-09-24T20:49:43+00:00

It will be possible to connect a local weather station as a source for current / actual conditions, but not as input to the forecast model. The station will be examined by Manna quality assurance algorithm to verify the accuracy of the data.

How to use the Plant Wetness Variability map?2019-06-19T13:50:31+00:00

What is the Plant Wetness Variability map?

The Plant Wetness Variability map shows the plant’s water potential (the amount of water in the plant), and provides an indication for the irrigation’s Distribution Uniformity (DU) and in plants’ water uptake across the field. The map uses a scale of ‘Dry’ to ‘Wet’, where ‘Dry’ is the lowest level of plant water potential value in the specific field and date, and ‘Wet’ is the highest plant water potential value in these field and date. This means that the scale changes from image to image to indicate the plant water potential uniformity in the field:

Image 1: Plant Wetness Variability Map.

Red areas represent the ‘driest’ areas and blue areas represent the ‘wettest’ areas of the field.

 

 While other layers show potential problems in the field which can be caused by several reasons (disease, nutrition, irrigation etc.), the Plant Wetness Variability map provides an indication for vegetation inconsistency related to water only, as it is monitoring the amount of water in the plant.

 

How is it being calculated?

Wet plants (with higher water potential in them) reflect sunlight differently than dry plants. Using spectral indices that apply mathematical manipulation on the satellite’s SWIR bands, the system assigns a “relative wetness score” for every pixel, and then paints them accordingly.

 

How to use the Plant Wetness Variability map?

Start by comparing the Plant Wetness Map of a specific date to the Vegetation Variability image of the same date. Normally, you will see one of the following patters:

  • Correlation between Plant Wetness and Vegetation Variability:

If the patterns in the Plant Wetness map match the patterns in the Vegetation Variability map, and they appear in a clear geometric shape, this may be an indication of irrigation system issue. Check the relevant irrigation zone for faults such as a broken valve or a clogged filter. Note that the same symptom can appear when some zones in the field were irrigated and other were not yet irrigated:

Image 2: Dry geometric shape may indicate irrigation system issue

 

If the patterns in the Plant Wetness map match the patterns in the Vegetation Variability map, but do not appear in a clear geometric shape, this may be an indication of plant uptake issue. This may be caused by salinity, soil type and other field parameters:

Image 3: Correlation between Plant Wetness and Vegetation Variability maps

 

  • Non-correlation between Plant Wetness and Vegetation Variability:

When there is no correlation between the Plant Wetness and the Vegetation Variability maps, this can indicate an issue in the field which is not related to irrigation.

If the Plant Wetness indicates the crop to have high water potential but the vegetation in the Vegetation Variability map seems low in areas of the field, this may be due to crop protection issue:

Image 4: Non-correlation between Wetness and Vegetation.

The yellow spot in the Vegetation Variability map may indicate the development of a disease, as the water distribution in the field is uniform.

 

Another scenario when such non-correlation may happen is when the field has poor water drainage conditions. In this case, standing water may cause the plants to have high water potential, but on the same time suffocate them and decrease the vegetation over time:

Image 5: Poor drainage, early in the season. Vegetation and water potential are high

 

Image 6: Same field, later in the season. Standing water caused damage to the vegetation

 

  • Early detection of irrigation problems:

Another reason for non-correlation between the Plant Wetness and Vegetation maps, is that the Plant Wetness map can help with early detection of irrigation problems as early as one month before they are apparent in the field. This will normally happen in ‘mild’ irrigation problems which develop over time, such as pressure issues:

Animation 1: Early detection of irrigation problem

 

When to use the Plant Wetness map?

Since the Plant Wetness maps present the water potential in the plants, they provide accurate indication only when the NDVI values are at medium-high levels (between 0.45 and 1). View the Wetness Maps with extra cautions when the vegetation in the field is low (emergence in row crops, right after bud break, very young trees etc.), as the indication may be misleading.

 

How to find the Wetness Variability map in the system?

The Wetness Variability map can be found in the Crop Monitoring tab. Note that the Wetness Variability map is produced using data sources which are only available in some of the constellations of satellites used by Manna, so the map will not be available for all images’ dates. Browse the Layers or the Dates selection menus in the Crop Monitoring tab to display these images when available.

We are currently working on adding this unique layer to all of our satellite images dates.

How to select the right Kc Protocol?2018-09-24T21:06:51+00:00

After selecting the crop and defining Season Start date, the system will present the available Kc Protocols. You can review the info presented such as season length, location, publisher, date of issue and more in order to select the right one for your needs. You can also view the actual weekly values of Kc in each Protocol by clicking the View button. Once you decide, click on the radio button on the far left side of the line and click the green Apply Selected button.

How is the planned water budget calculated?2018-09-24T21:00:32+00:00

Based on 10 years averages of weather data, and the selected Kc protocol, Manna model can calculate the planned water usage in every week of the season, and aggregates the total for the entire season.

How does the system know the soil type of every field?2018-09-24T20:53:50+00:00

We use Soil Grids: http://www.isric.org/explore/soilgrids

How does Manna’s model calculate Water demand by Satellite?2018-09-24T20:47:43+00:00

Based on the evapotranspiration equation: ETc = Kc*ET0, When ETc is the crop (field) evapotranspiration or the crop water demand, Kc is the crop coefficient as observed by satellite images, and ET0 is the reference evapotranspiration from hyper local meteorological service. The resulting Observed Water Demand is presented daily and weekly sums of last, current and next week.

How do I upload files with fields’ boundaries?2018-09-24T21:02:48+00:00

When creating a new field (or editing an existing one), in the first step of defining field boundaries – click on the Upload File button at the upper right part of the window. It will then open a file directory on your desktop. Locate the file, select it and click Open in the directory window. The field’s outer boundaries should be displayed in the New Field / Step 1 window. You can now edit the polygon or click Next to continue.

How do I manually draw a field’s boundaries / polygon?2018-09-24T21:03:29+00:00

When creating a new field (or editing an existing one), in the first step of defining field boundaries – click on Draw Polygon button on the bottom left side of the map. Then start defining the boundaries of the field (it may be easier to click on Full Screen in the top left corner of the map) by clicking on the map along the perimeter. Be as accurate as you can, make sure not to include trees or other vegetation outside of the field.

How do I edit or delete an existing zone?2018-09-24T21:05:47+00:00

When creating a new field (or editing an existing one), in the first step of defining field boundaries – click on Edit Polygon button on the bottom left side of the map. All polygon’s joints become editable so you can reposition them and change the geometry of the field and its zones. Click Save in the mini-toolbar next to the Edit button when done.

How do I edit an existing field?2018-09-24T21:03:57+00:00

Go to Settings by clicking the cogwheel on the top right corner of every page. In Farms/Fields tab click on the farm name and then on Edit button in the line of the required field.

How do I edit actual Water Budget data?2019-06-18T08:57:32+00:00
  1. In the Water Budget tab, click on the ‘Edit Actuals’ button.
  2. Edit the ‘Irrigated’ column.
  3. When done, click the ‘Save’ button.
How do I delete an existing field?2018-09-24T21:04:26+00:00

Go to Settings by clicking the cogwheel on the top right corner of every page. In Farms/Fields tab click on the farm name and then on Delete Field link in the line of the required field.

How do I define irrigation zones / sectors?2018-09-24T21:05:26+00:00

When creating a new field (or editing an existing one), in the second step “Field Zones” you can create zones by slicing the field’s polygon as needed. Place the mouse cursor on the outer boundary until it turns from a hand to pointing hand. While it is pointing hand, left click and release and move the mouse to the other side of the field to create an irrigation zone. Confirm the zone by selecting Continue in the pop-up window. You can now repeat this process between any two points on the field’s outer or inner boundaries (between zones already created).
Tips:
1) it is easier to do this in Full-Screen mode (click the button on the top left of the map) and zoom in until the field is spread on the entire screen
2) use the measuring tools (distance and area – ruler buttons on the map area) to identify the right places for the zone boundaries

How do I change map type display?2018-09-24T20:58:49+00:00

Click on “Map / Satellite” button on the upper left corner of map

How do I change map display size?2018-09-24T20:58:29+00:00

Click on “Full Screen” button on the upper left corner of the map

How can I see weather forecast in my farm?2018-09-24T20:58:06+00:00

Click on “Next” button on upper right part of the farm weather widget, or “Next” in the Recommendation Tab, than expand to view daily details by clicking “Details”

How can I see current / past weather in my farm?2018-09-24T20:57:32+00:00

Click on “Previous” button on upper left part of the farm weather widget, or “Previous” in the Recommendation Tab, than expand to view daily details by clicking “Details”

How can I export Water Budget Data?2018-11-03T09:19:57+00:00

In the Water Budget tab, click on the Report button. Note: the report in the water budget is for the whole Farm, data is shown per crop, field and totals.

How are Manna’s irrigation recommendations calculated?2018-09-24T20:47:43+00:00

The recommendations for application amounts are based on Water Demand by Satellite – the actual crop evapotranspiration. The model also factors in parameters such as soil type, salinity, organic matter, irrigation system efficiency and effective rain.

Does Manna’s recommendation model consider weeds level?2018-09-24T20:47:43+00:00

Yes, Manna recommendations are corrected to consider vegetation of weeds – in case of cover crops between the crop rows, the model will deduct this observed vegetation. in field crops, weeds vegetation will be added to the crop vegetation levels so the Water Demand includes the weeds transpiration.

Does Manna’s recommendation model consider soil parameters?2018-09-24T20:47:43+00:00

Yes, Manna recommendations take into consideration the soil texture based on public soil data as default or the user input, soil salinity and organic matter in the soil.

Does Manna’s recommendation model consider irrigation system efficiency?2018-09-24T20:47:43+00:00

Yes, the recommendations factor in the system efficiency so there is compensation for water losses.

Can I pay only for part of the system features?2018-09-24T20:55:00+00:00

Currently the solution is packaged as all-included, one-fee.

Can I edit a field during the irrigation season?2018-09-24T21:04:46+00:00

Yes, but it is not recommended. The system will recalculate recommendations, water budget and crop monitoring and the data of the field before the change will be lost.

Can I add a crop that isn’t on the list of crops when creating a new field?2018-09-24T21:06:30+00:00

No, but you can send us a request to support@manna-irrigation.com

Video Tutorials

Manna-Irrigation System Overview

Water Budget video guide

How to create a new User

How to create a new Field

How to create a new farm

Irrigation Recommendation guide

Manna, an Irrigation Intelligence leader, provides growers around the world with the actionable information they need to make better-informed and more confident irrigation decisions. Its sensor-free, software-only approach leverages high-resolution, frequently refreshed satellite data and hyper-local weather information to deliver highly affordable and accessible solutions for site-specific irrigation recommendations.

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