Nitrate-nitrogen fertigation strategies

Dennis Van Dyk's avatarONvegetables

Christoph Kessel, Nutrition (Horticulture) – Program Lead, OMAF & MRA

Keeping fertigated nitrate-nitrogen in the crop rooting zone is an important management strategy to ensure maximum uptake.  Nitrate-nitrogen is very mobile in the soil.  It can move with water out of the rooting zone and down through the soil profile.

The timing of the nitrate-nitrogen fertilizer injection during the irrigation event is key to keeping it in the rooting zone and available to plants.  Inject it too early and nitrate nitrogen can move beyond the rooting zone; injecting it too late means higher concentrations around emitters and uneven distribution in the root zone.

California researchers studied nitrate-nitrogen distribution from subsurface and surface drip systems in different soil textures1.  The fertilizer was injected either at the beginning, middle or end of the irrigation event.

Their observations, shown in the figures below, demonstrate three important points to keep in mind…

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Violence against women a global health problem of epidemic proportions

Violence against women a global health problem of epidemic proportions

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Surface Runoff Calculator Widget

This Wolfram-Alpha widget calculates the surface runoff (mm) based on the value of precipitation (mm) and the Natural Resource Conservation (NRCS) Curve Number (CN).  More information on the methodology can be obtained from the following reference:  Fangmeier, D. D., W. J. Elliot, S. R. Workman, R. L. Huffman, and G. O. Schwab, 2005. Soil and Water Conservation Engineering, Fifth Edition. pp. 528.  Values of CN for various land covers, soils and antecedent moisture conditions are available in the NRCS Pond Construction Handbook.  Click here to download

Note to user:  Sorry about all the digits to the right of the decimal point.  I couldn’t find a way to control this when creating the widget.

DISCLAIMER: The information is provided “as is”. The authors and publishers of this information disclaim any loss or liability, either directly or indirectly as a consequence of applying the information provided herein, or in regard to the use and application of said information. No guarantee is given, either expressed or implied, in regard to the accuracy, or acceptability of the information.

 

 

CROP WATER USE ( HARGREAVES ET EQUATION) NEW WOLFRAM ALPHA WIDGET

CROP WATER USE ( HARGREAVES ET EQUATION) NEW WOLFRAM ALPHA WIDGET. Reference: Hargreaves, G. H. and Z. A. Samani, Reference Crop Evapotranspiration from Temperature. Appl. Eng. Agric., ASAE. 1(2). 1985,. pp.96-99.

Widget Application: Suppose you want to schedule irrigation by replacing the water evapotranspired by your crop each day. 1. Click on the appropriate link to get yesterdays solar radiation for your location: Puerto Rico or Northern Caribbean, 2. Check the internet for the average daily air temperature at your location (average = (minimum + maximum)/2), 3. Get the appropriate crop coefficient for your crop from this link, and 4. Finally, enter solar radiation, air temperature and crop coefficient into the widget to estimate ET. Multiply ET x acres x 1069.0663 to get the number of gallons of water you need to apply to your field.

NOAA CREST SUMMER CAMP at UPRM

Students from across Puerto Rico attended the NOAA CREST Summer Camp this week on the UPRM Campus.  This afternoon, they attended a workshop by Dr. Eric Harmsen, which focused on the use of GOES-PRWEB for scheduling irrigation in Puerto Rico.  Irrigation scheduling is important for water conservation and for achieving optimal crop yields.  The presentation is provided below:

DOWNLOAD PDF PRESENTATION HERE

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New Chilean agriculture-climate observation centre to boost early warning for drought events

New Chilean agriculture-climate observation centre to boost early warning for drought events

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Food Security: Nine principles that promote it

Thanks Rhea Harmsen for this great post on Food Security.

rheaharmsen's avatarRhea Harmsen

Food Security: Nine principles that promote it

A very interesting article in Grist by Dr. Vandana Shiva about the food security of the world and the forces that control it was followed by a revealing exchange of comments between a big corporation executive and environmentalists and sustainable agriculture advocates.

http://grist.org/sustainable-food/dr-vandana-shiva-occupy-our-food-supply/?fb_ref=fbrw

I felt there were so many issues being thrown around (including a very disturbing suggestion that overpopulated poor countries should simply let a portion of their population starve out to restore the natural balance as per their food production/distribution capacity), that I thought of some broad principles (common sense stuff) that could help us think about where we actually want to go.

Granted, I’m not an expert in food security but I am passionate about it. Yes, so many nations don’t have it, and their policy makers seem barely aware of it. So, we the people, could start to move…

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Gender Equality is Essential to Progress

Gender Equality is Essential to Progress

Peace is only possible, according to Baha’i teachings, once women have been accorded full participation across all fields of human endeavor. Until such gender equality becomes reality, Baha’is believe a climate in which international peace will emerge cannot be fully realized.  Read more….

v42 n01 - International service opens new vistas

Teen’s tech promises 20-sec phone charge

Teen’s tech promises 20-sec phone charge

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