The Importance of Post-Harvest Irrigation in Almond

Multiple entries have covered the aspects of ensuring irrigation during the post-harvest period. This practice has been based off of previously conducted research and is recommended due to the detrimental effect that post-harvest water stress has on the following year's crop. Never-the-less, many growers do not recognize the importance of this practice.

An irrigation stress or deficit during the post-harvest period has been shown to reduce bloom, fruit set, fruit load, and individual fruit weight. For example, a University of California study conducted between 1989-1990 that deprived trees of post-harvest irrigation resulted in a 10% reduction in fruit set, a 33% reduction in fruit load, and a 43.3% decrease in kernel yields for the nonpareil variety*. It is thought that the sensitivity of the almond to the lack of post-harvest irrigation is most likely due to the late fruit bud differentiation which occurs from late August to early September.

As the first "round" of harvesting is completed, keep in mind the need to irrigate the trees. It is easily forgotten with the hustle and bustle of harvest, but the potential consequences of forgetting should turn the practice into a priority.

*Research paper cited: Goldhamer, D.A., Viveros, M. 2000. "Effects of preharvest irrigation cutoff durations and postharvest water deprivation on almond tree performance." Irrigation Science. Vol 19: 125-131.

Collecting a Harvest Sample - Is It Worth It?

Taking a harvest sample is simple, but time consuming. Never-the-less, it should be done because damage is hidden by the handling that occurs during sweeping, pickup, and processing. In some cases, we have found 4% more damage in harvest samples than what was indicated in the grower's processor report.  In other words, when we found an estimated 5% damage/reject level in the harvest sample, the processor indicated a 1% rejection level. The 4% discrepency is most likely due to damaged nuts lost during the steps of harvest.

Another reason for performing a harvest sample is to account for the damage that does occur in the field. Often times processors lump all worm damage together, not separating out NOW, PTB, OFM, or other worms. Ant damage often does not show up because the chewed out pellicles are blown out the back of the pick-up machine. Gummy nuts due to deficiencies, feeding, or other conditions are all lumped together.

Collecting a harvest sample is easy. In each block of concern, collect 500 nuts from the ground after shaking but before pickup and place them in a paper bag. Two samples of 250, or 4 samples of 125 nuts from differing areas of the block can also be collected, but try to keep the total number of nuts per block at 500. Store the bags in a freezer until they can be cracked out. Once able to crack out the almonds, check for signs of pests and disease. Pictures of damaged nuts can seen in a previous post or at the UC IPM website. A hand-sheller can be helpful in processing many samples. It can take 60-90 minutes for each sample depending on size. 500 nuts split into 4 125 nut samples should suffice for a 40 acre block.

So, is a harvest sample worth the time and energy? Using the 4% discrepency in the example above, and assuming that pest management practices will be implemented will reduce total damage by 1%, the marketable yields will increase by 30 pounds/acre in a 3000 lb crop year. Take that times 20 acres - a small block-  totaling 600 pounds of increased marketable production, which would provide a $900 gain for 90 minutes of work. This doesn't include any premiums that may occur from the processor for the improvement of quality.

 Knowing the damage that occurs provides the ability to develop the most cost-effective way to manage orchard pests. If practices are changed within the orchard for a season, the harvest sample can provide the information to see if the changed practices provided an increase in marketable yields. If not, it may be best to modify or return to the previous year's program.

2010 Almond Harvest Around the Corner...

Harvest has started in the Southern San Joaquin Valley, and will be starting in the Northern San Joaquin Valley in the coming week. Here are some points to consider for the upcoming harvest:

A few articles posted last year can provide a few tips to help with the decision of harvest timing:
1. Preparing for Harvest.
2. Taking a Harvest Sample for an IPM checkup.

Keep in mind that earlier harvested nuts may have to dry on the ground for 1-2 weeks, while nuts partially dried on the tree will require less time. Nuts that remain in the tree will have a longer period of susceptibility to NOW, while almonds on the ground are susceptible to ants, mold (due to increased humidity), and rain events. A quick orchard walk through looking for fire ants and pavement ants should provide the information needed for this decision.

As soon as the almonds are picked-up, irrigate the trees. Adding a little nitrogen at this point is also advised. It may be possible to water the trees earlier dependent upon the irrigation system. Drip users may be able to irrigate as soon as the trees are shaken, while some micro-sprinklers may have small enough pattern that does not wet wind-rowed nuts.

If stockpiling in the field, cover the almonds with a white tarp - or better yet, a two tarp system that includes a black under layer and a white tarp on top. The white tarp or b/w combo has been shown to reduce stockpile temperature and condensation, helping to reduce the environmental conditions favorable for aflatoxin production. Uncover the piles when possible to prevent the accumulation of moisture underneath the plastic. Fumigation of the stockpiles may be necessary.

If rain is imminent, keeping the almonds in the tree will increase the dry time of the almonds after the harvest.

Hope this helps!

Central Valley Water Board Expands to Protect Ground Water

Please read. This will have a direct effect on the industry and growers should be involved in the commenting process.

La Nina Predicted for Winter 2010-2011 - Dry Year Expected

A La Nina is predicted for the winter of 2010-2011 which suggests that we will be experiencing below normal precipitation for the coming year. The prediction report can be found below:

EL NINO/SOUTHERN OSCILLATION (ENSO)

DIAGNOSTIC DISCUSSION
issued by
CLIMATE PREDICTION CENTER/NCEP
5 August 2010

ENSO Alert System Status: La Niña Advisory

Synopsis: Synopsis: La Niña conditions are expected to
strengthen and last through the Northern Hemisphere winter 2010-11.

During July 2010 La Niña conditions developed, as negative sea
surface temperature (SST) anomalies strengthened across the central and
eastern equatorial Pacific Ocean. All of the Niño indices
decreased with values less than -1.0oC in Niño 1+2, 3, and 3.4
regions at the end of the month. The subsurface heat content (average
temperatures in the upper 300m of the ocean) continued to reflect a
deep layer of below-average temperatures east of the Date Line. Also
convection was enhanced over Indonesia, while remaining suppressed over
the western and central tropical Pacific. Enhanced low-level easterly
trade winds and anomalous upper-level westerly winds continued over the
western and central equatorial Pacific. Collectively, these oceanic and
atmospheric anomalies reflect the development and strengthening of La
Niña conditions.

Nearly all models predict La Niña to continue through early
2011. However, there is disagreement among the models over the eventual
strength of La Niña. Most dynamical models generally predict a
moderate-to-strong La Niña, while the majority of the
statistical model forecasts indicate a weaker episode. Given the strong
cooling observed over the last several months and the apparent
ocean-atmosphere coupling (positive feedback), the dynamical model
outcome of a moderate-to-strong episode is favored at this time.
Therefore, La Niña conditions are expected to strengthen and
last through Northern Hemisphere Winter 2010-11.

Expected La Niña impacts during August-October 2010 include
suppressed convection over the central tropical Pacific Ocean, and
enhanced convection over Indonesia. Temperature and precipitation
impacts over the United States are typically weak during the Northern
Hemisphere summer and early fall, but strengthen considerably during
late fall and winter. Also, La Niña can contribute to increased
Atlantic hurricane activity by decreasing the vertical wind shear over
the Caribbean Sea and tropical Atlantic Ocean (see the August 5th
update of the NOAA Atlantic Seasonal Hurricane Outlook).

This discussion is a consolidated effort of the National Oceanic and
Atmospheric Administration (NOAA), NOAA's National Weather Service, and
their funded institutions. Oceanic and atmospheric conditions are
updated weekly on the Climate Prediction Center web site (El
Niño/La Niña Current Conditions and Expert Discussions).
Forecasts for the evolution of El Niño/La Niña are
updated monthly in the Forecast Forum section of CPC's Climate
Diagnostics Bulletin. The next ENSO Diagnostics Discussion is scheduled
for 9 September 2010. To receive an e-mail notification when the
monthly ENSO Diagnostic Discussions are released, please send an e-mail
message to: ncep.list.enso-update@noaa.gov.

Climate Prediction Center
National Centers for Environmental Prediction
NOAA/National Weather Service
Camp Springs, MD 20746-4304

Mid-August Almond Market Outlook Update

Almond Market Update provided by Paul Ewing at Hilltop Ranch

Almond Update

Posted on August 11th, 2010

Today the Almond Board of California reported:

July 2010 shipments were 112 million lbs. 

-  Down 7.4% from July 2009 shipments of 121 million

- Domestic shipments were up 2.9% and exports were down 12.4%

Following the NASS Objective estimate and June ship figures, pricing dropped quickly and then recovered very quickly as well.  Prices have been fairly steady for the past 2 weeks.  This was the final position report for the 2009 crop year.

SHIPMENTS/DEMAND:

Today’s report brought shipments for the season to 1.47 billion lbs, vs. 1.389 billion last season, up 5.9%.  Domestic shipments finished up 9.3% while exports were up 4.4%.  The majority of export growth went to China/Hong Kong, where the industry shipped 133 million lbs. vs. 99 million lbs. last season.  Spain remained the #1 export destination at 143 million lbs. 

THE 2009 CROP:

Crop receipts at the end of the season totaled 1.4059 billion lbs. - just 4.14% above NASS’ objective estimate.

THE 2010 CROP:

Crop development has continued without any major concerns.  Harvest is running at least 10 days behind last season.  We do not anticipate having a good idea of yields for at least another 45 days.

OUTLOOK:

Expectations are critical when it comes to the almond industry’s monthly position reports.  We believe expectations were for something in the range of 95-100 million lbs., with hope for better.  So the 112 million, while down, is a bullish factor at the moment.  This brings the carry-out to just 306 million lbs., a number which may be adjusted slightly next month once the Almond Board calculates the final loss & exempt.  With this lower than anticipated figure (306), we are now anticipating a 2010 crop year supply much closer to 1.9 than 1.95 billion lbs, and which is also assuming the NASS estimate is correct. 

After hitting rock bottom shortly following the shocking NASS estimate release, sentiment has improved significantly. 

We still believe certain varieties, sizes, and qualities may be in short supply for the transition period into the new crop.  We are already seeing a shortage in nearly all sizes of Cals and Mission types. 

The late crop will likely decrease August shipment figures (of inshell particularly), but otherwise we expect stronger shipments and inquiry levels going forward. 

The next position report is due September 10.

Questions regarding the report should be directed to Paul Ewing (paul@hilltopranch.com).

Uptake Damage from 2,4-D from a handgun application

A call to a Butte/ Padre 7th leaf orchard in the Hilmar/Livingston area provided some interesting symptoms associated with uptake from herbicides. Five days after a flood irrigation, the grower noticed that a few trees on the end of five  rows were collapsing (Figure1). The damage was occurring across varieties affecting two out of three scaffolds. The soil texture was a sand common to the Hilmar/Livingston area.

Figure 1: Overview of tree collapse. Figure 2: Damaged tissue progressing from the tree roots into the trunk

A closer inspection of the tree showed a sunken area on the bark, but no gumming was present. Bark removal revealed a large red canker progressing up the tree from the soil (Figure 2). Removing the soil, the damaged plant tissue was visible on the roots, but stopped about five feet from the trunk (Figure 2). At that point, the roots beyond that point appeared healthy. Leaves of the tree were yellow, maintaining green veins - similar to a few different nutrient deficiencies. Creating a cross section, it became clear that something was trans-located up the tree through the xylem - as evident by the dis-colorization of the tissue (Figure 3 and 4). This suggested that the problem was not due to a disease, but rather something chemical. 

Figures 3 and 4: Bark removal and cross section of the almond tree affected by 2,4-D uptake through improper herbicide application.

Speaking with the grower, we went through a variety of orchard activities that may have caused the damage.  That led to discussions about fertilizers, herbicides, and any other cultural practices. Everything seemed to be reasonable, so the conversation turned towards orchard activities that occurred prior to the flood event. The grower admitted that an herbicide application of 2,4-D was made  36 hours prior to the irrigation. 2,4-D was applied at the full label concentration and was used to spot treat weeds by handgun through the orchard.  

In most situations, properly applied herbicides will stay within the area of application. When over-applications of products are made, the product can move and cause tree damage due to its concentration. Since these products are water soluble, their ability to move increases when an irrigation occurs shortly after product application. Using a handgun to apply any herbicide is very inaccurate in applying the proper dose. In many occasions, handgun applications lead to a 10 X rate or greater application within the treated area. This over-application of product can be dangerous to trees - as shown above. I doubt that this damage would have occurred if a 1X concentration would have been applied.

Hull Samples for Boron Analysis

Roger Duncan, Pomology Farm Advisor, UC Cooperative Extension, Stanislaus County

What is the most common nutrient deficiency in Northern San Joaquin Valley almonds? If you said nitrogen or zinc you are wrong. While zinc and nitrogen are commonly applied to area orchards, boron is often neglected and therefore boron deficiency is far more common. If you haven’t applied boron TO THE GROUND recently and your orchard is east of the San Joaquin River, you are almost certainly deficient. Boron is essential for pollen tube growth. There are no obvious foliar symptoms of moderate boron deficiency, but less than optimum boron can reduce nut set. Analysis of mature almond hulls is a much better indicator of boron status than a leaf analysis. Wait until harvest to collect hulls because they will continue to accumulate boron while splitting. Trees with hull boron levels of less than 120 ppm may benefit from a postharvest boron spray (1-2 lb of a 21% B product in 100 gallons of water per acre). This will help with pollen germ tube growth in the flowers next spring but will not improve overall boron status of the tree.

Hull boron of less than 80 ppm indicates the need for a ground application. Fertilize with the equivalent of 10 – 20 pounds of a 21% boron product per acre. Boron can be injected through micro-irrigation systems, broadcast or sprayed on the ground, or included in a herbicide spray. Herbicide sprays containing glyphosate may need to be buffered to prevent reduction of herbicidal activity. Hull levels over 200 ppm indicate excessive boron.