The question has come up more than a few times from industry participants on how to adjust nitrogen (N) inputs for strawberry varieties more productive and of larger plant size than Albion for which the original DRIS study was done.

Simple math says one could just increase simply N uptake estimate to cover the added fruit and bigger plant, so if Monterey produces 20% more fruit, and is that much larger a plant, one just adds 20% more nitrogen to the standard annual fertility program to make up the difference. However, as simple as this math may seem, it could quite possibly be incorrect, since it is not at all unknown that different strawberry varieties have variations in N content in the fruit and leaves.

The work to determine N content of Monterey compared to that of Albion was done over two samplings (one in early May, the other mid-July) of five fields of Albion and five fields of Monterey. We found that Monterey had marginally higher N concentrations in both the leaves (Table 1) and the fruit (Table 2) on both sample dates. An evaluation of plant size, without fruit, found that Monterey also ran about 20% larger than Albion from the five fields sampled.

From this information, we can say that N uptake is at least as high in Monterey as in Albion per unit of plant growth. That is to say, if a grower expects and has experienced 20-25% increases in fruit yield with Monterey over that of Albion, then the amount of N uptake to support that level of productivity will also be 20-25% higher than for Albion.

We need to be careful here however. This is not a call for growers of Monterey to automatically increase their N fertilizer additions by 25%. If a grower is finding his or her seasonal practices in the lower half of typical grower practice, then an increase in nitrogen application could be tested, but if a grower is already using a lot of N, say above 250 lbs per acre, then that might be enough to absorb the higher N requirement of Monterey.

Table 1: Nitrogen (N) concentrations in dry leaves

Table 2: Nitrogen (N) concentrations in dried fruit

Many thanks to the growers who participated in this study, and generously allowed me to tear plants out of their fields for the plant size sampling.

This post is to announce a meeting on strawberry mineral nutrition to take place this coming January 30.  I think it might be good to spend a little bit of time on the current salt situation as well, seeing as it is related to nutrition and water.

First presentation will be in Spanish, and the second in English, with translation provided for both.

Growers and PCA's - bring a copy soil and/or tissue sample analysis for review of sufficiencies/deficiencies/toxicities in our final exercise.

Look forward to seeing you there!

I was brought out to the situation in strawberry pictured below.  Yellowing leaves and very little flowering or fruiting.   For whatever reason, the street’s call on this was that it is iron, but to me the youngest leaves being as green as they are (Photo 2 below), is a dead giveaway that it’s not iron, because the youngest leaves in iron deficient plants are the first to yellow, not the last.

No sense standing around arguing about the problem, we just have to roll up our sleeves, get dirty and figure it out! 

The charts below are threefold replicates of sampled leaves and soil of affected plants in the field.

Table 1 : Tissue analysis

Table 2: Soil analysis

So, it looks like the main culprit here is indeed a lack of nitrogen, seeing that at an average of 1.4% it is well under the 2.4% tissue concentration threshold given in the UCCE nutrient guidelines.  Just to be sure though, we should check to see if any of the other nutrients are low, but they are not and everything else is within normal ranges.  I would have some concern about the high levels of sodium (197 ppm) and chloride (7930 ppm), but beyond some marginal burning of the leaves, these plants don’t seem to be exhibiting symptoms consistent with real salt poisoning.

Looking to the soil, sure enough we get confirmation of what we are seeing at the tissue level, and see that nitrates are pretty low here, running at a lean 4 ppm.  I would probably want to bump that up a bit.

So what does cheap natural gas do for California berry growers?  Not a lot apparently, if one extrapolates from an excellent article written by Colin Carter and Kevin Novan and recently released by the Giannini Foundation of Agricultural Economics titled “Shale Gas Boom: Implications for California Agriculture.”

http://giannini.ucop.edu/media/are-update/files/articles/V16N3_1_1.pdf

As most Americans know by now, the ability to access through hydraulic fracturing (known in the common parlance as “fracking”) previously unavailable shale gas resources portends an big shift in the energy dynamics of the United States.

The enormous amounts of shale gas becoming available through fracking in the US has brought about a drop in the price of natural gas nationwide, but this has not been followed with a worldwide drop in natural gas prices.   Natural gas, moved as a gas through pipelines domestically, can only be transported to overseas markets once it has been converted to liquefied natural gas (LNG) at facilities where the gas is turned into liquid form and then pumped into tankers for transit. The current lack of such facilities in the US and subsequent difficulty to get our natural gas to foreign markets has resulted in huge price discrepancies globally, with natural gas prices in the US at approximately $3.30 per thousand cubic feet, at the same time in Europe for example prices are $12 per thousand cubic feet.

This price discrepancy of course presents a real cost advantage for users of energy and natural gas in the US over their overseas competitors.  How much of this price advantage accrues to California berry growers is a question worth examination.

According to the article cited above, only 0.8% of total natural gas consumption in the US occurs in the agricultural sector.  A lot of farm equipment, from tractors to motorized implements to trucks, use gasoline or diesel rather than natural gas.  Obviously, if a lot of this equipment were to be converted to use natural gas there would be some cost advantage, but this is very much a proposition for the long term.

On the other hand, natural gas is the main input in the production of ammonia, which is subsequently converted to the nitrogen fertilizers which are a mainstay of California berry growers, who use anywhere between 160 to 250 lbs of the stuff per acre.  However, fertilizer costs in the berry industry, according the UCCE Cost and Return studies make up only 1% percent of the total cost of production, meaning that price changes in nitrogen fertilizer are not that meaningful in one direction or another to the total cost of running a berry operation.  Furthermore, fertilizer prices are arbitraged internationally, meaning prices tend not to vary too much from country to country, so low fertilizer costs stemming from cheap natural gas feedstock in the USA don’t really translate to much of a cost advantage to local growers anyway.

The other possibility where cheap natural gas prices could confer an advantage to California berry growers would be a reduction in the price of electricity, more than half of which in California is generated from natural gas.  The heavy reliance on irrigation and the use of electricity to get that water out of the ground in California agriculture and the berry business at least superficially points to some savings from reduced energy costs.  However, digging into our latest Cost and Return studies, pumping irrigation water constitutes only about 1.5% percent of the total cost of production of berries.   The gains from cheaper gas and subsequently cheaper electricity will be not that significant in other words.

In conclusion, the increasing amounts of shale gas becoming available through fracking in the US, while offering some possibility of advantage over the long haul in terms of energy inputs for traction and transport, does not appear to give a lot of advantage currently to California berry growers over their foreign competitors in terms of cost of production.