nutrient deficiencies in plants can be caused by several factors, not always a direct lack of a nutrient. and even in that case, it’s useful to understand how adding a nutrient can affect the availability of others. soil ph, level of water saturation, and species peculiarities can be a factor.
a while ago i re-produced Mulder’s chart, which shows how the increased presence of a nutrient affects availability of specific other nutrients, either negatively or positively. I didn’t like the chart with all those cross-overs…so here is same chart with just one cross-over on the graph. the green lines with arrows show positive influence on availability of another nutrient by adding a specific nutrient, whilst red lines show such negative relationships…e.g. adding too much nitrogen can make boron less available, which shows up as very poor growth on beetroot, which are susceptible to boron deficiency.
the chart is a guide, and all other available information should be considered in concert.
chart url = http://members.optusnet.com.au/~chriswww/mulder_chart_redrawn.pdf

hey – wats this? – all the male forumites are pontificating late on a mundy afternoon..

i see the chart and it remains mysterious. LOL
i am interested in knowing if borax should be applied to any plants at present – the wife bought this jar of it for a tiny problem – so now i have to find a use for the remaining 99.9%.

Hmm.. now I am more confused :)

I bought some Borax ages ago as my lemon tree was showing signs of boron deficiency. However now it just looks generally unhealthy, not boron deficient, so I wasn’t going to use the borax anymore, just a general mineral product I bought that also has boron. From the look of this chart I think this may be a more sensible idea.

Poor lemon tree has been waiting ages for this – well now it is tree number 3 on the list so should be done in a weekend or two :)

it depicts the direct relationships between nutrients.
instead of trying to understand the whole chart as a whole….pick a nutrient (that say you’ve recently added in bulk to soil) and you can see any outgoing arrows from that nutrient will affect the other nutrients pointed to. the affected nutrient(s) will be less available when it’s a red arrow, and more available if a green arrow.
the chart can be used in several ways but main thing that can be learnt and better understood is any overfertilizing with particular nutrient, which will show up drastically on some plants, and is indicated by the chart.
the other thing is that the chart shows these complex relationships, and explains why a nutrient can show up as a deficiency in some plants when adding the deficient nutrient doens’t help…..this can be because another overabundant nutrient can depress another’s availability.

now it makes sense

so i’ve added liquid potash to the tomatoes thus -
- iron and manganese become more available
- boron and magnesium become less available

case in point is citrus…..which is said to be a gross feeder however, young saplings are prone to drop leaves or show a huge deficiency of various yellowing. the yellowing leaves surely are a sign of deficiency but, the deficiency could have been caused by too much NPK. and no amount of iron chelates or such will correct it…just need to wait or flush out some of the NPK, so iron becomes available again.

regards borax (boron)…as per the chart it doesn’t show any red outgoing arrows to other nutrients. therefore it will not depress another nutrient availability. it is though a salt based mineral, so should not be overdone anyway.

Yes Pepe….and as tomatoes are not that sensitive to boron deficiency, if you were to see a magnesium deficiency show up on the tomatoes, then it would have most likely been caused by too much potash. and thus the direct relationship of nutrients affecting other nutrients is revealed in Mulder’s chart. also note that if you’re unable to fix such a magnesium deficiency by directly adding magnesium, then some more nitrogen might help…which suppresses some potash and increases magnesium.
but as i said it’s only one part of the story….soil ph etc should always also be taken into consideration.

pepe said:

now it makes sense

so i’ve added liquid potash to the tomatoes thus -
- iron and manganese become more available
- boron and magnesium become less available

aquarium said:

case in point is citrus…..which is said to be a gross feeder however, young saplings are prone to drop leaves or show a huge deficiency of various yellowing. the yellowing leaves surely are a sign of deficiency but, the deficiency could have been caused by too much NPK. and no amount of iron chelates or such will correct it…just need to wait or flush out some of the NPK, so iron becomes available again.

I have a young citrus that has dropped heaps of leaves – but nothing has been added to it in AGES. What should I do? It is due for some feeding anyway…

i reckon wet feet, if in a pot. same thing happened to my young/new lemon tree. i’m now just holding back on the watering a bit, and the existing (older) leaves have gone green again.

bon008 said:

aquarium said:

case in point is citrus…..which is said to be a gross feeder however, young saplings are prone to drop leaves or show a huge deficiency of various yellowing. the yellowing leaves surely are a sign of deficiency but, the deficiency could have been caused by too much NPK. and no amount of iron chelates or such will correct it…just need to wait or flush out some of the NPK, so iron becomes available again.

I have a young citrus that has dropped heaps of leaves – but nothing has been added to it in AGES. What should I do? It is due for some feeding anyway…

aquarium said:

i reckon wet feet, if in a pot. same thing happened to my young/new lemon tree. i’m now just holding back on the watering a bit, and the existing (older) leaves have gone green again.

Cool, thanks aquarium. I thought it might be that so I took the pot out of the tray it was sitting on. There were a bunch of roots trailing out the bottom – should I trim them?

Hoping to move this tree into the ground later, but was going to wait until the retic has gone in.

the roots sticking out the bottom normally aren’t much of a problem, except if the saucer is full of water they’d be drowning a bit. i took my lemon off the saucer for a bit, to let it drain out.
bon008 said:

aquarium said:

i reckon wet feet, if in a pot. same thing happened to my young/new lemon tree. i’m now just holding back on the watering a bit, and the existing (older) leaves have gone green again.

Cool, thanks aquarium. I thought it might be that so I took the pot out of the tray it was sitting on. There were a bunch of roots trailing out the bottom – should I trim them?

Hoping to move this tree into the ground later, but was going to wait until the retic has gone in.

about nutrient deficiencies in general i forgot to mention that the chart also shows (sometimes) the folly of adding a single nutrient to counter a deficiency…as sometimes a nutrient must be added together with another, so as not to cause a different deficiency.

thanks to the chart i understand now some of my earlier mistakes, being too heavy handed with certain fertilizers.
some moons ago i stopped beetroot growing further from half grown, because i caused a boron deficiency by throwing around potash too frequently.
anyway, useful reference when things start going out of kilter.