Term 2 – Week 6 – Soils & Fruit Tree Pruning

This week was split between soil science and fruit tree pruning.

Soil science delved further into soil creation (pedogenesis), looking at the influence of parent material, topography, climate, soil organisms and time. I won’t go too much into that except to say they all play a role in how a soil forms.

We also learnt more about cation exchange capacity of a soil and its water and nutrient holding capacity.

Clay particles and humus are negatively charged, attracting positively charged nutrients in the soil. They will be held in the soil and not leached out. The acidity of the soil (concentration of hydrogen ions) controls which nutrients will be forced off, back into solution in the soil.

88693fff0cb4d614b08ae11f9ffe14e9

Clay will sometimes have a positive charge but phosphate will snag them all leaving sulphate and nitrate anions to be lost by leaching if not taken up by the plant right away.

In sandy soils the macro pores are too big to retain much water. It pretty much drains straight through taking nutrients with it. Clay and humus can improve the structure of the soil, providing more micro pores that hold onto water.

This is where the water holding capacity of the soil comes in. You only want to irrigate to field capacity – the point where the soil is holding as much water as it can without leaching.

d6a19e0c6da7ed4c15652a6a0b99458c

Nitrogen is the nutrient that is lost most easily from the soil. Aside from traditional fertilisers, nitrogen fixing plants can be helpful to add nitrogen to the soil. Plant roots and bacteria in the soil form a symbiotic relationship where the plant provides energy for the bacteria and the bacteria provide nitrogen to the plant. When that plant dies and breaks down in the soil other plants can then take up the nitrogen.

a634f0c810f506834c9a77ceeebd1822

We’ve come full circle now and are back to pruning – this week we’ve started pruning the fruit trees at Bannockburn Road. Pruning when trees are dormant means there will be a flush of new growth in spring. If you want to make a cut to a tree without encouraging growth you need to do it in summer.

Apricot trees are trained to grow in a vase shape, cutting back last seasons growth 2/3rds to an outside bud. This lets as much light into the centre of the tree as possible. Also taking out any diseased wood, branches growing in or crossed over.

IMG_20170608_205621

Pruning apricot trees – Karen and Praneel

Last week’s weather:

weather

Advertisements

One thought on “Term 2 – Week 6 – Soils & Fruit Tree Pruning

  1. Hi Katie…this is an AMAZING blog – the model for everyone else! You write very clearly and there is a huge amount of very interesting reflection on your experiences, as well as reporting on what you have learned. I am totally impressed with this! Congratulations!The link to your blog could be used in a CV.

    Just the last few weeks to cover then you will have the full year’s record of what you have learned….plus the credits! Well done! Jo

    Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s