Dry season

I once again find myself struggling with a blog topic that I has all my research completed and enough pictures to keep my wonderful audience returning.  I have a couple of items I need to put on record before we move on to the topic today.  

First up:  I will be making my yearly stateside trip arriving Dec 12 and departing the afternoon of Sunday Jan 15.  I will be available to do talks either about my life and work here or about Full Dimension Ministry (or some combination of those two).  Please contact me at steveintanzania@gmail.com and I will put you in contact with the person helping to schedule talks.  

Mark your calendars that I will be doing a dinner talk at Mauldin United Methodist Thursday December 15th that will be a fundraiser for the team coming over in June 2017.  As the ability to register for the dinner becomes available I will pass it along.

The last item is that if you were following the wish list items I posted several months ago, that list has been updated to cover items that have been provided for.  Let me know if you are interested in any of the remaining items.

This weeks topic is our dry season.  Many people ask me about if it is our winter or summer season.  Here those seasons don't really exist.  Yes we have temperature changes and there is a season for things to be green and a season for the leaves to fall etc.  But describing it by terms used back home are very misleading.  The cooler time of the year is actually the windy part of the dry season normally.  What it really is like is a mild summer back home with cool nights.  The one this year was cooler than normal most likely due to Global Warming like everything else.  Quick note my problem with global warming arguments don't have to do with if the hypothesis proposed that carbon emissions have caused a rise in temperature.  My problems is after that hypothesis  was formulated they have not followed any form of good scientific practices and because it is a media driven/political hot button issue they have been given a pass on their work not being up to quality scientific standards.  (nuff of that)

What really caused the cooler temperatures this year was heavy rains during our last rainy season which were caused by this being an El Nino year (at that time).  It actually got cool enough I wore a windbreaker a couple of mornings.  brrr!

So what we have here is really rainy season (starts late November in the valley and runs to April) and dry season (the rest of the year)  Growing season starts after enough rain softens the soil they can till and plant it through June when they harvest.  Of note most droughts I am aware of here actually consist of not getting rain the  last couple of months so the crops die before the harvest.  

Right now is the worst of the dry season.  It has a negative impact on a lot things.  

Money-One of the big issues here is that everyone grows crops at the same time and harvests at the same time and sells their crops at the same time.  For those who took an economics course along the way understand the idea of supply and demand and when everyone (and I mean everyone) goes to sell the same items at the same time it drives the  price down.  They then take that money and live off it until the next harvest.  So right now everyone is looking at needing things to start planting and being over six months into their allotted money for the year.  

Attitudes-people are normally in a bad one right now.  Partly because of the money and partly because it is hot and dry and has been since June.

Lack of water resources-those who store water like we do on our site are running out (We have two tanks with water still but they are low and we collect more water than anyone in the valley)

Soil quality-the soil is so dry it is very dusty and we see wind erosion and what I call sweeping erosion.  This is where the normal Tanzanian tendency is to constantly sweep the dirt around buildings (everyday) and they lose a fair amount of the top layer of soil (I would not quantify it as top soil which is normally the layer good for growing things) it is all sand.

Currently it is hot here-hot enough that I carried the type of cheese like Happy Cow that come in slices wrapped in aluminum foil from the store to my hotel and they melted in the 20 minute walk.

The sand and dust in the air causes constant health issues.  My nose has not been unclogged in over a month now.  The heat cycle wears on other things than my health.  Everything that is glued starts to come unglued as all moisture is drawn out and things are overheated.  For example I normally have to reglue the gutter piping right now because they start to fall apart.  The batteries around site have to be monitored to make sure they are staying cool to prevent shortening of their life.  The truck battery typically goes bad during this time of year from both the heat of the atmosphere and the diesel engine.  I may try a maintence battery next time so I can add fluid to it.

I already mentioned in another blog post about how dry the soil and construction materials are that it caused me to add 20 to 25% more water to concrete mixes to account for the lack of moisture in those materials (thank you Sergi my concrete professor).

While the mission team was here, Nathan and Blake took moisture readings around site. (that is them in the picture above) They were surprised at how low the moisture content was.  They left those devices and I did some very extensive testing this last week.

Bare soils which have no ground cover at all which Tanzanians love because it cuts down on mosquitos and snakes and they can sweep them.  These soils are the worst and will be the worst eroded areas during the rainy season as well.  The reading taken after scraping the surface soil away was 4%.  The reading at about 1 foot deep was just 5%.  The reading at 2 feet down was still at 5%.

Light covering soil-this is soil that has grass growing but is cut to a couple of inches.  The grass covering helps to provide stability during rainy season and high winds to prevent soil erosion.  Keeping it cut helps keep the mosquitos down and typically is not too bad for snakes.  Actually the worst area for snakes is near their flowers they love because mice/rats like to live in the roots.  The reading near the top was still very low at 6%.  At a foot down it was 8% and at 2 feet down was only10%.

Coverd soil-this is the soil we grow grass on but it is not cut that often so the dead grass is about a foot high.  This could be a mosquito problem but there is not enough water present really.  It is only in the areas away from buildings (basically open field area of our site.  The near surface reading was 8% and at 1 foot it was 11% and at 2 feet it was actually 15%.

What do those numbers mean-really depends on which source you look at but for most guides our soil is between loamy sand and sandy clay loam.  Typically the change is as you go down getting more clay at lower depths.  For all of those soil types the numbers are in the wilting point (unable to grow  plants) which if you see our grass and plants right now that we don't water you would say Yep!

Why does the area with more grass retain more moisture.  A couple of reasons.  The first is that the grass acts like shade to the soil and keeps it slightly cooler.  Next is that it is a windbreak keeping the heavy winds from drawing the moisture out.  Lastly is that more soil covering helps to retain moisture by creating a miniature canopy effect.  In a jungle the canopy is one of the reasons why the area stays humid.  

The funny thing is William has told us about a time when he was growing up when the area was all trees.  During that time I bet the moisture level in the soil was much better than it is now.  Probably significant enough to keep things green most of the year.

One last fact about our dry and very hot season right now is  Kirchhoff's law of thermal radiation. No I am not going to do the whole science talk. in most basic terms it is one object has more thermal energy than another (it is hotter).  The desire of those objects is to reach equilibrum.  They do this by radiant heat being given off by the object that has more thermal energy and the other object absorbing the thermal energy until they reach a state of equality.

Well a tin roof in Africa gets really hot and it radiates that heat into my house.  It was so bad this last month it fried my thermometer.  I had to work on the computer to complete some work and I was glad I could type without looking at the keyboard because I had to cover it with a towel to protect it from all my sweat.