AGRICULTURAL
17 | Pollution in Vaal River
SOIL LIFE
The new division at SGS laboratory
analyses the microbial activities in
your soil. The report indicates the
extent to which microbial activities
in your soil can contribute to making
nutrients available to the planted
crop. A number of nutrients were
deposited over years and can be
made available once again. Organic
N and total nitrogen (feed source for
microbes) can also be analysed at
the same time.
Recently opened soil profile and
the impact of a build-up of silt in the
top soil on water infiltration is clearly
visible.
• Vegetative growth of crop
becomes problematic in relation
to production.
SOIL NITROGEN ANALYSES
Fertiliser is an expensive input prod-
uct and, depending on your tilling
practices (conventional versus no-till-
ing), the fertiliser quantities com-
pared to what is removed with the
harvest, has an impact on, inter alia,
the distribution of nitrogen in the soil.
It is recommended that consideration
be given to analysing your soil for
NO3- as well as NH4+ every season
before planting time. Current analy-
ses of clients in the central produc-
tion area indicate available N-levels
in the top 40cm of between 20 kg/
ha N – 150 kg/ha N. At R12-R15 per
kg N, it could have a huge impact on
your input costs. Remember, nitro-
gen can be your best friend, but also
your worst enemy when it comes to
harvest time.
FERTILISER ANALYSES
It is a good practice to have your
fertiliser analysed to confirm that you
receive what you actually pay for.
When possible nutrient shortages
are noted on crops, production dam-
age has already been done - include
it in your planning to have fertiliser
analysed periodically.
LEAF ANLAYSES
If there is one thing that our experi-
ence as farmers has taught us, it is
to do regular leaf analyses during the
growing season in order to have bet-
ter information to respond to during
the growing season. Reflection after
the harvest is also used as a good
point of reference to make changes
to the fertilising programme for the
coming season. It is also recom-
mended that the dry leaf analysis be
followed methodically since norms
at different growth stages are well
documented. Bi-weekly NDVI images
are used to identify inspection points
for a more representative recommen-
dation. Fast turning times at the SGS
laboratory are essential in order to
take corrective action.
process whereby micro-organisms found natu-
rally in soil, are used to dissolve contamination
in water and soil. The micro-organisms dissolve
the chemicals and change in into water and
harmless gases, such as carbonic acid gas. The
rate at which it is dissolved can be accelerated
by adding oxygen and nutrients which contribute
to the growth and increase of micro-organisms.
It is a very effective process which requires no
chemicals.
Using plant and tree roots
The roots of plants and trees can remove pollution,
such as metals, herbicides and oil, from soil and
water. When roots take up water and nutrients,
they also take up chemicals, which are stored
in the roots, trunks and leaves. The plants can
then convert the chemicals to gasses, which are
released as the plant transpires. The vegetable
matter is not suitable for animal use..
Some of these methods are affordable should the
consumer establish the necessary infrastructure
away from the polluted water source. The objec-
tive is not to purify the water to drinking water
standards, but to standards which are set for irri-
gation purposes.
The pollution ratio of E-Coli will obviously
decline during the rainy season, but it will remain
important to do regular water analyses in order to
monitor E-Coli levels.
Hinterland has the skills to design external
structures and to establish some of the above
processes away from the source of pollution.
Hinterland also has the support of external spe-
cialists in, for example, filtration, to meet the chal-
lenges being faced.
SENWES SCENARIO | SUMMER 2018
19