SGS Laboratory Services - Support of better planning and management prior to and after the planting season

Services offered by the laboratory?

Water analysis 
We are all aware that the quality of water in irrigation schemes is declining to the extent where it is starting to have a negative impact on production. By analysing the quality of water used for irrigation purposes, better planning can be done in respect of the management of the detrimental impact of poor quality water for the coming season.

The sodium index of water used for irrigation has started to increase and the impact on the crops planted becomes evident as the growing season progresses, when the damage has already been done.

Chlorosis on potatoes due to the high sodium content of irrigation water. The damage can be managed better with prior planning, by changing fertiliser and irrigation strategies. 

The silt content of some of our large rivers and the content of nutrients such as nitrate, nitrogen, etcetera is on the increase. The continuous use of irrigation water is creating production problems, which can be addressed in good time. As silt increases in the top soil, we achieve more on particularly sandy soil - a point where top soil silt + clay become higher than the horizon directly below it. The net result is:

  • Poor water infiltration 
  • Poor top soil aeration 
  • A build-up of soil-carried diseases 
  • Imbalance of nutrients 
  • Ineffective scheduling of irrigation
  • Vegetative growth of crop becomes problematic in relation to production.

Soil Nitrogen Analysis
Fertiliser is an expensive input product and, depending on your tilling practices (conventional versus no-tilling), 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 analysis of clients in the central production 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.

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.

Fertiliser Analysis
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 damage has already been done - include it in your planning to have fertiliser analysed periodically.

Leaf Analysis
If there is one thing that our experience as farmers has taught us, it is to do regular leaf analyses during the growing season in order to have better 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 recommended 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.