By Benson Kibiru
We are alive at critical time where climate change is real. Generally, it has become a challenge for the farming fraternity to plan events because of the unpredictable weather patterns. As a result, for the agripreneurs, some has closed shops while others irrigation has been made inescapable. However, surface water is also unavailable in adequate amounts, making ground water an obvious choice.
Irrigation water for both greenhouse and field crops must be analysed and quality determined before use. The groundwater level is a key indicator for evaluating spatial and temporal changes in groundwater environments. The groundwater level is influenced by various factors. Climate change, as reflected in precipitation and evaporation rates, influences the groundwater level fluctuation and quality. Numerous studies have revealed groundwater salinity changed with the fluctuation of groundwater level whereby low salinity is recorded in wet season and increases to maximum levels during the dry season. It is for this reason, knowledge of hydrological processes and their effect on the ground water quality is essential.
To mention but a few and having the latter in mind, Sodium (Na), Chloride (Cl) and bicarbonates (HCO3-) levels in groundwater must be monitored against given standards depending on crop of interest. This will ensure only sound levels are in the root environment at any given time. Additionally, different studies have acknowledged spatial variations in concentrations of Nitrogen derivatives among other nutrients in groundwater because of geology and seasonal variations.
How does the above-mentioned affect crop production?
Like any other investor, the main objective of every farmer/ agripreneur is to generate returns within the a given period from the investment made. Specific to an agripreneur, worth remembering is a simple function “Profit making with sustainability= Nature impact + expert advisory + informed farm manager’s decisions” and have it in mind that, all the factors are equally important. Additionally, to achieve sustainability, efficiency, high precision and optimal yield, availability of essential nutrients must be in the right quantity and balance. This can only be attained through use of quality irrigation water and other agri-inputs (lime, fertilizers, gypsum e.t.c), where all nutrient credits are acknowledged. As it is well known to many “Quality is not a one-time activity but a continuous process” and for this reason, routine evaluation of Irrigation water as the carrier of essential nutrients most especially in a fertigation system must be synchronized with seasonal changes. This is meant to ensure nutrient solutions are adapted to the water quality otherwise accumulation of these ions can occur in the root environment, applied nutrients rendered unavailable and increased clogging of the emitters.
In summary, to have a smooth-running irrigation/fertigation system the subject practice “routine quality monitoring of irrigation water (Ground or Surface)” coupled with filtration at recommended mesh size, daily chlorination and acidification where applicable, bimonthly lateral flushing and regular lateral discharge monitoring are prerequisite practices.
Benson Kibiru is a Lead Scientist / Agronomist
with SGS Kenya Ltd