While farmers are constantly seeking ways to optimise soil health by adopting conservation agricultural practices to combat soil erosion, water run-off, and loss of organic matter and/or nutrients, simultaneously it is necessary to optimise the use of applied nutrients to the soil and crops in order to enhance the so-called nutrient use efficiency (NUE) of fertilisers.
The term NUE denotes to the efficiency by which a soil can deliver the correct amount of plant nutrients to a crop in relationship to the amount of plant nutrients applied.
NUE is expressed in terms of crop quality and yield per unit of applied plant nutrients. A lower NUE could be the result of over-application of fertiliser, leading to leaching; antagonism of different elements; or maybe over-application of lime, resulting in fixation of certain elements.
Kynoch’s yield-enhancing team is equipped to assist farmers in an innovative way by obtaining knowledge based on their farms’ soil type, soil form, chemical characteristics of the soil through sampling and analysis, as well as taking into account soil health factors when making decisions.
Yield enhancement does not always refer to the highest yield, but also to more effective ways of obtaining yield, while caring for the crop and soil. It is of outmost importance that you know YOUR farm, the soil you work with, the climate you have to deal with, and the outcomes you work towards.
When considering the success of NUE, a concept like 4R nutrient stewardship provides a framework to achieve the necessary outcomes, namely to increase farmer profitability, enhance environmental protection, and improve sustainability. The 4R concept incorporates the following:
- Right fertiliser source, at the
- Right rate, at the
- Right time and in the
- Right place
Some trial results (see Figure 1) that were generated by Kynoch in the Western Cape on potatoes can illustrate the aforementioned principles, when optimising NUE and subsequently increasing the farmer’s profitability. The focus was on phosphate (P) application on potatoes, either by spreading or band placement directly beneath the tubers at planting.
There are three different mechanisms of nutrient uptake by the roots of crops, namely mass flow, diffusion, and root interception. As in the case of P uptake by plant roots, the uptake is mainly by diffusion, and to a lesser extent, by root interception and mass flow.
The mechanism of diffusion implies that a concentration gradient is necessary in the rhizosphere for optimal uptake. This leads to the deduction that P fertilisation should be placed in close proximity to the roots and preferably in a concentrated band placement, versus spreading over the entire crop area.
As potato plants have a relatively poor developed root system, the aforementioned principle becomes critically important in the production and quality of potatoes.
The results obtained in Figure 1 can be summarised as follows:
- Band placement of P is more effective below tubers than broad spreading;
- The extent of NUE is reflected in obtaining the same yield with less P;
- Therefore 1,5t/ha P in broad spreading achieves the same as 1t/ha in band;
- The addition of trace elements (Ultra) furthermore enhances the farmer’s return on investment.
No matter your farm management system, your crop rotation system (whether it consists of cash crops, cover crops or the presence of livestock), your objectives or your means to the end, Kynoch’s agriculturists are ready to take your hand and support your goals.
Kynoch doesn’t just supply fertiliser to farmers, but work with them to ensure a sustainable future for South Africa’s agriculture.
Sources: Cooke, GW. 1982. Fertilizing for maximum yields, third edition. Granada Publishing; Havlin, JL, Beaton JD, Tisdal, SL and Nelson WL. 1999. Soil Fertility and Fertilizers: an introduction to nutrient management, sixth edition. Prentice Hall, London; IPNI. 2012. ‘4R plant nutrition: A manual for improving the management of plant nutrition, North American version.’ Bruulsema TW, Fixen PE, and Sulewski GD eds. International Plant Nutrition Institute, Norcross, Georgia.
