Is it possible to improve crop productivity?

A systems approach and specialist support could be the answer...

Globally, crop production sustains humans and animals alike, and it is pivotal to human survival. By nature, the two main focal points of the crop production system are productivity and profitability. All inputs into the crop production system have one or both of these two end goals in mind. Productivity is managed by the application of numerous inputs, including fertilizers, crop protection inputs, irrigation (where needed) and plant manipulation (e.g., pruning of trees).

The question that arises when one considers the future of crop production is if every single aspect of the farming system is optimized in a way that there is no more room for improvement. Are we harvesting yields equal to the genetic potential of the crop and if not, what can we do to do better?

In my opinion, there are two ways of thinking which as not entered agricultural production systems comprehensively and they are firstly a “systems approach” to the production unit, be it under cover, in orchards, in greenhouses or in open fields. The second is for specialist support to crop protection.

In South Africa, crops have been produced for hundreds of years. In earlier years, just as in other places, significant yield loss was experienced as a result of pests and diseases. Over years, as options for crop protection became available, the risks posed by pests and pathogens could be managed better. Genetic improvement of plant material, research on best production practices and the wider availability of affordable chemical control options also, amongst others, contributed to gains in productivity.

Of the known methods for protecting crops, a strong focus currently still lies on the use of agrochemicals, which has often proved to be a “silver bullet” eliminating the target organism and sparing the yield.

Yet, in recent years, agrochemicals have become less of a “silver bullet” since:

1)????Some of the existing, registered products are exhibiting lower levels of efficacy than in the past. This is mainly due to tolerance or resistance (to the product) in the organism targeted. In response, farmers sometimes add additional fungicide sprays to their crop protection programs or in desperation they might start using higher dosages of the agrochemical, which in return further encourages tolerance and resistance in the harmful organism’s populations

2)????Regulatory demands for reduced agrochemical use from local and foreign markets. These regulations are often driven by consumer pressure, for the sake of the environment and human health, since agrochemicals may be toxic to off-target organisms – which includes humans (more often for those who work with agrochemicals on farms)

3)????Increased infection and infestation pressure from pathogens and pests as temperatures warm and become more suitable for faster completion of their life cycles. This means that populations of harmful organisms grow faster than anticipated, and agrochemical application may come too late. When this happens, the agrochemical will not successfully control the pest or disease (as evidenced by locust populations causing havoc all over the world for instance)

So, these factors are forcing us to rethink how we go about protecting crops and reaching the full genetic potential of the crop. We are all the more being driven towards sustainable, non-toxic solutions for managing pests and diseases of crops. But what exactly does this mean? Do we have to take a giant leap towards only environmentally friendly products? Not at all. We need to work towards a best-of-both-worlds approach, where the crop protection approach is mixed.

In this mixed approach I suggest the following:

?A systems approach to crop health

The crop production system, despite requiring varied inputs, is a single unit, with many complex input components interacting at any given moment (Figure 1). These include crop protection inputs, the condition of the soil, water quality, and nutrition. Crop health management, therefore, requires a holistic approach to optimize and maintain the health of plants. Such a system focuses on cultivating and maintaining the health of plants as a first priority. This is done by limiting or eliminating the biotic and abiotic factors that inhibit plants and prevent the achievement of full genetic potential. Healthy plants are more resilient and less susceptible to stressors.?In this context, the judicious use of fertilizer, the application of biostimulants which supports biotic and abiotic stress tolerance and crop-specific production practices that optimize plant health should be considered. In field crops, this could mean using an optimal planting density so that plants need not compete, in tree crops, appropriate drainage can support the prevention of soilborne diseases occurring when the soil remains moist.

Figure 1: The inputs in a crop production system are not independent but are continuously interacting – bringing about the health or the decline of the crop

Specialist support for crop protection

Accurate application of products – backed by science and specialist support

Other reasons for failure in protecting the crop with agrochemicals include an incorrect product choice, wrong dose, inappropriate spray application methods, and insufficient coverage of the canopy/plant tissue to which applications are made. Since chemical spray options are dwindling, we must be sure that applications of agrochemicals are as accurate as possible. This calls for specialist on-farm support, where calibration of equipment can be audited, the best choice of product for specific situations is known, and the optimal spray apparatus for coverage of the plant material is used.

?Integrated management– backed by science and specialist support

Integrated management considers the prevention of pests and diseases occurring in a system over the long term. Orchard sanitation, a cultural method of lowering pest and disease pressure is an example of a factor that will be applied in an integrated management system. This requires monitoring for the presence and abundance of unwanted organisms, accurate identification of the problem, and consideration of management strategies other than agrochemical spray applications. These strategies could include biological control, where a predator or parasite of a pest is released, cultural control, such as not overusing nitrogen (which makes plants more susceptible to disease) or mechanical – which requires physical removal of sources of inoculum or infestation.

In South Africa, the appreciation of a systems approach is growing and specialist scientific support for on-farm decisions is becoming all the more available as businesses have specifically started focusing on these needs. Notably, with the advent of the 4th Industrial Revolution Technologies, accurate application of products is becoming all the more feasible. This also holds for accurate pest and disease identification, which will allow for best-integrated management methods, but also better pest and disease management with agrochemicals combined with other mixed approaches. ?

This article was originally published in the online magazine Agri About ?Magazine Editions ? Agri About - I am sharing it as a LinkedIn publication for a wider reach.

Contact the author: [email protected]