How are arable crops grown?
In the previous Step, you learnt what arable crops are, and the challenges faced in crop production. In this Step, you’ll look at the common processes that have conventionally been involved in growing arable crops - from seed to harvest. There are downsides to many of these practices, such as loss of biodiversity, pollution and soil compaction. These drawbacks are being addressed by new practices aiming to create sustainable cultivation systems. Some of these new practices are described in Step 2.11.
The first thing a farmer has to decide is whether to sow or plant their new crop . Sowing requires seeds, while planting requires recently germinated live plants. Using live plants reduces the risk of problems occurring at germination stage but can be more labour-intensive than sowing seeds.
The next important consideration is crop density. This refers to the space between plants that allows them to reach their expected size at maturity. It needs to be tailored to each plant to maximise growth and yield . Densities that are too low or too high give lower yields than the land is capable of (Figure 1).
Figure 1: Overlapping runs of sowing. As the opposite ends of the field are not parallel to each other there will be a double density of crop over this section © Allan Murray-Rust Source
The farmer also needs to consider timing. The growth cycle would normally start earlier if using seeds than with germinated plants and the time of sowing or planting determines what conditions the crop will face as it grows, such as the risk of being exposed to adverse weather or diseases . As European farmers adapt to climate change, particularly summer droughts and extreme heat, they are choosing to grow crops earlier in the year so they mature before the weather conditions get bad.
Plant growth: requirements for a successful yield
Precise growth stages and times vary between crops, but there are three basic development phases :
Foundation phase: This phase starts after germination. At this stage growth is slow and farmers need to monitor and apply chemical compounds such as herbicides, insecticides and fungicides if necessary.
Construction phase: During this stage the plant reaches maturity and growth is fast. Crop protection practices continue but as growth is fast, the farmer needs to focus on any additional nutrients the plant may need in addition to what it gets from the soil.
Production phase: The last stage of plant growth is when the parts of the plant that become our food are formed and uninterrupted nutrient and water absorption is vital. Growth is hardly noticeable. The success of this stage is determined by how well the plant was protected and nurtured during Construction phase.
|Foundation (up to 6 months)||Construction (up to 2 months)||Production (up to 2 months)|
|First roots are forming and the stem that acts as the trunk for all over-ground parts, rises. The first branch (node) makes its appearance.||Roots grow thicker and stronger and fruit bearing branches proliferate.||After flowering, grains are filled. Yield is affected by the exposure of the crop to diseases and extreme environmental conditions.|
Figure 2: The three stages of plant growth.
You may like to watch this video (hosted on Youtube), which is a timelapse of a bean seed as it germinates and develops its root system.
Challenges: Crop care and machinery
The farmer needs to manage pests effectively. A pest is considered ‘anything that impedes or competes with crop plants’ . Pests can include weeds, insects and rodents, fungi and diseases.
Control techniques include:
- Chemical treatment: Pesticides and herbicides (Figure 3).
- Mechanical and cultural control: Non-chemical control such as mechanical de-weeders, disease resistant varieties, crop rotation, controlled irrigation, integrated pest management practices.
- Sensors for monitoring problems (still not very common): thermal or fluorescent sensors that can detect the presence of disease or pathogens by temperature, colour or composition changes in the plant.
- Combinations of the above 
Figure 3: Farmer spraying pesticide as part of pest management plan. Georgia © Jeff Vanuga Source
Crop protection is a labour-intensive process that requires close monitoring of crops. The use of sophisticated machinery that automates activities that were previously done manually leads to:
- Increased land productivity: higher yields, minimised losses and increased quality.
- Increased labour productivity: working hours per hectare are allocated efficiently.
- Decreased production costs: less labour is required (in € per hectare).
- Preserved natural resources: the precision possible with machines leads to less waste of resources, nutrients and water.  
To produce crops that are safe to eat and ensure future food security, it is vital to adopt sustainable cultivation systems. Fortunately, this aim is increasingly endorsed by farmers, consumers, retailers, legislators and stakeholders alike. The foundation for sustainable food production lies in protecting and ensuring resilient ecosystems as the basis for healthy and resilient crops .
References can be found under the ‘Downloads’ heading at the bottom of this Step.
© EIT Food