Harvest Season Arrives Earlier Than Expected, Affecting Crop Yields

Harvest Timing Shifts

The start of the harvest season has moved forward by three weeks compared to 20 years ago. This shift impacts both the quality and quantity of crops as plants ripen more quickly due to rising temperatures. The crops have managed to survive winter flooding (almost) and two heatwaves, but another hot spell is on the way as we embark on the enormous task of harvesting our crops. Winter barley for seed is usually first, followed by oilseed rape (OSR), then probably wheat. Beans are nearly always last to be cut, often in September, but even these are heading towards the exit now in early July.

Harvest 20 years ago would start around the third week in July, but has crept forward by three weeks since then. The earlier harvest is good in a way, although it does curb our yields as the plants cannot ripen properly and the heat accelerates growth, but it does mean we’re cutting crops in longer daylight and don’t have to spend money drying them. Moisture content is also vital: to be acceptable to the merchant, wheat and barley must be below 15% moisture and oilseed rape below 9%, as that helps prevent storage issues such as moulds and pests. But moisture is also susceptible to the heat: crops are showing signs of stress due to high temperatures, with OSR moisture as low as 3%, as I’ve read.

The all-important number is 35C – that’s the point where pollination becomes unviable and the plant simply shuts down, and it’s of increasing relevance in the UK. For now, the culmination of a year’s hard work is in front of us. My son has replaced me at the wheel of the air conditioned behemoth combine, and I just hope everything falls into place. A rainfall delay now not only creates quality issues but can also mean the uncertainty of not knowing which crop to prioritise. It’s always been a gamble to grow milling bread wheat as well as marrowfat peas for the fish and chip shop trade; add in spring malting barley and delayed OSR, and the pressure ramps up. In less than six weeks’ time, with luck, all will be safely gathered, and we begin again with the gamble of growing human-grade crops in an ever more volatile climate.

Source: The Guardian