A gardener wants to find out if the type of soil cover (mulch) used affects the yield of strawberry plants.
He grows strawberry plants in pots containing compost:
After four months, the gardener harvests the strawberries from each pot, dries them to find their dry mass, and calculates the mean dry mass of strawberries per pot.
State the independent variable in this investigation.
Describe the steps the gardener takes to make sure his results are reliable.
To make a valid comparison, the gardener needs to control abiotic factors. He keeps all the pots in the same greenhouse to control the ambient temperature. Name three other abiotic factors the gardener should control.
Suggest two reasons why the strawberry plants yield a higher dry mass of fruit when the soil is covered with a black polythene membrane compared to being left uncovered (no mulch).
