1 Fig. 1.1 shows a grain store on a farm. (a) State two features of this building that help to keep stored grain dry. [2] (b) Give one reason why the floor ...

Labelled answer diagram:

(a) Two features that help keep stored grain dry:

1. A sloping (pitched) roof that allows rainwater to run off quickly rather than pooling on the surface. [1]
2. Overhanging eaves that direct rainwater away from the walls, keeping the wall surfaces and interior dry. [1]

Other acceptable features: a concrete or raised floor to prevent ground moisture rising into the grain; ventilation openings to allow air circulation and reduce humidity; waterproof roofing material such as corrugated iron sheets.

(b) The floor should be raised above ground level to prevent dampness from the ground reaching the grain. [1] Rising moisture (by capillary action) would increase the moisture content of stored grain, promoting mould growth and spoilage. Raising the floor also helps prevent rodents from burrowing in and allows air to circulate underneath.

(c) Two methods to protect stored grain from insect pests:

1. Fumigation with approved chemicals: sealing the store and introducing a fumigant gas that penetrates the grain bulk and kills all insect life stages including eggs and larvae. [1]
2. Dusting grain with insecticidal powder, which coats the grain surface and kills insects on contact. [1]

Other acceptable methods: ensuring the store is properly sealed before fumigation; regular inspection and removal of infested grain; use of hermetic (airtight) storage containers or bags.

(d) A grain store should not be sited in a low-lying area because low-lying areas are prone to flooding or waterlogging. [1] Flood water could enter the store and soak the grain, causing rapid spoilage through mould and germination. Poor drainage also increases the ambient humidity around the building.

(e) One cereal crop that could be stored: maize. [1] Other acceptable answers: rice, wheat, sorghum, millet, barley.

(f) Grain must be dried before storage to reduce the moisture content and prevent mould growth. [1] High moisture levels create warm, humid conditions inside the grain bulk that encourage fungi, insect breeding and even germination of the grain, all of which reduce quality and quantity.