Verily...
Verily, each article of food: fruits, nutritious seeds, and vegetables have some interesting properties which can be studied, separately, in our lifetime and many things can be learned from them to enlighten us and give us insight into the wonders that they contain. Then, to explain the nourishments and their origins, it says: That We pour down the water, pouring it in abundance. The term /sab/ means 'to pour water over from above', and here it means 'sending down rain'.
The term /sabba/ at the end of the verse, is used for emphasis and to note the abundance of water. Water, which is very necessary for every living creature, often comes down sufficiently, because of Allah's grace. And we know that the essential source of water existing in rivers, streams, springs, subterranean canals and wells is rain, so that if it does not rain one year, all of them will dry up.
Thus, while studying articles of food, first and foremost, Man should refer to the importance of the regularity of rainfall. The sun shines over the seas where vapor, in the form of clouds, rises from and moves above the earth where winds scatter the clouds high in the sky. At cold points in the atmosphere, the clouds change into pure, harmless water again and fall gently on the ground in the form of droplets of rain or little pieces of snow that soak into the ground.
Trees, plants and living things draw up water from the ground. After mentioning water, which is an important factor in human life, it refers to another great factor; the earth, and says: And We split the earth in fragments. Many commentators have said that this splitting is the splitting of the land by plant seedings. It is really wonderful that a little smooth seedling can break the hard, solid land and sometimes it shoots up through stone.
What a surprising power the Creator has given to this tiny smooth seedling which enables it to do so! Some others have said that the split may be the splitting of the land when man ploughs it or even when some worms burrow through it; a kind of ploughing for the purpose of some other life activities. Ploughing is one of Man's activities, of course, but Allah has given him all its necessary means, therefore it relates to Allah.