What are the things that come to mind when you think about California? I think about Hollywood, San Francisco, the Golden Gate Bridge, then Silicon Valley is here somewhere, right?

We landed in a town called Fresno which is pretty central to the California valley. The valley has an amazing climate all of its own. It is about 100 miles wide and stretches north-south for 700 or 800 miles. It is also sheltered by two mountain ranges, one to the east and one to the west.

For the last four years there has been a considerable drought in the valley but this year all the farmers we met were very excited because they got rain, and lots of it. Sounds like Ireland I was thinking until they spoke of annual rainfall of between 6in and 8in. I recorded 16in in December alone on my farm.

Snowfall

However, it only rains in California in the winter and most of the rain falls as snow in the mountains and is naturally held in a big white reservoir (snow) that melts in the spring time. In the distant past this melt water would have flooded into the valley and deposited rich soil along the way.

From the 1930s, Californians tried to harness this resource by building a series of hydroelectric dams and water storage facilities along the valley. This water can then be sent through a vast network of pipes and dykes to almost any part of the valley. It is a very complicated system with some water owned by federal bodies and some by local government, depending on who put up the capital.

The farmers have rights to the water but do have to pay to use it. Two thirds of the rainfall and storage is in the northern end of the state while two thirds of the population and the best farmland is in the southern end of the state.

Agriculture is an important part of the Californian economy and the farmers grow a vast array of produce. I have seen acres and acres of vines for grapes with some used for wine and some for raisins. However, it is nut crops that are the real hot product to be in over here.

Almonds are the number one crop to grow, followed by walnuts and pistachios. They say that each walnut takes a gallon of water to produce and from what I saw I would believe it. The first farm we visited had a beautiful crop of almond trees with micro-sprinklers feeding them water and fertiliser when needed.

Water is measured here by units called an acre/foot which is 271,328 gallons or more than 1.23m litres of water. To put it another way, it is 12in of water on an acre. So rainfall might be 6in to 8in and they will apply a further 52in to 60in of water to bring the total to 5ac/ft per acre. That is a lot of water, I mean a crazy amount of water, but remember this is a hot Mediterranean-type climate and some of the best land in the world. By the way, the land here trades for anything up to $30,000/acre.

So where does all this water come from?

Before the drought most of the water came from the dykes or canals that flow around the valley with farmers paying for the water albeit at a cheap cost. Then the drought started four years ago and water was cut back by 60% or more so farmers then turned to the second most valuable resource they have – a huge aquifer with vast amounts of water deep underground.

The wells in California can cost as much as $500,000 to install and can take up to a month to drill. My understanding is that it starts with a 26in hole in the ground that goes deep, anything from 1,000ft down to 1,600ft. This is then cased with a stainless steel sleeve all the way down with some of this perforated at different points to leave water in.

Outside the case is filled with gravel to provide a natural filter. In California, most of the pumps are just lift pumps with maybe two propellers fitted. They are driven by a spinning shaft from a power source on top of the well with mostly three phase electric motors but some gas or diesel engines. The best bit is the power, with 200hp to 300hp being common, allowing these pumps to lift 240,000 gallons per hour.

Sometimes the water flows into a dyke or into a storage pond for use in the farm. Because the water is coming up from so far underground it can be quite warm. Anything up to 20°C is not uncommon but there can be pH and salt issues.

Diversity

We spent six days in total in California and we saw a very wide and diverse range of farms and farming enterprises. The highlight for me has to be the livestock farms. Maddox dairy is milking 3,400 high-yielding Holsteins in an indoor system.

The cows are milked three times a day with four 13-unit double-up herring bone parlours. The breeding of the cows is remarkable. A few years ago the best of the best were selected and an embryo transfer program was put in place. Today all the cows can be traced back to just 11 cow families with showring success a hallmark of this remarkable dairy.

We also went to see Harris ranch – a remarkable feedlot. It measures one mile by one mile square with cattle held in outdoor pens and shade from the intense summer sun. On the day we visited there were 85,000 head of cattle on the feedlot. As we move into summer and spring grass disappears off the hills (no rain) they will fill up the place with 120,000 head of cattle.

They have their own feed mill which mixes up the concentrate and roughage mix with seven feed trucks keeping the animals fed three times a day. The site also uses 100,000 gallons of water per day. It is an integrated company with many divisions including a restaurant that sells steak, a transport company to move livestock and feed and a slaughter house with capacity to kill 1,100 head of cattle per day. The ranch also includes a thoroughbred horse stable, with the top earning stud horse in America last year.

A four-legged stool

We visited many more exciting places, such as Sun Maid Raisins and a fantastic asparagus farm. The amount of manual handling in asparagus farming surprised me. It is all cut and picked by hand, then most of it sorted and packed by hand also.

To sum up Agriculture in California, it is like a four legged stool:

1) Fantastic soil.

2) Abundant water above and below the ground, although it’s not sustainable to keep pumping from underground.

3) Fabulous climate.

4) Abundant labour that is mostly Mexican.

It’s not all hard work here on our GFP. We had Easter Sunday off, so we struck for Yosemite National Park on Saturday evening. We stayed in glamping-style accommodation which was a little daunting given that bears roam around the area and we only had the protection of a fancy piece of fabric between us and the great outdoors.

Fortunately there were no issues and on Sunday some of the group went on a mighty hike up to the top of a spectacular waterfall, while I indulged my love of skiing on the slopes of Badger Pass.

That is another chapter of my travels complete, now we are off to Mexico. The adventure continues and you can keep up to date with Tom on @BoRuaFarmer on Twitter or follow the hashtag #Nuffield16.