Water & Irrigation
Sprinkler systems are where its at on a black truffle farm. Expensive initially but pays for itself after a short time. In Spain now, the sprinkler systems are installed above ground once the truffle trees start to produce black truffles. They are usually installed once the trees are about 5 - 7 years old. The pipes are laid down the center of the rows and the sprinkler heads are placed to give maximum coverage. Word of caution!!!!!!! You must drain or bleed the sprinkler system of all water after every usage. Any water left in the black polyurethane pipes that are exposed to the sun during the day can actually reach boiling point. You dont want scalding water seeping onto the tree roots when you start the irrigation system, which will also kill the black truffle mycelium. You can some what avoid this problem by simply watering at night or 1st hour of the morning. Of course you will need a water supply, be it by well or what ever. Wells are expensive to dig but well worth the investment. There are many type of sprinkler systems on the market today, find out what suits you best. Use caution when watering your trees. People argue about how much water to use, how often to water and what time of year is best to water your black truffle farm. Make it your priority to find out. I dont have irrigation installed yet, so I have no 1st hand knowledge of this area yet.
Avoid!!!!!!!! They save alot of water but the water is concentrated in one area and will eventually drown the black truffle spore. If you have a couple of truffle trees in the back yard and you can move the drip pipe by hand, so a new area is always receiving water, it might be ok. But realistically on a commercial black truffle farm that is at least a hectare (about 2.2 acres) or more, can you imagine moving hundreds if not 1,000´s of drip pipes every time you want to water?¿??¿¿? One way or the other, dont even contemplate using drip feeds. I am amazed at how many times I have had to explain this point to people. Their argument is that it saves water, my answer back is that you will ruin your black truffle farm. As some wise man said " You can teach Einstein's theory of relativity to a monkey for 20 yrs but in the end, its still a monkey ". I know people will argue about using drip feed to water your trees but here in Spain its considered a practice to avoid.
Same as drip feeds - Avoid!!!!!! Flooding your olive grove, almond trees, citric trees, etc., was a common practice here in Spain. If I´m not mistaken, it is no longer permitted as it isnt a efficient way to irrigate your land and it is a waste of water. It basically consisted of letting water flood your land and let the water seep into the ground. It's a good way to drown your mycelium (truffle spore) and ruin your black truffle farm, so dont do it.
Avoid at all costs any water tank that has previously held bleach, chlorine or any chemical along that line. Does not matter how well you have cleaned it. These chemicals kill bacteria and that is exactly what a truffle spore is. Almost all regions of the world have chlorinated drinking water. So if you will be using tap water to water your trees, it might be a good idea to let the water stand some days before using to let any chemicals evaporate. Try this test at home - Take a glass of tap water and let it stand for a day or 2. Then drink it. You can taste the difference for the better once all the garbage that was added has evaporated. Some people argue this reasoning but it doesnt hurt to be safe. You can also add a aerator to the water tank to help break down any chemicals. When planning for the water irrigation tank, try to place it at the highest point on your land. Even thou you cant / shouldn't use drip feeds to water the trees, you might have enough gravity pressure to get by without a pump. See above - Drip Feeds for more about why you cant use drip feeds.
Be it your own well water, from an irrigation canal or collected rain water ( not practical but certainly possible ), it isnt a bad a idea to have your water analyzed every so often. You want to know the mineral content and quality of the water that you are feeding your trees. High iron content plays havoc with sprinkler systems and metal tubing. I am located roughly 250 kms from the Atlantic ocean and about 200 kms from the Mediterranean sea, but the town I live in has a natural salt water spring on the out skirts of town. Many moons ago, this area of Spain was sea bed. This salt water is great for using as a weed killer but I take care where I apply it. I do not use it anywhere near any of my trees but there are many other areas that I apply it on 4 ha (12 acres). Digging a well can be expensive initially but it has been proven to be very cost effective, a good investment and will improve your annual black truffle yield. How often and how much water to use when irrigating your black truffle farm is still open to hot debates. So erring on the side of caution is recommended here.