Irrigation text only - Sustainable Market Farming
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1. 70 cm lengths through the flat side wide enough to easily fit your rebar axle Screw the 12 30 cm pieces between the long pieces about 5 12 7 cm in from the ends of the long pieces Screw the other pieces across the shuttle offset from each other a little above and below the axle holes These cross braces strengthen the shuttles and give a handy place to tuck the starting end of the drip tape We found it convenient to cut several boxes full of shuttle parts when the lumber became available and then make the shuttles later when time allowed One shuttle this size can hold 400 122 m of tape maybe more We generally wrap two lengths at once onto one shuttle Using Shuttles To wind used drip tape from the field first open the ends of the drip tape and flush water through to clear sediment If this can be done the day before winding it makes the job drier and easier Then line up your cart with a shuttle on the axle between two runs of drip tape at the top of the field Disconnect the drip tape from the supply pipe and tug at the end of the tape nearest the cart Sometimes it will just pull through any accumulated crop debris and weeds sometimes it won t If it won t walk back down the line tugging the tape and free it from what is snagging it If you have two people to work on each shuttle two lines can be wrapped at once Tuck the starting ends of the drip tape around the shuttle and under one of the cross braces Then stea2. Irrigation Pam Dawling 2012 Providing sufficient water can make a lot of difference to the vigor and productivity of crops In most cases the times to prioritize watering are when the seeds or transplants first go in the ground and when the plant is producing the part that will be eaten Overhead rotating sprinklers are cheaper to buy and easier to understand than drip irrigation and in some circumstances they do a better job for instance when you need to water in a broadcast cover crop or closely drilled rows Commercial growers often use some drip irrigation as it greatly reduces the amount of water used and waters only the crop not the weeds between the rows Overhead Sprinklers We have seven mobile overhead sprinklers in our vegetable plots and when we need to water we run three at a time overnight Having more sprinklers than we are going to use at once means we don t have to move them and their hoses far usually just up and down in one plot We water at night as it reduces evaporation losses and also makes it more convenient for working during daylight hours We run three at once because this is the highest number we have enough water pressure for and it keeps the well pump running full time at 15 gallons per minute 57 liters min If a pump has to cycle on and off while water is running it will wear out sooner and pulling and replacing a pump in a deep well is not the easiest job Running too many sprinklers at once will m
3. dily turn the shuttle end over end wrapping the tape around the shuttle If the field has any slope at all it will be drier work if you are at the high end of the field and the drip tape is draining as you wrap it If you re rolling two lengths at once obviously the two people will need to co operate and stop if one length gets snagged up When you get to the final end of the drip tape check that the length is marked on the tape and tuck the loose end under a couple of rounds of wrapped tape We also write the contents of the shuttle on the side with a permanent marker eg 2 150 We store our shuttles of drip tape in a barn tied by rope through the axle holes and the rope thrown over a beam as if storing food safe from bears when backpacking Another shuttle balances the weight of the first This keeps the drip tape fairly inaccessible to mice To reuse the drip tape next season use the cart and the rebar axle again Unrolling is much quicker than winding up especially if you have two lengths of drip tape on one shuttle Two shuttles can be put on one axle side by side and two people can walk out with two runs of drip tape each one in each hand Uses for Old Drip Tape There are several ways you can use old drip tape rather than search for a recycler The longer pieces can be kept for repairs Short pieces can be cut to use as end caps or you can make dead ends to close unneeded connectors in a supply pipe used in previou
4. ean they stop going round at some point and make an eroded washed out area I m an advocate for buying good quality sprinkler heads to reduce problems I notice each spring when I test the sprinklers before setting them out in the fields that the Rainbirds and Nelson sprinklers start right up while the economy models have to be coaxed into performing Sprinkler heads can be attached to tripods made at home from rebar with a bit of welding or adjustable tripods can be bought Each of our tripods has a toothbrush attached to it with a length of thin wire This basic toolkit is often enough for cleaning the filter washer in the inlet or clearing a dead spider from the jet If you are going to irrigate at night you will also need a light a headlamp with LED bulbs works well as long as the batteries are well charged LED flashlights seem to fade fast when batteries are failing If we are going to rotate around an area repeatedly such as our raised beds where we grow a variety of crops very intensively we use stake flags to mark the sprinkler spots For our system watering from 10pm to 7am provides about 34 2 cm of water Test with a rain gauge or tuna can That s 5500 gallons 20819 liters for 3 sprinklers By contrast three drip zones for 2 hours use less than half this amount of water and water perhaps 3 times the area of crops because the water is focused on the crop rows not the whole area Drip Irrigation Drip irrigation
5. er spaced emitters Agricultural Plastics We have been hesitant to embrace the use of agricultural plastics because of decreasing world stocks of oil increasing air pollution climate change and problems of how to dispose of plastics responsibly But sometimes plastics are so useful they re irresistible So our policy is to use plastics if they offer a significant advantage and then make them last as long as possible find uses for the scrap plastics where possible and find somewhere to recycle the final mess Drip tape is a good example drip irrigation reduces water use and decreases foliar diseases compared with overhead irrigation Because only the rows of crops are watered and there are no losses to evaporation it enables larger areas to be irrigated well with a given amount of water which is increasingly important as droughts become more common For widely spaced rows drip tape offers the advantage of not watering weeds in between the crop rows We buy the thickest drip tape 15mil so that it will last as long as possible 4 or 5 years We try our utmost not to mow or till it We attach the ends to stake flags with string so we know where they are We add a little extra length to each new run of drip tape to compensate for future shortening when the tape springs a leak and needs to be spliced We make a practice of writing the approximate length on each end of each piece of drip tape A China Marker Grease Pencil in yellow white o
6. ion of Biological Farmers field day we saw a shuttle system with an A frame shuttle holder developed by Marlin Burkholder Marlin s system of raising beds laying drip tape and plastic mulch is tractor based I got together later with another grower at the field day to modify the system for use without tractors Making Shuttles Our shuttles rotate on lengths of rebar resting on the top of a garden cart The rebar is held in place on each side of the cart by two large spring clamps from the woodshop like giant clothes pins Visegrips would work if you have enough Or you could make permanent wood or metal additions to the sides of your cart to hold the rebar We have 6 carts and they stray a lot so we could never be sure of finding the cart with the axle set up so it s easier for us to find 4 spring clamps each time We use scrap white oak stretcher bars from our hammocks business to make shuttles The dimensions are 1 25 x0 75 3x2 cm but anything similar would work We have the larger style of garden cart Carts Vermont and Johnny s have them We found that a 28 70 cm height of shuttle was the tallest workable For a smaller cart make 24 60 cm shuttles Here s a parts list for one large shuttle 1 25 3 cm x 0 75 2 cm lumber 2 pieces 28 70 cm long 2 pieces 13 5 8 34 5 cm long 2 pieces 12 30 cm long 16 screws approximately 1 5 3 8 cm long Drill a hole in the center of each of the 28
7. m or 1980 537 m 12 more than calculations suggest If the drip tape is old full of repairs or leaky you won t be able to run so much at once If there are no other draws on our 15 gpm 56 7 Ipm well at the same time we could run 2 zones at once There is an easy to use calculator on the Dripworks website You provide figures for the water available in gph the total length of feet of driptape you want to run and the type of drip tape you will be using The calculator tells you how many zones you need to divide the area into or whether it can all be one zone When in use the drip tape will look round and taut It is also useful to calculate how long to irrigate to achieve 1 2 5 cm depth of water We usually run ours twice a week for 2 hours each time We test the soil by digging down in between emitters or between rows of tape depending on the crop Most of the calculations P ve seen suggest that every spot of the soil needs to be watered but with widely spaced crops I do not think this is the case so I prefer to dig and look rather than calculate The type of soil you have will determine how close together to put the rows of drip tape and the emitter spacing to choose Low flow drip tape enables you to run longer individual lengths Closer spaced emitters are more important for sandy soils where the water seeps down rather than sideways but the maximum tape length and the amount you can run at once will be shorter than with wid
8. ow flow tape with 8 20 cm spaced emitters which according to the suppliers has a maximum single length of 460 140 m on flat ground 700 213 m downhill if uninterrupted by fittings that reduce the flow Using the barbed LSB connector it s 380 116 m Design your sub systems so the run lengths don t exceed the maximum for the tape you re using To calculate the total length of drip tape you can run at one time you need to know the rate at which your tape emits water and the output per minute of your water supply Our tape at 8 psi 0 55 bar can provide 20 4 gallons per hour 100 or 0 34 gallons per minute 100 254 liters per hour 100 m 4 23 liters per minute 100 m Our calculation We measured 7 5 gpm 28 4 lpm at the hydrant 450 gph 1704 Iph by running the water into a bucket while we timed it Calculating at 80 efficiency to allow for friction losses we can get 360 gph 1363 Iph Divide by the 20 4 gph 100 the tape can provide 1764 1363 Iph divided by 254 Iph 100 m 537 m This is the maximum total length of tape in one zone on our system running at one time from one faucet In terms of well pump life it is better to run a bit more than calculations suggest rather than less We run this 1764 537 m as 10 lengths of 180 54 8 m the width of our West garden or 7 lengths of 265 80 7 m our East Garden In practice we still get acceptable results with 11 x 180 54 8
9. r orange works well This simplifies re use and minimizes the frustration of setting out a piece too short We learned the hard way to always keep a big supply of splicing connectors and several rolls of sticky PVC electrical tape for repairs We learned to do electrical tape repairs on small holes while the water is running This causes the electrical tape to conform better to the in use shape of the drip tape and leak less Wrapping diagonally up and down over the hole a few times will give a good repair Yellow electrical tape is more visible than black which can be an advantage At some point with old drip tape the cost of connectors making repairs in a length becomes more expensive than replacing that run and salvaging the connectors In terms of cash simple mathematics provides the answer But many of us just hate throwing plastics away and so we do less than or more than rational decision making on this For most people the throw away point seems to be around 2 connectors per 100 200 30 60 m We haven t developed a firm rule for ourselves on this yet Drip Tape Storage At the end of the season some growers pull the drip tape to the side of the field and leave it there Others ball it up stuff it into bags and store it that way We want to get the most use out of ours minimize the damage from mice and voles which we have lots of over the winter and make it easy to set out the tape again the next year At a Virginia Associat
10. s years Rather than remove the connectors and use goof plugs to fill the holes leave the connectors and attach 6 15 cm capped off pieces of drip tape The pipe will stay in better shape goof plugs can be hard to remove and the dead ends are easy to find the following season when they may be in just the right place for that season s drip tape runs I ve taken to writing on the supply piping too with a China Marker the length and the distribution of drip tape connectors I ve often wished for quick connectors as are available for hoses so I could quickly switch different pieces of supply piping So far they don t exist do tell me if you find some The main use for old drip tape is as batten tape for fastening plastic sheeting to wood for hoophouses and cold frames It s more weather resistant than bicycle inner tubes and cheaper than the real batten tape sold by greenhouse suppliers If you don t need it maybe another grower does Try advertising on Freecycle or asking at your local farmers get togethers Resources Roberts irrigation products Ro Drip User Manual www trickl eez com rodrip pdf Aquatraxx Drip Irrigation calculator dripirrigation org Calculator Calculator html Dripworks calculator www dripworksusa com ttape 2 php Ink left Penn State Drip irrigation for Vegetable Production agalternatives aers psu edu Publications DripIrrigation pdf
11. uses plastic tubing with emitters at fixed spacings and a reduced pressure water supply to slowly provide water for a row of plants The water seeps into the soil so very little is lost to evaporation even if plants are watered in the middle of the day If you are new to drip irrigation consult the catalogs and websites of the suppliers and try a pilot scheme for one season Our pilot scheme was our 3 long rows of paste tomatoes and 2 of sweet peppers partly because we wanted to reduce foliar diseases which are often spread by water droplets These crops have long seasons so once the system was in place in May we could leave it until November Our pilot scheme convinced us to use more drip irrigation Now we have about 10 or 12 sub systems in place each year A sub system is a set of runs of drip tape operating from a single faucet along with its timer pressure reducer and 200 mesh screen filter and the header pipe the drip tape runs are attached to The first item off the hydrant the timer has its own conical filter washer Once a month we clean both the filter washer and the screen filter with a toothbrush The screen filter can also be backwashed for a quick clean If you are using surface water from a river or pond you will need a sand filter first to remove coarse particles Each type of drip tape has a maximum functional row length depending on the spacing of the emitters and whether it is made for low or high flow rates We use l
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