By Sjoerd Willem Duiker
August is a great time to establish alfalfa or alfalfa/grass mix with no-till practices into small grain stubble.
According to the forage chapter of the Agronomy Guide, you need to establish alfalfa at least 8 weeks before the incidence of first killing frost, which is late October in southern, mid-October in central, and late September in northern PA or high altitudes. By using no-till you can dramatically reduce soil erosion, save moisture, build soil health, and reduce expenses. For success, make sure there are no swaths of heavy chaff that would compromise seed-to-soil contact and make sure all weeds are killed. Use gramoxone or glyphosate to kill established and emerging weeds. However, it may not be necessary to apply herbicide if your field is clean, so check before you spray.
Any no-till drill can work as long as the seed can be placed within ¼ to ½ inch deep. The greatest threat is to place the seed too deep! Seeding depth is more critical than seeding rate. So the equipment needs to be able to place the seed at the right depth and uniform spacing across all units, and press the seed into the soil gently so it is covered and has good seed-to-soil contact. Make sure the drill is well-maintained. Drill units should be tight and not wobbly – check bearings and parallel linkages. Make sure all units are in the same plane. Coulters, if present, need to cut through residue. The coulters should not run deeper than the planting depth to avoid dropping seeds too deep. Double disk or single disk openers are the most common for no-till alfalfa seeding. Shoe types can also be used but tend to handle residue less well, do more soil disturbance and can easily place the seed too deep. Make sure the double disk openers are not worn too much and have the right point of contact (check by placing two business cards between the disks to the point of contact – there should be something like an inch between them depending on the drill type). The depth gauge wheel is often also the press wheel. It is very critical to set it to the right depth. There are also often ‘dough-nut' shaped washers controlling seeding depth on the hydraulic cylinders. Play with the number of doughnuts and the settings on the press wheel to come to the right depth. Two-inch wide closing wheels seem to work best – they cover the seed firmly while still controlling depth well. Narrower wheels lose to ability to control depth well, while wider wheels do a poor job closing the seed slot.
To determine seeding rate, use the seed charts on the drill as a first approximation or do your own calibration. You should also keep track on the acres planted and quantity of seed used to check actual seeding rate. It is easy to use too much seed and then you are just wasting money! After planting, continue to monitor the stand and address any issues. Guidance is available in the Penn State Agronomy Guide for weed and pest control. After about 5 weeks the alfalfa should be 3-5 inches tall.
Source : psu.edu