Last summer we had a really tough time with the rice. Transplants being eaten, unfinished irrigation and lack of nutrients lead to a crop failure. During the summer we were able to help control the chipmunks and laid out our irrigation lines so those two problems should be taken care of for next year. The next challenge was the soil.
When we built our rice paddies we removed the topsoil and had to dig down into subsoil. Because of our budget we were limited in the amount of material we could move, so we were not able to spread it back onto the new built paddies. Our hope was that through the nutrients in the pond water as well as some supplemental compost and manure from the animals we would be able to get a decent yield. This turned out to not be the case. We were not able to supply all the nutrients that were needed and the plants suffered for it.
To get our soils back on track we new we had to do some supplementation from outside sources. Once we had a good base line of nutrients we could work with the system to eliminate the need for outside inputs. But how would we know what we would need to add? Thats where the lab at Umaine came in. I collected soil samples from two paddies and sent them off. 2 weeks later we had the results and started making a plan.
The Umaine test is nice for visual folks because they give you a nice graph that shows what your levels are compared to what you would want for the given crop you are growing. The first item on the chart is soil pH. This one blew us away. We thought we were way off given what had been growing on the site before we made the paddies. It turns out we are exactly were we wanted to be. Meadow’s father thinks that there is a marble vein that may interact with our spring aquifer. This would lead to the nice pH and the high calcium levels you can see on the chart.
Organic matter(OM) is a real problem as you can see. 1% is far to low especially for our rice paddies. This we expected since we had gone down into the subsoil. All sorts of things happen as you increase your OM. The biggest noticable change is the soils ability to hold water. There is more than a hundred percent increase in water holding potential from increasing OM from 1% to 2%. The increase diminishes as you get to higher percentages but it is still well worth it. Nutrient retention, soil and plant health are the other two major benefits from higher OM levels.
We will be employing two strategies for increases the OM levels of the soil. One is adding compost to the paddies on a yearly basis. Compost is very high in OM and by integrating it into the soil every year we will be increasing our nutrients and OM. The second strategy is cover cropping and grazing. Our plan for the next few years is to have two paddies out of rice and into a oats clover mix and a sudangrass/sorgum clover mix. The cover crops will increase our OM by shedding there roots during the growing season and then by their top growth die back in the winter. During the summer we also will be running our animals through the cover cropped paddies to graze and to spread their manure. Adding nutrients and increasing OM again.
After organic matter, phosphorus was the next problem child on the list. We were wondering why our azolla(the water fern we were trying to grow for nitrogen fixation) was doing so poorly. Its limiting nutrient is phosphorus. It loves the stuff and with out it, the fern just sits there. The chart says we are at 1.4 pounds per acre. Ideally that number would be between 20 and 40. We’ve got some major catching up to do. The cover crop and grazing will help a great deal but since that is only happening in two paddies we needed to add some phosphorus in the other 5 paddies. Some will come from compost, a the rest will come from Bone Char. It is an organically certified form of phosphorus that is a mix between quick and slow release. The recommendation on the test result is for 40lbs of blood meal per 1000 sqft. The smaller number of 4.9 lb is how much phosphorus is needed for the 1000 sqft. That means in 40 lbs of Bone meal there is 4.9 lbs of phosphorus available. I made up a spread sheet that calculates how much each paddy would need based on that recommendation and then we were able to figure out how much we had to order. About a thousand pounds to do every paddy.
We were also low in Potassium(K) but we will be able to take care of that with the alfalfa meal we get for the nitrogen.
The nitrogen recommendation was 50 lbs of alfalfa meal per 1000 sqft. For other crops the recommendation was 100lbs. When growing a small grain you have to be careful with how much nitrogen you have in the soil. To much N leads to tall weak growth that can make the plants susceptible to lodging(plants falling over due to wind or heavy rains). The nice thing about alfalfa meal is that is also contains Potassium and with the amount we need for the N we more then cover our K needs. Thanks to my handy spreadsheet we found that we will need 1600 pounds of alfalfa meal to do the job.
That does the major nutrients and the major problems we faced this year. The micro-nutrients will be helped with compost and a few foliar sprays we will apply throughout the summer. Without the soil test we would be blindly guessing what we needed to do to improve the soil. Because we had it done we can make smart choices on amendments and how we can change our rotations to better suite what our soil needs. The soil test from Umaine is $25 dollars and is well worth it.