The growth chamber soil has still been giving me problems. On monday, the leaves were curling and I had pock marks on the leaves. I think it was likely Oedema, where there is too much water. Combined with this the air exchanger in the lab had broken so humidity was slightly higher than normal 60%-70% instead of 50%.
I fixed the air exchanger and held off on watering for 2 days until the water tension went up to 30kPa. Most of the leaves recovered, and I got some of the first fruit buds forming. I think I had been over watering, which may also have been the problem with the nutrient deficiency. Too much water means not enough root development. After all this I found a guide to hydroponic irrigation timing for commercial tomatoes and they generally use the EC (electrical conductivity) of the nutrient run off to guide timing. They also allow for a drying down at night to promote root development. Unwittingly, I may have done the right thing by withholding water as often high EC and dry conditions are used to push the plants into a generative fruit producing state in plants about the size mine are currently.
Ultimately though, soil is bad choice for validation as the correct water tension at each stage is another unknown variable. I’ll run the current experiment until I get some ripe fruit and compare to B H E Vanthoor’s model, but I doubt the yield will be as high as the model given all the non-optimal fertilizer and watering issues. For the next experiment I’ll change to hydroponic substrate, even if that’s not the end goal and also allow for each plant to be removed from the growth chamber individually for bettering scanning.
I worked on implementing Vanthoor’s tomato yield model in Modelica. The greenhouses-Library for Modelica had already done this but… That model would not compile. I fixed it so it would compile and it always gave zero yield. So I started fresh and wrote my own implementation, dividing the plant into sections and testing the leaves, stem, buffer, etc individually. I found the error, there was a typo in Vanthoor’s manuscript. It was correct in the paper he cited though, so I got that part working. I still need to put in the details for fruit development, but I should have it working by next week.
Sun Aquasystems 