Biology

is amazing. The reason I'm posting about it is that I think it might interest you if you are into sustainable agriculture. Depending on how would you define sustainable agriculture. I agree with the definition in my biology book: farming methods that are "conservation-minded, environmentally safe, and profitable" I would also add local to this because it takes into account the fossil fuels consumed in transport of goods.

This chapter was on plant nutrition. The essential elements that plants require and how environmental factors effect them. Did you know that a deluge of rain is more likely to wash away negatively charged ions (e.g. sulfate ions) than positively charged ones? This is because they are bound less tightly to the slightly negative soil particles and likes repel like. This also means that positively charged ions are more complicated for plants to get. They have to release hydrogen ions (also positively charged) to replace and release the many bound ions they need for nutrition (including calcium, potassium, and magnesium.) Acid rain has the same effect of putting hydrogen ions in the soil and will deplete the soil of positively charged ions as well as negative ones that normal rains affect.

If a plant is deficient for a mineral chances are it is nitrogen. Various plants get it in different ways but one thing that amazed me was the system that legumes have developed. You know when you put that black stuff on peas before planting them? I had never realized but what you are doing there is rolling the seed in bacteria so that it will be infected from the get-go. This bacteria is called Rhizobium and it is the reason that legumes are often known as "nitrogen fixers" (meaning that they take atmospheric nitrogen and make it available in the soil.) The legumes have nothing to do with the fixing. It is the nodules on their roots that are formed by and contain a strain of nitrogen-fixing bacteria that do this. This symbiotic relationship gives the plant nitrogen and the bacteria organic nutrients that the plant synthesizes during photosynthesis. The infection takes place after a longish molecular "conversation" between the two organisms which leads scientists to hope that, with greater understanding of the process they could "learn how to induce Rhizobium uptake ... in crop plants that do not normally form such nitrogen fixing symbiotic relationships" which would lead to less need for fertilizer.

This leads me to another question. If this sort of genetic engineering/modification could cause a significant increase in plant productivity without a need for expensive harsh chemicals would it be worthwhile? Or does it so go against all natural/sustainable farming principles as to be ridiculous? I don't know the answer. Plants like these and "smart plants" that enable a farmer to tell when there is beginning to be a mineral deficiency in his field before damage from it has occurred could save unnecessary fertilization....

Anyway... those are my thoughts for the day.... I will try to post more regularly henceforth but it is end of semester test time so... forgive me.
M.