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How much nitrogen is there in moringa stem versus leaf tissue?


ECHO South Africa research update

In one of our field experiments in South Africa, we are looking at the production of moringa leaf powder in an alley cropping system with legumes grown at the base of the moringa trees. So far, we’ve been able to get two cuttings of leaves each year. Each time we harvest the leaves, we also prune the moringa trees back to a height of 1 meter. Pruning results in branches being cut, which we chop into short pieces and leave on the ground as mulch.

We were curious to find out how much nitrogen that woody stem biomass contains in comparison to moringa leaves. So, we dried and ground some moringa stem tissue and sent the resulting powder off to a lab for tissue analysis. We found that moringa stem/branch tissue contained 1.7% nitrogen. As expected, this was quite a bit lower than the 4.8% found in the leaf tissue. However, it compared quite well to the 1.2% nitrogen in our chicken manure. While plant mulch would not provide the cation exchange capacity (for purposes of retaining nutrients and preventing leaching losses) that manure does, it is helpful to know that even the moringa stem residues can contirbute to soil fertility when left on the soil. Interestingly, potassium was more concentrated in moringa stem (3.1%) than leaf (1.9%) tissue.