Interaction of Organic Fertilizer and Irrigation Levels on Some Morphological and Physiological Indicators of Mentha piperita L.

Peppermint is one of the medicinal and aromatic herbs that has many medicinal, nutritional, cosmetic and hygienic uses. One of its prominent properties is its antimicrobial properties. In order to evaluate the effect of organic fertilizer and different levels of irrigation on the growth stages of peppermint, a greenhouse experiment was conducted in a greenhouse research environment in Ferdowsi University of Mashhad in spring 1977 in a two-factorial completely randomized design with 3 replications. Peppermint pepper was done. Experimental treatments included irrigation treatments at 4 levels (50, 75, 100 and 120% of plant water requirement) and 4 levels of organic fertilizer (cow manure at 2 levels (5 and 10 t ha-1) and poultry manure at 2 levels (20 and 70 G / l) that were used at different stages of pepper plant growth. The results showed that the interaction of irrigation and fertilizer levels on morphological characteristics of peppermint such as plant height and stem diameter were not significant on leaf fresh weight, root fresh weight and root dry weight (at 0.01 level). It was very meaningful. It can be concluded that the highest amount of irrigation and cow and poultry manure increased leaf fresh weight and organic fertilizer had no effect on fresh and dry root weight. Interaction of irrigation and fertilizer levels on physiological characteristics of peppermint such as stomatal conductance, leaf relative water content and electrolyte leakage were not significant and were highly significant at chlorophyll a, chlorophyll b and total chlorophyll at 0.01 level. The lowest irrigation and the highest amount of poultry manure increased chlorophyll a and the lowest irrigation and the lowest amount of organic fertilizer increased chlorophyll b and total chlorophyll and was significant at 0.05 level of leaf chlorophyll index (chlorophyll spd index). The lowest amount of irrigation and the highest amount of organic fertilizer increased leaf chlorophyll index. It can be concluded that peppermint was more sensitive to different levels of irrigation and fertilizer levels did not have a positive effect on peppermint yield and among organic fertilizers the effect of poultry manure was more than cow manure.