The effect of compost and combination of compost and biochar application in soil bulk density of planting bed, seedling emergence rate and early growth of saffron ecotypes

Emergence of saffron buds is sensitive to soil compaction and structure. Soil bulk density is introduced as the most important index of soil physical quality. Accordingly, this study was done to evaluate the effect of compost and compost-biochar in planting bed on the emergence and early seedling growth of saffron ecotypes and its relationship to soil bulk density. Experimental treatments consisted of planting beds (without any organic amendment (control), incorporation of 20 t.ha-1 compost and 10 t.ha-1 compost 8 t.ha-1 biochar (cellulosic material of hardwood)) and different ecotypes of saffron (Bajestan, Estahban, Ferdows, Gonabad, Natanz, Qaen, Sarayan, Torbate-Heydarieh and Zarand). Data obtained from experiment were subjected to combined analysis of variance among planting beds based on randomized complete block design. The results showed that application of compost and compost渪ᲅ, improved emergence of the main and lateral buds as well as leaf growth parameters compared to the control. Zarand, Torbate-Heydarieh and Estahban ecotypes responded differently to the planting bed types in terms of emergence percent and rate of main bud compared to other ecotypes. Considerable variation was observed among the ecotypes in terms of all studied parameters, which indicated the adaptability of ecotypes to climatic conditions of corm provenance. Generally, the Bajestan, Ferdows and Qaen ecotypes showed superiority in terms of leaf area and dry weight. Compost and compost-biochar significantly (12%) reduced the soil bulk density compared to the control. Linear regression analysis indicated that there was a negative relationship between soil bulk density and the studied parameters, and significant decrease in all parameters was observed with increasing of soil bulk density.