Water use efficiency, nutrient leaching, and growth in potted marigolds affected by coconut coir dust amended in substrate media

Abstract

Coconut coir dust amended in substrate had effects on water use and some growth in potted marigolds (Tagetes erecta ‘Antigua Yellow’). This study was performed to clarify the effect of coir dust amended in substrate media on water use efficiency and nutrient leaching in potted marigold. ‘Antigua Yellow’ seeds were sown in peat moss to develop 2 pairs of true leaf, then seedlings were randomly transplanted into 15 cm plastic pots containing soilless mix media (40% rice husk charcoal, 20% rice husk, 20% sand and 20% compost leaves; by volume) and followed by coconut coir dust amended treatments with 0, 25, 50 and 75% (v/v). The results exhibited that all amended coconut treatments could improve the physical properties of mix media by decreasing the estimated bulk density, but increased the total porosity (%) and water filled pore (%). Fifty percent coir dust treatment seems to reduce accumulated ET, crops evapotranspiration (ETc) and transpiration per leaf area unit per day. Hence, 50% coir dust portion gave the highest water use efficiency (WUE) and the lowest crop co-efficient (Kc) parameter. Nevertheless, 75% coir dust portion also reduced some nutrient leachate in the runoff solution; nitrate (NO3−) leachate at early growth stage and phosphate leachate (PO43−) at flowering and senescence. Positive correlation was observed between total leachate volume and total phosphate concentration leachate (R = 0.98). Almost all plant growth parameters had diverse responses during the comparison of each different coconut coir dust portion, but flowering yield (total FW and total number) were prone to be promoted by 75% coir dust treatment.