The Combined Effect of Substrate Composition and Irrigation Amount on Growth and Water Consumption of Zucchini Seedlings

Abstract

【Objective】 Selecting a right substrate composition is of paramount importance for facility agriculture. This paper is to determine the optimal nursery substrate composition and irrigation amount for the cultivation of zucchini seedlings. 【Method】 Using Nongyuan NO.1 zucchini as the model plant, we compared four nursery substrate ratio: peat: perlite (3∶1, CK), peat: vermiculite: perlite (3∶1∶1, T1), peat: vermiculite (2∶1, T2), and peat: vermiculite: perlite: coconut bran (2∶1∶1, T3). The bulk density and porosity of T2 and T3 were 0.22 g/cm3 and 53.29%, and 0.34 g/cm3 and 56.93%, respectively. For each substrate, there were three irrigation treatments by setting the irrigation amount at 100% (I1), 75% (I1), and 50% (I2) of the evaporation capacity (ET). We evaluated the combined effect of substrate and irrigation amount on growth, water consumption and water use efficiency of the seedlings. 【Result】 Among the three substrates, the physical and chemical properties of T2 were the best for the zucchini seedling. Its combination with irrigation I2 gave the largest stem diameter, which was 12.40% to 26.98% greater compared to other substrates under the same irrigation amount. The vigor of the seedlings under irrigation I2 and I3 was significantly greater than that under I1. The combination of T3+I3 increased water use efficiency by 11.87% to 45.97%, respectively, compared to other two substrates under the same irrigation amount. The total water consumption per seedling increased with the increase in irrigation amount and decreased with the increase in substrate bulk density. 【Conclusion】 The experimental results show that the optimal substrate and irrigation for the growth of zucchini seedlings is bulk density between 0.22 g/cm3 and 0.34 g/cm3 and porosity between 53% and 56%. These, combined with the irrigation I2, can enhance seedling quality and improve its water use efficiency.

Keywords

• irrigation amount
• substrate ratio
• seedling water consumption
• growth index
• water use efficiency