Growth, yield and mineral content of basil and cultivated rocket due to plant density and nitrogen level

ABSTRACT

There is limited information on how plant density and nitrogen (N) application rate for basil (Ocimum basilicum L.) and cultivated rocket [Diplotaxis tenuifolia (L.) DC.] affect crop growth, and yield and quality. A field trial was conducted to assess effects of plant density, N application rate, and their interaction, on growth and yield of basil and cultivated rocket during 2016 and 2017 growing seasons. The N levels (60, 90, 120, 150 or 180 kg ha⁻¹) and plant densities for basil at 40000, 62500 and 93750 plants ha⁻¹, and plant densities for rocket at 40000, 80000 or 133333 plants ha⁻¹ were used. Leaf chlorophyll content of basil was improved by application of N at 120 kg ha⁻¹ while that of rocket was improved at 120–180 kg ha⁻¹ N. Leaf yield of basil and rocket was not improved with N application at 60–180 kg ha⁻¹. Fresh leaf mass and area increased with increased plant density for both crops, with higher yield in 2016 than 2017. Potassium leaf content of basil was highest at 150 kg∙ha⁻¹ of N and plant density of 40000 plants ha⁻¹. Plant density at 40000 plants ha⁻¹ for rocket produced high K leaf content at 120 kg∙ha⁻¹ of N. Leaf N, Ca and Mg contents for basil were improved at 62500 or 93750 plants ha⁻¹. Application of 60 kg ha⁻¹ N at 93750 plants ha⁻¹ for basil, and 60 kg∙ha⁻¹ of N at 133333 plants ha⁻¹ for rocket were suitable for improved leaf yield. Increasing plant density and providing a reasonable amount of N could be useful to obtain high marketable leaf yield along with efficient N management to reduce environmental cost of production.

KEYWORDS:

• Diplotaxis tenuifolia
• Ocimum basilicum
• leaf chlorophyll content
• mineral nutrition
• yield