Soil Moisture Requirements for Germination of Sorghum, Millet, Tomato, and Celosia1

Abstract

AbstractIn most tropical countries, tomatoes (Lycopersicon esculentum Mill.) are first started in nursery flats and transplanted to the field 4 to 6 weeks later to ensure good establishment. Seed of Celosia argentea (Amaranthaceae L.) usually fail to germinate under the slightest droughty condition. While sorghum (Sorghum vulgare L.) seeds germinate well in arid zones, field establishment and seedling growth are poor under very low soil moisture condition. It is suspected that if adequate soil moisture is maintained, good emergence and field establishment are possible by direct seeding of these crops into well‐prepared seed beds. A greenhouse study was carried out to investigate the optimum soil moisture required for the germination of these crop seeds. Two temperatures, 25 to 28 and 34 C and four moisture regimes, 25, 50, 75, and 100% of field capacity were used. The soil was a sandy loam belonding to Iwo series, derived from coarse‐grained granites, gnesses, and pegmatites.A 2 ✕ 4 ✕ 4 factorial arrangement in a randomized, complete‐block design was employed. Germination and early seedling growth of tomatoes were best at soil moisture between 50 and 75% of field capacity while Celosia seeds germinated best at 75% soil moisture regime. The optimum moisture requirement for the germination of sorghum and millet (Pennisetum americanum L.) ranged between 25 and 50% of field capacity. Celosia seeds seemed to have a narrower soil moisture tolerance than tomato, while tomato seeds seemed to be more temperature sensitive than Celosia. Both sorghum and millet seed germination were adversely affected by soil moisture in excess of 50% of field capacity, but were less temperatures sensitive than tomato. The observation that sorghum and millet performed well at low soil moisture regime partly explains their ability to survive in dry ecological zones. The moisture requirements of Celosia and tomato seeds suggest supplementation of natural precipitation with irrigation to maintain the required soil moisture for best seedling emergence and growth.