Phosphorus Rate in Combination with Cultural Practices Reduces Excessive Growth of Tomato Seedlings in the Float System

Abstract

<jats:p>Conventional tomato (<jats:italic>Lycopersicon esculentum</jats:italic> Mill.) seedling production can be labor intensive. The float system of production may be a less labor-intensive alternative. Float system technology is used extensively to produce tobacco seedlings, but is currently used very little for horticultural crop seedlings. Potential advantages of the float system include lowered production cost, more efficient use of water and nutrients, elimination of wetting of plant foliage thus reducing disease, and elimination of nutrient leaching to groundwater below the greenhouse. When grown in float culture using a tobacco nutritional regimen, tomato seedlings produced undesirably long stems. Greenhouse experiments were conducted to identify production practices that may limit this excessive growth. Practices evaluated included two fertilizers with either 2.2% or 0.87% P combined with brushing, clipping once, ethephon application, delay of fertilization for 10 days after seeding, brushing combined with delayed fertilization, and two levels of air movement. Greatest height control was obtained with a combination of practices. Most height control practices, except delayed fertilization (with nor without brushing), were more effective if combined with low P fertilizer. The combination of brushing with delayed fertilization using either fertilizer provided the best height control and the highest quality seedlings. Ethephon and brushing in combination with low P fertilizer were also effective. These experiments show that with use of height-limiting management techniques good quality tomato seedlings can be produced in the float system. The experiment did not address the field performance of the seedlings.</jats:p>

Fertilizer Composition, Concentration, and Irrigation Method Affect Growth and Development of Oxalis regnellii and O. triangularis

“…In both species, final plant height was significantly shorter for P-free fertilizer treatments. Phosphorus deficiency is known to reduce plant height (Hansen and Nielsen, 2001;Nelson et al, 2002;Rideout and Overstreet, 2003).…”

Field Growth and Yield of Tomato Transplants Grown in the Float System Using Low Phosphorus Fertilizer and Height Restricting Cultural Practices

“…Tomato transplants can be grown successfully in the fl oat system (Rideout and Overstreet, 2003;Wyatt, 1998). Excessive stem elongation, a potential problem both in fl oat and conventional culture, can be controlled by using a fertilizer with a low P content along with cultural practices such as delayed fertilizer application, brushing, clipping, or a single ethephon application (Rideout and Overstreet, 2003). However, it has not been determined what, if any, effect these practices have on posttransplant fi eld growth of tomato plants.…”

“…Low P fertilization in a fl oat system reduces the P concentration of the transplant tissues (Rideout and Overstreet, 2003). Nutrient solution P concentrations below 2 mg•L -1 in greenhouse production reduced root growth and early tomato yield in fi eld production (Liptay et al, 1992).…”

“…While fl oat-grown tomato seedlings produced higher early yields than conventional transplants, overall yields were not affected (Wyatt, 1998). Wyatt (1998) used water soluble 20N-8.8P-16.6K fertilizer, which provided much higher P rates than 15N-2.2P-12.5K or 15N-0.87P-16.6K fertilizers used by Rideout and Overstreet (2003). Given the potential benefi ts in control of stem height by lower P fertilization, along with other cultural practices, it seems prudent to test the fi eld performance of these seedlings.…”

“…This study was conducted to determine if production of tomato transplants in the fl oat system using the cultural systems proposed by Rideout and Overstreet (2003) has detrimental effects on fi eld performance. Specifi cally, the objectives of this study were to determine the effects of low P fertilization and height-restricting cultural practices in the fl oat system on: 1) post-transplant plant growth; 2) fruit yield; and 3) fruit size.…”