Nitrogen and Water Use Efficiency of Zucchini Squash for a Plastic Mulch Bed System on a Sandy Soil

Abstract.
Zucchini squash (Cucurbita pepo L.) is an economically important vegetable crop in Florida.  Typically, it is intensively managed with 
high inputs of fertiliser and irrigation water. Our objectives were to evaluate the interaction between fertilisation rates and
irrigation treatments, and to quantify nitrate leaching in a plastic mulched/drip irrigated zucchini squash production systems. Three 
studies were carried out. The first study evaluated different depth placement of drip and fertigation lines on plant growth and fruit yield. 
Treatments included SUR (both irrigation and fertigation drip lines placed on the surface); S&S (both lines buried 0.15 m deep); and 
SDI (irrigation line placed 0.15 m below the fertigation line on the surface). The second and third studies compared three different 
N-rates and different soil moisture sensor-based irrigation strategies. Nitrate-N leaching was monitored by zero tension drainage 
lysimeters and soil samples. N leaching increased when irrigation and N-rates increased, with values ranging from 2 to 45 kg ha-1 of N. 
Use of SDI increased yields by 16% compared to the S&S treatment, and reduced nitrate leaching by 93% while increasing the water 
use efficiency by 75% compared to a fixed 2-hour irrigation event per day treatment. Application of N above the standard recommended 
rate of 145 kg ha-1 did not increase yield, although yields were reduced at the lowest N-rate. The use of soil moisture sensors for automatic
 irrigation control reduced irrigation application and minimized nitrogen leaching. In addition, combining the soil moisture controlled SDI
 system that had surface applied fertigation resulted in similar or higher yields, while reducing both water use and potential N leaching 
because of improved nutrient retention in the root zone. 

Zotarelli, L., M.D. Dukes, J.M. Scholberg, T. Hanselman, K. Le Femminella, and R. Munoz-Carpena. 2008. Nitrogen and water use efficiency
of zucchini squash for a plastic mulch bed system on a sandy soil. Scientia Horticulturae 116:8-16.

This page is maintained by Lincoln Zotarelli. Please e-mail lzota@ufl.edu with any questions or comments pertaining to this site. This site was last updated on December, 2008.