Use of Reduced Irrigation Operating Pressure in Irrigation Scheduling. I. Effect of Operating Pressure, Irrigation Rate, and Nitrogen Rate on Drip-irrigated Fresh-market Tomato Nutritional Status and Yields: Implications on Irrigation and Fertilization Management

Abstract

<jats:p>Increasing the length of irrigation time by reducing the operating pressure (OP) of drip irrigation systems may result in decreased deep percolation and may allow for reduced nitrogen (N) fertilizer application rates, thereby minimizing the environmental impact of tomato (<jats:italic>Solanum lycopersicum</jats:italic>) production. The objectives of this study were to determine the effects of irrigation OP (6 and 12 psi), N fertilizer rate (100%, 80%, and 60% of the recommended 200 lb/acre N), and irrigation rates [IRRs (100% and 75% of the target 1000–4000 gal/acre per day)] on fresh-market tomato plant nutritional status and yields. Nitrate (NO<jats:sub>3</jats:sub><jats:sup>−</jats:sup>)–N concentration in petiole sap of ‘Florida 47’ tomatoes grown in Spring 2008 and 2009 in a raised-bed plasticulture system was not significantly affected by treatments in both years and were within the sufficiency ranges at first-flower, 2-inch-diameter fruit, and first-harvest growth stages (420–1150, 450–770, and 260–450 mg·L<jats:sup>−1</jats:sup>, respectively). In 2008, marketable yields were greater at 6 psi than at 12 psi OP [753 vs. 598 25-lb cartons/acre (<jats:italic>P</jats:italic> &lt; 0.01)] with no significant difference among N rate treatments. But in 2009, marketable yields were greater at 12 psi [1703 vs. 1563 25-lb cartons/acre at 6 psi (<jats:italic>P</jats:italic> = 0.05)] and 100% N rate [1761 vs. 1586 25-lb cartons/acre at 60% N rate (<jats:italic>P</jats:italic> = 0.04)]. Irrigation rate did not have any significant effect (<jats:italic>P</jats:italic> = 0.59) on tomato marketable yields in either year with no interaction between IRR and N rate or OP treatments. Hence, growing tomatoes at 12 psi OP, 100% of recommended N rate, and 75% of recommended IRR provided the highest marketable yields with least inputs in a drip-irrigated plasticulture system. In addition, these results suggest that smaller amounts of irrigation water and fertilizers (75% and 60% of the recommended IRR and N rate, respectively) could be applied when using a reduced irrigation OP of 6 psi for the early part of the tomato crop season. In the later part of the season, as water demand increased, the standard OP of 12 psi could be used. Changing the irrigation OP offers the grower some flexibility to alter the flow rates to suit the water demands of various growth stages of the crop. Furthermore, it allows irrigation to be applied over an extended period of time, which could better meet the crop's needs for water throughout the day. Such an irrigation strategy could improve water and nutrient use efficiencies and reduce the risks of nutrient leaching. The results also suggest that OP (and flow rate) should be included in production recommendations for drip-irrigated tomato.</jats:p>

Yield, Water-, and Nitrogen-use Efficiency in Field-grown, Grafted Tomatoes

“…This is in line with results reported by Zotarelli et al (2009a) who in a three-year study did not find any significant difference in fruit yields of the same tomato cultivar Florida 47 in north Florida in response to three N rates (176, 220, and 330 kg · ha -1 ). With the same tomato cultivar (non-grafted) and experimental site as our study, Poh et al (2011) observed a difference in yields as a result of interannual environmental disparities. In one season, these authors obtained fruit yields of 44, 43, and 49 Mg · ha -1 at 134, 179, and 224 kg N/ha, respectively, with a significant difference between the highest N rate and the other two lower N rates, whereas such a trend was not found in the other season.…”

An Appraisal of Calcium Cyanamide as Alternative N Source for Spring-Summer and Fall Season Curly Endive Crops: Effects on Crop Performance, NUE and Functional Quality Components

“…It may also improve the crop NUE [12] through a better modulation of N supply [13]. Several researches have demonstrated that nitrogen use efficiency (NUE) and NO 3 − accumulation are affected by numerous interrelated factors such as fertilization rate and source, irrigation type, and growing season [14][15][16][17][18][19][20]. CaCN 2 application represents an easy, efficient and practical technique for leafy green vegetables fertilization.…”

Advances in Research on Fertilization Management of Vegetable Crops

“…In general, equipment that allow increasing water use efficiency at a field scale may also increase nitrogen use efficiency and reduce nutrient leaching losses. Poh et al (2011) also observed in tomato fields that increasing the length of drip irrigation time by reducing the operating pressure can lead in reduced water drainage. Water percolation in the areas closer to the source of water delivery is frequent and so are nutrient leaching losses.…”