Session 6. Fertigation and Management of Microirrigation Systems
Fertilizer Timing and Pan Evaporation Scheduling for Drip Irrigated Tomato
S. J. Locascio and A. G. Smajstrla
Tomatoes (Lycopersicon esculentum Mill.) were grown with black polyethylene mulch and drip irrigation in field studies during two seasons to evaluate the effects of time of nitrogen (N) and potassium (K) application and irrigation scheduling using pan evaporation on production of fresh market fruit. Irrigation treatments were water applied daily at 0, 0.17, 0.34, and 0.50 times pan evaporation. The N and K were applied 100% preplant or 40% preplant with the remaining 60% applied in either daily or weekly applications by fertigation. During the two 12-week seasons, rainfall averaged 1 cm/wk-1 and pan evaporation averaged about 2.6 cm/wk-1. Total marketable fruit yield increased an average of 40% with the application of water and increased linearly from 61.2 to 67.0 Mg/ha-1 with an increase in water quantity from 0.17 to 0.50 pan evaporation. Total marketable fruit yield was 10% higher with N and K applied with the drip system than with all N and K applied preplant. The number of fertilizer applications per week (one or seven) had no significant effect on marketable fruit yield. Leaf tissue N concentrations were reduced and K concentrations were not affected by an increase in water quantity applied.
Keywords: Lycopersicon esculentum, irrigation scheduling, microirrigation, fertigation
Abstract taken from paper found on pages 175 to 180 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Drip-Irrigation Management and Fertilization of Bell Pepper in a Humid Area
R. P Bracy, R. J. Edling, and E. B. Moser
Buried drip tape for supplemental irrigation of bell pepper (Capsicum annuum L.) is becoming more widely used in Louisiana because of the excellent control and high efficiency of water use afforded by drip irrigation and the existence of many low-capacity wells in the area. The increase in the use of drip irrigation in this area has indicated a need for reliable recommendations concerning timing and quantity of irrigation and effects of drip irrigation on current fertilizer and plant spacing practices. Experiments were conducted during spring 1993 and 1994 on bell peppers transplanted onto polyethylene-mulch-covered raised beds. Two irrigation levels (optimum and 2X rate) and three nitrogen (N) fertility levels were evaluated for effect on yield, weight, and grade of bell pepper grown at four plant densities (two plant spacings and two row configurations).
Fertilizer rate had a linear effect on total and early yield and percentage of extra-large fruit harvested during 1993 but did not significantly affect yields in 1994. Total yields during both years were increased by planting in double-row configuration; however, plant spacing increased yield in 1994 only. Applying twice the calculated optimum rate of irrigation did not affect bell pepper production during either year.
Keywords: Drip irrigation, Fertigation, Fertilization, Peppers, Water use efficiency
Abstract taken from paper found on pages 181 to 186 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Fertilization Requirements for Drip-irrigated Bell Peppers Grown on Loamy Sand Soils
Philip E. Neary, Craig A. Storlie, and James W. Paterson
The effect of fertilizer rates and frequency of application on drip-irrigated bell peppers (Capsicum annum L.) were evaluated at two sites in 1992 and one site in 1993 in southern New Jersey. Yield and fruit quality were maximized at 166 kg/ha-1 of N, P2O5, and K2O at the site with a sandy loam soil with a cation exchange capacity of 4 me/100 g of soil. Yield and fruit quality responded to additional fertilizer up to 203 kg/ha-1 of N, P2O5, and K2O at the sites with loamy sand soils and cation exchange capacities of 2 me/100 g of soil or lower. Average fruit weight of marketable fruit increased with increasing fertilization rate at one of the two loamy sand sites. The incidence of sun scald decreased with increasing fertilization rate. The frequency of fertilizer application, 11 days versus 22 days, through the drip irrigation did not affect yield or fruit quality in either year when the same amount of fertilizer was applied for the season. These results suggest that bell peppers grown on loamy sand soils with relatively low cation exchange capacities may require higher rates of fertilization than previously recommended.
Keywords: Capsicum annum, Soil texture, Cation exchange capacity, Plastic mulch
Abstract taken from paper found on pages 187 to 193 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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FERTIGA: A Computer Program for Fruit Tree Fertigation
J. Vera, J. M. de la Peña
Fertigation is a technique that applies water and fertilizers to plants. However, the quantitative nature of the factors involved means cumbersome computations are necessary, for which reason a simple computer program FERTIGA has been developed to help daily fertigation scheduling throughout the season.
Keywords: Fertigation, microirrigation, decision model, fruit trees, deficit irrigation
Abstract taken from paper found on pages 194 to 199 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Tomato Response to Phosphorus Nutrition via Drip Fertigation
B. Bar-Yosef and Patricia Imas
Meager information is available on effects of drip fertigation with P on vegetable yield, fruit quality and plant development. The objective of this study was to investigate the response to P of greenhouse tomatoes (Lycopersicone sculentum Mill., cv. F-144) grown on different substrates, in order to establish the optimal P fertigation management for this crop.
Four levels of P (0, 10, 30 and 60 mg P/L) supplied in the water at each irrigation were tested in combination with three growth media: scoria (yellow tuff), rockwool and sandy soil. Phosphorus concentration in the water (Cp) affected fruit yield significantly by increasing the number of fruits per plant. The concentration that resulted in maximum fruit yield depended on the growth medium's P sorption characteristics and indigenous P content. All substrates obtained an equal tomato yield response to P when the mean P concentration of the irrigation and leachate solutions (Cps) was used. The threshold Cps, above which no increase in fruit yield was obtained, was 8-10 mg P/L, corresponding to a marketable yield of 60 tons/ha in six harvest weeks. This threshold Cps was 30% of that required for maximum P uptake rate per unit root weight. Increasing Cp in all substrates reduced the glucose, TSS and titratable acid content in fruits. The reduced fruit taste parameters underscore the importance of optimizing Cp in order to obtain the desired balance between fruit yield and quality.
Keywords: P uptake, Lycopersicone esculentum, Fruit quality, Drip irrigation, Roots, Dry matter, Water use efficiency
Abstract taken from paper found on pages 200 to 208 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
