The effects of humic acid (HA) on nutrient accumulation and growth of tomato seedlings were evaluated in a solution of limited nutrient availability in a greenhouse. HA additions were made to the nutrient solution at rates of 0, 640, 1280, or 2560 mg/L. The addition of 1280 mg/L HA produced significant increases in shoot accumulation of P, K, Ca, Mg, Fe, Mn, and Zn as well as increased accumulation of N, Ca, Fe, Zn, and Cu in roots. Fresh and dry weights of roots were also increased, However, on comparing nutrient accumulation in plants treated with 1280 mg/L HA and those given an additional supply of nutrients equivalent to those supplied by HA at the 1280 mg/L rate, shoots accumulated more N, P, K, Fe, and Cu, while roots accumulated more K and Ca. Therefore these increases do not appear to be associated with nutrients contained in HA. Eectrolyte leakage, as an indication of membrane permeability, did not differ as a consequence of HA additions. However, electrolyte leakage correlated positively with HA rate. A shift in solution pH from 5.8 to 7.0 had no effect upon on nutrient accumulation or growth of tomato seedlings. The interaction of pH and addition of HA was not significant 1. Partial funding for this research is from U.S.D.A.

Boron deficiency in fresh-market tomatoes (Lycopersicon esculentum Mill.) is a widespread problem that reduces yield and fruit quality but is often not recognized by growers. Tomatoes were grown in field and hydroponic culture to compare the effects of foliar and soil applied B on plant growth, fruit yield, fruit quality, and tissue nutrient levels. Regardless of application method, B was associated with increased tomato growth and the concentration of K, Ca, and B in plant tissue. Boron application was associated with increased N uptake by tomato in field culture, but not under hydroponic culture. In field culture, foliar and/or soil applied B similarly increased fresh-market tomato plant and root dry weight, uptake, and tissue concentrations of N, Ca, K, and B, and improved fruit set, total yields, marketable yields, fruit shelf life, and fruit firmness. The similar growth and yield responses of tomato to foliar and root B application suggests that B is translocated in the phloem in tomatoes. Fruit from plants receiving foliar or root applied B contained more B, and K than fruit from plants not receiving B, indicating that B was translocated from leaves to fruit and is an important factor in the management of K nutrition in tomato.

Abstract.– Fish and vegetable production were linked in a recirculating water system designed to achieve a high degree of efficiency of water use for food production in addition to functional and technological simplicity. Hybrid tilapia Oreochromis mossambicus×O. niloticus L. were grown in tanks associated with biofilters (sand beds) in which tomatoes Lycopersicon esculentum were grown. The effect of four biofilter volume (BFV)/fish rearing tank volume ratios (0.67/1, 1.00/1, 1.5011, 2.25/1) on water use efficiency was evaluated.‘Laura’(first experiment) or‘Kewalo’tomatoes were grown 4/m2 in biofilters of four different sizes and surface‐irrigated 8 times daily with water from the associated fish tanks. Daily water consumption increased with BFV/tank ratios and with time. Fish production rates increased with biofilter volume in the first experiment, but were not significantly different in the second experiment. Total tomato fruit yield per plot increased from 13.7 to 31.7 kg (Experiment 1) and from 19.9 to 33.1 kg (Experiment 2) with increasing BFV/tank ratio. For fish plus fruit, total energy production increased from 4,950 to 8,963 kcal/ plot and from 4,804 to 7,424 kcal/plot in Experiments 1 and 2, respectively, and protein production increased from 536 to 794 and from 352 to 483 g/plot in Experiments 1 and 2, respectively, with increasing BFV/ tank ratio. Trends in water use efficiency for production of food energy (kcal/L.) and of protein (g/L) in tomatoes and fish were complex. Water use efficiency

One or two plants per hill of `Prince Charles' and `Royal Jubilee' watermelon were grown with drip fertigation at five in-row spacings, with or without polyethylene mulch, in four location × year combinations (environments). Rows were 1.5 m apart and in-row spacings were 45, 60, 90, 120, and 150 cm. `Royal Jubilee' yielded more than `Prince Charles' in all environments, and the highest yields were associated with low percent culls and high fruit numbers per hectare. Highest yields of marketable fruits (≥4.5 kg/melon) were obtained using polyethylene mulch and areas per plant between 0.4 and 0.9 m2. Average weight per melon, however, was ≥9 kg only at areas per plant >0.9 to 1.0 m2. Unless there is a market for small fruits (≥4.5–9 kg), optimum area per plant was ≈1.0 m2. Results for one plant per hill at one in-row spacing were similar to those for the alternative planting pattern of two plants per hill at half the in-row spacing, thus supporting the feasibility of using the more economical alternative planting pattern.

Soil water is a major limiting factor in the production and quality of potatoes (Solanum tuberosum L.). The objectives of this research were to determine the effects of trickle irrigation under controlled soil matric potential and two row spacings on the yield, quality, and nutrient contents of potatoes. Potatoes, trickle irrigated with nutrient solution and grown on 100‐cm row spacing (CSI) on sandy loam (Typic Palendult) soil, yielded 76% more marketable potatoes than those trickle irrigated under a plastic mulch and grown on twin row spacing (TRI) and 206% more than 100‐cm spaced, nonirrigated potatoes (CSNI). Water deficit, calculated by subtracting rainfall from 80% of pan evaporation, was 14.0 cm. Soil matric potentials 15 cm from the soil surface were not different for the CSI and TRI treatments irrigated, respectively, with amounts of water equivalent to 60 and 43% of the water deficit. The N and Mg contents of tubers were increased by irrigation. Leaf petiole nitrate N of CSI and TRI potatoes was consistently greater than 16,000 ppm, a critical level for Russett Burbank potato production in Idaho, but fell significantly below that level for the CSNI potatoes after an extended drought.