In Santa Fe, Argentina, strawberries (Fragari ×ananassa Duch.) are cultivated in the area of Coronda where N fertilization usually exceeds crop requirements. The objective of this work was to test four types of fertilization methodology to optimize fertilizer use efficiency. Experiments were carried out at the horticultural center of the Facultad de Agronomía y Veterinaria, in Esperanza, Santa Fe, 31.15° S latitude, on a typical argiudol soil. `Chandler' was planted 13 Mar. 1996. Nitrogen demand was related to the dry matter production with N content decreasing to increment of biomass (W), soil N mineralization was estimated according to the program EDAFO version 3. Using previous data, a monthly balance was calculated and four treatments were devised: control (T0) = without fertilization; treatment 1 (T1) = N fertilization covering the accumulated monthly deficit, 53 kg·ha-1 (47 lb/acre); treatment 2 (T2) = N fertilization covering the monthly deficit 66 kg·ha-1 (58 lb/acre); treatment 3 (T3) = N fertilization covering the total crop demand 117 kg·ha-1 (104 lb/acre). All N treatments significantly increased yields over the control. Yield increased to increasing N rates from 0 to 53 kg·ha-1. This response was due to an increase in fruit number but not in fruit weight. High N rates promoted runner growth without increasing fruit yield. The use N balance method for strawberry fertilization showed satisfactory results. Accumulated N balance (T1), required the least amount of N fertilizer while producing good yield, thus it should be the method adopted to reduce costs and environmental risks of N fertilization.
The effects of different levels of phosphorus fertilization and water provision on the mineral nutrition of two clonal rootstocks of Prunus were studied. Two-year-old Prunus seedlings, Hybrid GF677 (Prunus persica × Prunus amygdalus) (PH) and Pollizo Puebla de Soto 101 (Prunus insititia) (PI) were planted in an uncultivated calcareous soil (a Xeric torriorthent derived from marl) under greenhouse conditions. They were drip irrigated with subterranean water of slightly alkaline pH (7.63), EC 0.88 dS·m–1, with a low chloride and high sulphate content. The experiment lasted two annual cycles. In October of the second year the leaf nutrient concentration and dry weight of the total leaf weight were determined in four trees of each combination of rootstock × irrigation level × fertilization treatment. The nutritive state of these trees was analyzed by vector analysis. The results point to a highly significant influence of the rootstock nature on the leaf concentrations of most nutrients. Very low Zn and Cu concentrations were recorded on both rootstocks, for both irrigation levels and several fertilizing treatments. Vector analysis confirmed the Cu deficiency resulting from several of the fertilizing treatments and both irrigation levels in PH rootstocks.
Double impatiens (Impatiens wallerana Hook.) `Blackberry Ice' (variegated-leaf) and `Purple Magic' (green-leaf) were grown on flood benches and irrigated with 50, 100, 200, or 300 mg·L-1 (ppm) N to study the effect of fertility on growth and development. Electrical conductivity (EC) levels at week 9 were similar for both cultivars at each fertilizer rate, except for the 100 mg·L-1 N where EC levels of `Blackberry Ice' were more than double those of `Purple Magic'. This indicated that the nutrient demands were less for `Blackberry Ice' and fertilization rates lower than 100 mg·L-1 N would be required. After nine weeks, plants grown with 100 mg·L-1 N had a 22% larger plant diameter than plants grown with either 50 or 200 mg·L-1 N. Fertilization rates of 50 mg·L-1 N resulted in plants which were covered with a higher percentage of blooms per unit of leaf area, but the plants were smaller. Plant tissue dry weight (leaf, bud, stem, and total) increased to the highest level at 100 mg·L-1 N, then decreased with further increases in fertilization rate. For maximum shoot growth with flood irrigation, growers should apply 100 mg·L-1 N when growing `Purple Magic' double impatiens and a fertilization rate between 50 and 100 mg·L-1 N for `Blackberry Ice'.
In a 3-year study on a fine sandy loam soil, `Atlantic' (1989), `Frontier' (1990-91), and `Russet Burbank' (1989-91) potato (Solanum tuberosum L.) response to rate and time of Ca fertilization was evaluated. Calcium was applied preplant at 0, 90, 180, and 270 kg·ha-1 as CaSO4 and side-dressed at 0, 34, and 68 kg·ha-1 as Ca(NO3)2, with treatments combined in a complete factorial. Preplant Ca fertilization increased soil Ca concentration each year. Calcium fertilization did not affect tuber yield or grade distribution. Tuber concentrations of P, K, and Ca in `Russet Burbank', Ca in `Frontier', and S in all cultivars increased with increasing preplant Ca rate. `Russet Burbank' tuber P, K, Ca, and Cu concentrations and `Frontier' tuber S concentration increased as side-dressed Ca rate increased. Tuber concentrations of most nutrients decreased between midseason and harvest. The incidence of internal brown spot (IBS) was very low in `Atlantic' and `Russet Burbank' tubers and was reduced in `Atlantic' by preplant Ca application. In 1990, IBS severity and incidence in `Frontier' were reduced by preplant and side-dressed Ca fertilization. In 1991, after 4 months of storage at 7C, severity and percentage of tubers with IBS were reduced by preplant and side-dressed Ca fertilization. During storage, IBS decreased in `Russet Burbank'. Brown center in `Russet Burbank' decreased as side-dressed Ca rate increased. In 1990, `Russet Burbank' french-fry color improved as preplant Ca rate increased.
Abstract
Interior longevity of chrysanthemum (Dendranthema grandiflora Tzvelev.) increased 9 to 16 days on plants maintained at a mean maximum PAR level of 500 μmol·s−1·m−2 compared to plants shifted to 100 μmol·s−1·m−2 7 weeks after the start of inductive photoperiods. Termination of fertilization 7 weeks after initiation of inductive photoperiods increased interior longevity 7 days at PAR levels of 100 and 300 μmol·s−1·m−2 compared to plants where fertilization was continued until flowering. Plant quality and interior longevity were higher at a simulated shipping temperature of 4C than at 16 or 24C. Shipping duration had little effect on longevity at 4 and 16C, but decreased longevity 7 days when duration was extended from 2 to 7 days at 24C. Termination of fertilization 3 weeks before flowering increased longevity from 6 to 10 days at all simulated shipping temperatures and durations.
Bareroot Corylus colurna were grown in 7.5-liter containers from 11 Apr. until 27 June 1994. The growing medium was fritted clay. Fertility levels included no fertilization, 100 ppm N, or 200 ppm N. Plants were root pruned to remove none or one-quarter to one-half of the primary roots. Root pruning at any level resulted in decreased height, shoot, and root dry weights and number and length of new shoots. One-quarter primary root removal resulted in lower root: shoot ratios compared to plants that were unpruned. One-half primary root removal further reduced root: shoot ratios. One-half primary root removal also reduced total leaf area compared to unpruned controls. Fertilization at 200 ppm N increased leaf numbers and total leaf areas compared to plants receiving no fertilization.
Abstract
Rabbiteye blueberries (Vaccinium ashei Reade) were fertilized with various sources and rates of nutrients over a 4-year period. There were no positive differences in plant growth responses to fertilizer source or rate. At the 80 g/plant rate, plants fertilized with Ca(NO3)2 were chlorotic and lower in plant height and vigor than control (no fertilizer) plants. Plants treated with 160 g of either 13N-6P-11K fast release, (NH4)2SO4, or Ca(NO3)2 fertilizer were shorter than control plants. Plants fertilized with cottonseed meal, 14N-6P-12K slow release, and NH4NO3 did not differ from control plants, regardless of application rate. Fruit yield was highest at the 40 g/plant rate regardless of fertilizer source.
The effects of fertilizer rates and application frequency on drip-irrigated bell peppers (Capsicum annuum L.) were evaluated at two sites in 1992 and one site in 1993 in southern New Jersey. Yield and fruit quality were greatest with 158N-69P-131K lb/acre at the site with a sandy loam soil. Yield and fruit quality responded to additional fertilizer at sites with loamy sand soils. Average marketable fruit weight increased with increasing fertilization rate at one of the two loamy sand sites. The incidence of sun scald decreased with increasing fertilization rate. Increasing the frequency of drip-applied fertilizer from 11 to 22 days did not affect yield or fruit quality in either year when the same amount of fertilizer was applied. These results show that maximizing the yield of bell peppers grown on loamy sand soils in New Jersey may require higher fertilization rates than previously recommended.
Five field experiments were conducted from 1986 through 1988 to evaluate the response of radish (Raphanus sativus L.) to rate and source of P (triple superphosphate and phosphoric acid) and to rate of K (KC1) on Histosols. Marketable radish root yields increased with P fertilization when the soil tested <13 mg P/dm3 using a test for water-soluble P. No significant differences were due to P source. Results of leaf tissue analysis suggested that the critical concentration of P in radish leaves was 0.45%. Radish did not respond to K fertilization in any of the five experiments, even though preliminary soil-test K levels ranged from 20 to 102 K/dm3. Histosols used for crop production in Florida rarely test below 20 mg K/dm3; thus, radish rarely would require supplementary K fertilization for optimal yield.
Abstract
Nitrogen fertilization of ‘Tifgreen’ bermudagrass (Cynodon sp.) through an irrigation system (fertigation) was examined in a replicated factorial design study on Pompano fine sand soil. Nitrogen was applied at 2 rates: 9.77 and 4.89 g/m2/month, by 3 methods: 1) fertigation daily with urea, 2) fertigation weekly with urea, and 3) dry fertilization bi-monthly with ureaformaldehyde. All plots received daily irrigation. Turf appearance and clipping yields were significantly better at the higher N rate, but were generally unaffected by the 3 methods of application. Fertigation appeared to be a practical and convenient method of making frequent light applications of N.