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Abstract

Effects of 16 nitrogen treatments were compared in 1974, 1975 and 1976 on a United States Golf Association (USGA) golf green planted with ‘Tifgreen’ Bermudagrass (Cynodon dactylon (L.) Pers × C. transvaalensis). Activated sewage sludge (Milorganite) was superior to ammonium nitrate and ureaformaldehyde (Uramite) at most rates and application frequencies. The best quality (by panel evaluation) turfgrass resulted from 1.80 kg per 92.9 m2 of Milorganite N applied monthly (May to November) or bimonthly applications of 5.40 kg. Biweekly applications of 0.45 or 0.90 kg of ammonium nitrate N ranked next, but monthly applications of 0.45 to 1.35 kg failed to provide acceptable turfgrass quality. Ureaformaldehyde N at monthly rates from 0.45 to 1.80 kg was inferior to other sources at the same rates and application frequencies. Foliar concentrations of N, P, K, Cu and Zn above critical levels were associated with increased quality and yield. Tissue Mg, S, Fe and Mn content had no influence on turf quality or yield. Foliage micronutrient levels were generally higher than previously reported by other workers.

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Abstract

Thirteen species of woody ornamentals were treated over-the-top with glyphosate in a 6 × 6, rate by time factorial experiment. The influence of application timing on glyphosate phytotoxicity was significant for all species. The times of maximum tolerance and injury were species dependent. Species were organized into 4 response groups based on the effects of application time. Group 1 species, including ajuga (Ajuga reptans L.), azalea (Rhododendron obtusum Planch. ‘Coral Bells’), and a variegated liriope (Liriope muscari L.H. Bailey), were injured on all application dates. Species in groups 2, 3, and 4 exhibited tolerance to fall applications of glyphosate. Group 2, including wax leaf privet (Ligustrum japonicum Thunb.), sustained maximal injury from spring applications. Group 3 species, including Compacta holly (Ilex crenata Thunb. ‘Compacta’), were injured most by summer applications of glyphosate. However, Blue Rug juniper (Juniperus horizontalis Moench ‘Wiltonii’), a representative of group 4, was tolerant of glyphosate applications, sustaining only temporary tip chlorosis from spring and early summer treatments. First season evaluations were not sufficient to describe the ultimate effects of glyphosate on plant quality. Visual and objective evaluations in the 2nd growth season also were necessary. Chemical name used: N-(phosphonomethyl) glycine (glyphosate).

Open Access

Abstract

A study of seasonal and landscape effects on residential water application rates used to maintain meso-phytic plants in Las Cruces, New Mexico showed a positive significant correlation between water applied and landscape area maintained. However, only one-half of the variation in water applied was accounted for in the analysis. In 2 years, about 40% more water was applied than the estimated requirement. The principal reason for excessive water use appeared to be consumers’ lack of knowledge about plant water requirements.

Open Access

Abstract

MnSO4 and Rayplex-Mn were found to be effective sources of Mn for tomato seedlings grown on a Mn deficient high organic sandy soil. Tomato seedlings absorbed Mn from MnSO4 or Rayplex-Mn applied in the starter band on or under the seed with equal effectiveness. The amount absorbed was directly related to the Mn concentration in the band. MnSO4 at 100 mg Mn/ft of row increased the Mn content of the tissue from 17 ppm to more than 100 ppm.

MnEDTA at a rate to supply 10 to 25 mg Mn/ft of row in bands on or under the seed did not affect seedling growth and Mn uptake was less than from the same rate of MnSO4. Rates of 50 and 100 mg Mn/ft of row from MnEDTA in the starter band on or under the seed caused death or severe stunting of tomato seedlings because of toxicity. Band applications of Mn sources increased Mn composition of the tomato tissue relatively much more than did the broadcast application.

Open Access

The effects of 15N-labeled fertilizer applied to mature summer-bearing red raspberry (Rubus idaeus L. `Meeker') plants were measured over 2 years. Four nitrogen (N) treatments were applied: singularly at 0, 40, or 80 kg·ha-1 of N in early spring (budbreak), or split with 40 kg·ha-1 of N (unlabeled) applied at budbreak and 40 kg·ha-1 of N (15N-depleted) applied eight weeks later. Plants were sampled six times per year to determine N and 15N content in the plant components throughout the growing season. Soil also was sampled seven times per year to determine inorganic N concentrations within the four treatments as well as in a bare soil plot. There was a tendency for the unfertilized treatment to have the lowest and for the split-N treatment to have the highest yield in both years. N application had no significant effect on plant dry weight or total N content in either year. Dry weight accumulation was 5.5 t·ha-1 and total N accumulation was 88 to 96 kg·ha-1 for aboveground biomass in the fertilized plots in 2001. Of the total N present, averaged over 2 years, 17% was removed in prunings, 12% was lost through primocane leaf senescence, 13% was removed through fruit harvest, 30% remained in the over-wintering plant, and 28% was considered lost or transported to the roots. Peak fertilizer N-uptake occurred by July for the single N applications and by September for the last application in the split-N treatment. This uptake accounted for 36% to 37% (single applications) and 24% (last half of split application) of the 15N applied. Plants receiving the highest single rate of fertilizer took up more fertilizer N while plants receiving the lower rate took up more N from the soil and from storage tissues. By midharvest, fertilizer N was found primarily in the fruit, fruiting laterals, and primocanes (94%) for all fertilized treatments; however, the majority of the fertilizer N applied in the last half of the split application was located in the primocanes (60%). Stored fertilizer N distribution was similar in all fertilized treatments. By the end of the second year, 5% to 12% of the fertilizer acquired in 2001 remained in the fertilized plants. Soil nitrate concentrations increased after fertilization to 78.5 g·m-3, and declined to an average of 35.6 g·m-3 by fruit harvest. Seasonal soil N decline was partially attributed to plant uptake; however, leaching and immobilization into the organic fraction may also have contributed to the decline.

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Uprooting and transplanting seedlings can cause root damage, which may reduce water and nutrient uptake. Initiation of new roots and rapid elongation of existing roots may help minimize the negative effects of transplant shock. In this study, seedlings with four true leaves were transplanted into diatomaceous earth and the plants were transferred to a growth chamber, where they were treated with NAA (0, 0.025, 0.25, and 2.5 mg·L-1; 36 mL/plant). The effects of drenches with various amounts of 1-naphthaleneacetic acid (NAA) on the posttransplant CO2 exchange rate of vinca [Catharanthus roseus (L.) G. Don] were quantified. Whole-plant CO2 exchange rate of the plants was measured once every 20 minutes for a 28 day period. Seedlings treated with 0.025 or 0.25 mg·L-1 recovered from transplant shock more quickly than plants in the 0 and 2.5 mg·L-1 treatments. Naphthaleneacetic acid drenches containing 0.025 or 0.25 mg·L-1 increased whole-plant net photosynthesis (Pnet) from 10 days, dark respiration (Rdark) from 12 days, and carbon use efficiency (CUE) from 11 days after transplanting until the end of the experiment. The increase in CUE seems to have been the result of the larger size of the plants in these two treatments, and thus an indirect effect of the NAA applications. These differences in CO2 metabolism among the treatments resulted in a 46% dry mass increase in the 0.025 mg·L-1 treatment compared to the control, but shoot-root ratio was not affected. The highest rate of NAA (2.5 mg·L-1) was slightly phytotoxic and reduced the growth rate of the plants.

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Nutrient release from Nutricote Type 100 (100-day N release; 16N-4.4P-8.1K), and from a 1:3 mixture of Nutricote Type 40 (40-day N release; 16N-4.4P-8.1K) and Type 100 was affected by time and temperature. The Type 40/100 mixture released nutrients more rapidly over a 5 to 35C range in laboratory studies. Seasonal growth of containerized cotoneaster (Cotoneaster dammeri C.K. Schneid `Coral Beauty') and juniper (Juniperus horizontalis Moench. `Plumosa Compacta') increased with increasing application rates of either Nutricote Type 100 or a 1:3 mixture of Type 40/100 over the range 2-10 kg·m-3. Between 25 June and 27 July, cotoneaster grew more rapidly in media with Type 40/100 Nutricote, but by the end of the season (27 Sept.), fertilizer type showed no effect on plant dry weight. Shoot N was higher in cotoneaster plants grown with Type 40/100 Nutricote than with the Type 100 formulation during the first 2 months of growth, reflecting the more rapid release and uptake of N from the mixture. During the last month the situation was reversed, as nutrients from the Type 40/100 mixture were depleted. Potassium and P shoot concentrations were not affected by fertilizer type. Juniper growth and shoot concentrations of N, K, and P were not affected by fertilizer type at any time during the season. The results provided no evidence that seasonal growth could be enhanced in either cotoneaster (grows rapidly) or juniper (slower growing) by mixing rapid and more slowly releasing types of Nutricote.

Free access

Fertilizer nitrogen (FN) recovery, and changes in nitrogen (N) and dry weight partitioning were studied over three fruiting seasons in June-bearing strawberry (Fragaria ×ananassa Duch. `Totem') grown in a matted row system. Fertilizer nitrogen treatments were initiated in 1999, the year after planting. The standard ammonium nitrate N application at renovation (55 kg·ha-1 of N) was compared to treatments where additional N was applied. Supplemental treatments included both ground-applied granular ammonium nitrate (28 kg·ha-1 of N) applied early in the season and foliar urea [5% (weight/volume); 16 kg·ha-1 of N] applied early in the season and after renovation. When labeled N was applied (eight of nine treatments) it was applied only once. The impact of no FN from the second through the third fruiting season was also evaluated. Fertilizer nitrogen treatment had no impact on total plant dry weight, total plant N, yield or fruit quality from the first through the third fruiting seasons. Net dry matter accumulation in the first fruiting season was 2 t·ha-1 not including the 4 t·ha-1 of dry matter removed when leaves were mowed during the renovation process. Seasonal plant dry weight and N accumulation decreased as the planting aged. Net nitrogen accumulation was estimated at 40 kg·ha-1 from spring growth to dormancy in the first fruiting season (including 30 kg·ha-1 in harvested fruit, but not including the 52 kg·ha-1 of N lost at renovation). Recovery of fertilizer N ranged from 42% to 63% for the broadcast granular applications and 15% to 52% for the foliar FN applications, depending on rate and timing. Fertilizer N from spring applications (granular or foliar) was predominantly partitioned to leaves and reproductive tissues. A large portion of the spring applied FN was lost when plants were mowed at renovation. Maximum fertilizer use efficiency was 42% for a granular 55 kg·ha-1 application at renovation, but declined to 42% just before plant growth the following spring, likely a result of FN loss in leaves that senesced. In June, ≈30% of the N in strawberry plants was derived from FN that was applied at renovation the previous season, depending on year. This stored FN was reallocated to reproductive tissues (22% to 35%) and leaves (43% to 53%), depending on year. Applying fertilizer after renovation increased the amount of remobilized N to new growth the following spring. The following June, 15% of plant nitrogen was derived from fertilizer applied at renovation 2 years prior.

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Abstract

Yield of fruit, fruit quality, and mineral composition of the leaves of ‘Valencia’ orange [Citrus sinensis (L.) Osb.] were essentially unchanged by widely different schedules of applying N and K. Single annual applications of NH4NO3 were made in fall, spring, or summer. Applications of KCl were made twice yearly, annually in fall or spring, or biennially in alternate springs. Two rates of N maintained average leaf levels of about 2.6 and 2.7%. A yield increase accompanied the higher level of N. Similar responses occurred on ‘Rough’ lemon (C. jambhiri Lush.) and ‘Cleopatra’ mandarin (C. reticulata Blanco) rootstocks.

Open Access

crabapple species and cultivars are limited ( Embree and Foster, 1999 ; McArtney et al., 2006 ; Stott, 1972 ; Williams, 1965 ). Successful application of blossom-thinning chemicals is highly dependent on understanding the rate of pollen tube growth among

Free access