scholarly journals Effects of nitrogen on accumulation and partitioning of dry matter and nitrogen of vegetables. 2. Leek

1995 ◽  
Vol 43 (4) ◽  
pp. 435-446
Author(s):  
H. Biemond

Two greenhouse and 2 field trials were carried out on leeks cv. Albana with different N fertilizer rates and application dates. Observations included frequent measurements of DM and N accumulation in leaf blades, leaf sheaths and, if present, scapes. Both the amount of N applied and the time of application affected the total accumulation of DM and N in the plant. The relative partitioning rates of DM increase to the shaft were affected in such a way that the final harvest indices for DM (which ranged from 0.32 to 0.53) were significantly lower at higher N application rates. The final harvest indices for N (0.21-0.35) were not significantly affected by amount or timing of fertilizer applications. The total N concentrations of leaf blades and leaf sheaths decreased with increasing leaf age. Average nitrate N concentrations over all plant parts were always below 40%.

2015 ◽  
Vol 154 (4) ◽  
pp. 632-646 ◽  
Author(s):  
L. H. HUANG ◽  
Z. W. LIANG ◽  
D. L. SUAREZ ◽  
Z.C. WANG ◽  
M. M. WANG ◽  
...  

SUMMARYSaline-sodic soils are widely distributed in the western Songnen Plain of Northeast China and planting rice has been found to be an effective and feasible approach for improving saline-sodic soil and increasing food production. Assessment of the effectiveness and sustainability of this method requires monitoring of the changes in soil salinity and nutrient content. The objective of the current study was to investigate the changes of soil salinity and nitrogen (N) contents over 1, 3, 6 and 9 years of cultivation, four application rates of N (N0: no N, N1: 100 kg N/ha, N2: 200 kg N/ha and N3: 300 kg N/ha) and two irrigation water types: ground water irrigation (GWI) and river water irrigation (RWI). Salinity and N contents of soil and water samples were analysed before planting and after harvest throughout the experiments. Soil pH and electrical conductivity (EC), especially in the surface layer of 0–40 cm depth, decreased with years of cultivation with both GWI and RWI, while soil inorganic N and total N contents increased. Moreover, with increasing N application rates, soil inorganic N and total N contents increased significantly in the 0–20 cm soil layer. Increasing N application had little effect on soil pH and EC. Reclaiming and planting rice promoted desalination of the surface and formation of a fertile tillage layer in saline-sodic paddy fields. In terms of irrigation and drainage in saline-sodic paddy fields, both soil salinity and N contents increased. Soil total salinity increased annually by 34 and 12·8 kg/ha, and inorganic N contents increased annually by 9 and 13·5 kg/ha with GWI and RWI, respectively. Therefore, comprehensive agricultural practices should be adopted for improving and cropping rice in saline-sodic paddy fields.


2020 ◽  
pp. 36-42
Author(s):  
E. Ndor ◽  
U. D. Faringoro

Field trials were conducted during 2017 and 2018 rainy season, to investigate the effect of nitrogen fertilizer rates and time of application on the growth and yield of cowpea. The treatment consisted of three levels of urea: 0, 40, 80 kg N ha-1 and the times of fertilizer application: during planting of cowpea, 2 weeks after planting, 4 weeks after planting and 6 weeks after planting; which were factorially combined to form twelve treatments and laid in Randomized Complete Block Design (RCBD). The results showed that, Nitrogen fertilizer rates and time of application had a significant increased on all the growth and yield parameters of cowpea in both years of trials. Application of 80 kg N ha-1 produced the highest number of cowpea leaves (134.45 and 139.23), number of branches (9.45 and 10.54), vine length (78.23cm and 80.12cm) and highest seed weight of 0.52 t ha-1 in both 2017 and 2018 trials. However, the control plots produced plants with the highest number of root nodules (14.78 and 12.49) in both years of cropping. Also, application of nitrogen fertilizer at two weeks after planting of cowpea produced the highest growth and seed weight of 0.68 t ha-1 in 2017 cropping; while in 2018 trial, application of nitrogen fertilizer at two weeks after cowpea planting produced seed yield of 0.69tha-1 which is statistically similar with application of nitrogen fertilizer on the fourth week after planting which produced 0.55 t ha-1 of cowpea seeds. The interaction between nitrogen fertilizer application rates and time of application did not showed any significant difference in cowpea yield and yield components in both years of cropping.


1995 ◽  
Vol 43 (4) ◽  
pp. 419-433
Author(s):  
H. Biemond ◽  
J. Vos ◽  
P.C. Struik

Three greenhouse trials and one field trial were carried out on Brussels sprout cv. Icarus SG2004 in which the treatments consisted of different N amounts and application dates. DM and N accumulation in stems, apical buds and groups of leaf blades, petioles and sprouts were measured frequently throughout crop growth. Total amounts of accumulated DM and N were affected by amount of N applied and date of application, but the final harvest indexes for DM and N (0.10-0.35 and 0.20-0.55, respectively) were not significantly affected by treatments in most experiments. Nitrate N concentrations were only high (up to about 2%) shortly after planting. The total N concentration of leaf blades and petioles increased with increasing leaf number. This increase resulted from a decreasing N concentration during the leaf's life. The total N concentration in sprouts changed little with leaf number.


HortScience ◽  
2006 ◽  
Vol 41 (5) ◽  
pp. 1332-1338 ◽  
Author(s):  
Sean M. Westerveld ◽  
Alan W. McKeown ◽  
Mary Ruth McDonald

An understanding of nitrogen (N) uptake and the partitioning of N during the season by the carrot crop (Daucus carota subsp. sativus [Hoffm.] Arkang.) is required to develop more efficient N fertilization practices. Experiments were conducted on both organic and mineral soils to track the accumulation of dry matter (DM) and N over the growing season and to develop an N budget of the crop. Treatments included two carrot cultivars (`Idaho' and `Fontana') and 5 N rates ranging from 0% to 200% of the provincial recommendations in Ontario. Foliage and root samples were collected biweekly from selected treatments during the growing season and assessed for total N concentration. Harvest samples were used to calculate N uptake, N in debris, and net N removal values. Accumulation of DM and N in the roots was low until 50 to 60 days after seeding (DAS) and then increased linearly until harvest for all 3 years regardless of the soil type, cultivar, and N rate. Foliage dry weight and N accumulation were more significant by 50 to 60 DAS, increased linearly between 50 and 100 DAS, and reached a maximum or declined slightly beyond 100 DAS in most cases. The N application rates required to maximize yield on mineral soil resulted in a net loss of N from the system, except when sufficient N was available from the soil to produce optimal yield. On organic soil, a net removal of N occurred at all N application rates in all years. Carrots could be used as an N catch crop to reduce N losses in a vegetable rotation in conditions of high soil residual N, thereby improving the N use efficiency (NUE) of the crop rotation.


1996 ◽  
Vol 44 (3) ◽  
pp. 227-239
Author(s):  
H. Biemond ◽  
J. Vos ◽  
P.C. Struik

Four greenhouse and 2 field experiments (the latter on a sandy soil) were carried out with different amounts and dates of N application to analyse the dynamics of dry matter and N accumulation in spinach (cv. Trias). Frequent measurements were carried out on dry matter and N accumulation in leaf blades, petioles and stems. The total accumulation of dry matter and N differed largely among and within experiments. Increasing N application increased yield of dry matter and N accumulation, whereas splitting N applications had much smaller effects. However, the partitioning of dry matter and N proved insensitive to N treatments. Harvest indices for dry matter (about 0.67) or N (about 0.74) of crops at a marketable stage were fairly constant over treatments and experiments. Increasing or splitting the N application affected N accumulation more than dry matter production, resulting in large effects on N concentrations. The lack of variation in response to N for different N regimes facilitates the development of N application techniques aimed at high yield, high quality and reduced emissions. The organic N concentration of leaf blades and petioles decreased with leaf age, although in most experiments this decrease was smaller at higher leaf numbers. The nitrate-N concentration decreased with increasing leaf number at any sampling date; it was higher when N was abundant. High yields in autumn crops were associated with high nitrate concentrations but also with potentially high losses of N.


2014 ◽  
pp. 169-176 ◽  
Author(s):  
Philipp Starke ◽  
Christa Hoffmann

High biogas yields are expected from sugar beet because of its high root yield. But it has not been analysed yet, which varieties are best suited to reach the highest biogas yield. The study thus aimed at identifying a parameter to estimate the biogas yield of sugar beet. To get a broad variation of yields and beet qualities, field trials were conducted from 2008 to 2011 at 2 sites (Göttingen and Regensburg, Germany) with different sugar beet varieties and fodder beet. Different N application rates were included and furthermore, autumn sown beets (winter beet). Dry matter composition was analyzed, biogas yield and methane concentration were determined in batch experiments. Sugar beet reached root dry matter yields of more than 20tha–1 and thereby exceeded fodder beet. Moderate N application increased root dry matter yield, whereas higher N rates only enhanced the leaf dry matter yield. But most likely, leaves will not be considered for fermentation because of their low concentration of dry matter and organic dry matter. Winter beet reached total dry matter yields of 12tha–1, but dry matter was not as easily digestible as that of spring sown beets. Biogas yield showed a close linear relation to the root dry matter and the sugar yield as well. Sugar beet varieties can therefore be assessed for anaerobic digestion by their sugar yield. As sugar yield is already the main target, breeding for biogas beets will not be substantially different from that for beets used for sugar manufacture.


1985 ◽  
Vol 48 (12) ◽  
pp. 1058-1061 ◽  
Author(s):  
W. A. DOZIER ◽  
K. S. RYMAL ◽  
J. W. KNOWLES ◽  
J. A. PITTS ◽  
R. B. REED

Daminozide residue levels in fruit and vegetative parts of apple trees were determined the year following foliar spray treatments with daminozide at recommended rates and times and at excessive rates and times closer to harvest than recommended. Trees were sampled in December, March and August following spraying. Daminozide residues were found in all vegetative plant parts, with the highest residue levels found in the buds, bark and xylem of spurs, and in terminal and lateral buds; the lowest residue levels were found in the bark and xylem of stems. Residue levels were affected by both rate and time of application. Residue levels increased as application rates increased, but the response to rate was less when treatments were applied 21 d after bloom (125 d before harvest) than when treatments were applied closer to harvest. The highest residue levels were from treatments applied the day of harvest. Higher residue levels were found in March samples than December samples. Residues had been dissipated to low levels by the August sampling date. No daminozide residues were found in apple fruit from trees treated the previous year with recommended levels of daminozide applied at the recommended time. However, low residue levels were found in fruit treated with 2 × and 4 × rates of daminozide at times closer to harvest than recommended.


1973 ◽  
Vol 53 (1) ◽  
pp. 73-77 ◽  
Author(s):  
R. J. RENNIE ◽  
D. A. RENNIE

Nitrogen balance (fertilizer N accounted for in the soil–plant system) and standard isotope (obtained on above-ground plant parts) criteria were used to evaluate the efficiency of nitrogen sources for barley grown on a Chernozemic and a Solonetzic soil under greenhouse conditions. The isotope criteria, percent total N in the plant tissue derived from fertilizer (% N d.f.f.), "A" values, and uptake of fertilizer N by the crop, clearly indicated the superiority, in terms of plant availability, of the NO3−-N source, followed by NH4+-N, with urea the least effective. In contrast, loss of nitrogen from the soil–plant system was greatest for the NO3−-N and least for the urea (i.e., 67 vs. 26% on the Solonetzic soil). Such conflicting results can be explained on the basis of slow hydrolysis of the urea and rapid plant uptake of N from the NO3−-N form. It is concluded that, although isotope-derived criteria such as % N d.f.f., A values, and uptake by the crop of fertilizer N provide precise measurements of the performance of N sources, serious errors in causative factors may be made unless "nitrogen balance" data are available. The significance of primary and corrected (rate of fertilizer N application corrected for fertilizer N loss) A values are discussed.


HortScience ◽  
1992 ◽  
Vol 27 (3) ◽  
pp. 228-230 ◽  
Author(s):  
J.L. Walworth ◽  
D.E. Carling ◽  
G.J. Michaelson

Head lettuce (Lactuca sativa L.) cv. Salinas was produced in field trials in southcentral Alaska with varying planting dates, planting methods, N sources, and N application rates. Variables measured included head weight and diameter and harvest date. Nitrogen source had little effect on head weight. Direct-seeded lettuce produced heaviest beads from early plantings; transplants produced heaviest heads when planted in mid- to late season. Transplanting generally produced heavier heads than direct-seeding. Head weight of transplanted and direct-seeded lettuce was maximized with ≈112 kg N/ha. The data suggest that 112 kg N/ha may be suitable for lettuce direct-seeded or transplanted throughout the growing season.


2015 ◽  
Vol 29 (2) ◽  
pp. 263-273
Author(s):  
Leslie L. Beck ◽  
Aaron J. Patton ◽  
Quincy D. Law ◽  
Daniel V. Weisenberger ◽  
James T. Brosnan ◽  
...  

Mesotrione, a 4-hydroxyphenylpyruvate dioxygenase-inhibiting herbicide, is labeled for PRE and POST crabgrass control. It has enhanced efficacy on smooth and large crabgrass when applied in conjunction with soil-applied nitrogen (N). The objectives of this study, using crabgrass as the weed species, were to (1) determine the influence of N rate and tissue N concentration on mesotrione activity, (2) determine the influence of N source on mesotrione activity, and (3) determine the influence of N application timing on mesotrione activity. Large crabgrass plants that received 12 kg N ha−1or more before mesotrione application had more bleached and necrotic leaves compared with plants that received 0 kg N ha−17 d after treatment (DAT) in the greenhouse. Although N application rates as high as 98 kg N ha−1were tested, 90% leaf bleaching and necrosis were observed with rates of 8.9 or 10.1 kg N ha−1in Tennessee and Indiana, respectively. Nitrogen concentration in large crabgrass leaf and stem tissue on the day of the mesotrione application was closely related to the bleaching and necrosis symptoms observed 7 DAT. Although N rate influenced mesotrione activity, N source did not. Nitrogen application timing was also important, with N applications 3, 1, and 0 d before a mesotrione application having the highest percentage of bleached and necrotic leaves in greenhouse experiments. Both greenhouse and field trials support the finding that N applications in proximity to the mesotrione application enhance herbicide activity. Thus, practitioners can pair N and POST mesotrione applications together or in proximity to enhance crabgrass control.


Sign in / Sign up

Export Citation Format

Share Document