scholarly journals Corn response to N applications and population densities at two locations in Puerto Rico

1969 ◽  
Vol 72 (1) ◽  
pp. 127-139
Author(s):  
Adolfo Quiles-Belén ◽  
Antonio Sotomayor-Ríos ◽  
Salvio Torres-Cardona

The effect of nitrogen applications and population densities on grain and dry matter yield, leaf area and agronomic traits of three commercial corn hybrids was studied at two locations in Puerto Rico. Treatments included sidedressed N at 0, 60, 120, 180, and 240 kg/ha and three population densities of 20,000, 40,000 and 80,000 plants/ha. For most traits, significant differences were found between locations, hybrids, population densitites and N levels, and there were significant interactions of location X hybrids, location X population densities, hybrids X population densities, location X N, hybrids X N and population density X N. Grain yield increased significantly with N rates. Pest results were obtained with 120 kg N/ha and 40,000 plants/ha. Over-all grain yield was higher in Sabana Grande, a drier southern location. Highest grain yield (8,607 kg/ha) was obtained with Pioneer Brand Hybrid 304C with 40,000 plants/ha and 120 kg N/ha. Highest dry matter yield (9,393 kg/ha) was obtained in Isabela, a more humid northern location, with Pioneer Brand Hybrid 5800 at 40,000 plants/ha and 120 kg N/ha. At both locations over-all leaf area was greatest with application of 120 kg N/ha.

1982 ◽  
Vol 18 (1) ◽  
pp. 93-100 ◽  
Author(s):  
S. U. Remison ◽  
E. O. Lucas

SUMMARYTwo maize cvs, FARZ 23 and FARZ 25, were grown at three densities (37,000, 53,000 and 80,000 plants/ha) in 1979 and 1980. Leaf area index (LAI) increased with increase in plant population and was at a maximum at mid-silk. Grain yield was highest at 53,000 plants/ha. There was no relation between LAI and grain yield but there was a positive correlation between LAI and total dry matter yield.


1988 ◽  
Vol 28 (1) ◽  
pp. 99 ◽  
Author(s):  
MJ Blumenthal ◽  
VP Quach ◽  
PGE Searle

The effect of soybean population density on soybean yield, nitrogen accumulation and residual nitrogen was examined at Camden, N.S.W. (34�S.). In the first experiment, treatments were soybeans (cv. Ransom) at 50, 100, 200 and 400 x 103 plants ha-1; maize (cv. XL66); and a weed-free fallow. Total dry matter yields of tops and grain yields were highest at 200x 103 plants ha-1 (6214 and 3720 kg ha-1, respectively). The yield component most affected by population density was number of branches per plant, with values decreasing with increasing population density. The proportion of unfilled pods was highest at the highest population density. Total nitrogen (N) accumulation in the tops and in the grain was also at a maximum at 200x 103 plants ha-1. The rate of dry matter accumulation declined during pod filling at all population densities. N accumulation continued at high rates throughout the growing season except in the 400x 103 plants ha-1 population. There was a trend for residual dry matter and N in residues to increase with increasing population density. After grain and forage harvest of the first experiment, a crop of wheat (cv. Kite) was sown over the whole area to determine residual N available at anthesis and at maturity (experiment 2). The values of N accumulation in the wheat at maturity were 24 kg N ha-l for the maize treatment, 40-60 kg N ha-l for the soybean treatments and 69 kg N ha-1 for the fallow treatment. Grain yield and grain N followed the pattern of dry matter production and N accumulation at final harvest. The data suggest that soybean depletes soil N to a lesser extent than does maize. For the soybean treatments, there was a trend of increasing residual N at the 3 highest population densities (40-60 kg N ha-1). This was probably a result of an increase in N in leaf fall and in decaying tops and roots at the highest population density. The high value (57 kg N ha-l) at the lowest population density may be due to soybean plants at this density not using as much soil N as the other soybean treatments. No benefit in residual N was gained from planting soybeans at a density beyond the optimum for grain yield when residues were removed by forage harvesting.


Author(s):  
Afolabi Michael Segun ◽  
Ojeleye Abiola Elizabeth ◽  
Olalekan Kazeem Kolapo ◽  
Shittu Kabiru Alani

To investigate the influence of three population densities (88,000, 44,000, and 29,000 plants/ha) on the growth and yield of five cowpea varieties (IT97K-461, IT97K-568-18, IT98K-131-2, IT99K-1060 and IT99K-`245), a field experiment was conducted at Teaching and Research farm of Landmark University. Growth parameters such as germination count, plant height, and number of trifoliate leaves per plant, number of branches per plant, flower production dynamics and dry matter determination were measured, while harvest index, shelling percentage, number of seeds per pod, see weight pods per plant and grain yield were measured at harvest as yield components. Data were subjected to statistical analysis of variance (ANOVA) using SAS Institute. Significant means were separated using Duncans Multiple Range Test at 5% probability level. Results revealed that there were no constant trends in growth parameters response to population density. Plant height and flower production decreased with increased population density, while number of leaves per plant and dry matter increased with increasing population density. There was no appreciable effect of population density on branching. All these parameters were significantly (p≤0.05) affected with variety, while there was no significant (p≤0.05) interaction effect. Most yield components decreased with increasing population density while grain yield however, slightly increased with increasing population density. All yield parameter and grain yield significantly varied with variety, while there were no appreciable interaction effect. In conclusion, a population density of 88,000 plants /ha gives the highest growth and grain yield. While, variety, IT97-568-18 gives the higher growth and grain yield than other varieties studied.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 481a-481 ◽  
Author(s):  
M. Rangappa ◽  
H.L. Bhardwaj

Sweet basil (Ocimum basilicum) is an important culinary herb in Virginia and other areas. The objective of this study, conducted during 1997, was to determine optimal N rate for fresh and dry matter yield. Seed of Broad Leaf sweet basil were direct-seeded on 18 June in rows 0.75 m apart in a RCBD design with 8 replications. Four N rates (0, 25, 50, and 75 kg N/ha) were used. Calcium nitrate (15.5% N) was used as the fertilizer source. All plants from 1-m row length from middle row of each plot were harvested by hand on 23 Sept. and fresh weights were recorded. The plant material was dried at 70°C for 48 h to record dry weights. The moisture content at harvest was calculated from fresh and dry weights. The fresh yields following 0, 25, 50, and 75 kg N/ha were 3.7, 5.4, 6.4, and 6.8 kg/m2, respectively. The yield difference between two highest N rates was not significant, however, both these rates had significantly higher yield than the two lowest rates. Similar results were also obtained for dry matter yields. The highest N rate of 75 kg N/ha resulted in significantly higher dry matter yield (1.3 kg/m2) as compared to the other three rates. The lowest dry matter yield was obtained after the control treatment (0.6 kg/m2). An opposite relationship between N rate and moisture content was observed when the highest moisture content resulted from control and 50 kg N/ha treatments. These results indicate that optimum N rate for sweet basil in Virginia is 50 to 75 kg/ha.


1996 ◽  
Vol 36 (4) ◽  
pp. 443 ◽  
Author(s):  
MG Mason ◽  
RW Madin

Field trials at Beverley (19911, Salmon Gums (1991; 2 sites) and Merredin (1992; 2 sites), each with 5 rates of nitrogen (N) and 3 levels of weed control, were used to investigate the effect of weeds and N on wheat grain yield and protein concentration during 1991 and 1992. Weeds in the study were grasses (G) and broadleaf (BL). Weeds reduced both vegetative dry matter yield and grain yield of wheat at all sites except for dry matter at Merredin (BL). Nitrogen fertiliser increased wheat dry matter yield at all sites. Nitrogen increased wheat grain yield at Beverley and Merredin (BL), but decreased yield at both Salmon Gums sites in 1991. Nitrogen fertiliser increased grain protein concentration at all 5 sites-at all rates for 3 sites [Salmon Gums (G) and (BL) and Merredin (G)] and at rates of 69 kg N/ha or more at the other 2 sites [Beverley and Merredin (BL)]. However, the effect of weeds on grain protein varied across sites. At Merredin (G) protein concentration was higher where there was no weed control, possibly due to competition for soil moisture by the greater weed burden. At Salmon Gums (G), grain protein concentration was greater when weeds were controlled than in the presence of weeds, probably due to competition for N between crop and weeds. In the other 3 trials, there was no effect of weeds on grain protein. The effect of weeds on grain protein appears complex and depends on competition between crop and weeds for N and for water at the end of the season, and the interaction between the two.


1987 ◽  
Vol 108 (3) ◽  
pp. 609-615 ◽  
Author(s):  
I. Papastylianou ◽  
Th. Samios

SummaryUsing data from rotation studies in which barley or woollypod vetch were included, both cut for hay and preceding barley for grain, it is shown that forage barley gave higher dry-matter yield than woollypod vetch (3·74 v. 2·92 t/ha per year). However, the latter gave feedingstuff of higher nitrogen concentration and yield (86 kg N/ha per year for vetch v. 55 kg N/ha per year for barley). Rainfall was an important factor in controlling the yield of the two forages and the comparison between them in different years and sites. Barley following woollypod vetch gave higher grain yield than when following forage barley (2·36 v. 1·91 t/ha). Rotation sequences which included woollypod vetch had higher output of nitrogen (N) than input of fertilizer N with a positive value of 44–60 kg N/ha per year. In rotations where forage barley was followed by barley for grain the N balance between output and input was 5–6 kg N/ha. Total soil N was similar in the different rotations at the end of a 7-year period.


2017 ◽  
Vol 30 (3) ◽  
pp. 670-678 ◽  
Author(s):  
ROGÉRIO PERES SORATTO ◽  
TIAGO ARANDA CATUCHI ◽  
EMERSON DE FREITAS CORDOVA DE SOUZA ◽  
JADER LUIS NANTES GARCIA

ABSTRACT The objective of this work was to evaluate the effect of plant densities and sidedressed nitrogen (N) rates on nutrition and productive performance of the common bean cultivars IPR 139 and Pérola. For each cultivar, a randomized complete block experimental design was used in a split-plot arrangement, with three replicates. Plots consisted of three plant densities (5, 7, and 9 plants ha-1) and subplots of five N rates (0, 30, 60, 120, and 180 kg ha-1). Aboveground dry matter, leaf macro- and micronutrient concentrations, yield components, grain yield, and protein concentration in grains were evaluated. Lower plant densities (5 and 7 plants m-1) increased aboveground dry matter production and the number of pods per plant and did not reduce grain yield. In the absence of N fertilization, reduction of plant density decreased N concentration in common bean leaves. Nitrogen fertilization linearly increased dry matter and leaf N concentration, mainly at lower plant densities. Regardless of plant density, the N supply linearly increased grain yield of cultivars IPR 139 and Pérola by 17.3 and 52.2%, respectively.


1969 ◽  
Vol 98 (2) ◽  
pp. 169-177
Author(s):  
Rafael Ramos-Santana ◽  
Yamil Quijano-Cabrera ◽  
Raúl Macchiavelli

An experiment was conducted to evaluate the dry matter yield and quality performance of Maralfalfa forage obtained at six harvest intervals (HI; 40, 50, 60, 70, 80, 90 d) on three dairies in northern Puerto Rico during the long day season. The 40-day harvest interval was significantly (P < 0.05) inferior in dry matter yield to those of 60, 80, and 90 days; no significant (P < 0.05) differences in yield were observed among intervals of 40, 50 and 70 days. The 40-day interval showed the highest forage quality as indicated by crude protein content, digestibility in vitro of dry matter and neutral detergent fiber, and estimated net energy, index of relative forage quality and theoretical milk production. Although significant (P < 0.05) differences were observed in some of these criteria between 40- and 50-day harvest intervals, the latter maintained a good nutritional value in contrast to drastic losses in quality observed with the longer harvest intervals under study. The simple regression equations between digestibility in vitro of dry matter and of neutral detergent fiber versus harvest interval showed a decrease in digestibility of 2.7 and 3.0 percentage points for each additional 10 days of harvest interval, respectively.


Author(s):  
Camelia RACZ ◽  
Ioan HAS ◽  
Voichita HAS ◽  
Teodora ŞCHIOP ◽  
I COSTE

The maize is one of the most important crops in the world due to its high productivity and multiplexing usage in human nutrition, animal breeding and industry. The isonucleus inbred lines study has been initiated from the demand of clarifying if the cytoplasm source has a positive or negative influence on the corn cars, plants, grain traits and some maize cultural features. The research has been conducted in the experimental field provided by the Maize Breeding laboratory from ARDS Turda, ARDB Târgu-Mureş, ARDS Secuieni, ARDS Livada, ARDS Suceava in 2009. The cell nucleus transfer activity for 12 elite inbred lines on various cytoplasm types has begun in 1992 starting from the assumption that among cytoplasm of different origin could exist differences in the genetic value. The ultimate objective of breeding works is to obtain a higher grain yield and the yield quality to be at the desired level of farmers. For this reason it was studied the effect of different types of cytoplasm on grain yield, kernel dry matter at harvest and unbroken plants percentage at harvest, all these traits are important to achieve secure yield, mechanized harvestable. The kernel dry matter at harvest is one of the indicators of vegetation period, the most used in choice of early single crosses.


1978 ◽  
Vol 90 (3) ◽  
pp. 569-577 ◽  
Author(s):  
G. O. Iremiren ◽  
G. M. Milbourn

SummaryTotal dry-matter yield of maize silage rose asymptotically as density was increased up to 17 plants/m2. Over the range 11–17 plants/m2, which is generally higher than is used in the U.K., the increase in yield was 1–1·6 t dry matter/ha which can justify the higher seed cost and although there was no adverse affect on time of maturity the risk of lodging increased at the highest density. During the harvest period whilst whole crop dry-matter percentage was rising from 23 to 28%, the ear dry-matter content rose steadily from 29 to 35%, whereas the leaf and stem dry-matter content remained essentially constant and only dried out at a later stage after a frost.Caldera 535 had a higher leaf area index and net assimilation rate than the earlier variety Julia which it outyielded by 15%. The additional yield was mainly stem tissue and the greater vegetative production caused an 11-day delay in reaching the silage stage of maturity (25% crop D.M.). NO differences occurred between density treatments and varieties in the forage quality components considered, namely percentage drymatter digestibility, modified acid-detergent fibre, crude protein and ash. Thus in U.K. conditions, total dry-matter yield exerts an overriding influence on the yields per unit area of these quality constituents. This contrasts with reports from the U.S.A. in which a reduced grain/stover ratio adversely influences silage quality.Removal of the whole ear (including husk and rachis) at an early stage in ear development resulted in a 50% reduction in the final dry-matter yield. In the earless plants, leaf area and net assimilation rate was lower, but the dry-matter content of the leaves and stem was considerably higher, and a marked purple coloration developed indicative of excess starch concentration. These results emphasize the need in maize silage not only for an adequate leaf canopy, best obtained early in the growing season by using high planting density and subsequently by using late maturing varieties, but also for sufficient sink capacity in the ear as well as in the stem fraction.


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