scholarly journals Corn Variety Trials on a Eutrustox in Puerto Rico

1969 ◽  
Vol 66 (3) ◽  
pp. 223-234
Author(s):  
G. L. Spain ◽  
S. P. Nightengale ◽  
J. Badillo-Feliciano
Keyword(s):  
Zea Mays ◽  
Puerto Rico ◽  
Zea Mays L ◽  
Northwest Coast ◽  
Grain Yields ◽  
Variety Trials ◽  
Fourth Trial ◽  
Agricultural Experiment

Four corn (Zea mays L.) variety trials were conducted during 1976-78 at the Isabela Agricultural Experiment Substation near the northwest coast of Puerto Rico. The Pioneer brand hybrid X304C ranked highest in three experiments with yields of 9, 782, 3,962 and 8,998 kg/ha of 15.5%-moisture grain, and was second only to X5800 (6,559 kg/ha) in a fourth trial with 5,856 kg/ ha. Other leading hybrids were X304A, X304B, X306B, X105A, H638 and H652. While certain hybrids and local open pollinated varieties yielded significantly less, grain yields among the top ranked entries in each experiment were not significantly different.

scholarly journals Performance of Twelve Corn Hybrids and Selections in Three Consecutive Crops on the Same Site in the Same Year.

1969 ◽  
Vol 63 (2) ◽  
pp. 170-179
Author(s):  
A. Sotomayor-Ríos
Keyword(s):  
Zea Mays ◽  
Puerto Rico ◽  
Zea Mays L ◽  
Average Height ◽  
Average Yield ◽  
Bipolaris Maydis ◽  
Corn Hybrids ◽  
F1 Hybrid ◽  
Soil Disinfestation ◽  
Grain Yields

Twelve corn (Zea mays L.) hybrids and selections were planted three times on the same site in the same year at Isabela, Puerto Rico, according to the following schedule: Nov. 5, 1975 (crop 1); April 21, 1976 (crop 2); and Aug. 13, 1976 (crop 3). Average time to midsilk for the 12 entries was similar in crops 1 and 3 (621 and 6 1.6 days, respectively) but was shorter in crop 2 (59.1 days). Average height to the base of the lowest ear for the 12 entries was 87.1, 106.3, and 99.0 cm for crops 1, 2, and 3, respectively. Average test weight was highest (81.2 kg/hl) in crop 1, decreasing to 72.4 and 55.0 kg/hl in crops 2 and 3, respectively. Average severity of leaf blight, caused by Bipolaris maydis (Nisikado) Shoemaker, was similar in crops 1 and 2. Tne best grain yielder in all three crops was hybrid Pioneer 304 C, with yields of 5,975, 4,103, and 3,729 kg /ha in crops 1, 2, and 3, respectively. The average yield for the 12 entries was 4,598, 3,180, and 2,523 kg/ha in crops 1, 2, and 3, respectively. Nematodes in plots were counted and identified after crop 3 was harvested. The nematode most commonly found in the rhizosphere was Pratytenchus zeae. Plots with Pioneer 304 C, the top yielder, had the second lowest nematode count, 480 per 250 cm3 of soil. Plots with PR-3 and the F1 hybrid PRMo2 x PR-3 had the highest nematode counts, 1040 and 1232 per 250 cm3 of soil, respectively. Although soil disinfestation might have resulted in higher yields, this study showed that three corn crops grown on the same site during the same year can produce grain yields of more than 13,000 kg/ha (205 bu/acre).

scholarly journals Sugarcane Variety Trials in Puerto Rico, 1951-55

1969 ◽  
Vol 41 (3) ◽  
pp. 147-160
Author(s):  
Ferdinand Méndez-Roig ◽  
George Samuels
Keyword(s):  
Puerto Rico ◽  
Puerto Rican ◽  
Sugarcane Variety ◽  
Commercial Variety ◽  
University Of Puerto Rico ◽  
Agricultural Experiment Station ◽  
North Central ◽  
Variety Trials ◽  
Agricultural Experiment ◽  
Entire Island

Sugarcane variety trials performed by the Agricultural Experiment Station, University of Puerto Rico, Río Piedras, P. R., During the period 1951-55, involved 19 separate experiments and 33 crops. The following results are significant: 1. In the production of available 96° sugar per acre B. 37161 was the outstanding variety of East and North Central cane areas of the Island. P.R. 980 was the leading variety in the Northwest, West, South, and Interior of Puerto Rico. 2. B. 40105, B. 37172, B. 41227, H. 328560, and P.R. 975 all were among the leading producers in tons of sugar per acre. 3. The check varieties M. 336, P.O.J. 2878, and P.R. 902, ranked poorly in the trials as compared with the leading varieties in tons of sugar produced per acre. 4. In terms of tons of cane per acre B. 37161 and P.R. 980 were the two leading varieties for the entire Island, with H. 328560, B. 41227, and B. 37172 also showing favorable cane-tonnage figures. All check varieties did poorly in tons of cane per acre as compared to the leading variety. 5. The varieties were also ranked according to their production of sucrose-percent- cane. P.R. 975 and B. 4362 were first and second, respectively. These two varieties also produced higher cane tonnage than the favored commercial variety M. 336, which ranked third. 6. Finally, the varieties were ranked according to the tons of sugar per acre produced per month, and P.R. 980 ranked first. The first eight experimental varieties produced over 0.60 ton of sugar per acre per month as compared with all commercial varieties, except B. 37161, which produced below 0.50 ton of sugar per acre per month. 7. The reluctance of Puerto Rican farmers to adopt the new cane varieties tested and proven superior to the old commercial varieties is very unprofitable to them. Yields are cited which show that if the land now used to grow the older cane varieties were planted to the new leading experimentally tested varieties discussed in this article, the present sugar crop in Puerto Rico could be produced on about two-thirds of the present acreage. This would release over 100,000 acres for other agricultural uses.

scholarly journals Nitrogen fertilizer rate for improving inbred maize (Zea mays L.) yield on the semi-arid southern coast of Puerto Rico

2017 ◽  
Vol 101 (2) ◽  
pp. 185-202
Author(s):  
Johanie Rivera-Zayas ◽  
David Sotomayor-Ramírez ◽  
Ricardo Barnes
Keyword(s):  
Zea Mays ◽  
Puerto Rico ◽  
Grain Yield ◽  
Plant Height ◽  
Cover Crop ◽  
Crop Production ◽  
Zea Mays L ◽  
Plant Density ◽  
Fertilizer N ◽  
Semi Arid

Nitrogen (N) is possibly the most limiting nutrient for crop production on the southern semi-arid coast of Puerto Rico. In efforts to improve inbred maize (Zea mays L.) grain yield, fertilizer N is sometimes aggressively managed. In this paper, we report on the results of a field experiment that evaluated the effect of six rates of fertilizer N (0, 34, 68,102,135 and 203 kg N/ha) and of cowpea (Vigna unguiculata cv. Iron-clay), planted as a cover crop during the offseason, on inbred maize grain yield. The soil was Jacaguas series (Loamy-skeletal, mixed, superactive, isohyperthermic Fluventic Haplustolls) on the Dow Agrosciences experimental farm in Santa Isabel, Puerto Rico. Cowpea was planted on 13 July 2013 and incorporated into the soil on 20 September 2013. An inbred maize line was planted on 19 December 2013 and harvested on 19 March 2014 at a plant density of 51,645 plants per hectare. Irrigation was provided via drip system, and fertilizer N was applied at three different stages during the growing season: at emergence, 21 and 37 days after planting. Measurements of plant height, chlorophyll readings using SPAD-502® and GreenSeeker®, and leaf N concentration were used as indicators of treatment response and N sufficiency. The maximum grain yield of 2,918 kg/ha was attained with the fertilizer N rate of 68 kg N/ha. The cowpea cover crop rotation did not affect grain yield (P>0.05). Plant height, and measurements by SPAD-502® and GreenSeeker® provided adequate indicators of crop N sufficiency during the vegetative stages V6 to V12, with optimum values of 149 cm, 46, and 0.67 NDVI, respectively, 52 days after planting with an application of 68 kg N/ ha. Crop response to fertilizer N occurred at a lower rate than in previous studies and those occurring under conventional commercial conditions. Other factors related to fertilizer N management, such as sources, placement and timing of application might be as important for grain yield improvement of inbred maize.

scholarly journals Effect of Intercropping Dates of Lablab (Lablab purpureus L.) with Maize (Zea mays L.) on Forage and Maize Grain Yields

2020 ◽  
pp. 1-4
Author(s):  
Meseret Redae ◽  
Desta Tekle
Keyword(s):  
Zea Mays ◽  
Dry Matter ◽  
Zea Mays L ◽  
Block Design ◽  
Forage Yield ◽  
Lablab Purpureus ◽  
Grain Yields ◽  
Maize Grain Yield ◽  
Randomized Complete Block Design ◽  
Maize Grain

This study was conducted to evaluate effect of intercropping dates of lablab (Lablab purpureus L.) with maize (Zea mays L.) on forage and maize grain yields. It was carried out at Gereb Giba in Tanqua Abergelle district, Tigray, Ethiopia. Randomized Complete Block Design (RCBD) with four treatments and four replications were used. The treatments were sole maize sown (T1) and lablab sown at 10, 20 and 30 days after emergence of maize for T2, T3 and T4 respectively. Intercropping did not affect height and days for 50% flowering of lablab. Similarly, it was not affected height and days for physiological maturity of maize. Lablab forage yield was significantly greater (p<0.01) in T2 and T3 than T4. Maize Stover dry matter (DM) yield was similar among treatments while total forage DM yield was significantly higher (p<0.0001) in T2, T3 and T4 than T1. Moreover, among the intercrops, total forage yield was significantly highest (p<0.0001) for T2 compared to T4 but similar in T2 and T3. Maize grain yield was significantly superior (P<0.0001) in T2 and T3 compared to T1 and T4. Though, T2 and T3 had similarity in all parameters measured, T2 provided higher forage and maize grain yields than T1 and T4. Therefore, lablab intercropping at 10 days after emergence of maize is appropriate in Tanqua Abergelle district and other areas with similar agro ecologies.

scholarly journals Impact of Increasing Maize Densities on Agronomic Performances and the Community Stability of Productivity of Maize/Peanut Intercropping Systems

Agronomy ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 150 ◽  
Author(s):  
Haiyong Xia ◽  
Lan Wang ◽  
Yanfang Xue ◽  
Weilin Kong ◽  
Yanhui Xue ◽  
...  
Keyword(s):  
Zea Mays ◽  
Community Structure ◽  
Zea Mays L ◽  
Agronomic Traits ◽  
Community Stability ◽  
Grain Yields ◽  
Arachis Hypogaea L ◽  
Biomass Yields ◽  
Maize Grain ◽  
Positive Correlations

Rational crop community structure plays an important role in maximizing the intercropping yield advantage. Effects of increasing maize densities in maize (Zea mays L.)/peanut (Arachis hypogaea L.) intercropping on yields and other agronomic traits, and the community stability of productivity were conducted across three different experimental sites. There were significant and positive correlations between maize densities and both maize grain/biomass yields and corresponding partial land equivalent ratios (LERs) across all three locations; but grain/biomass yields and partial LERs of peanut were all negatively correlated with maize densities in each or across all locations. LERs of grain yields averaged over three locations ranged from 0.89 to 0.98, while LERs of biomass yields ranged from 0.94 to 1.09 (>1.0 except for the maize inter-plant distance of 27 cm), indicating the intercropping advantage on biomass yields but not grain yields. Peanut had significantly lower kernel harvest indexes than those in monoculture. Excessive narrowing maize inter-plant distances reduced the community stability of productivity severely (especially for maize and total LERs) and are more likely to lead to abnormal maize and peanut plants. Therefore, a rational increase of maize densities in intercropping is suggested to keep the balance between maize and peanut and the comprehensive yield advantage.

Corn yield, nitrogen uptake and nitrogen use efficiency as influenced by nitrogen fertilization

1994 ◽  
Vol 74 (2) ◽  
pp. 235-240 ◽  
Author(s):  
B. C. Liang ◽  
A. F. MacKenzie
Keyword(s):  
Zea Mays ◽  
Nitrogen Use Efficiency ◽  
Zea Mays L ◽  
Quadratic Functions ◽  
Price Ratio ◽  
Fertilizer N ◽  
Fertilizer Rate ◽  
Nitrogen Use ◽  
Grain Yields ◽  
Use Efficiency

Improving efficient use of applied nutrients in crop production is a desirable agronomic, economic, and environmental goal. Field experiments with corn (Zea mays L.) were carried out at two sites with contrasting soil textures in southwestern Quebec from 1988 to 1990. Objectives were to establish an optimum N fertilization rate for grain production, and to study fertilizer N use efficiency on a Chicot sandy clay loam (Grey Brown Luvisol) and a Ste. Rosalie clay (Humic Gleysol). Under favourable heat units and rainfall, yields of grain corn were quadratic functions of fertilizer N rates on both soils. Maximum grain yields of corn were calculated to require from 300 to 350 kg N ha−1 fertilizer application. However, large amounts of N fertilizer at both 285 kg ha−1 and 400 kg ha−1 were not recovered by the crop. Optimum economic grain yields at a price ratio of 10:1 N:grain were found at 273 kg N ha−1 on the Ste. Rosalie site in 1990, and 286 and 179 kg N ha−1 for 1989 and 1990, respectively, on the Chicot site. A normal fertilizer rate (170–44–141 kg N–P–K ha−1) and a high fertilizer rate (400–132–332 kg N–P–K ha−1) were used in 1989 and 1990 for 15N microplot experiments. Grain and stover fertilizer N recovery (FNR) varied with N rate and year from 9 to 58%. Favourable climatic conditions substantially increased crop yield, and thus crop FNR. Residual FNR the second year was less than 5% of the initial applied N. Key words:15N, grain yield, Zea mays L., nitrogen use efficiency, fertilization

scholarly journals Sugarcane Variety Trials in Puerto Rico, 1952-57

1969 ◽  
Vol 43 (1) ◽  
pp. 1-18
Author(s):  
F. Méndez-Roig ◽  
G. Samuels ◽  
A. Colón
Keyword(s):  
Puerto Rico ◽  
Sugarcane Variety ◽  
University Of Puerto Rico ◽  
Agricultural Experiment Station ◽  
North Central ◽  
Eastern Area ◽  
Variety Trials ◽  
The North ◽  
Agricultural Experiment ◽  
The University

The sugarcane variety trials performed by the Agricultural Experiment Station of the University of Puerto Rico, Río Piedras, P.R., during the period 1952-57, involved 24 separate experiments and 51 crops. The following results are significant: 1. In the production of available 96° sugar per acre P.R. 980 was the outstanding variety of the Southern, Western, Northwestern, and Interior Areas of the Island. B. 37161 was first in the Eastern Area and in Caguas Valley, and it tied P.R. 980 in the North Central and B. 41227 in the Northeastern Areas of Puerto Rico. 2. P.R. 980 was first in 10 and B. 37161 in 6 of the 24 experimental sites in terms of tons of cane produced per acre. 3. The check varieties, M. 336, P.O.J. 2878, and P.R. 902 and 905, produced low yields in both tons of cane and of sugar per acre as compared with the leading varieties. 4. M. 336, P.R. 1016, M. 975, and P.P.Q.K. were the leading varieties in sucrose-percent-cane. 5. P.R. 980 and P.R. 1013 ranked first in tons of sugar produced per acre per month. 6. For agronomic evaluation, the leading varieties were ranked in a table in which consideration was given to such factors as germination, stooling, ratooning habit, girth, erectness, flowering, trashiness, and disease resistance.

INFLUENCE OF HERBICIDE USE AND INTER-ROW TILLAGE ON CORN YIELDS AND SOIL CONDITIONS

1984 ◽  
Vol 64 (2) ◽  
pp. 405-409 ◽  
Author(s):  
D. R. COOTE ◽  
W. J. SAIDAK
Keyword(s):  
Zea Mays ◽  
Bulk Density ◽  
Soil Structure ◽  
Zea Mays L ◽  
Soil Bulk Density ◽  
Soil Conditions ◽  
Grain Yields ◽  
Tillage Operation ◽  
Hand Weeding ◽  
Herbicide Use

Six herbicide treatments and hand weeding of grain corn (Zea mays L.) were compared with and without a single inter-row tillage operation in June. Grain yields were significantly increased by tillage and negatively correlated with weed weights. In a subset of plots, surface soil bulk density was lower, and air-filled porosity was higher after the tillage. Bulk densities were decreased in September by a possible interaction between inter-row tillage and herbicide use. Grain yields were negatively correlated with bulk density in June and positively correlated with soil moisture in September, suggesting that some of the yield improvement from tillage was the result of better soil physical conditions.Key words: Zea mays L., atrazine, herbicides, tillage, soil structure, bulk density

The effects of dazomet and nitrogen fertilizer on successive crops of maize (Zea mays L.) grown for either grain or forage

1982 ◽  
Vol 98 (1) ◽  
pp. 7-15 ◽  
Author(s):  
A. J. Barnard ◽  
D. Hornby
Keyword(s):  
Zea Mays ◽  
Nitrogen Fertilizer ◽  
Dry Matter ◽  
Zea Mays L ◽  
Grain Yields ◽  
Nodal Roots ◽  
Seminal Roots

SUMMARYMaize was grown for grain or forage on the same site at Woburn for 7 consecutive years. Yields were satisfactory and there were no serious pest or disease problems, provided the small plots were netted until young plants were established. Different rates of nitrogen fertilizer were tested with and without annual applications of a soil sterilant, dazomet. Average yields of grain (85% dry matter) and forage (dry matter) were respectively 4·5 and 8·8 t/ha with 50 kg N/ha and 5·0 and 9·5 t/ha with 100 kg N/ha. Without dazomet there was a further increase with 150 kg N/ha. Weather influenced the response to nitrogen, and the response to a split dressing of the highest rate was variable. Except for plots receiving the split dressing of N in 1973 and 1974 dazomet always increased yields: grain yields were increased on average by 1 t/ha and forage by 1·6 t/ha. Dazomet-treated plots had taller and heavier plants with more stems, leaves and nodal roots, but fewer seminal roots than untreated plots. Dazomet-treated plots also had fewer migratory nematodes and smaller and less varied root myoofloras. Most of these differences were greatest in the young crop and possible reasons for this ‘early boost’ are discussed.

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