scholarly journals Effects of Irrigation at Different Growth Stages, and of Nitrogen Levels on Corn Yields in Lajas Valley, P.R.

1969 ◽  
Vol 45 (2) ◽  
pp. 85-105
Author(s):  
Roberto Vázquez
Keyword(s):  
Field Experiments ◽  
Root Zone ◽  
Growing Season ◽  
Growth Stages ◽  
Nitrogen Levels ◽  
Field Corn ◽  
Different Growth Stages ◽  
Active Root

Two field experiments using nine irrigation and three nitrogen levels were conducted at Lajas Substation in order to determine the effects of irrigation at different growth stages on the production of field corn. Some plots were frequently irrigated, irrigated when 20 percent of the available moisture had been depleted from the active root zone; and intermediately irrigated, irrigated when the depletion was 60 percent throughout the whole growing season. Other plots were frequently irrigated from planting to the tasseling, silking, and hard-dough stages, not being irrigated thereafter; while others still were not irrigated after the crop was established until the tasseling, silking, and hard-dough stages; these plots were frequently irrigated thereafter. Nonirrigated plots were used as checks.

Effects of Irrigation, Nitrogen Levels, and Plant Population on Corn Yields in Lajas Valley, P. R.

1969 ◽  
Vol 44 (3) ◽  
pp. 121-137
Author(s):  
Roberto Vázquez
Keyword(s):  
Nitrogen Fertilizer ◽  
Field Experiments ◽  
Root Zone ◽  
Plant Population ◽  
Plant Populations ◽  
Nitrogen Levels ◽  
Field Corn ◽  
Active Root

Three field experiments using three irrigation, three nitrogen, and three plant-population levels were conducted at Lajas Substation in order to determine the effect of irrigation in combination with nitrogen fertilizer and different plant populations on the production of field corn. "Frequently irrigated" plots were irrigated when 20 percent of the available moisture had been depleted from the active root zone, "intermediately irrigated" plots when the depletion was 60 percent, and "nonirrigated" plots were used as a check. The nitrogen levels tested were 0, 80, and 160 pounds per acre, and the plant-population levels were 9,600, 14,500, and 19,400 plants per acre.

scholarly journals Response of Native White Sorghum to Irrigation under Different Nitrogen-Fertility Levels and Seeding Rates in Lajas Valley, Puerto Rico

1969 ◽  
Vol 50 (2) ◽  
pp. 92-112
Author(s):  
R. Vázquez ◽  
A. Eschenwald-Hess ◽  
M. J. Martínez-Luciano
Keyword(s):  
Puerto Rico ◽  
Soil Moisture ◽  
Field Experiment ◽  
Dry Matter ◽  
Root Zone ◽  
High Moisture ◽  
Nitrogen Levels ◽  
Nitrogen Fertility ◽  
Native White ◽  
Active Root

A field experiment was conducted at Lajas Substation in order to study the effects of four irrigation and three nitrogen levels under three different seeding rates on dry-matter yields of White Native sorghum. The following irrigation treatments were tried: High moisture, plots irrigated when the average soil-moisture suction in the active root-zone reached 0.7 atm.; medium moisture, irrigated when the average soil-moisture suction reached 2.0 atm.; low moisture, irrigated when the average soil-moisture suction reached 5.0 atm., and nonirrigated plots were used as check. The nitrogen levels tested were 40, 80, and 120 pounds per acre per harvest. The seeding rates used were 10, 20, and 30 pounds per acre.

scholarly journals Development of Chlorophyll-Meter-Index-Based Dynamic Models for Evaluation of High-Yield Japonica Rice Production in Yangtze River Reaches

Agronomy ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 106 ◽  
Author(s):  
Ke Zhang ◽  
Xiaojun Liu ◽  
Syed Tahir Ata-Ul-Karim ◽  
Jingshan Lu ◽  
Brian Krienke ◽  
...  
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
High Yield ◽  
Accurate Estimation ◽  
Growth Stages ◽  
Rice Grain ◽  
Japonica Rice ◽  
Ripening Period ◽  
The Third ◽  
Different Growth Stages

Accurate estimation of the nitrogen (N) spatial distribution of rice (Oryza sativa L.) is imperative when it is sought to maintain regional and global carbon balances. We systematically evaluated the normalized differences of the soil and plant analysis development (SPAD) index (the normalized difference SPAD indexes, NDSIs) between the upper (the first and second leaves from the top), and lower (the third and fourth leaves from the top) leaves of Japonica rice. Four multi-location, multi-N rate (0–390 kg ha−1) field experiments were conducted using seven Japonica rice cultivars (9915, 27123, Wuxiangjing14, Wunyunjing19, Wunyunjing24, Liangyou9, and Yongyou8). Growth analyses were performed at different growth stages ranging from tillering (TI) to the ripening period (RP). We measured leaf N concentration (LNC), the N nutrition index (NNI), the NDSI, and rice grain yield at maturity. The relationships among the NDSI, LNC, and NNI at different growth stages showed that the NDSI values of the third and fourth fully expanded leaves more reliably reflected the N nutritional status than those of the first and second fully expanded leaves (LNC: NDSIL3,4, R2 > 0.81; NDSIothers, 0.77 > R2 > 0.06; NNI: NDSIL3,4, R2 > 0.83; NDSIothers, 0.76 > R2 > 0.07; all p < 0.01). Two new diagnostic models based on the NDSIL3,4 (from the tillering to the ripening period) can be used for effective diagnosis of the LNC and NNI, which exhibited reasonable distributions of residuals (LNC: relative root mean square error (RRMSE) = 0.0683; NNI: RRMSE = 0.0688; p < 0.01). The relationship between grain yield, predicted yield, and NDSIL3,4 were established during critical growth stages (from the stem elongation to the heading stages; R2 = 0.53, p < 0.01, RRMSE = 0.106). An NDSIL3,4 high-yield change curve was drawn to describe critical NDSIL3,4 values for a high-yield target (10.28 t ha−1). Furthermore, dynamic-critical curve models based on the NDSIL3,4 allowed a precise description of rice N status, facilitating the timing of fertilization decisions to optimize yields in the intensive rice cropping systems of eastern China.

Effect of silicon at panicle initiation on the growth of rice (Var. ADT-36) plants at different growth stages

2002 ◽  
Vol 50 (2) ◽  
pp. 179-184
Author(s):  
P. M. Arthanari ◽  
P. Gnanamoorthy ◽  
S. Ramasamy
Keyword(s):  
Tamil Nadu ◽  
Dry Matter ◽  
Field Experiments ◽  
Dry Matter Production ◽  
Growth Stages ◽  
Maturity Stage ◽  
Maturity Stages ◽  
Matter Production ◽  
Initiation Stage ◽  
Different Growth Stages

Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India during the Rabi (November 1997-March 1998) and Kharif (July 1998-November 1998) seasons to identify the effect of silicon at panicle initiation on the growth of rice plant (Variety ADT-36) at different growth stages. Furnace slag was applied as a silicon source at 2 t/ha at the panicle initiation stage along with other nutrients. The dry matter production was recorded at the active tillering, panicle initiation, booting, flowering, one week after flowering and maturity stages in both the seasons. The total dry matter production was greater in the Kharif season than in the Rabi season. The application of slag at the panicle initiation stage along with N and K at the flowering stage had a significant influence over the dry matter production. A similar trend was observed in both the seasons. The silicon uptake was recorded at the panicle initiation and maturity stages. About 30-40% of the silicon absorbed during the early stages and the maturity stage was present in the shoot, whereas 20-30 % of the silicon absorbed during the maturity stages was present in the leaf blades. Based on the results, it is concluded that the supply of silicon during the panicle initiation stage is most important for plant growth.

SENSITIVITY OF CROP PLANTS TO WATER STRESS AT SPECIFIC DEVELOPMENTAL STAGES: REEVALUATION OF EXPERIMENTAL FINDINGS

1995 ◽  
Vol 43 (2) ◽  
pp. 99-111 ◽  
Author(s):  
Zvi Plaut
Keyword(s):  
Water Stress ◽  
Irrigation Water ◽  
Field Experiments ◽  
Developmental Stages ◽  
Growth Period ◽  
Soluble Solids ◽  
Growth Stages ◽  
Mild Stress ◽  
Uniform Reduction ◽  
Different Growth Stages

It has been suggested that in many crops differences in sensitivity to water stress occur at different growth stages. Since identical amounts of water may be applied, irrespective of whether a crop is exposed to relatively severe and short periods of stress or to extended periods of mild stress, the responses to such differing conditions should be compared. Unfortunately, such a comparison has not been conducted in most studies on sensitivity to water stress at different growth stages. In the present study, based on three field experiments conducted for different purposes, such a comparison was made for three crops: corn, sunflower, and tomato. In corn, distinct responses of ear and kernel yields to the timing of water stress were found. Withdrawal of irrigation water during flowering and cob formation resulted in greater yield losses than during other stages, indicating that this is a critical growth stage. However, slight and uniform reduction of water during the entire growth period resulted in significantly less damage to kernel or ear production, although the total amount of water applied was similar to that under staged withdrawal. In sunflowers, the withdrawal of irrigation water even at noncritical growth stages caused a more marked reduction in grain yield than did a uniform reduction throughout the entire season. In tomatoes, on the other hand, the withdrawal of irrigation water during specific growth stages caused minimal damage to fruit and total soluble solids yield as compared with fully irrigated control; reduction of irrigation water throughout the season brought about a significant decrease in yield. The difference between these crops is interpreted on the basis of the determinance of their floral meristems.

Field Pea and Lentil Tolerance to Interrow Cultivation

2017 ◽  
Vol 32 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Katherine A. Stanley ◽  
Steven J. Shirtliffe ◽  
Dilshan Benaragama ◽  
Lena D. Syrovy ◽  
Hema S. N. Duddu
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Yield Loss ◽  
Growing Season ◽  
Field Pea ◽  
Crop Damage ◽  
Growth Stages ◽  
Row Crops ◽  
Narrow Row ◽  
Mechanical Weed Control

AbstractInterrow cultivation is a selective, in-crop mechanical weed control tool that has the potential to control weeds later in the growing season with less crop damage compared with other in-crop mechanical weed control tools. To our knowledge, no previous research has been conducted on the tolerance of narrow-row crops to interrow cultivation. The objective of this experiment was to determine the tolerance of field pea and lentil to interrow cultivation. Replicated field experiments were conducted in Saskatchewan, Canada, in 2014 and 2015. Weekly cultivation treatments began at the 4-node stage of each crop, continuing for 6 wk. Field pea and lentil yield linearly declined with later crop stages of cultivation. Cultivating multiple times throughout the growing season reduced yield by 15% to 30% in both crops. Minimal yield loss occurred when interrow cultivation was conducted once at early growth stages of field pea and lentil; however, yield loss increased with delayed and more frequent cultivation events.

Response of Chickpea Cultivars to Imidazolinone Herbicide Applied at Different Growth Stages

2016 ◽  
Vol 30 (3) ◽  
pp. 664-676 ◽  
Author(s):  
M. Laura Jefferies ◽  
Christian J. Willenborg ◽  
Bunyamin Tar'an
Keyword(s):  
Great Plains ◽  
Growth Stage ◽  
Field Experiments ◽  
Northern Great Plains ◽  
Yield Reduction ◽  
Growth Stages ◽  
Resistant Cultivars ◽  
Node Development ◽  
Different Growth Stages ◽  
Chickpea Cultivars

POST broadleaf weed control options in chickpea are very limited on the Northern Great Plains. Field experiments were conducted in 2012 and 2013 in Saskatchewan to evaluate the response of chickpea cultivars to imidazolinone (IMI) herbicides applied at different growth stages. Conventional cultivars ‘CDC Luna’ and ‘CDC Corinne’ were compared with IMI-resistant cultivars ‘CDC Alma’ and ‘CDC Cory’. Treatments comprised a combination of imazethapyr + imazamox herbicides at 30 and 60 g ai ha−1(1× and 2× rates, respectively) applied at the 2 to 4-, 5 to 8-, and 9 to 12-node growth stages. Visual injury estimates were > 50% for CDC Luna and CDC Corinne for all growth stage applications. Conventional cultivars also experienced height reduction and decreased rate of node development compared with the nontreated controls. Flowering and maturity of CDC Luna and CDC Corinne were delayed for herbicide applications at all growth stages; however, application at the 9 to 12-node stage caused the most severe delay. All treatments of IMI herbicide caused yield reduction in the conventional cultivars in 2013. In contrast, IMI-resistant cultivars CDC Alma and CDC Cory demonstrated no negative response at any growth stage of IMI herbicide application. Visual injury estimates were negligible, and height, node development, days to flowering, maturity, and yield did not differ significantly between IMI-treated plants and the respective controls. These results demonstrated the potential of in-crop use of IMI herbicide on resistant chickpea cultivars to control broadleaf weeds.

Critical concentrations of potassium in cotton (Gossypium hirsutum)

1992 ◽  
Vol 118 (1) ◽  
pp. 71-75 ◽  
Author(s):  
D. Singh ◽  
M. S. Brar ◽  
A. S. Brar
Keyword(s):  
Gossypium Hirsutum ◽  
Field Experiments ◽  
Relative Yield ◽  
Development Stage ◽  
Growth Stages ◽  
Flower Initiation ◽  
Flowering Stage ◽  
Plant Parts ◽  
The Third ◽  
Different Growth Stages

SUMMARYPotassium concentrations in various plant parts of cotton (Gossypium hirsutum L.) at different growth stages were determined in field experiments in Punjab, India, in 1987, for plots fertilized at sowing and flowering, and these were compared with the final seed cotton yield. The optimum time of sampling for predicting relative yield depends on the time of K fertilizer application: if applied at sowing, plants should be sampled before the peak flowering stage (70 days after sowing, DAS); if applied at flowering (50 DAS), plants should be sampled 90–115 DAS. Critical K concentrations (% K. in dry matter) in the plant parts measured at different growth stages were 3·26 in the petioles of the third leaf from the top at flower initiation; 0·69 and 0·90 in blades and petioles of a lower leaf (first or second healthy leaf from the bottom of plant) respectively, and 2·60 in the petioles of the third leaf (young, fully mature leaf from the top of the plant) at peak flowering stage; 0·85 in blades of the third leaf, 0·53 and 0·50 in blades and petioles of a lower leaf, respectively, at the boll development stage; 0·70 and 2·85 in blades and petioles of the third leaf and 0·68 in petioles of a lower leaf at boll opening stage.

Efficacy of increasing application rates and combination of herbicides and mowing at different growth stages of common teasel (Dipsacus fullonum)

2020 ◽  
pp. 1-27
Author(s):  
Juan F. F. Daddario ◽  
Guillermo Tucat ◽  
Osvaldo A. Fernandez ◽  
Diego J. Bentivegna
Keyword(s):  
Field Experiments ◽  
Growth Stages ◽  
Invasive Weed ◽  
Leaf Stage ◽  
Additional Information ◽  
Application Rates ◽  
The Impact ◽  
North And South America ◽  
North And South ◽  
Different Growth Stages

Abstract Common teasel is a troublesome invasive weed in North and South America. Additional information on the efficacy of herbicide application and mowing at different growth stages will help in common teasel management. Firstly, an outdoor pot experiment was performed to assess increasing application rates and combinations of glyphosate and 2,4-D amine, when applied at four leaf, rosette and bolting stages. Secondly, field experiments were performed to evaluate the impact of time of cutting on invasive common teasel plant height, head number, and head length. Finally, germinability of seeds collected from naturally growing plants was determined to evaluate the feasibility of mowing invasive common teasel after flowering. Only glyphosate applied at 1.08 kg ae ha-1 at four leaf stage provided adequate control (>90%). Although control was not satisfactory (<90%) when applying glyphosate at 2.16 kg ae ha-1 at rosette and bolting stages, and 2,4-D at 1.75 kg ae ha-1 at four leaf stage, significant injury and biomass decline were observed. Glyphosate and 2,4-D combinations did not improve common teasel control compared with single applications. Cutting rosettes strongly reduced inflorescence production (34-42%) and cutting flowering plants prevented total regrowth. Germination of seeds averaged 14% when harvested 10 d after flowering, and maximum seed germination (>90%) was found 30 d after flowering. Glyphosate applied alone at the recommended commercial rate early in the growing season together with cutting at the flowering stage, may be the most beneficial way of controlling invasive common teasel.

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