Effect Of Different Fertilizer Levels Research Articles

VARIATION OF CHLOROPHYLL AND CAROTENOID PIGMENTS IN SOME WINTER WHEAT FLAG LEAF UNDER DIFFERENT FERTILIZER REGIMES

Five Romanian winter wheat genotypes were analyzed during two experimental years (2019-2020) under four different regime fertilizers for chlorophyll a, chlorophyll b and carotenoid contents from flag leaf, respectively, number of grains/spike, weight of grains/spike, thousand kernel weight. The results showed that the application of additional fertilization increase the analyzed traits, also causing an increase of traits variability. Regarding the variation of photosynthetic pigments from flag leaf as an effect of different fertilizer levels, their concentration is specific to each variety. The highest value of chlorophyll a type is observed in Cezara variety (665.83 mg/kg DW) at N150 kg s.a./ha fertilization level applied in a boot stage. The variation of chlorophyll b concentration in flag leaf is similar to chlorophyll a concentration as a reaction of different nitrogen dose aplication, the highest value for this type of chlorophyll being registered in T. 109-12 at F4 (519.64 mg/kg DW). Carotenoid concentration from flag leaf varies from 3.93 mg/kg DW at Dumitra variety (F3) to 97.63 mg/kg DW at Andrada variety in F2 fertilization level.

Effect of Different Fertility Levels on Growth and Production Potential of Rice Genotypes

A field experiment was conducted during kharif season of 2019 at Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar (Uttarakhand) for evaluation of six rice genotypes (IET-27263, IET-26418, IET-26420, NDR-359, PD-19 and PD-26) under varying fertility levels (Control, 100% RDF, 150% RDF). Treatments were tested in Split Plot Design with three replications keeping fertilizer levels in main plots and genotypes in sub plots.
 Application of fertilizer at 150% RDF and genotype IET-27263 resulted in significantly taller plants, highest number of tillers, highest dry matter accumulation over all other fertilizer levels.
 So, it can be recommended that application of fertilizers at higher dose is essential for obtaining higher yield of rice as most of the parameters of growth, development and yield were responding well up to 150% RDF. The new rice genotype IET27263 was found superior to all other tested genotypes.

Effect of different fertility levels on various varieties of scented rice

Effect of different fertility levels on various varieties of scented rice

Effect of different fertilizer levels on yield performance of black cumin in Brahmaputra and Jamuna floodplain soil of Bangladesh

Although black cumin is an important spice and medical crop, the average yield is low in Bangladesh. The imbalance of fertilizer and local cultivar use are the major causes of the low yield of black cumin. Therefore, an attempt was made to develop and evaluate the performances of different fertilizer doses (in terms of crop productivity and economic performance) for improved varieties of black cumin in the farmers’ field at the Multi Location Testing site, Bhuapur, Tangail in 2017-18 and 2018-19. Treatment included Soil Test Based fertilizer dose - STB (106-32-30-12-2-1 kg NPKSZnB ha-1) as per Fertilizer Recommendation Guide, 2012, STB + 15% extra NPK (122-37-35-12-2-1 kg NPKSZnB ha-1), STB + 30% extra NPK (138-42-39-12-2-1 kg NPKSZnB ha-1) and Farmer’s practice (35-15-19 kg NPK ha-1) and two varieties of black cumin namely V1 = BARI Kalozira-1 and V2 = Local. The experiment was conducted in a Randomized Complete Block Design with six replications. Among the treatment combinations, the highest average seed yield (1.24 t ha-1) and gross margin (Tk. 130179 ha-1) along with BCR (2.74), were obtained from STB with BARI Kalozira-1. The lowest average seed yield (0.54 t ha-1) and gross margin (Tk. 24414 ha-1), along with BCR (1.38), was recorded from a local variety with farmer’s practiced fertilizer dose.

A study of wheat-weed response and economical analysis to fertilization and post-emergence herbicides under arid climatic conditions

A two-year field experiment was conducted in two consecutive rabi seasons under arid climatic conditions to examine the effect of different fertility levels and herbicides on weed dynamics and the performance of wheat (Triticum aestivum L.). Results revealed that a significantly minimum weed dry weight was recorded with 75% RDF (Recommended Dose of Fertilizer) (90-30 kg N-P2O5/ha). Application of 100% RDF (120-40 kg N-P2O5/ha) recorded significantly higher weed dry weight at 35 DAS (Days After Sowing) (16.50 g/m2) and harvest (28.15 g/m2), growth and yield attributes i.e. plant height (89.14 cm), crop dry matter accumulation (300.8 g/meter row length), crop growth rate (17.08 g/m2/day), leaf area index at 50 DAS (3.06, net assimilation rate 50-75 DAS, length of the spike (13.36 cm), number of grains/spike (41.52), grain yield (4083 kg/ha), straw yield (5019 kg/ha) and biological yield (9103 kg/ha) over 75% RDF. This treatment remains at par with 125% RDF (150-50 kg N-P2O5/ha) except for the leaf area index at 75 DAS. Among the herbicidal treatments, application of the ready-to-use herbicides clodinafop-propargyl 15% + metsulfuron methyl 1% @ 64 g/ha provided a superior value of weed indices i.e. higher weed control efficiency (91.30), crop resistance-index, and herbicide efficiency-index, and lower weed-index (1.91) over other herbicides. This treatment also exhibited significantly higher plant height (92.33 cm), crop dry matter accumulation (325.5g/meter row length), crop growth rate (16.49 g/m2/day), leaf area index (3.15), net assimilation rate, length of the spike (14.28 cm), number of spike/meter row length (153.0), number of grains/spike (44.52), grain yield (4374 kg/ha), straw yield (5381 kg/ha) and biological yield (9755 kg/ha) over weedy check plot, which was followed by sulfosulfuron 75% + metsulfuron methyl 5% @ 32 g/ha, both of which remained statistically at par with each other except for the number of grains/spike. The application of 100% RDF and clodinafop-propargyl 15% + metsulfuron methyl 1% @ 64 g/ha recorded higher net returns and maximum B: C ratio.

The residual effect of different levels of rice mill ash on maize-soybean intercrop

A two year (2013 and 2014) field trial was conducted to study the residual effect of different fertility levels of rice mill ash (RMA) on maize-soybean intercrop. The experiment was arranged in a randomized complete block design (RCBD) comprising of nine (9) treatments and three (3) replications. The treatments where sole maize (SMO), sole soybean (SBO), maize/soybean intercrop without application of rice mill ash (IMBO), soybean + 10 t/ha rice mill ash (SB10), sole maize + 10 t/ha rice mill ash (SM10), maize - soybean intercrop + 10 t/ha rice mill ash (IMB10), sole maize + 20 t/ha rice mill ash (SM20); sole soybean + 20 t/ha rice mill ash (SB20) and maize/soybean intercrop + 20 t/ha rice mill ash (IMB20). Data generated was subjected to analysis of variance of which the result of the study showed that for 2 years under study, incorporated rice mill ash (RMA) and intercropping system significantly increased the soil productivity, yield and yield components of maize and soybean studied. The RMA at the rate of 20t/ha performed competitively better than the other treatments with strong residual impact on the parameters assessed. Findings from the study equally showed an intercrop advantage.

Effect of different crop management practices for better economic returns from Kharif onion

The present study was undertaken at the Agricultural Research Substation, Sumerpur-Pali to find out the effect of different fertilizer levels and crop geometry on kharif onion (Allium cepa L.) production. The experiment was laid out in split plot design with NPKS levels as main plot and crop geometry as subplot with three replications. Spacious crop geometry with highest dose of fertilizer (15 cm x 15 cm + 140 N: 80 P: 80 K: 40 S kg ha-1) produced maximum plant height (98.20 cm), leaves plant-1 (20), bulb polar diameter (79.34 mm), equatorial diameter (85.10 mm), bulb weight (137.44 g) and harvest index (51.30) with huge quantity of split/multiplier bulbs (6.54 t ha-1). Marketable yield (43.71 t ha-1), gross return (` 5.25 lakhs), net return (` 4.25 lakhs) and B: C ratio (4.25) were higher in the closer crop geometry (10 cm x 10 cm) with highest dose of fertilizer, whereas maximum biological yield (126.75 t ha-1) and total bulb yield (61.60 t ha-1) were reported in the closest spacing with highest dose of fertilizer (7.5 cm x 7.5 cm + 140 N: 80 P: 80 K: 40 S kg ha-1), which also produced the highest quantity (28.69 t ha-1) of unmarketable bulbs. It is concluded that for maximum production of better quality of kharif onion bulb, the seedlings should be planted at 10 cm x 10 cm spacing with the highest level of fertilizer dose (140 N: 80 P: 80 K: 40 S kg ha-1).

Effect of Fertility Levels and Biofertilizers on Growth Parameters, Root Architecture and Quality of Chickpea (Cicer arietinum L.)

The present field experiment was conducted during Rabi season of 2017–18 at the Student's Instructional Farm of Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh to evaluate the effect of different fertility levels and biofertilizers on growth parameters, root architecture and quality of late sown chickpea (Cicer arietinum L.). The experiment comprised of 12 treatment combinations in split plot design which comprised 4 treatments [F1 (control), F2 (RDF 100%), F3 (75% RDF), F4 (50% RDF)] in main plot and 3 treatments [B1 (Rhizobium + PSB), B2 (Rhizobium + PGPR) and B3 (Rhizobium + PSB + PGPR)] in sub plots with three replications. Results showed that among the different fertility levels, application of 100% RDF significantly enhanced growth parameters, root architecture and protein yield over the control. Among the different biofertilizers treatments application of Rhizobium + PSB + PGPR had significantly improved growth parameters, root architecture and protein yield as compared to Rhizobium + PGPR. The combined application of 100% RDF with Rhizobium + PSB + PGPR resulted in significantly higher growth parameters, root architecture and protein yield of late sown chickpea during winter (Rabi).

Effect of Fertility Levels and Bio-fertilizers Application on Yield, Yield Attributes, and Economics of Chickpea (Cicer arietinum L.)

The experiment was conducted during Rabi season of 2017–18 at the Students' Instructional Farm of Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh to evaluate the effect of different fertility levels and bio-fertilizers application on yield, yield attributes, and quality of late sown chickpea (Cicer arietinum L.). The experiment comprised of 12 treatment combinations in split plot design which comprised 4 treatments [F1 (control), F2 (RDF 100%), F3 (75% RDF), F4 (50% RDF)] in main plot and 3 treatments [B1 (Rhizobium + PSB), B2 (Rhizobium + PGPR) and B3 (Rhizobium + PSB + PGPR)] in sub plots with three replications. Results showed that among the different fertility levels, application of 100% RDF significantly enhanced yield and yield attributes over other treatment. Among the different bio-fertilizers treatments application of Rhizobium + PSB + PGPR had significantly improved yield attributes and seed yield as compared to Rhizobium + PGPR. The combined application of 100% RDF with Rhizobium + PSB + PGPR resulted in significantly higher seed yield of late sown chickpea during winter (Rabi). Higher values of economics viz., gross return, net return and B:C ratio in chickpea were observed with the application of 100% RDF + (Rhizobium + PSB + PGPR) treatments except cost of cultivation.

Effects of fertilization levels on growth performance of micro-propagated <em>Cryptocoryne wendtii</em> (Water Trumpet)

This study was conducted to evaluate the effects of different fertilization levels on growth performance of micro propagated water trumpet, Cryptocoryne wendtii to find the most suitable hardening medium. Micro-propagated ninety-six individual plants potted in the commonly used substrate of coir particles were used for the experiment and subjected to different fertilization levels of Albert’s solution. Plants were potted just after being taken from the vessels and eight plant pots kept in the tanks (25.5 L water) containing 0.5 gL–1, 1.0 gL–1, and 2.0 gL–1 of Albert’s solution, and fertilizer was not added into the control. Each treatment and control had three replicates and the experiment was conducted for nine weeks under natural light and temperature conditions. At the end of the experiment, plant growth performance in terms of plant height, root height, number of leaves etc. and water quality parameters were compared in One Way Analysis of Variance using SPSS (16.0). The electrical conductivity (EC) of the 0, 0.5, 1.0, 2.0 gL–1 treatments were 0.075, 0.75, 1.5, 3.0 µS/m, respectively. At the end of the experiment, plants grown in 0.5 gL–1 showed the best growth performance giving significantly highest plant height (11.77 ± 0.40 cm), root height (5.77 ± 0.03 cm), number of leaves (10.0 ± 0.3), number of roots (8.3 ± 0.3), wet weight of whole plant (0.3180 ± 0.0200 g), dry weight of whole plant (0.0206 ± 0.0003 g) and the largest leaf area (2.54 ± 0.01 cm2) in compared to other two treatments and control. In contrast, the uptake of Albert’s solution significantly increased with the increasing EC level. The results of this study revealed that, 0.5 gL–1 Albert’s solution is the most suitable fertilization level among tested three fertilization levels for the hardening process of micro-propagated C. wendtii.

Effect of different levels of NPK on growth and yield attributing characters of Cowpea (Vigna unguiculata L. Walp var. Kashi Kanchan)

A field experiment was conducted during Kharif season 2019 to know the effect of different fertility levels on growth and yield attributing characters of cowpea (Vigna unguiculata L. Walp var. Kashi Kanchan). Data revealed that higher growth and yield parameters were recorded under the treatment (T2) 150% RDF i.e. plant height (97.26 cm), branches number (7.5), leaves number (30.67), pod number per cluster (3.6), pod number per plant (14.43), pod length (22.7cm), yield of pod per plot (3.18 kg), pod yield in (q/ha) (66.41 q/ha). The nutrient application of NP0K (T5) was most effective for higher pericarp weight (3.08g). The restricted nitrogenous fertilizer application was most appreciated for nodule count at the time of harvesting of the crop 18.8 nodules/plant. Higher protein content in 150% RDF T2 (28.3%). B:C ratio is an important parameter to understand the economics of any treatment among the treatments evaluated, application of 50% RDF (T3) was most impressive with higher B:C ratio (5.58) followed by 100% RDF (T1) with (5.52).

Effect of fertility levels and biofertilizers on agrophysiological performance, productivity and quality of chickpea (Cicer arietinum)

A field experiment was conducted during winter (rabi) of 2016–17 at the Students' Instructional Farm of Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, Uttar Pradesh to evaluate the effect of different fertility levels and biofertilizers on agrophysiological performance, productivity and quality of late sown chickpea (Cicer arietinum L.). The experiment comprised of 12 treatment combinations in split plot design which comprised 4 treatments [F1 (control), F2 (RDF 100%), F3 (75% RDF), F4 (50% RDF)] in main plot and 3 treatments [B1 (Rhizobium + PSB), B2 (Rhizobium + PGPR) and B3 (Rhizobium + PSB + PGPR)] in sub plots with three replications. Results showed that among the different fertility levels, application of 100% RDF significantly enhanced agrophysiological performance, yield attributes, yield, and protein yield over the control. Among the different biofertilizers treatments application of Rhizobium + PSB + PGPR had significantly improved agrophysiological performance, yield attributes, seed yield and protein yield as compared to Rhizobium + PGPR. The combined application of 100% RDF with Rhizobium + PSB + PGPR resulted in significantly higher seed yield of late sown chickpea during winter (rabi).

Effects of different fertilization levels on the concentration of high molecular weight glutenin subunits of two spring, hard red bread wheat cultivars

AbstractBackgrounds and objectivesHigh molecular weight gluten subunits (HMW‐GS) are generally considered to play a key role in gluten formation and structure and are closely related to wheat quality. In this study, two spring wheat cultivars (PAN3497 and SST806) with the same HMW‐GS composition (1Ax1, 1Bx7, 1By8, 1Dx2, and 1Dy12) were tested in the greenhouse, over 2 years, in order to determine how different genetic backgrounds, and low‐nitrogen and low‐phosphorus treatments, influenced the expression and quantity of the HMW‐GS, as measured by reverse‐phase high‐performance liquid chromatography (RP‐HPLC).FindingsCultivar effect was highly significant for all HMW‐GS, except for 1By8. A large treatment effect was found on subunits 1Ax1, 1Dy12, and 1By8. Cultivar‐by‐treatment interaction was highly significant and contributed to variation of subunit 1Dx2. Subunits 1Dy12 and 1By8 were highly influenced by low‐N conditions. Ratio of HMW‐GS x type/y type was higher for PAN3497 than for SST806. Furthermore, a strong treatment effect was observed for the ratio of x type/y type, which was 45% higher in PAN3497 under optimal and low‐N conditions, compared to SST806.ConclusionsThis study showed that fertilization level had a considerable effect on HMW‐GS composition and on FPC, with low‐N conditions having the largest influence, followed by a combination of low N and low P.Significance and noveltyThe results highlighted the importance of the y‐type subunits in the bread wheat quality breeding programs, especially under low‐N and low‐P growing conditions.

Effect of Fertilization on Yield and Quality of Sisymbrium officinale (L.) Scop. Grown as Leafy Vegetable Crop

Sisymbrium officinale is a wild Brassicaceae species that is known for its use in the alleviation of vocal inflammatory states. Since this species is particularly rich in bioactive compounds, there is an interest for developing cultivation protocols to use this plant as a leafy vegetable harvested at the 13th BBCH growth stage. Two wild populations of S. officinale (L.) Scop., denominate MI (Milan) and BG (Bergamo), have been used, and three different levels of nutrients (g/m2) have been provided such as 13 N, 7 P2O5, 8 K2O (100%); 9 N, 5 P2O5, 5.5 K2O (70%); and 6.5 N, 3.5 P2O5, 4.0 K2O (50%). The effects of different fertilization levels were evaluated on the yield, leaf pigments (chlorophylls, carotenoids), nitrate concentration, sugars content, and on the antioxidant compounds such as anthocyanins, total phenols and glucosinolates (GLS). Plant stress monitoring was performed by measuring the chlorophyll a fluorescence. Results indicated that yield was not affected and ranged from 0.18 to 0.47 kg/m2, and differences were not statistically significant for chlorophylls, carotenoids, and total sugars content. Nitrate concentrations were higher in the BG wild population (4388.65 mg/kg FW) during the second cultivation cycle and lower (1947.21 mg/kg FW) in the same wild population during the first cultivation cycle, both at the 100% fertilization level. Total phenols and anthocyanins were higher in the highest fertilization rate in the MI wild population during the second cycle. The GLS were higher in the lowest fertilization rate in the BG wild population (19 µmol/g FW) grown at the fertilization level of the 50%, and significant differences were observed in the second cycle. In conclusion, the 50% fertilization level can be considered the most suitable for our experimental conditions.

Effect of planting geometry and timing and source of nitrogen application on growth attributing characters and yield of rice (Oryza sativa L.) under system of rice intensification (SRI)

An experiment was conducted at Agronomy Research Station, Orissa University of Agriculture and Technology, Bhubaneswar during Kharif season of 2012 to study the effect of different fertility levels, planting patterns per hill and their interaction on productivity of rice variety 'Lalat' under SRI. Four fertility levels and different planting patterns affected the growth characters as well as yield significantly. F 2 {FYM @ 15 t ha -1 + vermicompost 2 t ha -1 + neem-cake 250 kg ha -1 } gave highest leaf m -2 , LAI, dry matter accumulation and CGR with highest yield (8.76 t ha -1 ). It was found that twice or thrice splitting of N was at par (7.62 and 7.57 t ha -1 ). Three plants per hill with wider spacing of 30×30 cm gave the highest yield among all planting patterns. Planting more than one plant per hill had not contributed much to growth attributing characters but had given increased yield due to higher plant population per m -2 in comparison to one plant per hill. Fertility level (F 4 ) with half of RDF of nitrogen, recorded the lowest yield (5.87 t ha -1 ). Among the sub-plots the lowest yield was recorded in P 3 i.e., one seedling per hill at 30×30 cm spacing (6.75 t ha -1 ).

Effect of planting geometry and timing and source of nitrogen application on yield and yield attributing character of rice (Oryza sativa L.) under system of rice intensification

An experiment was conducted at Agronomy Research Station, Orissa University of Agriculture and Technology, Bhubaneswar during Kharif season of 2012 to study the effect of different fertility levels, planting patterns per hill and their interaction on productivity of rice variety ‘Lalat’ under SRI. F 2 (FYM @ 15 t ha + vermicompost 2 t ha + neem cake 250 kg ha) gave highest yield (8.76 t ha). It was found that twice or thrice splitting of N was at par (7.62 and 7.57 t ha). Highest harvest index was recorded from F 2 (51.11 %) among main plots and P 1 (25×25cm spacing with 1 seedling hill) i.e. 50.41 per cent among subplots. F 4 (FYM @ 5 t ha + N : P 2 O 5 : K 2 O @ 30:30:30 kg ha basal) and P 3 (30×30 cm spacing with 1 seedling hill) gave the lowest harvest index (45.74 % and 43.33 %, respectively). Three plants per hill with wider spacing of 30×30 cm gave the highest yield among all planting patterns. Wider spacing was found more beneficial. More than one plant per hill had given increased yield due to higher plant population per m in comparison to one plant per hill. Fertility level (F 4 ) with half of RDF of nitrogen, recorded the lowest yield (5.87 t ha). Among the subplots the lowest yield was recorded in P 3 i.e. one seedling per hill at 30×30 cm spacing (6.75 t ha).

Effect of fertility levels and micronutrients on growth, nodulation, yield and nutrient uptake by pea (Pisum sativumL.)

A field experiment was conducted during winter season of 2006–07 and 2007–2008 to study the effect of different fertility levels (Fertility level F1: 30-20-2.5, P2O5-S-Zn kg/ha and Fertility level F2: 60-40-5, P2O5-S-Zn kg/ha) and micronutrients on plant growth, nodulation, production potential of pea. Results indicated that fertility level F2 (60-40-5, P2O5-S-Zn kg/ha) was found most effective in enhancing the plant growth, nodulation, yield attributes, yield, nutrient content in nodules and nutrient uptake by crop. Improvement in different form of N viz NH4-N, NO3-N, organic N, available N and total nitrogen were registered with higher fertility level. Amongst the micronutrient, combined application of micronutrients enhanced the plant growth, nodulation, yield attributes, yield, nutrient content in nodule and nutrient uptake. NH4-N, NO3-N, organic N, available N and total nitrogen were also recorded higher with combined application of micronutrients. Grain yield and nutrient (N, P and S) uptake by crop also increased to a great extent by the combined application of micronutrient (B 0.3% + Co 2+ Mo 1 kg/ha) under fertility level F2.

Evaluation of promising varieties of Ethiopian mustard (Brassica carinata) and Indian mustard (Brassica juncea) at different fertility levels under rainfed conditions

A field experiment was conducted during the winter seasons of 1996 97 and 1997 98 at the Crop Research Centre, Pantnagar, to study the effect of different fertility levels on yield attributes, seed yield, haricots index, oil content and oil yield of promising Brassica varieties. Brancheslplant (31.86), seed weightlplant (4.75 g), 1,000 seed weight (4.4 g), seeds/siliqua (9.7) and seed yield (1,350 kg/ ha) were highest in PBC 9221 ( Kiran ) of Brassica carinata A.Braun whereas harvest index (1 6.7%) was lower in this variety. Oil content of Kranti Brassica juncea (L.) Czernj. Cosson was higher but oil vield was higher in BC 9221 Brassica carinata. Variety DLSC 1 had higher FUE (N) (43.6) and Kranti recorded lower (1.7) FUE (N) compared with PR 8988 . With each successive increase in fertility level up to 125% of the recommended, the FUE (N) increased. With the application of fertilizer, oil content decreased and, contrary to it, oil yield increased owing to higher seed yield of pronounced yield contributing attributes.

Aptitudes germinatives comparées de graines de Rumex acetosella issues de populations correspondant à des stades distincts d'une succession postculturale

Germination of Rumex acetosella L. was studied under a variety of experimental conditions to determine whether populations from old fields of different ages (fallow for 6 months to 15 years) differed in seed weight and germination rate and in plant biomass and flowering rate of the resulting plants. Fresh seeds collected from these natural populations showed differences in germination that varied with the date of harvest and the number of years since the field was last cultivated: seeds of the youngest population harvested in July germinated the best and were lighter than those of the other populations. Different fertilizer levels applied during the growth of the mother plants from seeds collected in the original old fields affected the mean weight and the germination rate of the resulting seeds, regardless of the density of cultivation of the mother plant. However, the effect of different fertilizer levels on mean seed weight varied with the origin of each population. Heavy seeds (mean weight > 0.6 mg) of mother plants from the populations of fields abandoned over 2 years ago germinated better than light seeds (mean weight < 0.6 mg). There was no significant difference between heavy and light seeds in terms of percent germination for seeds from mother plants that came from the "youngest" field. These differences in germination rate observed in field-collected seeds were also found in light seeds of the offspring generation: light seeds of the mother plant from the population belonging to the more recently abandoned old field germinated the best. Plants grown from heavy seeds that came from the other populations of older fields had more biomass than those resulting from light seeds. This difference has not been observed between individuals resulting from light and heavy seeds of the youngest population. On the other hand, these individuals had a higher flowering rate than those resulting from the older populations. These results are interpreted in relation to the successional status of the populations: high flowering and early germination rates are suitable characteristics for establishment of plants on bare ground or after a disturbance, whereas heavy seeds with more reserves ensure germination and enough biomass of the resulting plants in density-dependent conditions.

Título en español.

Se determinó el efecto de tres niveles de nitrógeno, ácido fosfórico y potasa en el rendimiento de café cultivado intensivamente en suelo Alonso arcilloso, en Castañer. El rendimiento promedio fué de más de 15 quintales de café pilado por cuerda durante 3 años consecutivos, lo cual compara favorablemente con el promedio de 150 libras por cuerda para la Isla en general. Hubo una reacción favorable en rendimiento a la aplicación de 150 libras de nitrógeno por cuerda durante todos los 3 años. Durante los 2 años de lluvia abundante hubo indicación fuerte de una reacción a la aplicación de 150 libras de nitrógeno adicionales. También hubo una reacción favorable en rendimiento a la aplicación de 150 libras de potasa por cuerda el primer año, y a la aplicación de 300 libras por cuerda el segundo año. Durante el tercer año hubo una reacción favorable a la aplicación de 150 y de 300 libras de potasa por cuerda. La aplicación de fósforo no afectó significativamente los rendimientos de café.