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1.0.0 VALIDATION OF AN ALTERNATIVE PRODUCTION SYSTEM 1.1.0 Materials and Methods 1.1.1 Land Preparation The field at Graeme Hall was located on the Lands of the Ministry of Agriculture and Rural Development near an irrigation well and running parallel to the highway. A crop of cassava was grown and harvested from this plot prior to land preparation which was started late November 1997 and a 1.31.ha was harrowed to a depth of 30 cm. In mid-December, 1997, the field was rotovated to a depth of 20-25 cm and ridges were formed at 70 cm apart. The ridges were aligned East-West running along the length of the field. At this stage the field was measured and a 0.91 ha (2 ac) plot on the Eastern side was allocated to the validation of an alternative Production System whilst the remainder 0.4 ha (1 ac) was left for the Breeding Block and the Plant Population Density Trial. The field was left to weather for five weeks after harrowing. 1.1.2 Seedlings Arrangements were made with a nursery sited in Airy Hill, St. George to produce the seedlings from certified seeds of West Indies Red cultivar supplied by CARDI. Shading was kept at 75% from seeding and during early growth. Seedlings were hardened in less shade of 25%. Insect pests and whiteflies (Bemesia tabaci) in particular were kept down by regular sprays of three different insecticides. Mist irrigation kept in potting media and relative air humidity at high levels in the seedling nursery. Five week-old seedlings were transported to a holding nursery at Graeme Hall where sprayings with Malathion® kept down insect pests. A soluble foliar fertilizer, Nutrex®, was also applied on seedlings prior to transplanting. 1.1.3 Transplanting The main point of the production system was to utilize a plant population density twice that used by farmers. Accordingly, plants were spaced 70 cm x 70 cm to give 20,000 plants/ha (8000 plants/acre). The seedlings were transplanted starting January 27, 1997 and took five days. The weather was extremely dry, the soil was parched and hot, dry winds were blowing steadily from the E-NE direction across the area. See meteorological data in Appendices 1a - 1e. 1.1.4 Irrigation An overhead sprinkler irrigation system was put in place on the third day of transplanting; wetting the field halted the high seedling mortality and the plot was supplied. The overhead sprinkler was used all day and was left on during the nights until the field was saturated. The harsh sun and the hot winds caused rapid drying of the field and of seedlings. For an entire week in mid-February, 1998, the field was left without watering due to unreliable labour. This caused stunting of plants and retarded early development. Mortality of seedlings was increased further. The new drip irrigation system was installed on March 1, 1998. This eased the problems associated with the overhead sprinkler system, which was removed. Wetting was then uniform and thorough over the entire field. Moreover, the drip system was adjusted to deliver about 47 m3 of water every two days except when rain fell. 1.1.5 Windbreak The windbreak rows were demarcated every 20 m along the length of the field and on the Northern and Eastern sides from where the predominant winds were blowing most of the time. Forage sorghum seeds were planted three weeks before transplanting; neither soil moisture nor watering was available and emergence was extremely poor. Upon the assembly of the drip irrigation system, the windbreak rows were all replanted. Germination was better than the previous planting but the rows had frequent gaps. 1.1.6 Weed Management The field was left to weather from harrowing to transplanting for a period of five weeks. Prior to transplanting, a pre-emergent herbicide, Dual® (a.i. acetamide) at a rate of 2.34 litres per hectare (2 pints per acre).was sprayed by boom sprayer mounted on a tractor The soil was parched and watering was done to increase the effectiveness of the herbicide. Upon saturation of the field by means of an overhead sprinkler irrigation system and continued wetting through the more efficient drip system, the weeds proliferated. By the second week after the commencement of transplanting, manual weeding was implemented and it took eight days to complete the field. By that time the weed regrowth was abundant. The seedlings were being overgrown by the weeds and manual weeding was mounted to clear around the plants on top of the ridges. A herbicide was sprayed; Prowl® (ai pendimethalin) at 7.0 l/ha (5 pints/ac) was applied with a shield to the ridges around the seedlings to kill germinating weed seeds. This spraying also resulted in phytotoxic symptoms on the pepper. The plants exhibited bright yellowing of youngest leaves and some stunting. This condition followed plant development for more than six weeks after the herbicide application. The weeds in the furrows were labouriously mowed down with a lawn mower and a systemic herbicide (a.i. glyphosate) mixed with the adjuvant Frigate® was sprayed onto the stubble at a rate of 2.5 l/ha (445 ml Roundup® in 100 l of water using 500 litres water per hectare). Due to the steady strong winds, extreme care was taken to keep spray drift off the seedlings. This prolonged the work and output was low. Spraying between the rows with the systemic herbicide using shields was done once a month. In addition to manual weeding on top of the ridges around the plants on a continuous basis, and to the spraying between the rows once a month, Fusilade® (a.i. fluazifop-P-Butyl) was spot sprayed where the true grasses were thickest. This was done 4 times during the life of the crop. A rate of 2.5 l/ha was applied. 1.1.7 Fertilizer Application Application of nutrients was mainly guided by the results of soil analysis (Appendix 2), adequacy or deficiency symptoms and according to recommendations in the literature (CARDI, 1996). Samples were taken from the field prior to land preparation. Providing adequate nutrients to the plants began in the seedling nursery where water-soluble fertilizers were sprayed onto the seedlings. In this way and through the mixing of slow release fertilizers into the potting media, Nitrogen, Phosphorus and Potassium (NPK) and micronutrients were supplied to the seedlings. Three weeks after transplanting, granular NPK fertilizer, 12-12-17+2, was incorporated into the soil at 500 kg/ha (440 lb/ac) as a side dressing 15 cm away from the base of the seedlings. Soil moisture was kept at an optimum. During the crop, fertilizers were supplied through the drip irrigation system, (fertigation), or as foliar sprays applied by a motorized sprayer, according to the schedule in Table 1. Table 1: Schedule and rate of application of supplementary fertilizers on a crop of hot Pepper at Graeme Hall in Barbados.
1.1.8 Pest and Disease Management A system of windbreaks was planted to keep out whiteflies. Coupled with this, sticky traps and an insecticide were used. Bright yellow plastic containers painted with grease on the inside, were placed at ground level. A number of straps (500) were distributed over the 0.91 ha plot at equal distances. The 3-week old seedlings were drenched with a systemic insecticide, Admire 2F®, a.i. imidacloprid, at a rate of 2.4 l/ha (2 pints/ac). The pH of the solution was adjusted to 4.5 before mixing the Admire 2F®. The main target insects were whitefly and aphid. Immediately, after transplanting Diazinon®, (an organophosphate), was sprayed against whitefly and other insects. The rate of application was 1.4 l/ha (1 pint/ac). This contact insecticide was sprayed another time on 8th July 1998 targeting a Heliothis sp., which drilled holes in the berries within which the larvae fed. Sherpa®, a.i. cypermethrin, was also sprayed on 16th April 1998 against the same insect, at a rate of 165 ml/ha (75 ml/ac in 30 gallons of water). In July, fungi and bacterial rots on berries and leaves were combated by two sprays 8 July 1998 and 23 July 1998, of Safer Insecticidal Soap® at 11 l/ha (1 gallon/ac) mixed with Spraytech Oil® at 1.4 l/ha (1 pint/ac). The schedule of sprays is shown in Table 2. Table 2: Schedule of sprays against insects and diseases on a hot pepper production plot at Graeme Hall, Barbados.
1.1.9 Harvest The fully developed berries attained a certain size and colour according to the description of the cultivar, West Indies Red. Fruit weight was about 10 - 13 grams, length 3 to 4 cm and width 3 to 4 cm. The market dictated the colour: green, orange and red upon full maturity. The berries for seed production were picked fully ripe. The berries for fresh sale, were manually harvested with the petioles attached. Grading and packing were done manually before the 13 kg crates were delivered to the buyers. 1.1.10 Direct costs Expenditures and incomes were recorded daily in a field book. 1.2.0 Results and Discussions 1.2.1 Harvest The first picking was on the fourth of May 1998, a little over three months after transplanting. Pickings continued almost on a weekly basis (Figure 1) up to the end of September 1998, after which the decline in yield made further picking unprofitable. The largest quantities of berries were picked in the month of June 1998, when the harvest in third week reached 2,705 kg (5,952 lb). This quantity was an outlier and when omitted from the computation, the average weekly harvest was 445 kg (978.63 lb). When included, the average weekly harvest was 558 kg (1,227 lb). The retardation of early transplant development shortened the duration of harvest, increased the number of days to the first harvest and generally decreased yields.
Figure 1. Weekly Harvests of hot pepper berries from May to September 1998 on a 0.91 ha (2 ac) plot at Graeme Hall, Barbados. The record harsh weather with drying winds and high ambient temperatures (Appendix 1) took its toll on early plant growth especially since the irrigation during the month after transplanting, was variable and inadequate. Nevertheless, a total yield of 11,157 kg berries (24,546 lb) was obtained. The yield 12,260 kg/ha (10,948 lb/ac) compared favourably to the standard average yield for Barbados of 7,800 kg/ha (6,965 lb/ac); (MARD, 1998, personal. comm.). 1.2.2 Pest and Disease Management The combination of practices succeeded in keeping insect pests and diseases at a very low level. The whitefly which was the biggest constraint to vegetable production generally, showed up in significant numbers only in September 1998 when the low yield per picking caused the crop to be abandoned. The infestation was associated with sooty mold, which covered fruits, leaves and stems of the plants. Some insects drilled holes in the berries and the larvae fed from the inside. They were identified as a species of Heliothis. Other destructive insect pests, which attacked the plants in small numbers, were aphids, stink bugs, thrips and armyworms. 1.2.3 Weed Management The cost of weed control was the second largest component of the costs of production and it comprised 18.99% of the total. (Table 3) The weed problem began with the previous utilization of the field where the preceding crop was cassava of very poor stand and very weedy. The pre-emergent herbicide, which was sprayed onto the bare soil, was ineffective due to the fact that the soil was not saturated before hand. The irrigation system arrived almost two weeks late. Upon saturation of the soil the weeds proliferated particularly during the early phases of growth. By flowering time, however, the close spacing of 70 cm x 70 cm permitted the canopy to close over the weeds wherever the stand was unbroken. This spacing provided 20,000 plants per hectare (8,0717 plants per acre) and was twice that generally used by the farmers. The wider spacing, however, facilitated mechanized inter-row cultivation and the spraying of insecticides, fungicides and bactericides by tractor mounted boom sprayer. The most effective herbicides were glyphosate and Fusilade®. However, because of the steady and strong winds, the application of the glyphosate was laborious and risky. Spray drift from this systemic herbicide onto the plants caused death. The true grasses were killed by the selective herbicide, which was safe to spray over the hot pepper plants on which no phytotoxic reactions appeared. Phytotoxic symptoms, of bright yellow chlorosis on the upper leaves and growth retardation were experienced when the pre-emergent herbicide Prowl® (a.i. pendimethalin) was sprayed onto the ridges when the transplants were 12-20 cm tall. It was sprayed with a shield and the chemical was directed to the soil around the plants. Unfortunately, the strong winds caused herbicide drift and the plants took about two months to recover from the chemical damage. The following weeds plagued the crop:
Weed management was particularly difficult because labour was very scarce and expensive. The casual labourers did not readily accept job work and productivity was very low. 1.2.4 Direct Costs of Production An analysis of the direct costs of production (Table 4) has shown a loss of Bds$4,194.00. Labour was scarce and expensive and this was reflected in the largest input of $15,249 (53.068%) into labour costs. The three operations which caused the high costs of labour were manual picking and grading, manual weed control and transplanting with supplying comprising 19.37%, 18.99% and 7.18%, respectively of the total direct costs of production. The cost of materials comprised 30.52% of the total and of this the largest component was the cost of the seedlings representing 14.99% of the total direct costs. Mechanized operations cost was 16.42% of the total. The cost of irrigation system represented 20% of the full costs assuming that its life span was 5 years. Transportation in field and as part of marketing made up 4.046% of the total. It was therefore obvious that the components of the costs of production, which needed to be decreased in order to lower the costs of production, were, viz.:
The direct costs for producing 1.0 kg of hot pepper berries were Bds$ 2.57 or $1.17 per pound. This compared very unfavourably with EC $0.67 reported for Antigua and EC$ 0.71 for St. Lucia. Table 3: An analysis of the direct costs of production on 0.91 ha (2 ac) of hot Pepper at Graeme hall in Barbados during 1998.
1.3.0 CONCLUSIONS
2.0.0 HOT PEPPER (cv. West Indies Red) PLANT POPULATION DENSITY TRIAL. The cultivar 'West Indies Red' (Capsicum chinense) was planted in this trial. 2.1.0 Materials and Methods The plant population densities tested are as shown in Table 4. Table 4: The hot pepper plant population densities tested in Barbados during 1998 at Graeme Hall.
A 6 x 6 Latin Square was systematically laid out with the six treatments so that no treatment was a neighbour itself. This design was specifically chosen to combat two sources of variability: a N>S incline and steady E>W winds. The experimental plots contained from 14 plants upwards allowing for border rows. The dimensions of the total experimental plot were 5.6 m x 5.6 m whilst the nett plot was 4.48 m x 4.8 m. All the plots were separated by 1.0 m wide paths. Data were recorded and analyzed on the following parameters:
The effects due to treatments were determined by analyses of variance (the ANOVA techniques) and differences between means were tested by the Least Significant Difference (LSD). 2.2.0 Results and Discussions The data are presented in Table 5 and Figure 2. 2.2.1 Yields (Table 5) Table 5: Yields (kg) ripe
berries in kg per 20 m2 plot harvested from a hot pepper trial comparing
six different plant population densities over six pickings during 1998
in Barbados.
At the first picking, the yield of ripe hot pepper berries from the control (9.68 kg) was very significantly less than that (18.70 kg) of the treatment with the highest population density (PŁ0.01). The difference between these two treatments diminished as the crop grew older and disappeared by the third picking. When the total yield over the 6 pickings was studied, a steady increase from low density to high density was observed. Figure 2: Yields (kg/plot) of mature fruits from six different plant population densities from six pickings during 1998 in Barbados.
Diagrammatically, (Figure 2), the first and second pickings the differences due to treatments were larger and very significant. At the 3rd picking, however, yields of all treatments dropped steeply and the difference between them got smaller. There was a very clear pattern at the first and second pickings for the highest plant population densities to produce the highest yields. However these distinct differences between treatments got significantly smaller by the 3rd - 6th pickings. Therefore, the data suggested that yield of ripe fruit per plot increased steadily with the increase in plant population density. The limit was not reached in this experiment. A further trial with still higher plant population densities was indicated. 2.2.2 Number of Berries per Plant Table 6: Means values
for the number of ripe berries harvested per plant in a trial comparing
six plant population densities over six pickings during 1998 in Barbados.
The number of berries per plant varied widely and was not affected by the treatments except at Pickings 2 and 4 (Table 6. At Picking 2, the control out-yielded Treatment F, the highest plant population density, very significantly (PŁ0.01). At picking 4, the control out-yielded Treatment F significantly (PŁ0.05). However, when the total yield of berries per plant over all 6 pickings, was examined, a general decrease from the treatment with the lowest population density towards the treatment with the highest (231-182) was observed. Therefore, the number of hot pepper berries per plant showed a decrease with the increase in plant population density and also a decrease as the plants grew older. 2.2.3 Plant Height Table 7: Means values for
plant height (cm) measured on a hot pepper trial comparing six plant population
densities trial over six pickings during 1998 in Barbados.
Plant height (Table 7) did not vary due to treatments except at the 6th picking. The values varied from 78.83 cm for Treatment F with the closest spacing to 97.50 cm for Treatment A with the widest spacing. The plants tended to grow taller when spaced wider and as they grew older. 2.2.4 Width of Plant Canopy Table 8: Means values for
width (cm) of plant canopy measured on a trial comparing six plant population
densities of hot pepper over six pickings during 1998 in Barbados.
Plant canopy width (Table 8) did not vary due to treatments at flowering, first and third pickings. However, as the plants reached their full potential growth especially by the 4th, 5th and 6th pickings, differences due to changes in plant population densities, appeared. The two general trends were a decrease in plant width as the population density increased and an increase from the first up to the 5th picking. 2.2.5 Fruit Weight Table 9: Mean values for
fruit weight (g) measured on a trial comparing six plant population densities
over six pickings of hot pepper during 1998 in Barbados.
Fruit weight (Table 9) did not vary significantly between treatments except at picking No. 5. Here, the trend was for the lower population densities to produce slightly larger fruits. The range of variation (10.08 g - 12.82 g) was very narrow at the 5th picking. The fruits of all the treatments were slightly heavier at the earlier picking than at the 6th. The trend was a gradual decrease in fruit weight as the plants got older. 2.2.6 Fruit Length Table 10: Mean values for
fruit length (cm) measured on a trial comparing six plant population densities
over six pickings of hot pepper during 1998 in Barbados.
The data showed that the length of fruit (Table 10) was not affected by the changes in plant population densities. 2.2.7 Fruit Width Table 11: Mean values for
fruit width (cm) measured on a trial comparing six plant population densities
over six pickings of hot pepper during 1998 in Barbados.
Fruit width (Table 11) did not vary significantly due to the treatments except in the 5th picking where there was a mild decrease from 3.53 cm - 3.20 cm, from the higher population densities to the lower. 2.2.8 Days to Flowering (Table 12) Table 12: Mean values for
days from transplanting to 50% flowering of hot pepper planted at six
different plant population densities in a trial during 1998 in Barbados.
There was no significant difference due to treatments. All the plots flowered between 61-65 days after transplanting. 2.3.0 CONCLUSIONS 2.3.1 Yields and yield components
Plant development characters
A larger number of plants in a plot yielded more than a smaller number of larger plants on the same area. Although the smaller plants yielded a smaller number of berries per plant, the larger number of closely spaced plants compensated for the reduction in yield per plant. The plots with the highest plant population densities out yielded those with the widely spaced plants as done by farmers. |
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