This activity was carried out by collecting data from farmers on a network of around 500 plots. These plots were selected in June 2023 in 50 localities, with 10 plots per locality (or cotton-growing zone). The plots were selected in proportion to the different decades or sowing periods. Agronomic data were collected on each plot, including the name of the cotton variety sown, the sowing date, the dates of cultivation operations, the sowing density (number of cotton plants/ha) and the seed cotton yield. Simple correlations between sowing density and seed cotton yield obtained by farmers were established for the major cotton companies. A one-factor Analysis of Variance (ANOVA) was also used to determine the optimum sowing densities for farmers.

A trial was set up in Bouaké (Cotton Station) and duplicated on the Observation Posts (PO). The experimental set-up is made of Fisher blocks with four repeats. Only one seeding rate factor was evaluated, with 19 levels ( Table 1 ). The elementary plot is 48 m², 10 m long and 4.8 m wide. The distance between two blocks is 2 m.

These observations were made on 10 plants chosen from the three central lines, taking care to leave 2 m at each end. On the first of the three lines, three consecutive plants are chosen by the observer. He then makes a lateral move to reach the second line. On this line, the observer travels 1 linear meter and will choose four successive plants. The same lateral movement is made to reach the third line. At this level, the observer travels another 1 meter and chooses three consecutive plants. This makes it possible to have ten plants per elementary plot.

These observations are made on the main pests of cotton. On each elementary plot, the count of the different insects is carried out on 30 plants taken in groups of five consecutively on the three central lines, according to the diagonal method. Observations of the cotton entomofauna are made on a weekly basis, from the 35^th to the 122^nd DAE. These direct observations on plants are supplemented by health analyses of green capsules. Three to six weekly health analyses (ASCV) are carried out on 25 green capsules of the same age (greater than 2 cm in diameter) between the 80^th and 115^th DAE. The harvested green bolls are carefully dissected with a knife to determine which ones have internal rot and which are healthy. Eventually, the rates of healthy and rotten capsules are determined as well as the number of lepidopteran larvae encountered.

The data collected were subjected to an analysis of variance (ANOVA) under the R.4.0.1 software, after verification of the normality of the distribution. When a significant difference is observed (p < 0.05) between seeding densities (treatments) for a given parameter, multiple comparisons are made using the Duncan test at the 5% threshold.

This activity is carried out through an experiment at the Cotton Station in Bouaké. The experimental set-up is made of Fisher blocks with four repeats. A single factor corresponding to the dose of zinc sulphate, with eight levels, is evaluated ( Table 2 ). The elementary plot measures 64 m², 10 m long and 6.4 m wide. The elementary plots are separated by 1 m and the blocks are 2 m apart.

These observations are made on 10 plants chosen from the three central lines, taking care to leave 2 m at each end of each line. On the first of the three lines, three consecutive plants are chosen by the observer. He then makes a lateral move to reach the second line. On this line, the observer travels 1 linear meter and will choose four successive plants. The same lateral movement is made to reach the third line. At this level, he travels another 1 meter and chooses three consecutive plants. This will make it possible to have ten plants per elementary plot.

The data collected are subjected to an analysis of variance (ANOVA) under the R.4.0.1 software, after verification of the normality of the distribution. When a significant difference is observed (p < 0.05) for a given parameter, multiple comparisons are made using the Duncan test at the 5% threshold.

This activity was conducted at the Bouaké cotton research station, through two (02) trials.

This test was conducted using a Fisher block design with four replicates. The objects compared are described in Table 3 .

This test was conducted using a Fisher block design with four replicates. The objects in comparison are described in Table 4 .

Observations were made on 10 plants chosen from the four central lines, taking care to leave 2 m at each end of each line. On the first of the three lines, three

consecutive plants were chosen by the observer. He then makes a lateral move to reach the second line. On this line, the observer travels 1 linear meter and chooses two successive plants. The same lateral movement is made to reach the third line. At this level, he travels another 1 meter and chooses two consecutive plants. The same lateral movement is made to reach the fourth row where three plants are chosen. This made it possible to have 10 plants per elementary plot.

$\text{Speed}\left(\text{cm}/\text{j}\right)=\frac{{\text{H}}_{\text{F}}-{\text{H}}_{\text{I}}}{\text{Number of days between HF et HI}}$

HI: Initial height of the cotton plant

HF: Final Pitch

$\text{Defoliation rate}=\frac{\text{NF}2-\text{NF}1}{\text{NF}1}\times 100$

NF2: Final number of live leaves

NF1: Initial number of live leaves

$\text{Desiccation rate}=\frac{\text{NS}2-\text{NS}1}{\text{NS}1}\times 100$

NS2: Final Number of Dry Leaves

NS1: Initial Number of Dry Leaves

green capsules were counted at the 60^th, 75^th, 90^th and 105^th JAL.

$\text{Boll opening rate}=\frac{\text{N}2}{\text{N}1}\times 100$

N2: number of boll opened

N1: total number of boll

The data collected were subjected to an analysis of variance (ANOVA) under the R.4.0.1 software, after verification of the normality of the distribution. When a significant difference is observed (p < 0.05) between seeding densities (treatments) for a given parameter, multiple comparisons are made using the Duncan test at the 5% threshold.

In CIDT zones, sowing density explains a significant part of the yield variations (R² = 0.1884; r = -0.434; p = 0.000) ( Figure 1 ). The best yields were observed with densities between 30,000 and 40,000 plants/ha ( Figure 2 ).

A weakly positive and non-significant relationship was observed between yield and seeding density in COIC (R² = 0.0033 r = 0.058 p = 0.458) ( Figure 3 ). However, the highest yield was given by seeding densities ranging from 60,000 to 80,000 plants/ha ( Figure 4 ).

The analyses revealed a negative and significant relationship between yield and seeding density in the SECO zone (R² = 0.0513; r = -0.226; p = 0.035) ( Figure 5 ). Seeding rates between 60,000 and 90,000 plants/ha yielded the best yields ( Figure 6 ).

A positive and significant relationship between yield and seeding density in the

Ivory Cotton zone R² = 0.0874; r = 0.296; p = 0.001 was observed ( Figure 7 ). Increasing seeding density would lead to an increase in yield. The best yields were given by densities between 80,000 and 100,000 plants/ha ( Figure 8 ).

The growth and production parameters at the different sites as a function of seeding densities are presented in Table 5 .

On the Seguela PO, the best yield was obtained with the low sowing densities based on spacings of 90 to 100 cm between rows and 15 to 30 cm between pockets.

At the Nambingué PO, it was the densities based on a spacing of 90 to 100 cm between the rows and 10, 15 and 40 cm on the row at a rate of 1 or 2 plants per pocket that gave the best yields.

At the Boundiali PO, the high densities with cotton rows spaced 70 cm apart and spacings of 15 and 25 cm between the plants, unmarried to 1 or 2 plants/pocket which were better.

Finally, in Bouaké, the best yields were obtained with sowing densities based on spacings of 80 and 100 cm between rows and 10 to 20 cm between pockets, unmarried to 1 or 2 plants/pocket.

H90: Height 90 JAL, CC: Capsular Load (Average Number of Capsules/Plant), STD: Stand at Harvest, PMC: Average Capsular Weight, RDT: Yield.

At the experimental station (Bouaké) and at the OP (Seguela), sowing density had no significant effect on pest attacks ( Table 6 ).

Analyses of the campaign data ( Table 7 ) indicate that the optimal rate would be 2 kg/ha ZnSO₄/ha. This dose generated a gain of about 35,100 CFA francs/ha.

The different doses of ethephon reduced the growth rate and increased the defoliation rate and the capsule opening rate, respectively. The rate of 4 L/ha at

Cap. S: Healthy green capsule rate, Cap. P: Rate of rotten green capsules, Cap. T: Rate of green bolls with holes, BEM: Average number of whiteflies (Bemisia Tabaci/30 plants), JASS: Average number of jasside/30 plants.

HREC: Harvest height, SML: Average capsular weight, RDT: Yield RevADD: Additional income.

100 days after emergence appears to be optimal for its effects on both growth ( Table 8 ) and production ( Table 9 ) parameters.

The different doses did not significantly alter the growth rate. However, they increased the defoliation rate and the opening rate of the capsules. The rate of 62.5 ml/ha applied at 100 days after emergence appears to be optimal for its effects on both development ( Table 10 ) and production ( Table 11 ) parameters.

VCC: Growth Rate, TxDef: Defoliation Rate, TxOC: Green Capsule Open Rate.

PRCT: Early production, RTD: Seed cotton yield.

VCC: Growth Rate, TxDef: Defoliation Rate, TxOC: Green Capsule Open Rate.