**5.2. Results**

The study was conducted during the three seasons representative of this region: winter or "North" from November to February; drought: March to June, rain or summer: July to October. Weather conditions for the experimental period by time are presented in

Experimental design and treatments. We used a completely randomized design with factori‐ al arrangement of 2 x 2: Conventional or minimum tillage, and fertilization or not, within

T1 and T3 were: P (22), S (25), K (18), Mg (20), Ca (100), Zn (3), Cu (2) and B (1) kg / ha. Each

into two parts along: one, conventional tillage; and another with minimum tillage. Then each part was subdivided again in width to the treatments with and without fertilization. Each treatment involved 12 observations (no repeats) within the corresponding area of 9 m2

Land preparation. In T1 and T2, were allocated strips of 3 m x 20 m, alternating with native grass, where the vegetation was slashed with desvaradora, followed by 4 to 5 passes of har‐ row and plowed with a hoe. On the strips, the distance between rows and plants within them was 80 and 50 cm, respectively. The legume is seeded with a seed depth of 15 cm.

Minimum tillage. For T3 and T4, there was a land clearing with machete, were traced rows of 20 m long, spaced every two meters, and the rows were holes (seed points) every 50 cm,

Planting dates were in Nov 29/1991, March 2/1992 and jul 15/1992, with plant material, plac‐ ing 3-4 stems of 15 cm long, with only three or four leaves in the air. After 30 days, treat‐ ments were applied "with" and "without fertilization. These works were carried out in each season and in the corresponding area. Weed control was made with a hoe, in the first three

Variables. Data were collected at 4, 8, and 12 weeks post-seeding for number of plants, and

T4). The first variable was the number of facilities within the useful area and in the second, the proportion was estimated visually apparent that the legume covered the area. The data were analyzed separately for each planting season, using ANOVA, and Tukey's test was used to compare means [9]. Regression coefficients were estimated to number of plants (lin‐

(T1 and T2) and 18 m2

for minimum tillage.

), divided

(T3 and

period included a an experimental area, with dimensions of 50 m x 40 m (2000 m2

each period and 12 observations (no repetitions) per treatment (T), resulting in:

Figure 9.

70 Soil Fertility

T1 = Conventional tillage plus fertilizer

T3 = Minimum tillage plus fertilizer

T4 = Minimum tillage without fertilizer

each for thorough preparation, and 18 m2

diameter and depth of 20 and 15 cm, respectively.

ear) and coverage (exponential) to observe trends.

4, 8, 12 and 24 weeks for coverage. The useful area was 9 m2

months, for each treatment and time.

T2 = Conventional tillage without fertilizer

#### *5.2.1. Winter season*

Number of plants. At this time, the average/treatment at 4, 8 and 12 weeks was 12.2, 15.3, 14.5 and 14.7 plants/9 m2 . A significant effect (P≤0.01) by fertilizer and ages was observed; by the contrary, the interaction week x treatment was not significant. The overall average was 14.1 plants/9 m2 with a coefficient of variation of 20.0%. Treatments 2, 3 and 4 had better per‐ formance at 12 weeks.

Regarding the rate of appearance of plants, expressed this as the time in weeks to bring a new plant, was similar among treatments 2, 3 and 4 in winter and rainy seasons, while T1 needed more time to build a new plant (Table 13).


**Table 13.** Appearance rate\* of *Arachis pintoi* plants on each planting season. Veracruz, Mexico.

Coverage. At 12 weeks, the best coverage was in T2 (P≤0.01) with 28%, while while T1 and T3 were similar, with 22.9% and 19.0% respectively. On the contrary, coverage at T4 was 18%. The overall average for this variable during the winter season was 22.1% with a coeffi‐ cient of variation of 38%.

There were statistical differences between treatments (P≤0.05), exceeding 28% of T2 with coverage, while T1 and T3 were similar, with 22.9% and 19.0% respectively. The average for T4 was 18.2%. The overall average for this variable during the winter season was 22.1% with a coefficient of variation of 38%.

Figure 10A shows the increase in coverage during the establishment period, for each treat‐ ment at 4, 8, 12 and 24 weeks. There is a considerable increase for all treatments from week 12. The maximum coverage at 24 weeks is presented in conventional tillage treatments.

The rate of coverage of the ground, expressed as the average time in weeks for the plants to cover 10% of area, is presented in Table 14.

*5.2.5. Coverage*

area (Table 14).

Mexico.

**Source of variation df**

Error 136

Veracruz, Mexico.

*5.2.6. Number of plants in each season*

During the rainy season, soil coverage was similar among treatments (Figure 10C). The overall average was 34.5% with a coefficient of variation of 26.1%. For the rate of ground coverage, the lowest average time was observed in T4 with 2.0 weeks to cover 10% of the

Soil Management for the Establishment of the Forage Legume Arachis pintoi as a Mean to Improve Soil Fertility...

http://dx.doi.org/10.5772/53318

73

The average of plants/m2 was largest during the rainy season (19.4 plants) followed by win‐ ter season (14.2 plants), and dry season (8,7 plants). The analysis of variance and regression

**Figure 10.** Percentages of soil coverage by *Arachis pintoi* planted in winter (A), dry (B) and rainy (C) seasons. Veracruz,

Treatments (T) 3 64.85 0.0001 185.64 0.0001 681.34 0.0001 Weeks (lineal) 1 384.00 0.0001 2.34 0.5901 2860.16 0.0001 T x W (lineal) 3 11.58 0.2532 1.37 0.9161 68.80 0.3772

Coefficients a b a b a b T1 10.08 0.26 6.14 0.11 14.80 1.03 T2 9.94 0.66 6.33 0.03 10.05 1.62 T3 10.49 0.50 11.07 -0.03 2.73 1.62 T4 10.11 0.57 10.30 0.04 6.50 0.98

**Table 15.** Analysis of variance and regression coefficient for number of plants by planting season of *Arachis pintoi*.

**Winter Dry Rainy MS P>F MS P>F MS P>F**

coefficients for number of plants/season are shown in Table 15.

**Figure 9.** Temperature and rainfall on each one of the planting seasons of *Arachis pintoi*. Veracruz, Mexico.


**Table 14.** Time in weeks to *Arachis pintoi* cover 10% of soil. Veracruz, Mexico.

#### *5.2.2. Dry season*

Number of plants. The averages for this variable were: 21.15, 19.75, 32.5 and 31.9 plants/9m2 assessment considering each week. T1 and T2 were statistically equal, but different from T3 and T4 (P≤0.05).

In conventional tillage, were less plants than at minimum tillage treatments. Theere are not significance for age effect, neither its interaction with soil treatment Table 13.

#### *5.2.3. Coverage*

The best coverage (>25%) was at at 3 and 4 treatments (P≤0.05). Figure 10B shows the soil coverage at each evaluation frequency. An outsatndinh behaviour was observed for T1 after 8 weeks, achievinig 80% coverage to 24 weeks.

The age effect and its interaction with treatments were statistically significant. The shortest time to cover 10% of soil was during dry and rainy seasons at T4 (Table 14).

#### *5.2.4. Rainy season*

Number of plants. At this time, the largest number of plants/9 m2 occurred at treatments 1 and 2 (23.0 plants), compared to T3 and T4 (17.3 and 14.3 plants, respectively). Was ob‐ served an increase of plants at 8 weeks, mainly in conventional tillage treatments. The short‐ est time or highest rate of occurrence of plants in T1 and T4 was 1.0 weeks in time for the emergence of a new plant.

### *5.2.5. Coverage*

**Figure 9.** Temperature and rainfall on each one of the planting seasons of *Arachis pintoi*. Veracruz, Mexico.

Winter 2.9 2.6 3.8 4.2 Dry 4.7 4.2 3.5 2.2 Rainy 2.2 2.8 2.6 2.0

Number of plants. The averages for this variable were: 21.15, 19.75, 32.5 and 31.9 plants/9m2 assessment considering each week. T1 and T2 were statistically equal, but different from T3

In conventional tillage, were less plants than at minimum tillage treatments. Theere are not

The best coverage (>25%) was at at 3 and 4 treatments (P≤0.05). Figure 10B shows the soil coverage at each evaluation frequency. An outsatndinh behaviour was observed for T1 after

The age effect and its interaction with treatments were statistically significant. The shortest

Number of plants. At this time, the largest number of plants/9 m2 occurred at treatments 1 and 2 (23.0 plants), compared to T3 and T4 (17.3 and 14.3 plants, respectively). Was ob‐ served an increase of plants at 8 weeks, mainly in conventional tillage treatments. The short‐ est time or highest rate of occurrence of plants in T1 and T4 was 1.0 weeks in time for the

significance for age effect, neither its interaction with soil treatment Table 13.

time to cover 10% of soil was during dry and rainy seasons at T4 (Table 14).

**Table 14.** Time in weeks to *Arachis pintoi* cover 10% of soil. Veracruz, Mexico.

8 weeks, achievinig 80% coverage to 24 weeks.

**T1 T2 T3 T4 Weeks by treatment**

**Planting season**

72 Soil Fertility

*5.2.2. Dry season*

and T4 (P≤0.05).

*5.2.3. Coverage*

*5.2.4. Rainy season*

emergence of a new plant.

During the rainy season, soil coverage was similar among treatments (Figure 10C). The overall average was 34.5% with a coefficient of variation of 26.1%. For the rate of ground coverage, the lowest average time was observed in T4 with 2.0 weeks to cover 10% of the area (Table 14).

#### *5.2.6. Number of plants in each season*

The average of plants/m2 was largest during the rainy season (19.4 plants) followed by win‐ ter season (14.2 plants), and dry season (8,7 plants). The analysis of variance and regression coefficients for number of plants/season are shown in Table 15.

**Figure 10.** Percentages of soil coverage by *Arachis pintoi* planted in winter (A), dry (B) and rainy (C) seasons. Veracruz, Mexico.


**Table 15.** Analysis of variance and regression coefficient for number of plants by planting season of *Arachis pintoi*. Veracruz, Mexico.
