Lantana (L. camara), which is acknowledged as one among the 100 most invasive and colonizing of the world’s weeds [1], has become a major threat to agriculture and forest ecosystems. [2,3].It has the ability to grow in widely varying environmental conditions [4,5], often forming large, impenetrable, thickets. This entry is to compare fertilizer-cum-pesticide effect of vermicomposts derived from cowdung and the toxic weed lantana. It has shown that vermicomposting transforms lantana into an organic fertilizer which is as benign and potent as vermicomposts based on cowdung and other manures are.
1. Background
The epigeic earthworm Eisenia foetida are used for vermicomposting lantana [[1]]]. Extensive investigations to characterize the lantana vermicompost (LVC) using Fourier transform infrared spectroscopy, thermal gravimetry, differential calorimetric analysis, gas chromatography, and scanning electron micrography (SEM) have revealed intense mineralization of the organic matter, degradation of lignocellulosic materials and polyphenols, reduction of toxic and allelopathic compounds (phenols and sesquiterpene lactones) in the course of lantana’s vermicomposting. SEM has reflected strong disaggregation of the organic matter content in LVC compared to the lantana matrices. Further, in a controlled study, Hussain et al. [[23]], have observed that LVC enhanced the germination of the seeds, and early growth of the seedlings of ladies finger, green gram (Vigna radiata) and cucumber (Cucumis sativus) when used at appropriate concentrations in soil. However, beyond certain level lantana vermicompost had shown adverse effects. This had raised apprehensions as to whether LVC behaves differently from cow-dung vermicompost (CDVC). It was, therefore, decided to compare the effects of LVC and CDVC under identical conditions. Accordingly, to carry out this study in which the effect of CDVC has been compared with that of lantana vermicompost on the growth, fruition and quality of the ladies finger produce.
2. Seed Germination
The findings are summarized in
Figure 1. Vermicompost treatments significantly enhanced the seed germination compared with the controls (
Figure 1a), however no statistically significant variation was seen between the effects of the cowdung and the lantana vermicompost treatments. The highest germination success (95%) was seen in 5 t ha
−1 lantana vermicompost (LVC) treatment. The next best success (94%) occurred in the 3.75 t ha
−1 cowdung vermicompost (CDVC) treatment. Even though seed germination is primarily an internally regulated mechanism which is governed by the genotype of the plant, several environmental factors and fertilization regimes can also alter the germination success
[[32]]. Several of the studies have suggested that besides the plant hormones and phenolic compounds, increased nitrate and ammonium concentrations in the vermicompost play a strong role in seed germination
[[4][5]].
Figure 1. Effect of LVC
and CDVC
on ladies fingerin terms of (
a) germination success; (
b) length of shoots; (
c) length of roots; (
d) plant biomass; (
e) shoot diameter; (
f) number of leaves; (
g) number of branches; and (
h) disease incidence. All the bars carry range of standard deviation. Bars topped with an asterisk indicate that the corresponding numbers do not differ significantly from the controls at
p ≤ 0.05. N indicate the vermicompost treatments.
3. Plant Growth
Ladies finger plants grown in VC amended soils have shown enhanced growth in terms of all the variables recorded (Figure 1b–g). Within the range of vermicompost concentrations explored by us, the trend of positive effect was: greater the vermicompost application more the benefit. Apart from the number of leaves in CDVC, all trends had the pattern 5 t > 3.75 t > 2.5 t ha−1 > control. Except for the length of the roots, the growth of ladies finger went up profusely even when the concentration of both the vermicomposts was increased only marginally (from zero to 2.5 t ha−1). Similar observations were recorded for flowering, where higher LVC treatments yielded a greater number of flowers and induced earlier flowering relative to the controls and the lower LVC treatments. In case of CDVC, the 3.75 t ha−1 treatment performed better than other treatments (Table 1).
Table 1. Flowering and yield of A. esculentus plants grown in soil fertilized with different levels of lantana and cowdung vermicomposts. The numbers which do not differ significantly from controls (p < 0.05) carry an asterisk. Single, double, and triple stars indicate the significance levels at p < 0.5, <0.01 and <0.001, respectively.
Parameters Observed |
Type of VC |
Vermicompost Concentrations (t/ha) |
ANOVA |
0 |
2.5 |
3.75 |
5 |
Type of Vermicompost (VC) |
Concentration of Vermicompost (N) |
VC*N |
Days to flower |
LCVC |
52.7 ± 4.85 |
43.2 ± 2.30 |
39.0 ± 3.37 |
37.3 ± 2.41 |
NS |
*** |
NS |
CDVC |
43.3 ± 2.75 |
38.6 ± 2.84 |
39.3 ± 2.79 |
No. of flowers |
LCVC |
2.9 ± 0.32 |
9.0 ± 1.05 |
16.3 ± 1.16 |
18.0 ± 2.16 |
*** |
*** |
*** |
CDVC |
8.3 ± 0.95 |
12.8 ± 1.32 |
10.1 ± 0.88 |
No. of pods |
LCVC |
1.7 ± 0.48 |
6.2 ± 0.63 |
13.7 ± 1.06 |
16.2 ± 2.10 |
*** |
*** |
*** |
CDVC |
6.5 ± 0.53 |
10.8 ± 1.03 |
8.6 ± 0.52 |
Length of pods (cm) |
LCVC |
7.1 ± 0.50 |
10.9 ± 1.11 |
11.6 ± 0.94 |
13.1 ± 1.34 |
NS |
** |
* |
CDVC |
11.1 ± 0.98 |
11.7 ± 0.69 |
11.5 ± 1.10 |
Diameter of pods (mm) |
LCVC |
11.4 ± 0.70 |
15.4 ± 1.04 |
16.0 ± 0.96 |
16.3 ± 0.72 |
NS |
* |
NS |
CDVC |
15.6 ± 0.77 |
16.7 ± 1.00 |
15.9 ± 1.21 |
Weight of pods/plant (g) |
LCVC |
5.4 ± 0.50 |
91.9 ± 9.30 |
143.8 ± 8.47 |
170.5 ± 16.2 |
*** |
*** |
*** |
CDVC |
61.8 ± 6.20 |
101.6 ± 8.98 |
85.7 ± 8.72 |
Yield t/ha |
LCVC |
0.5 ± 0.05 |
9.0 ± 0.91 |
14.1 ± 0.83 |
16.8 ± 1.60 |
*** |
*** |
*** |
CDVC |
6.1 ± 0.61 |
10.0 ± 0.88 |
8.4 ± 0.86 |
Percentage infected fruits |
LCVC |
39.2 ± 12.39 |
9.3 ± 3.79 |
9.1 ± 5.42 |
8.0 ± 4.73 |
NS |
* |
NS |
CDVC |
13.4 ± 6.46 |
7.6 ± 2.77 |
7.6 ± 3.63 |
In comparison to CDVC, the shoot length and the plant biomass were significantly higher in the ladies finger plant grown in LVC amended soil; however there was no statistically significant difference vis a vis shoot diameter and the number of branches. As elucidated by Hussain and Abbasi
[[2]], vermicompost amendment in soil enhances the available nutrient content of the soil, besides making the soil porosity, density, and water holding capacity more plant-friendly. In addition, soils amended with vermicomposts were seen to be rich in fulvic and humic acids, and plant hormones
[[6]], which apparently boost the growth of plants compared to the controls. The results of the present investigation show that in some aspects LVC has outperformed CDVC while in some other aspects no significant difference was seen between the two. This makes it evident that lantana loses its toxic and allelopathic constituents during its vermicomposting and the resultant vermicompost, has positive influence on the growth of ladies finger. Equally significant is the finding that the positive influence matches—at times even surpasses—that of CDVC.
43. Yield and Biochemical Aspects
Vermicompost treatments are seen to have significantly enhanced the yield of the ladies finger pods as reflected in the average numbers and weights of pods per plant, and the average length and diameter of the pods (
Table 1). In comparison to the CDVC, LVC had significantly higher number of pods per plant. It also led to pods of higher average weight. However, no significant difference was seen in case of length and diameter of the pods. Vermicompost treatments had also significantly increased the concentrations of chlorophyll and carotenoids in the ladies finger leaves, and the total solids and ash content of its fruits in comparison to the control plots (
Figure 2a–d). No statistically significant difference, however, was seen between the LVC and the CDVC in terms of influence on chlorophyll, carotenoids, total solids, protein and carbohydrates content (
Figure 2e–f). These gains, like the plant growth parameters, can perhaps be attributed to the increased plant available nutrients in soil fortified with vermicomposts, compared to the controls. This is consistent with similar effect reported when manure−based vermicomposts were deployed
[[7][8]]. Overall, LVC appears to be as beneficial for the cultivation of ladies finger as CDVC.
Figure 2. Effect of LVC
and CDVC
on ladies fingerin terms of (
a) total chlorophyll in the leaves; (
b) carotenoids in the leaves; (
c) total solids; (
d) ash; (
e) protein in pods; and (
f) carbohydrates in pods. All the bars carry range of standard deviation. Bars topped with an asterisk indicate that the corresponding numbers do not differ significantly from the controls at
p ≤ 0.05. N indicate the vermicompost treatments.
54. Disease Incidence
Both the vermicomposts were able to induce disease resistance in the test plants (
Figure 1h,
Table 1). In terms of reducing the incidence of disease, LVC has performed marginally better than CDVC; however, the difference was not statistically significant. The fractions of infected fruits was lesser in CDVC treatments of 3.75 and 5 t ha
−1 than in the corresponding LVC applications. However, again, the difference was not statistically significant. In a recently published review, Hussain and Abbasi
[[2]] have documented a number of scientific studies reporting the positive role of manure-based vermicomposts in reducing pests and disease in several botanical species. The present work shows that LVC also possesses a similar virtue.
Previous reports on pathogen-protecting attribute of manure–based vermicomposts reveal that better nutrient availability, and presence of antimicrobial compounds such as flavonoids, phenols and humic acids in the vermicomposts, are the likely factors that may have imbibed the vermicomposts with the ability to resist pathogens
[[9]]. Evidently these beneficial attributes are also present in LVC.