Influence of lime and farm yard manure( Télécharger le fichier original )par Dieudonne MUGOBOKA ISAE Busogo  Bachelor's Degree 2008 
4.1.4. Available phosphorusThe available phosphorus in soil varies from 60ppm to 60.5ppm and 59.8ppm to 75.815ppm, respectively before and after experiment. This range classifies the soil into «high content» range (MUTWEWINGABO et RUTUNGA, 1987), (Van Der Zaag, 1981). The variation of available phosphorus before and after experiment according to treatments is shown on the figure below: Erreur ! Source du renvoi introuvable. Figure : Available phosphorus before and after experiment. It is observed from the figure above that there is a decrease in available phosphorus content for T_{0 }.This may be caused by crop uptake, leaching by rainfall water and phosphorus retention by acidic cations as both p H and Total exchangeable acidity has increased. For other treatments, there has been an increase in available phosphorus content. The ANOVA table below shows whether the difference observed among treatments is significant. Table : ANOVA table for available phosphorus after experiment.
CV %= 15.1 From the above table, it is clear that a high significant difference at threshold of 1% occurs between treatments as F. observed is greater than F. table at 1% threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Tableau : Mean separation for available phosphorus observed after trial
Considering the mean separation of available phosphorus, it is remarkable that all treatments are classified into five groups (A, B, C, CD, and D). In the treatments that have received FYM, increase in available phosphorus is due to liberation of phosphorus in the decomposition phase of organic matter (Russell, 1980).In this phase, the organic acids formed also dissolve the unavailable phosphorus and become available phosphorus (Rayar, 2000). For the treatments that have received lime, the increase in available phosphorus is due to neutralization of power of active acidic cations by lime as it has been discussed in chapter 2. 4.2 PLANT GROWTH4.2.1 Height of plants at 30 daysThe results obtained on plant heights after 30 days in different plots as per 7 treatments are presented on appendix 2 while the mean heights are presented on the following figure: Erreur ! Source du renvoi introuvable. Figure : Heights of plants after 30 days in the study zone It was observed that the mean heights vary from 8.3cm to 18cm with the general mean of 11.8cm.The T_{2} and T_{3} showed the highest values while T_{0} shows the lowest value. Though the difference between treatments has been revealed, ANOVA test is to be conducted to know whether the difference observed between treatments is significant. Table : ANOVA Test for heights of plants at 30 days
C.V %=8.04 From the table above, there is a significant difference between treatments at 1%threshold as the value of F Ratio is greater than the value of F on the table at the mentioned threshold. The difference observed between blocks is not significant as the F ratio is lower than the value of F .table at the same threshold. Table : Mean separation of plant s heights after 30 days of sowing
The table mentioned above shows that the treatments are classified into 6 groups (A, B, C, CD, and DE, E).The group A shows the best results T_{3}.The group B represents the mean heights of T_{2}, while the group C shows the mean heights of shows the mean heights of T6.The treatments T_{5}, T_{1}, T_{4}, and T_{0} are almost the same. The best results for T_{3}, followed by T_{2} are due, according to Miller and Donahue (1990), the supply of the plant nutrients, especially Nitrogen which is the limiting factor for plant growth. 
