Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya
Striga hermonthica, a parasitic weed, has long been believed to be correlated with the declining soil fertility status. However scientists have recently come to question this statement since some recent studies have shown contradictive results. To investigate whether soil fertility status and inf...
| Autor principal: | |
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| Formato: | H1 |
| Lenguaje: | Inglés sueco |
| Publicado: |
SLU/Dept. of Soil and Environment
2012
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| Materias: |
| _version_ | 1855570690622619648 |
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| author | Larsson, Miriam |
| author_browse | Larsson, Miriam |
| author_facet | Larsson, Miriam |
| author_sort | Larsson, Miriam |
| collection | Epsilon Archive for Student Projects |
| description | Striga hermonthica, a parasitic weed, has long been believed to be correlated with the
declining soil fertility status. However scientists have recently come to question this statement
since some recent studies have shown contradictive results. To investigate whether soil
fertility status and infestation of Striga hermonthica were correlated and the impact of it were
caused by farmer management, 120 farmers in Western Kenya, where Striga hermonthica
infestation is prone, participated in this study. In three districts with two sub-locations each,
farmers answered a structural questionnaire and identified two fields, one with high and one
with low soil fertility. These fields later came to be the basis for this study and soil were
therefore also sampled from them. Different soil variables such as: pH, ohlsen-P, texture, C,
N, and seed bank of Striga hermonthica, were then analyzed. The Striga seed bank differed
significantly between the districts, but there were no differences between the farms or the two
fields (high and low soil fertility) on each farm. pH, C and N gave significant results for the
amount of Striga seeds found in the soil. Soils with lower C:N ratio also contained fewer
Striga seeds, while fields with high pH had more Striga seeds present. In Nyabeda, one of the
sub-locations, trials were installed on the identified fields at 11 farms to measure actual Striga
emergence in the field. Local and IR-maize were planted, both with and without fertilization.
Variety was significant for both Striga emergence count and maize yield. Field status was
also significant for Striga emergence. Fertilisation played no significant role in Striga
emergence nor did it increase the yield. The local maize variety gave significantly higher
yields than the IR-maize did. Furthermore IR-maize resulted in significantly higher
emergence of Striga. Striga infestation seems to be correlated with soil fertility status, though
the impact of farmer management has not been fully investigated due to the limited amount of
time and data available. Further studies are needed to understand the impact of farmer
management practices on Striga infestation and soil fertility. |
| format | H1 |
| id | RepoSLU4488 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2012 |
| publishDateSort | 2012 |
| publisher | SLU/Dept. of Soil and Environment |
| publisherStr | SLU/Dept. of Soil and Environment |
| record_format | eprints |
| spelling | RepoSLU44882012-07-05T13:45:58Z Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya Larsson, Miriam soil fertility Striga hermonthica parasitic weed crop losses Western Kenya Striga hermonthica, a parasitic weed, has long been believed to be correlated with the declining soil fertility status. However scientists have recently come to question this statement since some recent studies have shown contradictive results. To investigate whether soil fertility status and infestation of Striga hermonthica were correlated and the impact of it were caused by farmer management, 120 farmers in Western Kenya, where Striga hermonthica infestation is prone, participated in this study. In three districts with two sub-locations each, farmers answered a structural questionnaire and identified two fields, one with high and one with low soil fertility. These fields later came to be the basis for this study and soil were therefore also sampled from them. Different soil variables such as: pH, ohlsen-P, texture, C, N, and seed bank of Striga hermonthica, were then analyzed. The Striga seed bank differed significantly between the districts, but there were no differences between the farms or the two fields (high and low soil fertility) on each farm. pH, C and N gave significant results for the amount of Striga seeds found in the soil. Soils with lower C:N ratio also contained fewer Striga seeds, while fields with high pH had more Striga seeds present. In Nyabeda, one of the sub-locations, trials were installed on the identified fields at 11 farms to measure actual Striga emergence in the field. Local and IR-maize were planted, both with and without fertilization. Variety was significant for both Striga emergence count and maize yield. Field status was also significant for Striga emergence. Fertilisation played no significant role in Striga emergence nor did it increase the yield. The local maize variety gave significantly higher yields than the IR-maize did. Furthermore IR-maize resulted in significantly higher emergence of Striga. Striga infestation seems to be correlated with soil fertility status, though the impact of farmer management has not been fully investigated due to the limited amount of time and data available. Further studies are needed to understand the impact of farmer management practices on Striga infestation and soil fertility. Man har länge ansett att det parasitiska ogräset Striga hermonthica gynnas av minskad markbördighet. Nyare studier har ifrågasatt detta samband. I denna studie, som gjorts i västra Kenya, ett område med stora angrepp av Striga hermonthica, deltog 120 bönder. Studiens syfte var att undersöka om det finns ett samband mellan markbördighet och skördeminskningar orsakade av Striga hermonthica och hur detta samband har påverkats av gårdarnas brukningshistoria. I tre distrikt med två underdistrikt vardera fick bönderna i intervjuer svara på frågor från strukturerade frågeformulär samt identifiera två fält på sina gårdar, ett med hög och ett med låg markbördighet. Provtagningar från dessa fält ligger till grund för denna studie. Markvariabler såsom pH, Ohlsen-P, textur, C, N och Striga hermonthicas fröbank analyserades på jordprover insamlade från dessa fält. Mängden Striga frön skiljde sig åt mellan de olika distrikten. Däremot kunde ingen skillnad mellan gårdarna eller mellan de båda typerna av de identifierade fälten påvisas. Strigas fröbank visade på samband med markens pH och innehåll av C och N. Jordar med lägre C:N kvot hade också lägre antal frön i jordproverna, medan fält med högt pH innehöll mera frön. I Nyabeda, ett av underdistrikten, lades fältförsök ut på 11 gårdar för att skatta uppkomsten av Striga i fält. Där planterades både en lokal majssort och s.k. IR-majs som på Striga-infetkterade fält ger högre avkastning på grund av bättre resistens mot Striga. Båda majssorterna fick sedan behandlingarna gödslat och ogödslat. Försökens resultat visade att planträkningen för uppkomna Striga-plantor berodde på vilken majssort som odlades. Uppkomst av Striga berodde även på om fälten hade identifierats ha hög eller låg markbördighet. Huruvida fälten var gödslade eller inte tycktes inte påverka antalet uppkomna Striga-plantor. De gödslade rutorna visade heller ingen skördeökning. Lokal majs gav högre skördar än vad IR-majsen gjorde. I de rutor där IR-majs hade planterats var antalet uppkomna Striga-plantor högre. Striga-angrepp verkar bero på markbördighet. Däremot har inte påverkan av böndernas brukningsätt kunnat studeras fullt ut. Detta på grund av begränsningar i tid, modell och data. Fler studier behöver göras för att bättre förstå hur böndernas brukningssätt påverkar förekomsten av Striga-angrepp och markbördighetens utveckling. SLU/Dept. of Soil and Environment 2012 H1 eng swe https://stud.epsilon.slu.se/4488/ |
| spellingShingle | soil fertility Striga hermonthica parasitic weed crop losses Western Kenya Larsson, Miriam Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya |
| title | Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya |
| title_full | Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya |
| title_fullStr | Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya |
| title_full_unstemmed | Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya |
| title_short | Soil fertility status and Striga hermonthica infestation relationship due to management practices in Western Kenya |
| title_sort | soil fertility status and striga hermonthica infestation relationship due to management practices in western kenya |
| topic | soil fertility Striga hermonthica parasitic weed crop losses Western Kenya |