 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Evaluation of Vetiver Grass Buffer Strips and Organomineral Fertilization for the Improvement of Soil Physical Properties) ผู้เขียน: Effiom Oku, Olajire Fagbola, Paul Truong สื่อสิ่งพิมพ์:pdf AbstractSoil erosion still remains the major cause of deterioration of soil physical qualities on cultivated lands worldwide. A study was carried out on erosion plots at the Teaching and Research Farm of the University of Ibadan, Nigeria to assess soil physical properties after five years of using vetiver grass buffer strips (VGBS) and organomineral fertilizer (OMF) with bare soil on which farmers had planted without soil conservation measures as the control. Samples were analyzed for water stable aggregates (WSA), mean weight diameter (MWD), bulk density, porosity and particle size distribution. The cone index (CI) was also assessed. Infiltration values were fitted to Philip’s and Kostiakov’s models. Results showed that the amount of WSA for the VGBS and OMF plots was the same (64%) and on the bare soil was 54%. The MWD on the VGBS plot was 6.11% higher than on the OMF plot and 19% higher than on bare soil. The bulk density for the bare soil was 4% higher than that of the VGBS plot. Porosity values for the VGBS and OMF plots were the same, being 8% higher than the bare soil plot. The CI was 15.7% and 7% lower on the VGBS and OMF plots, respectively, compared to the bare soil. Cumulative and initial one-minute infiltration increased by 39.4% and 35%, respectively, on the VGBS plot when compared with the bare soil. Hydraulic conductivity increased by 41.7% on the VGBS plot when compared with bare soil. The initial capacity of the soil to accept water increased on the VGBS plot by 19% over the OMF plot and 39% over the bare soil plot. The index of soil sorptivity (reflecting rate of decline of infiltration capacity) was the same for the VGBS and OMF plots and 21.78% higher than for the bare soil plot. The use of vetiver grass buffer strips on erosion-prone cultivated fields over the years could act as a source of organic fertilizer, improving soil physical properties. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Vetiver Seedlings Multiplication in Rice Husk Amended Soil and Crops Performance on Erosion-Prone Hillside under Vetiver Buffer Strips) ผู้เขียน:Effi om Oku, Ambrose Aiyelari, Olajire Fagbola, Ayuk Essoka สื่อสิ่งพิมพ์:pdf AbstractVetiver buffer strips hold back soil on cultivated hillsides. A major constraint in their adoption is the low availability of seedlings for the establishment of buffer strips. Two experiments were conducted. In the fi rst, vetiver grass strip spacing (VGSS) at 5, 15, 25 m and farmers’ practice (FP) (no soil conservation measures used) were established as treatments on erosion plots sited on a cultivated hillside with a view to identifying the VGSS that would best increase crop yields. In the second experiment, 0, 25, 33.33, 41.67 and 50 t.ha-1 of rice husk were applied as soil organic nutrient enhancer to identify the rice husk rate that would maximize vetiver seedling multiplication on degraded soil. A traditional crop mixture of maize and cassava was introduced on mounds. Maize grain yield was signifi cantly infl uenced by VGSS and FP. Maize yields were 18.7, 8.7 and 11.6% higher on VGSS at 5, 15 and 25 m, respectively than on the FP plot. Maize dry matter accumulation between the VGSS and FP plots were signifi cantly different. Fresh cassava tuber yields were signifi cantly infl uenced by VGSS. Fresh cassava tuber yields were; 36.6, 12.2 and 13.2% higher on the VGSS at 5, 15, and 25 m, respectively, than on FP. The signifi cant benefi cial effect of VGSS in increasing crop yields on the cultivated hillside was evident. The farmer’s fi eld soil used for the vetiver multiplication was degraded having a sand fraction of 886 g.kg-1 of soil and a clay fraction of 40 g.kg-1. The soil was naturally very low in calcium and effective cation exchange capacity, low in organic carbon, nitrogen, magnesium and sodium and medium in potassium. Plant nutrient analysis of the rice husk used in amending the soil showed that it was high in available phosphorus and potassium, and medium in organic carbon and nitrogen. Vetiver tillers increased with the application rate of rice husk. A rice husk rate at 33.33 t.ha-1 could be the optimum rate of application as there was no signifi cant tiller increase beyond this rate. |