 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. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Variability in Soil Properties Along an Udalf Toposequence in the Humid Forest Zone of Nigeria) ผู้เขียน:Effiom Oku, Ayuk Essoka, Eunice Thomas สื่อสิ่งพิมพ์:pdf AbstractUniform soil management without any knowledge of the variability of soil properties could result in some parts of an agricultural field receiving insufficient inputs, while other parts receive an excess. Profile soil samples were collected and analyzed for some physico-chemical properties along an Udalf toposequence and their variability assessed. Soil pH was consistently least variable along the toposequence and at all depths. Highly variable properties on the upper slope (crest) included Ca, Mg, Na, K, and P; on the middle slope (hill slope) they were K, organic C, N, silt and clay; and on the foot slope (valley floor) they were Mg, organic C, available P, EA, silt and clay. Moderately variable properties were: C. electrical conductivity (EC), effective cation exchange capacity (ECEC), bulk density, clay, gravimetric moisture, volume wetness and degree of saturation on the upper slope; Mg, Na, EC, and ECEC, base saturation, sand, bulk density, gravimetric moisture and volume wetness on the middle slope; and on the foot slope Ca, N, EC, ECEC, base saturation, bulk density, gravimetric moisture, volume wetness and degree of saturation were moderately variable. The use of bulk samples randomly collected to determine soil properties should be minimized. Large soil sample sizes are needed for soil property studies along the toposequence, as most properties varied from highly to moderately variable. Uniform soil management along the toposequence should be avoided. |