Rural livelihood benefits from participation in the taungya agroforestry system in Ondo State of Nigeria

This study examines the strategies and benefits of the taungya farming system to both the government and the rural economy in Nigeria. An interview survey was conducted in which data were collected from 115 randomly selected farmers in five villages in the Oluwa forest reserve, Ondo State, Nigeria. The study examines the extent of participation of rural dwellers in plantation development through taungya farming and the degree of success of this system as an afforestation method. The farmers were predominantly illiterate, within the age bracket of 35–54 years and with small farm holdings. Twenty nine percent relied totally on food from the forest reserve for their livelihood, while 71% also had farm holdings in free areas. Land within the reserve is allocated to farmers free of charge but compensation is paid to landlords on land from free areas. A statistically significant difference was detected in income from the two sources of farmland for the households and but not in the size of land allocated under taungya and free areas. About 184 farmers are involved in taungya annually, and 410 ha of Tectonia grandis has been established for the government of Ondo State.     

Aboveground biomass,transpiration and water use efficiency in eucalypt plantation fertilized with KCl,NaCl and phonolite rock powder

Potassium has important physiological functions in eucalypt plantations, increasing their productivity when applied to soil via mineral fertilizers. There is interest in identifying alternative sources to KCl owing to its high cost and limited reserves. The aim of the study was to test the effect of replacing KCl with NaCl and phonolite rock powder. Two comparisons were made: (1) application of 283 kg ha^?1 of KCl compared with that of 2125 kg ha^?1 of phonolite rock powder (equivalent to 170 kg ha^?1 of K₂O in both treatments); (2) application of 139 kg ha^?1 of NaCl compared with that of 183 kg ha^?1 of KCl (equivalent to 2.33 kmol Na and K, respectively). Radial growth, soil water content, leaf water potential (Ψ), accumulated transpiration, stem volume and biomass increment, as well as water use efficiency (WUE) were evaluated. In the first comparison, both fertilizations presented equal values for all characteristics evaluated. In the second, the accumulated transpiration in trees fertilized with KCl was 17% higher than that in plants fertilized with NaCl. In contrast, the WUE was 20% higher in the trees fertilized with NaCl than in those fertilized with KCl, reflecting the lower water consumption for the same increment in stem volume and biomass. We conclude that phonolite rock powder and NaCl are possible substitutes for conventional K fertilization performed with KCl.

     

Performance of a short tool to assess dietary intakes of fruits and vegetables, percentage energy from fat and fibre

OBJECTIVES: We describe the methods used to develop and score a 17-item 'screener' designed to estimate intake of fruit and vegetables, percentage energy from fat and fibre. The ability of this screener and a food-frequency questionnaire (FFQ) to measure these exposures is evaluated. DESIGN: Using US national food consumption data, stepwise multiple regression was used to identify the foods to be included on the instrument; multiple regression analysis was used to develop scoring algorithms. The performance of the screener was evaluated in three different studies. Estimates of intakes measured by the screener and the FFQ were compared with true usual intake based on a measurement error model. SETTING: US adult population. SUBJECTS: For development of instrument, n=9323 adults. For testing of instrument, adult men and women in three studies completing multiple 24-hour dietary recalls, FFQ and screeners, n=484, 462 and 416, respectively. RESULTS: Median recalled intakes for examined exposures were generally estimated closely by the screener. In the various validation studies, the correlations between screener estimates and estimated true intake were 0.5-0.8. In general, the performances of the screener and the full FFQ were similar; estimates of attenuation were lower for screeners than for full FFQs. CONCLUSIONS: When coupled with appropriate reference data, the screener approach described may yield useful estimates of intake, for both surveillance and epidemiological purposes.     

Critical roles for Rac1 and Rac2 GTPases in B cell development and signaling

The Rac1 guanosine triphosphatase (GTPase) has been implicated in multiple cellular functions, including actin dynamics, proliferation, apoptosis, adhesion, and migration resulting from signaling by multiple receptors, including the B cell antigen receptor (BCR). We used conditional gene targeting to generate mice with specific Rac1 deficiency in the B cell lineage. In the absence of both Rac1 and the highly related Rac2, B cell development was almost completely blocked. Both GTPases were required to transduce BCR signals leading to proliferation, survival and up-regulation of BAFF-R, a receptor for BAFF, a key survival molecule required for B cell development and maintenance.     

Macronutrient uptake,translocation, and tissue concentration of soybeans infested with the soybean cyst nematode and elemental composition of cysts isolated from roots 1

The soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is a major pest of soybeans (Glycine max L. Merrill) in the central and southern United States. Soybean cyst nematode causes stunted top growth, root pruning and symptoms of mineral element deficiency in soybeans. The objective of this study was to determine the effect of two selections of SCN (I selected on PI209332 and IV selected on PI 89772) on macronutrient uptake, translocation, and tissue concentrations of soybean and to determine the elemental composition of cysts isolated from roots. Soybeans were grown in plastic tubes in the greenhouse where the middle one‐third of the Hodge fine sand (Typic Udipsamment) contained 0, 25,000, or 50,000 SCN eggs. After 35 days, plants were harvested and tissue nutrient element concentrations were determined. Plants infested with both SCN selections were smaller and had much less root volume than controls. Dry weight of each plant tissue decreased as SCN population was increased. Root concentration of potassium (K) and magnesium (Mg) was decreased, whereas root calcium (Ca) and phosphorus (P) concentrations were increased with SCN treatments. Leaf Mg and Ca concentrations increased with SCN treatment. Magnesium uptake per unit root volume was decreased, but Mg translocation (% of total plant content in aerial portion) was increased with SCN treatment. Calcium uptake per unit of root volume was increased, but translocation was unchanged by SCN treatment. The Ca and P concentration of cysts isolated from the soybean roots was high. This high concentration of Ca in cysts is interesting based on the greater root Ca concentration and uptake per unit of root volume in SCN infested plants. Since total uptake and root concentrations of both K and Mg were decreased by SCN treatment, infested soybeans might require very high levels of K and Mg fertilization. These results indicate that K and Mg fertility should be followed closely in SCM‐infested soybean fields.