Effects of fertility management strategies on phosphorus bioavailability in four West African soils

Low phosphorus (P) in acid sandy soils of the West African Sudano-Sahelian zone is a major limitation to crop growth. To compare treatment effects on total dry matter (TDM) of crops and plant available P (P-Bray and isotopically exchangeable P), field experiments were carried out for 2 years at four sites where annual rainfall ranged from 560 to 850 mm and topsoil pH varied between 4.2 and 5.6. Main treatments were: (i) crop residue (CR) mulch at 500 and 2000 kg ha^-1, (ii) eight different rates and sources of P and (iii) cereal/legume rotations including millet (Pennisetum glaucum L.), sorhum [Sorghum bicolor (L.) Moench], cowpea (Vigna unguiculata Walp.) and groundnut (Arachis hypogaea L.). For the two Sahelian sites with large CR-induced differences in TDM, mulching did not modify significantly the soils' buffering capacity for phosphate ions but led to large increases in the intensity factor (C_p) and quantity of directly available soil P (E_1min). In the wetter Sudanian zone lacking effects of CR mulching on TDM mirrored a decline of E_1min with CR. Broadcast application of soluble single superphosphate (SSP) at 13 kg P ha^-1 led to large increases in C_p and quantity of E_1min at all sites which translated in respective TDM increases. The high agronomic efficiency of SSP placement (4 kg P ha^-1) across sites could be explained by consistent increases in the quantity factor which confirms the power of the isotopic exchange method in explaining management effects on crop growth across the region.

Is export orientation a major motivator for the adoption of food safety systems in the Turkish dried fig firms?

Food safety management systems (FSMSs) and the scrutinisation of the food safety practices that are intended for adoption on the firm level both offer strategic value to the dried fig sector. This study aims to prove the hypothesis that export orientation is a major motivating force for the adoption of food safety systems in the Turkish dried fig firms. Data were obtained from 91 dried fig firms located in Aydin, Turkey. Interviews were carried out with firms’ managers/owners using a face-to-face questionnaire designed from May to August of 2010. While 36.3 percent of the interviewed firms had adopted one or more systems, the rest had no certification. A binomial logistic econometric model was employed. The parameters that influenced this decision included contractual agreements with other firms, implementation of good practices by the dried fig farmers, export orientation and cost-benefit ratio. Interestingly, the rest of the indicators employed had no statistically significant effect on adoption behaviour. This paper focusses on the export orientation parameter directly in order to test the validity of the main research hypothesis. The estimated marginal effect suggests that when dried fig firms are export-oriented, the probability that these firms will adopt food safety systems goes up by 39.5 percent. This rate was the first range observed among all the marginal probability values obtained and thus verified the hypothesis that export orientation is a major motivator for the adoption of food safety systems in the Turkish dried fig firms.

Evaluation of major feed resources in crop-livestock mixed farming systems, southern Ethiopia: Indigenous knowledge versus laboratory analysis results

Evaluation of major feed resources was conducted in four crop-livestock mixed farming systems of central southern Ethiopia, with 90 farmers, selected using multi-stage purposive and random sampling methods. Discussions were held with focused groups and key informants for vernacular name identification of feed, followed by feed sampling to analyse chemical composition (CP, ADF and NDF), in-vitro dry matter digestibility (IVDMD), and correlate with indigenous technical knowledge (ITK). Native pastures, crop residues (CR) and multi-purpose trees (MPT) are the major feed resources, demonstrated great variations in seasonality, chemical composition and IVDMD. The average CP, NDF and IVDMD values for grasses were 83.8 (ranged: 62.9–190), 619 (ranged: 357–877) and 572 (ranged: 317–743) g kg^(−1) DM, respectively. Likewise, the average CP, NDF and IVDMD for CR were 58 (ranged: 20–90), 760 (ranged: 340–931) and 461 (ranged: 285–637)g kg^(−1) DM, respectively. Generally, the MPT and non-conventional feeds (NCF, Ensete ventricosum and Ipomoea batatas) possessed higher CP (ranged: 155–164 g kg^(−1) DM) and IVDMD values (611–657 g kg^(−1) DM) while lower NDF (331–387 g kg^(−1) DM) and ADF (321–344 g kg^(−1) DM) values. The MPT and NCF were ranked as the best nutritious feeds by ITK while crop residues were the least. This study indicates that there are remarkable variations within and among forage resources in terms of chemical composition. There were also complementarities between ITK and feed laboratory results, and thus the ITK need to be taken into consideration in evaluation of local feed resources.