Systems approaches to innovation in pest management: reflections and lessons learned from an integrated research program on parasitic weeds in rice

This paper provides a retrospective look at a systems-oriented research program, on the increasing occurrence of parasitic weeds in rainfed rice in sub-Saharan Africa, to qualitatively assess merits and identify challenges of such approach. We gained a broad contextual overview of the problem and different stakeholders' roles, which enabled identification of entry points for innovations in parasitic weed management. At the crop level parasitic weed infestation is associated with poor soil fertility and water management. Farmers' infrequent use of inputs to control them was caused by various factors, ranging from fears of undesired side effects (agronomic) to a lack of quality control of products (institutional). Furthermore, there may be enough extension agents, but they lack the required training on (parasitic) weed management to provide farmers with advice, while their organizations do not provide them with the necessary means for farm visits. At even higher organizational levels we observed a lack of coherent policies on parasitic weed control and implementation of them. Merits and challenges of an integrated multi-stakeholder and multi-level research project are discussed

The bashful and the boastful : prestigious leaders and social change in Mesolithic Societies

The creation and maintenance of influential leaders and authorities is one of the key themes of archaeological and historical enquiry. However the social dynamics of authorities and leaders in the Mesolithic remains a largely unexplored area of study. The role and influence of authorities can be remarkably different in different situations yet they exist in all societies and in almost all social contexts from playgrounds to parliaments. Here we explore the literature on the dynamics of authority creation, maintenance and contestation in egalitarian societies, and discuss the implications for our interpretation and understanding of the formation of authorities and leaders and changing social relationships within the Mesolithic

Improving rice-based cropping systems in north-west Bangladesh: diversification and weed management

Improving total productivity in the rice-rabi cropping system in Bangladesh depends on elevating component yields whilst minimizing the risk of drought to both crops. Direct seeding of rice has the potential of advancing crop establishment with the onset of monsoon rains and allowing greater opportunities for subsequent rabi (chick-pea, mustard, linseed) crops on residual moisture as the dry season commences. Agronomic studies over three years indicated that rice yields could be increased over traditional transplanting by use of direct seeding in both a widely used (Swarna) and more recently introduced cultivar (BRRI dhan 39). Oxadiazon applied pre-emergence controlled major weeds but one manual weeding was needed for yield protection from weed competition from Altenanthera sessilis, Cyperus iria and Paspalum distichum in particular. Socio-economic evaluation indicated that adoption of direct seeded rice was more likely to occur on large farms where competition for labour at times of peak demand was intense and where there was a greater proportion of land area favourable for rabi cropping

Weed management implications of introducing dry-seeding of rice in the Barind Tract of Bangladesh

A single crop of transplanted rainfed rice each year provides a major component of livelihoods for farm families in the Barind Tract of Bangladesh. Variable rainfall, frequent drought during grain filling and limited irrigation constrain intensification of the cropping system in this region. Dry seeding allows earlier rice establishment, reduces the impact of late drought and allows timely planting of a subsequent chickpea crop to exploit residual soil moisture. Although the potential of this modified cropping system has been demonstrated in research trials, early season weed growth, which is suppressed by puddling and partially controlled by flooding in transplanted rice, remains a major constraint to farmer adoption. On-farm studies indicated that yield gap between production of transplanted rice under farmer management and the potential yield under weed free conditions in three villages in Rajshahi averaged from 0.29 to 0.47 t/ha, with 34% of farmers losing over 0.5 t/ha. Labour availability constrains timeliness of first weeding in this system. A range of weed management practices, including the integration of a pre-emergence herbicide with inter-row weeding with a hand-pushed weeder, resulted in similar yields of direct seeded rice to hand weeding. The use of these labour saving practices in relation to the potential adoption of dry seeding, maintaining rice yield and increasing the productivity of the cropping system is discussed