Actual challenges: Developing low cost no-till seeding technologies for heavy residues; small-scale no-till seeders for two wheel tractors

Small farmers from South Asia and other parts of the world use two wheel tractors as the main means of land preparation and other farm operations due to small farm and field size combined with an affordable price. These units have become very popular, and over 500,000 are manufactured annually worldwide. There are over 350,000 operating in Bangladesh alone. Two low cost and robust no-till seeders to suit two wheel tractors (12HP) have been developed at the Wheat Research Centre (WRC), Dinajpur, Bangladesh (with support from the Australian Centre for International Agricultural Research). This follows initial research and development work assisted by CIMMYT and Bangladesh Agricultural Research Institute from 1995 to 2004

Conservation agriculture for small holder rainfed farming: Opportunities and constraints of new mechanized seeding systems

Small holder farmers in rainfed agriculture believe that soil tillage is needed to maximize crop yields. However, as cropping intensity, and hence tillage intensity, increases there may be a decline in particular physical, chemical and biological properties of the soil which limit crop yield. This is primarily caused by declining soil organic matter, its oxidation being accelerated by tillage, particularly in warmer climates, and exacerbated by the limited return of above-ground biomass to the soil due to its competing use for other purposes. In large-scale commercial agriculture declining soil quality has been effectively addressed by conservation agriculture-cropping systems based on minimum tillage, crop residue retention and appropriate crop rotations and associations, preferably including legumes. This has required development of minimum tillage planting equipment along with herbicide technology to achieve weed control that is traditionally achieved through tillage. However, a shortage of mechanized options suitable for small holder farmers is creating an impediment to the adoption of conservation agriculture practices that would arrest the decline in soil quality in their fields. In South Asia, two-wheel tractors are replacing animal-drawn ploughing in small holder plots. This speeds the tillage operation and hence the turnaround time between crops, which may increase opportunities for crop intensification, but the problems associated with full tillage remain. Over the previous decade planter attachments to two-wheel tractors have been developed which permit seed and fertilizer placement with minimum to zero tillage in a single-pass. Recent tests have demonstrated that use of these implements can produce crop yields equal to or better than conventional tillage involving hand broadcasting of seed and fertilizer. Further, fuel and labour costs, seed and fertilizer inputs and turnaround time between crops can be reduced. In Africa, the introduction of animal-drawn rippers and direct seeders, originally developed for small-scale farmers in Brazil, is considered as a major breakthrough to small-scale farmer mechanization. It significantly reduces labour required for planting and benefits may be even greater if herbicides can be effectively used for weed control. Nevertheless, movement towards minimum tillage with two-wheel tractor mounted planters and animal-drawn direct seeding equipment is constrained by weed management issues. There are problems of availability and of safe and effective use of herbicides by resource-poor farmers and there is a need to develop more integrated weed management strategies that can be combined with small-scale planters. There is also a need to optimize the performance of small-scale planters to suit farmers' needs in different agro-ecological environments. Tools and concepts are now available to implement conservation agriculture for small holders and thereby increase profitability of their cropping practices and at the same time improve soil quality and sustainability of their livelihoods. However, much more adaptive research and on-farm evaluation is needed across a diverse range of soils, cropping systems and agro-ecological regions to bring conservation agriculture to more small holders

Minimum-tillage, mechanized sowing of pulses with two-wheel tractors

Pulse crops in Bangladesh are mainly low-input rainfed crops with broadcast sowing. Since the 1990s, rotary tillage two-wheel tractors (2WT) have largely replaced animal draft for crop establishment. However, rotary tillage causes excessive evaporation from seedbeds in rapidly-drying soils. Therefore 2WT-based minimum tillage (MT) options were explored to optimize seedbed moisture for lentil and chickpea establishment. Two types of 2WT-mounted seeding units were manufactured, a strip tiller retaining rotary blades only in front of the tynes and a tyne seeder in which the rotary tiller shaft is removed. In some soil types, seedling emergence and grain yields of lentil and chickpea with these seeders matched those with broadcasting. In wet soils, the minimal soil disturbance with MT resulted in anaerobic conditions around seedling roots thereby limiting root growth and nodulation. In clay soils with rapid surface drying traction was inadequate for tyne tillage and strip tillage could not adequately penetrate rice paddy hardpans to allow adequate growth of seedling roots. Potential solutions to these limitations are under test so that 2WT-based MT can be adapted for more timely and economic sowing of crops, including pulses, in smallholder plots and to achieve the agronomic benefits of line sowing over broadcast sowing

Manual for Smallholders' Conservation Agriculture in Rice-Based Systems

...This is the first version of the CA Manual. It is designed to describe the current state of knowledge about the practices that represent CA systems for smallholders in rice-based cropping in Bangladesh..