Richard Bell

Development of efficient farm machinery and availability of effective herbicides have resulted the higher profitability in conservation agriculture (CA) that in turn has been identified as an effective tool for sustainability of agriculture (Farooq et al., 2011). But weed species shifts and losses in crop yield caused from increased weed density have been cited as major hurdles of CA adoption (Dahal and Karki, 2014). Crop yields in CA can be similar to conventional systems if weeds are controlled (Chauhan et al., 2012). The availability of pre-plant, pre-emergence and post-emergence herbicides provides an opportunity to control weeds in CA. But weed control strategies adopted must reduce the development of herbicide resistance by weeds. The presence of crop residues on the soil surface may reduce weed infestation by affecting weed seed germination and emergence patterns. Considering the above facts, this on-farm experiment was conducted to examine the performance of strip tillage, residue mulching and weeding regimes on crop yield and weeds.

Continuation of soil puddling for rice transplanting will negate the benefits of conservation agriculture (CA) particularly minimum soil disturbing in other crops in the rotation as is reported for the rice–wheat system (Singh et al., 2011). Although, development of non-puddled transplanting of rice with minimum soil disturbance methods has created the opportunity to adopt CA in rice-based cropping systems (Haque et. al., 2016), critics suggest that during transplanting of rice seedling, significant soil disturbance has occurred in non-puddled field due to foot-steps or wheel traffic of the transplanter. To minimize the soil disturbance during transplanting rice seedling in non-puddled condition, two experiments were conducted at Durgapur and Godagari upazila of Rajshahi, Bangladesh during the boro rice season of 2016.

The densely-populated region of the Eastern Indo-Gangetic Plain relies on rice-based cropping systems. However, the sustainability of the system under conventional cultivation is jeopardized by soil and water resource degradation, and increasing scarcity and cost of inputs (Gathala et al., 2011). In rice-dryland crop systems, rice is grown in puddled and submerged soil while the dryland crop is grown after rice with intensive tillage and limited residue retention. Although puddling is beneficial for establishing rice by transplanting, it can harmful for the next dryland crop (Gathala et al., 2011). Conservation agriculture (CA), comprising minimum soil disturbance along with increased residue retention and suitable crop rotation may hold the key to address these problems (Johansen et al., 2012). Conservation agriculture practices are emerging but there is still limited understanding on dryland crop performance in rice-based systems of Bangladesh. This paper focuses on the effects of CA on grain yields of cool dry season crops over three years in a rice-based system.

Effects of conservation agriculture (CA) on crop yield may be positive or negative (Pittelkow et al., 2015) depending upon the crop species, growing e nvironment, and the duration and extent of the CA system. CA involves use of minimum tillage, stubble retention and Minimum tillage can slow down the residue decomposition and reduce the release of mineral forms of nitrogen (N) (Hobbs et al., 2008). Hence, N in the system might be less available under minimum tillage, at least in the initial years. However, no data are yet available to assess the requirement of N fertilizer under CA in the rice-based cropping systems. Lundy et al. (2015) found in the tropical and subtropical regions that decreased yield with the implementation of minimum tillage was sensitive to the rate of N fertilization. Thus, the present study was undertaken to determine the effect of strip tillage with increased residue retention on system productivity, soil organic matter and N requirement in a rice-wheat-mungbean cropping system.

The cropping intensity of Bangladesh is increasing year after year because most small holders start growing three or more crops in a year. Over a 5-year cycle due to changing profitability of crops, farmers cultivate 4-6 crops with diverse seed sizes, seed rate, row spacing, fertilizer rates, and seed depth. Hence a planter for such diverse cropping systems needs to have multi-functional capabilities. Service providers also need to be able to hire out their planter for business all year round to justify the investment cost. There are a number of other criteria and challenges that would need to be satisfied by potential purchasers of a planter. The VMP (Versatile Multi-crop Planter) is such a unique machine for two-wheel tractor which can meet the above criteria and successfully establish a diverse range of crops since 2008 (Haque et al., 2011). It has designed with capability for seeding and fertilizing with fluted roller or vertical plate meters in lines for single-pass shallow-tillage, strip planting, zero tillage and bed planting. The service providers remove seeding unit from VMP and convert only for high speed rotary tiller (HSRT). Most of the grain seeds like wheat, paddy, maize, jute, pulses, oilseeds etc. can be sown in line using VMP. It owners are using this device for their own land cultivation and earning cash income through custom hiring to other farmers and could improve their livelihood through this machine. Therefore, an attempt was made to assess the profitability of VMP operations at farm level and the impacts of its operations on service providers’ livelihood.

One disadvantage of conservation tillage is increase in weed pressure (Hossain et al, 2014). Weed control in conservation tillage is dependent on the use of herbicides, but other cultural options may help in reducing weed infestations. There is limited knowledge about effective weed control under conservation tillage in intensive rice based cropping systems in Bangladesh. The objectives of this study were to examine the effect of herbicides and hand weeding with or without residues on weed control in rice

Labour-intensive and water-demanding practices for rice cultivation such as soil puddling and transplanting of rice seedlings are no longer feasible in many parts of Asia due to declining labour and irrigation water availability. Non-puddled transplanting into soils with minimum soil disturbance (NPT) is a possible approach for rice seedling establishment that could decrease the labour and water requirements and cost of establishment of rice while maintaining some of the advantages that transplanting and flooding of soils bring, namely weed control and increased nutrient availability. The present paper reviews earlier work on the NPT technology in the Indo-Gangetic plain and then examines the findings for minimum tillage NPT of rice seedlings in Bangladesh.

Field traffic has many beneficial effects of labour saving and timeliness, but little thought has been given to the potential deleterious consequences of soil compaction. The process of soil compaction reduces total porosity and increases bulk density, resulting in changes in soil physical properties. Excessive compaction in the seedbed may impede seedling emergence. Although greater soil compaction by heavier vehicle traffic has been reported worldwide, a lighter vehicle can cause soil compaction when used repeatedly. The spatial variability of soil physical properties from light farm machinery traffic with minimum tillage and or controlled traffic compared to conventional tillage are unknown. Hence, the objectives of the current study were: (i) to identify changes in soil physical properties as influenced by compaction during controlled traffic minimum tillage by a 2-wheel tractor and (ii) to determine the effect of soil physical properties on chickpea (Cicer arietinum) seedling emergence.