Optimal design and setting of rotary strip-tiller blades to intensify dry season cropping in Asian wet clay soil conditions

Abstract

Highlights Strip-tillage of Asian wet clay soil to intensify cropping resulted in poor seedbed. Conventional blades and setting (four per row) created optimum clods, but low backfill. Contrary, an improved blade (> 50 mm depth) created optimum clods and high backfill. Backfill increased further for 6 straight blades/row, but furrow volume increased. Straight blade (four per row, ≥ 75 mm depth setting) is recommended for Asian wet clay soil.

Furrow design for improving crop establishment of two-wheel tractor operated strip tillage planters in loam and clay loam soils

“…In clay loam soil, the higher uncovered seed percentage was due to (1) higher soil moisture content in the clay loam soil in both years (Table1), and (2) clay loam soils being more sticky in nature due to their high clay content and stronger particle bonds (this leads to the production of larger clods during strip tilling than with loam and sandy loam soils [32] ). Seed coverage can be further improved by placing the press wheel behind the furrow openers in both soils [8,12] . With mung bean, furrow openers followed the same trend as in maize seeding, with F1 (shoe-type) and F2 (modified shoe-type) seed coverage being poor, compared to F3, F4 and F5 (inverted T-type openers).…”

“…In general, seed placement requires increasing seed depth with increasing seed size and in consideration of soil moisture status; small seeds required shallower depth in a range of 12-25 mm; medium-sized seeds such as mung bean typically require a depth in the range of 30-35 mm (but this is also related to their coleoptile length), and the depth of large seeds such as maize, chickpea, cotton and pea should be in the range of 50-80 mm (these depths all apply universally including in for Bangladesh [35] ). Optimum seeding depth can also vary depending on the surface soil moisture condition at the time of sowing -deeper sowing is often recommended in dry soil conditions [8,36] .…”

“…The small shank shoe-type furrow openers align with the imported PTOS, facilitating an airdrop seeding mechanism and simultaneous covering with a laddering operation. This configuration however leads to poor crop germination and establishment, due to poor seed to soil contact and coverage, and quick drying of top soil [8] .…”

“…A greater forward speed of tractor increases the displacement of soil, and crop stubble may lead to poor soil backfill and influence the other parameters [24] . In Bangladesh, 2WT operated seeders are mainly operated as walk-behind machines during field operation with a forward moving rate of approximately 3.0±0.5 km/h; as such, soil displacement should -at least theoretically -not be considered an influencing factor [8,9] . The greater and smaller rake angles of the different openers significantly influence soil movement within the furrow, penetration ability, soil furrow backfill, and optimum rake angle suggested in the previous study was 45°-60° as this created the lowest soil disturbance.…”

“…The depth of sowing is influenced by the depth of furrow tilling and opener penetration [25] . Research indicates that the seedbed should extend downwards only to the seeding depth, as working to greater depths is costly and can bring about unnecessary loss of soil moisture [8] . The optimum seed furrow depth is also governed by crop requirements (e.g.…”