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

Conservation agriculture(CA)based production systems may help in achieving more sustainable intensification of cropping systems that use less labour and energy and have higher profit margins,in addition to soil conservation and environmental impact mitigation advantages.But these objectives can only be achieved when the right mechanization options,including appropriate crop establishment equipment,are in place to assist in timely field operations.An urgent need exists,therefore,to fine tune and re-adjust the existing two-wheel tractor(2WT)operated seed drills,with specific reference to the design of blade and furrow openers,while at the same time considering performance in different soil types and environments.To this end,experiments were conducted during 2013-2014 and 2014-2015 at two BARI Regional Agricultural Research Stations in Jamalpur and Barisal,Bangladesh,on a loam and clay loam soil,respectively,to evaluate five types of furrow opener for strip tillage.Shoe and modified shoe-type furrow openers were tested and compared with three inverted-T furrow openers with rake angles of 75°,65°and 55°.The newly designed inverted-T furrow openers were narrower than the shoe-type openers;they also had a longer,hollow shanks and provided better options for adjustment to achieve the desired seeding depth and line spacing.Compared to shoe-type openers,better seeding depth,uniformity and higher degree of seed coverage were recorded with use of the inverted-T furrow opener with a 65°rake angle.This resulted in better seed coverage in the furrow,a higher emergence rate index,and the highest emergence percentage of maize and mung bean.Our research findings can be generalized to smallholder production systems on loam and clay loam soils where farmers utilize 2WT operated seed drills for crop establishment in both traditional and conservation agriculture-based planting systems.

Strip deep rotary tillage combined with controlled-release urea improves the grain yield and nitrogen use efficiency of maize in the North China Plain

Inappropriate tillage practices and nitrogen(N) management have become seriously limitations for maize(Zea mays L.) yield and N use efficiency(NUE) in the North China Plain(NCP). In the current study, we examined the effects of strip deep rotary tillage(ST) combined with controlled-release(CR) urea on maize yield and NUE, and determined the physiological factors involved in yield formation and N accumulation during a 2-year field experiment. Compared with conventional rotary tillage(RT) and no-tillage(NT), ST increased the soil water content and soil mineral N content(Nmin) in the 20–40 cm soil layer due to reduction by 10.5 and 13.7% in the soil bulk density in the 0–40 cm soil layer, respectively. Compared with the values obtained by common urea(CU) fertilization, CR increased the Nmin in the 0–40 cm soil layers by 12.4 and 10.3% at the silking and maturity stages, respectively. As a result, root length and total N accumulation were enhanced under ST and CR urea, which promoted greater leaf area and dry matter(particularly at post-silking), eventually increasing the1 000-kernel weight of maize. Thus, ST increased the maize yield by 8.3 and 11.0% compared with RT and NT, respectively, whereas CR urea increased maize yield by 8.9% above the values obtained under CU. Because of greater grain yield and N accumulation, ST combined with CR urea improved the NUE substantially. These results show that ST coupled with CR urea is an effective practice to further increase maize yield and NUE by improving soil properties and N supply, so it should be considered for sustainable maize production in the NCP(and other similar areas worldwide).

Suction Cup Samplers for Estimating Nitrate-Nitrogen in Soil Water in Irrigated Sugarbeet Production

Efforts have increased to measure nitrate losses from farmland under different management practices due to environmental and public concerns over levels of nitrate-nitrogen (NO3-N) in surface and ground waters. This study evaluated the effect of conventional tillage (CT) and strip tillage (ST) practices and three N application rates on NO3-N concentrations in soil water at a 76 cm depth under irrigated sugarbeet (Beta vulgaris L.) in a clay loam soil. Nitrogen rates were applied as dry urea at 120, 150, 180 kg N ha-1 in 2006;130, 160, 190 kg N ha-1 in 2007;and 110, 140, 170 kg N ha-1 in 2008. Soil water volumes were measured weekly during each growing season using three ceramic suction cup samplers per plot placed at a 76 cm depth below the soil surface under each tillage. Results indicated that NO3-N concentrations at the 76 cm depth in the soil profile were not significantly affected by either tillage practice or by N application rate due to soil variability across the field and due to suction cup samplers’ biased estimate of soil water. The three N rates under CT and ST practices maintained NO3-N concentrations below the root zone to levels exceeding the 10 mg L-1 safe drinking water maximum level in all three years. There were large variations in NO3-N concentrations among replicates within each tillage and N rate that were likely caused by variability in soil physical, hydraulic and chemical properties that impacted water movement through the soil profile, N dynamics and leaching below the root zone of sugarbeet. In conclusion, suction cup samplers are point water measurement devices that reveal considerable variability among replicates within each treatment due to the heterogeneity of field soils. Further, these samplers are not recommended in heterogeneous soils with preferential flow characteristics.

Optimization and experiment on key structural parameters of no-tillage planter with straw-smashing and strip-mulching

Accelerate the quality of smashed-straw laying and enhance the effect of seed-bed arranging for no-tillage planter with straw-smashing and strip-mulching in full stubble covered paddy have become imperative in implementing modern conservation tillage.Considering the perfect operating performance(passability and stability)of the developed no-tillageplanter,this study intends to optimize the structure design of smashed-straw diversion device and strip-rotary tillage device.Dynamics equations of smashed straw and kinematics models of rotary blades were established through theoretical analysis,and the principal factors that affecting straw strip-laying quality and seed-bed arranging effect were specified.The influence of out-enlarge angle(η)and slide-push angle(γ)of the diversion device on the coefficient of variation(ζ1)of cover-straw width,and the influence of rotary tillage-blade number(N)and configuration in a singlerotary plane on the broken rate(ζ2)of strip soil were completely analyzed.And then,based on the systematic analysis and integrated scheme,operating performance and field verification tests using the optimized no-tillage planter were thoroughly performed.The results of the performance tests indicated that the out-enlarge angle(η)had a highly significant influence on the coefficient of variation(ζ1),and the slide-push angle(γ)had a significant influence on(ζ1).The rotary tillage-blade number(N)had a highly significant influence on the broken rate(ζ2),and the slide-push angle(γ)had a significant influence on(ζ2).The obtained optimal combination of these key structure parameters through comprehensive analysis wasη=45°,γ=40°,and N=4.Field verification test results indicated that the optimized no-tillage planter achieved mean values of ζ1=10.47%and ζ2=90.95%,which satisfied the relevant operation quality and cultivation agricultural requirement of conservation tillage equipment,and provided technical references for developing the similar no-tillage planter of straw crushing and returning.

Field experimental study on optimal design of the rotary strip-till tools applied in rice-wheat rotation cropping system

The rice-wheat rotation system plays a significant role in Asian agriculture.The introduction of strip-tillage into the rice-wheat system for wheat planting offers a way to use conservation tillage practices to improve the seedbed quality,retain residue between rows and reduce energy input.A field experiment was conducted using an in-situ test rig.Three types of blade(bent C,straight and hoe)were evaluated in four tool configurations at four rotary speeds(180 r/min,280 r/min,380 r/min and 510 r/min)in a paddy soil.Furrow shape parameters,tillage-induced soil structures and energy consumption were assessed.Results showed that the straight blade configuration failed to create a continuous furrow at either 180 r/min or 510 r/min.The bent C blade configuration produced a uniform furrow profile but its furrow backfill was poor and unsuitable for seeding.The hoe blade configuration cut a continuous furrow and better tillage-induced soil structure,but it produced a much wider and non-uniform furrow shape.The mixed blade configuration(central hoe blades with two straight blades aside)provided a uniform furrow with good backfill and fine tilth by utilizing both the cutting effect of straight blades on the furrow boundaries and tensile fracturing of the furrow soil by the hoe blades.The torque of the mixed blade configuration was comparable with the bent C blade but was less than the hoe blades.Hence,a mixed blade configuration was recommended for rotary strip-tillage seeding using in rice-wheat system.