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In winter, the paddy residues become wet during morning and late evening due to dew, which restricts the operation of sowing machines (Happy Seeder and Super Seeder) into paddy residues, as

wet residues do not slide on furrow openers/tines. A PAU Smart Seeder (PSS) was developed and evaluated for a four-wheel tractor that can sow wheat with optimum crop establishment in

combined harvested rice fields. The PSS were evaluated for its performance under varying straw load, forward speed, and rotor speed in terms of fuel consumption, field capacity, seed

emergence, and grain yield. The crop establishment and wheat yield of PSS was also compared with the existing straw management machines Happy Seeder (HS) and Super Seeder (SS) under heavy

paddy residue conditions. The effect of the straw load was more pronounced on dependent variables than the effect of the speed index. PSS performance was best at a forward speed of 2.6 km 

h−1, rotor speed of 127.5 rpm, and a straw load of 6 t ha−1. Average fuel consumption using PSS was lower than SS but higher than HS. Wheat emergence was higher by 15.6 and 25.7% on the PSS

plots compared to HS and SS, respectively. Average wheat grain yield in PSS plots was significantly higher by 12.7 and 18.9% than SS and HS, respectively in one experiment, while the grain

yield was similar for both PSS and HS in other experiments. PSS has a novel mechanism to manage paddy straw and simultaneously sow wheat into a heavy straw load (> 8 t ha−1) mixture of

anchored and loose straw. In conclusion, PSS showed promise for in-situ management of rice straw as it eliminates most of the operational problems encountered by the existing seeders (HS and

SS).

The rice–wheat (RW) is a major production system in the Indo-Gangetic Plains of India covering nearly 10.5 million hectares including 4.1 million hectares in the north-western (NW) states of

the country1. In the early 1970s, the introduction of high-yielding rice and wheat cultivars, high inputs of chemicals, availability of machinery and highly subsidized electricity for

irrigation, and provision of assured minimum support price were responsible for achieving food security in the country. Since the mid-1980s, the practice of manual harvesting has been

replaced by the advent of combine harvesters that leave a heavy load of residue scattered and anchored residues on the field. Unlike wheat straw which is collected from the fields and used

as fodder, rice straw is rich in silica content which makes it unsuitable for animal feed2. Due to the lack of alternative economic use of rice straw and a short window for preparing the

land for the next crop (wheat), it is subjected to burning in open fields3,4. Rice residue burning has become a serious problem causing phenomenal environmental pollution with serious

consequences on both human and animal health5,6,7. It is estimated that about 23 million tonnes of rice residue are burnt annually in the two NW states (Punjab and Haryana) of India1.

Burning also results in the loss of precious carbon as well as nutrients present in the rice straw8.

In-situ residue management provides the most convenient mode of recycling organic carbon and nutrients, thereby positively impacting soil health and crop performance. The two sustainable

options for in-situ management of straw are surface retention (mulching) and incorporation. For managing rice straw, the Turbo Happy Seeder (or Happy Seeder, HS) machine was developed,

refined, and validated over several years under diverse farming systems to establish its significance9. The HS represented a breakthrough for direct drilling of wheat in the combined

harvested rice fields and retaining rice residue as surface mulch in a single operation in NW India. Another technological development was the attachment of the Super straw management system

(Super SMS), a simple loose straw chopping and spreading mechanism, that can be attached to the rear of the combine harvester, enabling uniform spreading of residue across the harvesting

width1,9. The Super SMS enhances the efficiency of the HS and improves the establishment of wheat1,10. Recently, Keil et al.11 have reported that HS has the potential to eradicate the

practice of rice residue burning due to its ability to sow wheat directly into large amounts of anchored and loose residues. The HS leads to significant savings in wheat production costs and

the benefits in terms of time and water savings, improving soil health, and the societal benefits of reducing air pollution through avoiding burning12,13. Despite these benefits of the HS,

its uptake by the farmers is much slower than expected. Some of the drawbacks of HS technology are; (i) non-uniform seeding depth, particularly on fine-textured soils leading to poor crop

establishment, (ii) lack of confidence in farmers due to slow germination and poor visibility of seed rows initially, (iii) low field capacity when the rice straw is wet due to untimely

rains or due to overnight dew in early morning hours thereby reducing working hours and field capacity, and (iv) occasional choking of seed and fertilizer delivery pipes when the rice straw

is wet9.

Crop residues can be incorporated partially or completely into the soil depending on the tillage system. Implements like stubble shavers, mouldboard plough, disc harrows, and cultivators are

generally used for residue incorporation14. However, in-situ incorporation of cereal residues with a high C/N ratio leads to temporary immobilization of soil and requires 3–4 extra tillage

operations and the use of a straw chopper and also requires one additional irrigation, thus making it a cost and energy-intensive option1,15. Given the limitations of HS technology listed

above, a high energy input seeder (requiring > 60 hp 4-wheel drive tractor) known as Super Seeder was developed by agriculture machinery manufacturers in Punjab, India for seeding wheat into

rice residue in a single operation. Super Seeder is a rotavator with the provision of drilling seed and fertilizer. The outlook of the field after the use of Super Seeder is very pleasing

to farmers as they are accustomed to viewing the wheat establishment in a clean field (free from rice residue). In 2020, the purchase and use of Super Seeders by the farmers outnumbered HS

in NW India. However, Super Seeder has also its drawbacks such as it requires high energy input and defeats the objective of conservation agriculture as it incorporates a major fraction of

residue in the soil leaving the surface plain. Results from several on-farm experiments (n = 159) conducted in NW India showed that on average net returns from wheat for Super Seeder were

about 15% lower compared to HS (H.S. Sidhu, Borlaug Institute for South Asia, personal communication). Furthermore, higher weed intensity and wheat lodging on a large acreage has been

reported in the case of super Seeder compared to wheat sown with HS.

Strip tillage is a conservation tillage system that uses minimum tillage by disturbing only the portion of the soil that is to contain the seed row16. A seeder that combines the benefits of

both straw incorporation and straw mulching may be a better technology for residue management as an alternative to HS or in-situ incorporation in the RW system. The strip tillage seeding

system tills the land in narrow strips (7.5 cm wide) in front of the furrow opener only and places seed and fertilizer in rows at a right depth in a single operation leaving the inter-row

with complete residue cover17,18. The findings19 involved the development of a strip-till drill for sowing wheat in rice fields. The average wheat yield was similar for conventional till and

strip-till drills on manually harvesting rice fields and after removal of the straw. Over the last decade, innovations have been made to design and develop a wide range of 2-wheel tractor

(2WT) driven no-till seeding implements (e.g. lightweight Versatile Multi-crop Planter, VMP) for smallholders which permit reliable seeding into minimally disturbed soil with moderate levels

( 8 t ha−1) mixture of anchored and loose straw even when the paddy residues become wet during morning and late evening due to dew in winters.

PSS can work from morning to late evening compared to HS, as it can handle moist paddy straw. The rotary action of PSS strip tillage blades pushes the tractor forward and due to this, it can

work in wet fields, which is not possible in the case of tine drills or HS. Therefore, the PSS can work for longer duration in a day compared to HS. This is an important consideration for

custom hiring operators as PSS can sow around 10 acres/day whereas HS can sow only 6.0 acres/day.

PSS works in conditions where it is difficult to work with HS such as; HS is sensitive to soil moisture of the field. In wet fields, soil in between consecutive furrow openers is sliced and

struck in tines which cause the choking of straw in the machine. Moreover, the tractor wheel slippage is excessive which makes sowing ineffective.

The wheat establishment in paddy residues is generally less visible in the initial growth stage due to the presence of surface residues in the field. This lesser visibility of wheat

establishment is a big bottleneck among farmers’ mindset for the adoption of HS. PSS sows wheat in a band width of 50 mm which is wider than the wheat sown by any other machine. This feature

is liked by farmers as it makes germination look broader and appears similar to wheat establishment in residue-free fields.

The combine harvester working in wet paddy fields causes ruts due to combined tyre movement. These ruts make the field uneven and zero till machines like HS cannot operate in undulated

fields. However, the PSS has rotary tillage blades which clears the undulations of combine tyers and can sow the wheat effectively.

The average fuel consumption of PSS was 23.3% lesser than SS, whereas, the field capacity of PSS 52% higher than SS. SS consumes more fuel over PSS as it does complete tillage/incorporation

of soil/residues for full machine width while PSS tills 37.5% of total machine width.

The SS requires high horse power (> 55 hp, double clutch) with a creeper gear having a travel speed of less than 1 kmh−1. On the other hand, PSS requires a 50 hp double clutch tractor,

generally available with the farmers.

The SS can sow only 5 acres/day due to its slower forward speed of travel (