Crop performance in permanent raised bed rice-wheat cropping system in Punjab, India

Abstract Raised beds are widely used in agriculture in developed countries and have proven to be an excellent option for wheat. Permanent raised beds may also offer benefits for rice–wheat (RW) systems in South Asia, in terms of both production and the possibility that furrow-irrigation may be more efficient than flood irrigation. The performance of a RW system on permanent raised beds (37 cm wide, 15 cm high, furrow width 30 cm) was compared with conventional cultivation on the flat on sandy loam and loam soils in replicated experiments in central Punjab, India. The experiments commenced with wheat sown in November 2002, and were continued for 8 crops. Yields of conventionally tilled wheat (CTW) ranged from 3.6 to 4.9 t ha −1 and tended to be higher on the loam than on the sandy loam. Yields of wheat on fresh and permanent beds (WB and DDWB, respectively) were similar to yields on CTW and direct-drilled wheat on the flat (DDW) except when establishment was sub-optimal on the beds on both soils in 2004–2005. It was also lower on the beds on the sandy loam in 2002–2003 when tillering did not compensate for the lower sowing rate on the beds. In each case, the poorer performance on beds appeared to be associated with the more rapid drying of the beds than the flats, and thus the need for greater precision in irrigation and sowing management with beds on sandy loam and loam soils. Yield on beds relative to flats did not change as the beds aged. Yields of transplanted rice on permanent beds (TRB) were depressed relative to yields of puddled transplanted rice (PTR) with the same alternate wetting and drying water management, regardless of age of the bed (from 1st to 8th crop) and soil type. Yields of TRB relative to PTR declined as the beds aged, over the first 2–3 years, from about 80 to 90% to less than 50% of PTR. Biomass production in TRB was always significantly less than in PTR, starting from 35 d after transplanting. Performance of direct-seeded rice on beds (DSRB) was even poorer. Serious root knot nematode infestation was also a serious problem in transplanted rice on the sandy loam in the absence of continuous flooding, on both TRB and PTR. The DSRB suffered from severe iron deficiency each year on both soils despite several iron sprays beginning as early as 15 days after transplanting, and yields declined from about 60% of PTR with the same irrigation scheduling in the first rice crop to less than 25% of PTR in the third rice crop. Total annual system productivity was highest using puddled transplanted rice (PTR) in rotation with fresh beds (WB) for wheat, CTW or DDW on the flat. Average productivity of these systems over the first 4 years was 9.5 t ha −1  y −1 on a sandy loam soil and 10.3 t ha −1  y −1 on a loam soil. Productivity of RW on permanent raised beds with transplanted rice declined as the beds aged, and averaged 77–79% of the productivity of the best systems mainly due to declining yield of TRB relative to PTR. Averaged over the first 3 years, productivity of permanent beds with direct-seeded rice (DSRB) was even lower (only 62–68% of the best systems) due to much lower yields of DSRB. Permanent bed RW systems seem to have limited potential under the prevailing soil and climatic conditions of Punjab, India, with current varieties and management. Further research on permanent raised beds for RW systems should focus on the selection of suitable rice and wheat cultivars, soil health issues such as nematodes and iron deficiency, weed control, irrigation scheduling, N management and soil compaction.