Soybean performance on raised beds in a rice irrigation layout

Transcription

1 Soybean performance on raised beds in a rice irrigation layout SK Mathews 1, BW Dunn 1, HG Beecher 1, JA Thompson 2, J Timsina 3, and DW Johnston 1 1 Department of Primary Industries, Yanco Agricultural Institute, YANCO Department of Primary Industries, Deniliquin Research and Advisory Station, DENILIQUIN CSIRO Land and Water GRIFFITH 2680 Abstract The performance of soybean is being investigated in a rice based farming system field experiment at Coleambally, Southern NSW. The increasing use of bankless channel irrigation layouts for rice growing, when combined with raised beds may mean that the current necessity to change the field from a rice style layout (across the slope) to a conventional furrow irrigation layout (down the slope) can be avoided as the crop sequence changes from rice to other irrigated crops. The same field layout incorporating raised beds could be used for rice and other summer crops as well as winter crops. Soybean were grown using either furrow or sub surface drip irrigated on raised beds within a bankless channel style rice layout during 2003/4. The soybeans were grown in rotation with barley following rice. Crop physiological development, growth, yield parameters and water use were monitored during the season. Yields were satisfactory, with furrow and sub surface drip treatments yielding 3.68 and 3.05 t/ha, respectively. There were large differences in water use between furrow irrigated (9.5 ML/ha) and sub surface drip irrigated soybeans (5.6 ML/ha). Applied water use efficiency thus differed between irrigation treatments with 0.39 and 0.55 t/ml achieved for furrow and sub surface drip irrigated soybeans, respectively. Soil moisture profiles suggest that irrigation may have ceased prematurely in the drip irrigated soybeans, thus reducing yields. Timing of the final irrigation based on the appearance of the leaves and pods may also need to account for the amount of soil moisture available to finish the crop. Soybeans grown under furrow and sub surface drip irrigation are currently in their second year of experimentation. This paper discusses soybean crop performance and water use when grown using furrow and sub surface drip irrigation during 2003/4. Results from the current season are also discussed. Introduction In the Riverina soybeans are typically grown on raised beds using furrow irrigation on slopes of 1:1500 or greater and with run lengths of m (Beecher et al., 1997). Irrigation layouts for rice growing have seen the development of bankless channel systems (Beecher et al., 2000). Typically the slope of the rice bay would be flat (zero grade) across the field and sloped (1:1000 to 1:2000) down the field through the bays. Recent developments have seen the rice fields terraced between bays in bankless channel layouts. The bays are stepped 5-15 cm between each bay down the field. Summer crop growers (generally maize) have adopted bankless channel systems on sloping bays (rooftopped) using conventional hills. In this system, high flow rates lead to fast watering/draining with the bankless channel acting as both supply and drain to individual bays. However this means watering from the bottom up, with part of the layout being inundated A similar irrigation layout to this has been used in the USA, principally Arizona (Dedrick et al., 1982) where it is variously referred to as level furrows, level basins, check flooding, basin flooding or check basin irrigation. Advantages in the US have included; deep percolation minimisation, high water application efficiency, reduced labour requirements and increased crop production.

2 Where lateral beds are constructed within rice bays (Mathews et al., 2004; McCaffery et al., 2002), a significant advantage for rice based farming systems is available, in that alternating between rice and other crops on raised beds does not require missing a crop season while the field layout is changed. The substantial costs involved in this change are also avoided. An experiment seeking to demonstrate the performance of permanent bed and traditional layouts for a range a crop sequences in rotation with rice including double cropping has been established at Coleambally. The performance of the irrigation layouts, crop sequences and irrigation methods, including irrigation and total water use efficiency, net recharge, profitability, labour productivity, soil condition, cropping flexibility is being evaluated. This paper reports on the performance of soybeans grown on permanent raised beds following barley using furrow and sub surface drip irrigation within a terraced, bankless channel layout. Materials and Methods Experimental design The experiment was conducted at the Murrumbidgee Shire Community Experimental Demonstration Farm, in the Coleambally Irrigation Area of south-eastern Australia. The soil is an association of a transitional red-brown earth and self-mulching clay, and classified as suitable for rice growing based on the rice soil suitability criteria (Beecher et al., 2002). The site was established for evaluation of permanent bed rice-based cropping systems in mid A Beeline GPS guidance system and furrowing equipment was used to create 1.84 m wide beds (centre to centre) east/west across the site. The beds run perpendicular to the slope of the field and had zero grades from east to west along the beds. Banks were constructed parallel to the beds to create bays 14.7 m (6 beds) wide by 140 m long. Bankless channels were constructed on eastern and western ends of the bays. In four of the bed bays, two drip lines were installed into each bed, 17 cm below the bed surface. The drip lines ran parallel to the beds, one quarter of the way onto the bed from the bed shoulder, giving a line spacing of 70 cm. The drip tape emitters were spaced at 35 cm intervals and are capable of 0.80 L/h output at a pressure head of 10 m. In 2003/4 soybeans were grown on raised beds with either furrow or sub-surface drip irrigation. There were four replicates and the two treatments were arranged in a randomised block design. In 2004/5 a second soybean crop was planted comparing the same treatments. Crop management 2003/04 Soybeans (cv Djakal) were sown at 100 kg/ha on the 9 th December 2003 into uncultivated, unirrigated, burnt barley stubble using a Connor Shea double disc drill. Four rows on each bed were sown so that there were two rows spaced 30 cm apart on either side of the drip lines. The beans were inoculated prior to sowing and received a germinating irrigation on 10 th December The flat grade of the irrigation layout, allowed water in the furrow irrigated soybeans to be raised close to the seed line level for germination, without flooding. In the sub-surface drip irrigated plots, water was applied through the drip line to germinate the crop. No fertiliser was applied to the soybean crop, as the previous barley crop had received 185 kg/ha DAP, at sowing and 500 kg/ha single superphosphate was applied prior to constructing the beds. Soybeans were sprayed twice for barnyard grass control; after soybean emergence using Fusilade (fluazifop-p) and at the initiation of pod development using Verdict (Haloxyfop). The soybeans were also inter-row cultivated at the initiation of flowering to control grass and broadleaf weeds.

3 Post soybean emergence, the drip irrigated plots were irrigated approximately every third day to replace ETo adjusted for crop coefficient (Kc) and rain. Drip irrigations occurred when G-Bug gypsum blocks had reached around -50 kpa at 30 cm soil depth. The furrow irrigated soybeans were irrigated approximately weekly at about 60 mm of accumulated ETo adjusted for Kc and rainfall. Once the furrow irrigated soybeans had commenced germinating, water was allowed to cover the beds ensuring that water had reached the centre of the beds before draining, taking around 24 hours to complete the irrigation cycle. Final irrigation at the end of the season was applied when 35% of plants had turned brown. Crop management 2004/05 Soybeans (cv Djakal) were sown into moist soil on the 15 th December 2004 using a stubble king parallelogram double disc seeder. One week prior to sowing soybeans, the barley was harvested, stubble burnt and bays pre-irrigated. Sowing rates, row spacing and crop management were consistent with the 2003/4 soybean crop. Crop measurements Plant establishment counts were taken after emergence. Dry matter (DM) production at V4 to V5 (50% plants with 4 to 5 nodes present), R3 (50% plants with 1cm pods), R5 (50% plants with beans at any node) and full maturity (95% pods brown; P95) were measured from quadrats (4 rows by 1m on the bed). At these stages, leaf and stem dry mater was measured and at R3 and R5 leaf area index (LAI) was measured. Grain yields were determined from plot header harvests. Yield parameters were determined from the P95 cuts. Phenological development was determined at the V4 and R4 stage sampling by dividing the plants into their growth stages (Fehr et al., 1971). Full maturity (P95) was based on visual estimates. Irrigation water use was measured through the drip lines or through supply and drainage flumes in the furrow irrigated bays. Results and discussion 2003/4 Soybean crop growth and yield Soybean establishment was similar in both treatments. Grain yields in the furrow and sub-surface drip irrigated treatments were 3.68 and 3.05 t/ha, respectively (Table 1). There were no significant differences between the two treatments for total DM production at the different sampling stages. Similarly, there was no significant difference for LAI between the drip and furrow irrigated treatments at the R3 stage (2.6 compared with 2.5 m 2 leaf/m 2 ) or the R5 growth stage (2.9 compared with 3.4 m 2 leaf/m 2 ). Table 1. Establishment, dry matter accumulation and grain yield of soybeans (cv. Djakal) grown using different irrigation treatments in 2003/4. Irrigation treatment Establishment Plants/m 2 V4 DM R3 DM R5 DM P95 DM g/ m 2 Grain Yield t/ha Furrow Drip lsd (P<0.05) ns ns ns ns ns 0.23 Yield component analysis showed little difference in plant numbers per unit area at P95 between treatments. Pod number per plant and seed number per plant were highest for the drip irrigation treatment but were not significantly different from the furrow irrigation treatment, whilst the seed weight was significantly higher in the furrow irrigation treatment (Table 2). Lower yields in the subsurface drip irrigated soybeans could be attributed to a lower average seed weight.

4 Table 2. Yield components of soybeans (cv. Djakal) grown using different irrigation treatments in 2003/4. Irrigation Treatment P95 Plants/ m 2 Pods/plant Seeds/plant Average seed weight (g) Furrow Drip lsd (P<0.05) ns ns ns /4 Soybean water use There was a large difference in water use between furrow irrigated (9.5 ML/ha) and sub-surface drip irrigated treatments (5.6 ML/ha), thus, applied WUE was significantly with 0.39 and 0.56 t/ml, for furrow and sub surface drip irrigated treatments, respectively (Table 3). Table 3. Total water use and applied (irrigation + growing season rain) water use efficiency (WUE) of soybeans (cv. Djakal) grown using different irrigation treatments in 2003/4. Irrigation Applied WUE (t/ml) Treatment Water Use (ML/ha) Furrow Drip lsd (P<0.05) Determination of the final irrigation was based on a visual estimate of 35% senesced plants (Thompson pers. comm. 2004). An inadvertent lapse in the drip irrigation supply around the 17 th March, 2004 meant that adequate amounts of water were not applied through the drippers for several days and early senescence of plants occurred due to drought stress. The final irrigation of the drip irrigated treatment following rapid senescence to 35% senesced plants occurred on 24 th March Lower individual seed weight and soil moisture profiles in the sub surface drip irrigated treatment suggest that drip irrigation may have ceased prematurely (Figure 1). Thompson (1977) found that irrigation scheduling should ensure that moisture is readily available to the crop until physiological maturity to maximise grain fill and crop yields. Cumulative moisture (mm) ETo (mm) x Kc Furrow irrigation Drip irrigation V4 V4 R3 R3 Furrow Drip Days after sowing 35% 35% P95 P95

5 Figure 1. Cumulative moisture supply (irrigation plus rainfall) for furrow and drip irrigated soybeans versus evapo-transpiration (adjusted for Kc) 2003/4 Soybean phenological development Both treatments had similar phenological development, but the sub surface drip irrigated treatment senesced and reached full maturity quicker than the furrow irrigated treatment, due to insufficient water supply during grain fill. The drip irrigated soybeans reached V4 stage 31 days after sowing (DAS) compared with 33 DAS in the furrow irrigated soybeans. Both the drip and furrow irrigated treatments reached R3 stage 57 DAS. The drip irrigated treatment had 35% senesced plants after 106 DAS, compared with 111 DAS in the furrow treatment. Full maturity was reached 114 and 127 DAS in the drip and furrow irrigated soybeans, respectively. 2004/5 Soybean crop growth and yield Soybean establishment was slightly higher in the drip irrigated treatment. At V4 growth stage the drip irrigated treatment had significantly higher total DM, stem DM, leaf DM and leaf area than the furrow irrigated treatment, but at the R3 growth stage, there was no significant difference between the two treatments for these growth parameters (Table 4). Table 4. Establishment, DM production and leaf area at V4 and R3 growth stage of soybeans (cv. Djakal) grown using different irrigation treatments in 2004/5. Irrigation treatment Establishment Plants/m 2 V4 DM V4 LAI (m 2 leaf/m 2 ) R3 DM R3 LAI (m 2 leaf/m 2 ) Furrow Drip lsd (P<0.05) ns ns ns Conclusion Soybeans can be grown successfully on zero grade raised beds within a bankless channel, rice style layout. Raised beds within a bankless channel, rice style layout can increase cropping intensity and reduce costs by eliminating the need to change layouts between different crop types. High soybean yields were achieved under both furrow and subsurface drip irrigation grown directly after barley in 2003/4 and soybean crop growth measurements indicate high yield potential in 2004/5. Significant water savings can be made by growing soybeans using sub surface drip irrigation. Adequate irrigation water application/status through to the end of the grain filling period is essential to maximise grain yield Acknowledgements This work was undertaken at the Murrumbidgee Shire Community Experimental Demonstration Farm with the financial support of NSW Agriculture, CSIRO Land and Water, ACIAR, RIRDC and GRDC. Other contributors include: Rice CRC, Coleambally Irrigation, Murray Irrigation, Irrigated Cropping Forum References Beecher HG, Hume IH, Dunn BW (2002) Improved method for assessing rice soil suitability to restrict recharge. Australian Journal of Experimental Agriculture 42, Beecher HG, Beale P, Clampett WS (2000) Land for ricegrowing. In Production of Quality Rice in South Eastern Australia. (Ed. LM Kealey and WS Clampett) Rural Industries Research and Development Corporation, Canberra.

6 Beecher HG, Thompson JA, McCAffery DW, Muir J (1997) Permanent beds for irrigated farming in Southern New South Wales. NSW Agfact. P Dedrick AR, Erie LJ and Clemmens AJ (1982) Level Basin Irrigation. Advances in Irrigation 1, Fehr WR, Caviness CE, Burmood DT, Pennington JS (1971) Stage of development descriptions for soybans, Glycine Max (L.) Merrill. Crop Science 11, Mathews S, Beecher G, Dunn B, Thompson J, Humphreys L, Johnston D (2004) Permanent beds for sustainable cropping systems. IREC Farmers Newsletter, Rice R&D edition, No. 165 Summer pp 4-6. McCaffery D, Thompson J, Humphreys L, Beecher HG, Ellwood N, Taylor M, Polkinghorn, B (2002) Best Bet guidelines for rice on beds. IREC Farmers Newsletter, No. 161 Large Area pp Thompson JA (1977) Effective irrigation termination on yield of soybeans in southern New South Wales. Australian Journal of Experimental Agriculture and Animal Husbandry 17,