SUGARBEET EMERGENCE AS INFLUENCED BY IRRIGATION METHOD AND POLYACRYLAMIDE PLACED IN SEED FURROW

Transcription

1 SUGARBEET EMERGENCE AS INFLUENCED BY IRRIGATION METHOD AND POLYACRYLAMIDE PLACED IN SEED FURROW C. D. YONTS University of Nebraska, Panhandle Research and Extension Centre, 4502 Avenue I, Scottsbluff. NE ABSTRACT Furrow or sprinkler irrigation is often used to assist in sugarbeet plant establishment, yet little information is available to compare the two methods Furrow irrigation saturates seed from below and leaves the soil undisturbed. Sprinkler irrigation saturates the seed from above and breaks down and consolidates soil particles near the surface. Adding synthetic compounds, such as polyacrylamide to the soil, is another method being tried to enhance plant emergence and/or reduce soil crusting. The use of polyacrylamide for this purpose has had mixed results The objective of this study is to determine the most effective method(s) of irrigating sugarbeet at planting time to enhance emergence. Sugarbeet was planted on two different dates during the spring of 2001 and Irrigation methods included no irrigation, furrow irrigation after planting, sprinkler irrigation after planting and sprinkler irrigation before and after planting Polyacrylamide was added to the seed furrow at planting time at a rate of 2.2 kg/ha This treatment was compared to no polyacrylamide added to the seed furrow at planting time. For 2001, polyacrylamide did not influence the final emergence for any of the irrigation treatments tested Multiple irrigations after planting gave the greatest final emergence for the first date of planting in For the second planting date both sprinkler irrigation before and after planting and sprinkler irrigation after planting had the greatest emergence. Emergence for furrow irrigation after planting was similar to sprinkler irrigation after planting The no irrigation treatment resulted in the slowest rate of emergence and least final emergence. Results for will be presented INTRODUCTON In the irrigated growing regions of the U.S, irrigation is often used at planting time when spring rain is not adequate in order to obtain an acceptable level of sugarbeet emergence As a method to reduce seeding and thinning costs, most growers are planting sugarbeet to stand. When planting sugarbeet to stand it is necessary to have good herbicide control, proper seeding rates and have a consistent emergence rate (Fornstrom, 1980). Planting to stand requires a sugarbeet emergence rate of approximately 70% or more to assure an adequate plant population and to achieve maximum yield (Durrant, 1988). In a Nebraska study, maintaining sugarbeet plant population between 40,000 to 100,000 plants/ha provided the best sugar yield (Yonts and Smith, 1997). Burcky and Winner (1986), in a study of the effect of plant population on yield at different 1st joint 1/RB-ASSBT Congress, 26th Feb.-1st March 2003, San Antonio (USA) 685

2 harvest dates, found sugar yield continued to increase when testing populations between 31,000 and 71,000 plants/ha Establishing a sugarbeet plant population of approximately 85,000 plants/ha is generally recognized as the plant population required in order to obtain maximum yield potential. In order to achieve plant to stand. growers must prepare seed beds in such a way that water stored in the soil during the winter and fall is conserved. If precipitation during the off season is not adequate or excessive pre-plant tillage drys the soil out, irrigation will be needed in order to obtain the desired plant population. When soil conditions are dry, applying water with either furrow or sprinkler irrigation systems can be effective in helping to establish sugarbeet stand Until recently there has been little information to compare the performance of the two irrigation methods During a three year trial, emergence counts were collected for approximately 40 varieties in a regional sugarbeet variety trial conducted in Colorado, Nebraska and Wyoming (Smith et al, 2000) Of the twenty sites that were a part of this study, fifteen were irrigated up. Six used a furrow irrigation system and nine used a center pivot system Furrow irrigated sites averaged 75% emergence while sprinkler sites averaged only 62% emergence. It is important to keep in mind that in these experiments, center pivots replaced the labor associated with furrow systems, but did not improve seedling emergence Part of the reason plant stand is reduced with sprinklers is a result of the difference in how water is applied by the two types of irrigation systems When water is applied for germination using furrow irrigation, the seed is saturated from below the seed and the surface soil remains undistrubed Sprinkler irrigation saturates the seed from above and can cause the soil near the surface to be broken down and consolidated forming a dense soil layer over the seed Development of a dense soil layer near the surface can occur as a result of a high intensity rain storm (Tackett and Pearson, 1965) When irrigation or rainfall breaks down the surface soil particles and a dense soil layer is formed followed by warm sunny weather, the potential for developing a surface crust is increased This crust is difficult for sugarbeet to emerge through and can cause a decrease in sugarbeet emergence To control or reduce the impact of soil crusting, Johnson and Law (1967) and Robbins, et al, (1972), added sulfuric and phosphoric acid, respectively to the soil as methods of improving seedling emergence. A solution of synthetic organic polymer was sprayed on the soil surface as a method to improve sugarbeet emergence but had no affect (Lehrsch et al, 1996). Conversion from furrow to sprinkler is occuring in many areas at a increased rate and will continue because center pivots provide a method for improving water application efficiency and reducing labor. The industry is therefore placed in a quandary If a water source is available for a center pivot and irrigation can easily occur anytime during the planting and emergence time period, why is plant establishment less with sprinkler irrigation compared to furrow irrigation? Information is needed to determine the best time for applying water and the amount of water to be applied. Proper water management techniques must be developed that will allow center pivot producers to obtain performance from irrigation during emergence that equals or exceeds that obtained with furrow systems. The objective of this study is to determine the most effective method (s) of irrigating sugarbeet at planting time to maximize the germination and emergence process st joint 1/RB-ASSBT Congress. 26th Feb.-1st March San Antonio (USA)

3 MATERIALS AND METHODS The study was conducted at the University of Nebraska, Panhandle Research and Extension Center near Scottsbluff, Nebraska using a center pivot irrigation system. The soil type was a Tripp very fine sandy loam (Typic Hapustolls) with a water holding capacity of mm/mm. To obtain different planting conditions, sugarbeets were planted in both a loose and firm seedbed condition. Main plots were a combination of the two seedbed condition treatments and four irrigation treatments. The irrigation treatments were: 1) No irrigation at planting time - No: 2) Sprinkler irrigation prior to planting to fill top 12 inches of soil profile followed by light sprinkler irrigations to maintain adequate soil water content at seeding depth - Prior; 3) Multiple sprinkler irrigations after planting - Multiple; and 4) Furrow irrigation after planting to fill soil profile- Furrow Main plots were split to include the application of a crosslinked, potassiumbased polymer (Stockosorb AGRO F, manufactured by Stockhausen, Inc.) in two of the four rows of the main plot treatments. Two separate emergence trials were conducted during each of 2001 and Planting dates in 2001 were May 8 and May 15. In 2002, planting dates were April 15 and April 25. Only the second planting date of each year was carried to harvest Plots were prepared using standard pre-plant tillage operations A ripper/packer was used to loosen and dry the soil for the appropriate seedbed treatment plots Each main plot was six, 56 em rows wide and 7.6 m long. Each treatment was replicated six times. The middle four rows of each main plot were randomized to include two rows with polyacrylamide and two rows without polyacrylamide. Polyacrylamide was applied at planting time directly in the seed furrow at a rate of 2.2 kg/ha A split plot randomized complete block design was used for both planting date trials Individual plots were irrigated independent of one another For the furrow irrigated plots every other furrow was irrigated using small plot irrigation equipment For the sprinkler treatments, the center pivot was equipped with individual sprinkler shutoffs that allowed irrigation of individual main plots The center pivot sprinkler system was equipped with low pressure spray devices located approximately 1 m above the ground Stand count measurements were collected on a three to five day interval to determine both a rate and final emergence. Emerged sugarbeet in the entire length of both rows of each subplot were counted. Harvest of the second planting date experiments were on October 10, 2001 and October 14, 2002 Root yield was determined by harvesting the entire two row subplot Approximately 7 kg sub-samples were collected and taken to Western Sugar for analysis of tare and sugar content RESULTS Irrigation and rainfall amounts during the germination and emergence period are given for 2001 and 2002, (Tab. 1 a and Tab. 1 b, respectively). 1 5 tjoint 1/RB-ASSBT Congress, 26th Feb.-1st March 2003, San Antonio (USA) 687

4 There were no significant differences found for the polyacrylamide treatments or the seedbed treatments and therefore only irrigation treatment differences are examined. Percent emergence (Tab. 2) is given for the 2001-early, 2001-late, 2002-early and 2002-late experiments, respectively. No irrigation at planting had the least percent emergence for all experiments except during the 2002-late experiment. The prior irrigation treatment was greatest only for the late experiment and was similar to the multiple treatment. The multiple irrigation treatment was in the greatest emergence category in three out of the four emergence experiments. The furrow treatment was in the greatest emergence category in two out of the four experiments. When all four of the emergence experiments were combined (Tab. 3), the multiple irrigation treatment was greatest and similar to the furrow treatment. No irrigation gave the least percent emergence of the treatments tested. Harvest data for the 2001-late and 2002-late experiments are given (Tab. 4). No significant difference was found among the irrigation treatments in Although sugar yield for the no irrigation at planting treatment was numerically smaller than the other irrigation treatments by nearly 1100 kg/ha, the variability among the plots was enough that significance could not be determined In 2002, the furrow irrigation treatment gave the highest sugar yield. All other irrigation treatments were similar and at least 2200 kg/ha less. Tah. Ia. Precipitation and irrigation amounts expressed in mm.fih thc carfl' and /arc experiments. I> ate Irrigation Irrigation Precipitation treatment amount 3/10-5/ early 5/10 2 and / /14 2 and /16 2 and late 5/ / /18 2 and / /25 2 and / / st joint 1/RB-ASSBT Congress, 26th Feb.-1st March 2003, San Antonio (USA)

5 Tah. lb. Precipitation and irrigation amounts expressed in mm for the early and late experiments. Date Irrigation Irrigation Precipitation treatment amount 4/1-4/ early 4/ / / / / / / / / / / late 4/ / / / / / / / / / st joint 1/RB-ASSBT Congress, 26th Feb.-1st March 2003, San Antonio (USA) 689

6 Tun. :!. Final emergence expressed in percent comhined urer secdhed and po!wcn1umide treatments/iii' the ear/1. 200/- late. 200]- car/1 und late ex Jeriments. Irrigation Treatment early late earlv late No :? Prior 48.:? Multiple :? Furrow :?. 56.:?. LSD (a' 5'V., 1:? :?.:?..6 :?.9.:? Tah. 3. Final emergence expressed in percent cmnhined orcr seedhed and eolmcn!amide treatments fin the 200 I and :!002 ear!r and late experiment1. Irrigation Treatment Final emergence No 44.3 Prior 53.4 Multiple 59.8 Furrow 57.5 LSD (a' 5% 4.4 Tah. -1. Sugar ric lei presented in kg./w comhined m er.1eedhed and po!rucrdamidc treatments jiji' the]()() I- lute and]()()]- lute nperiment.l. Irrigation Treatment late late No 8:?.70 84:?.0 Prior 9:?.80 7:?.:?.0 Multiple Furrow 9:? LSD (a' 5% N.S CONCLUSIONS The use of a polymer to enhance sugarbeet emergence was not effective during the years of this trial The combination of water and sunshine also did not result in the formation of a soil crust in any of the experiments. Sugar yield was not significantly different for any of the experiments in In 2002, the furrow irrigation treatment was greater when compared to all of the other irrigation treatments. In the spring of 2002 during emergence of the late experiment, freezing temperatures were recorded. The additional amount of soil water held in the furrow irrigation treatment coupled with slightly different 690 1st joint 1/RB-ASSBT Congress, 26th Feb -1st March San Antonio (USA)

7 stages of emergence for the different irrigation treatments could have reduced plant stand in selected treatments. For the two years of this study, the multiple irrigation treatment provide the greatest plant emergence but was similar to the furrow irrigation treatment This study will be repeated again in 2003 before final conclusions are made. REFERENCES BURCKY, K AND WINNER, C. The effect of plant population on yield and quality of sugar beet at different harvesting date. J. Agronomy anc Crop Science , DURRANT, M.F. A survey of seedling establishment in sugar-beet crops in 1980 and Ann. Appl. Bioi , FORNSTROM, K J Planting sugarbeets to stand in Wyoming J Am So Sugar Beet Techno!. 20(6) , JOHNSON, R.C. AND LAW, J.B., Controlling soil crusting in sugar beet fields by applying concentrated sulfuric acid. J. Am So. Sugar Beet Technol , LEHRSCH, GA, SOJKA, R.E AND BJORNEBERG.D L. PAM spray effects on sugarbeet emergence p In SOJKA, R. E AND LENTZ, R.D Managing Irrigation-Induced Erosion and Infiltration with Polyacrylamide Univ of Idaho Mise Pub USDA-ARS, Kimberly, ID 6. ROBBINS, C W., CARTER, D.L. AND LEGGETT, G. E. Controlling soil crusting with phosphoric acid to enhance seedling emergence. Agron. J , SMITH, JA, WILSON, R.G, YONTS,C D, HEIN, G L AND HARVESON, R. M 2000 University of Nebraska Sugarbeet Variety Trial. Publication No PHREC 00-06, TACKETT. J L AND PEARSON, R.W. Some characteristics of soil crusts formed by simulated rainfall. Soil Sci 99: , YONTS, C D AND SMITH, JA Effects of plant population and row width on yield of sugarbeet J. of Sugar Beet Research. 34(1-2) 21-30, st joint 1/RB-ASSBT Congress, 26th Feb.-1st March 2003, San Antonio (USA) 691