Progress 07/01/00 to 06/30/06

Outputs
Wheat seed yields in two drought years were 66% lower when planted at sunflower or soybean harvest relative to planting after an eleven-month fallow period (4881 kg/ha). Wheat leaf area at anthesis was proportional to stored soil water at spring green-up and to water use during vegetative growth. Land productivity (annualized grain yield) in two drought years was greatest for wheat-fallow (2440 kg/ha) and wheat-grain sorghum-fallow (2358 kg/ha) crop sequences. Land productivity of seven continuous cropping sequences ranged from 866 to 1850 kg/ha. Sap flow heat gauges indicated daily transpiration of irrigated corn was 84% of potential evapotranspiration calculated from weather data. Under replicated field plot conditions, the devices could detect differences in transpiration rates of 30 W/m2 (about 10% of mid-day transpiration rates). Low-cost infrared thermometers indicated the apparent canopy-air temperature difference was proportional to vapor pressure deficit and similar for corn under full (7.6 mm/day) and limited (3.8 mm/day) irrigation capacities; apparent canopy temperatures for rain-fed crop exceeded ambient under radiation loading. The duration (thermal time) of sunflower achene development phase was correlated with daylength at floral initiation and floral bud appearance stages. Photoperiod altered thermal time to maturity as well as thermal time required for floral development. The result is most significant for crop grown at latitudes < 40 degrees, where growing season photoperiod is frequently < 15 h, an apparent threshold; and for double-cropped sunflower under limited irrigation. Control of stem weevil pests increased irrigated sunflower seed yield by 34% relative to non-control yields of 2524 kg/ha; planting after late May contributed to pest avoidance. Several pest resistant sunflower accessions (provided by the ARS Sunflower Research Unit) exhibited up to 90% reduction in number of stem weevil per stalk, relative to susceptible lines. Sorghum cold tolerance studies showed that both male and female parents affected thermal requirements (thermal time) for germination and meristematic growth. Studies indicated seedling growth is negatively related to release of CN upon chilling stress. Photosynthesis and CO2 assimilation responses to near-optimal (35C) and chilling (12C) temperatures were similar for grain sorghum lines adapted to cool temperate (Shan Qui Red, SQR) and warm tropical (TX 430) environments. The ratio of quantum efficiencies for PSII and CO2 flux was 13.4 (35C) and 13.1 (12C) though internal CO2 increased from 104 ppm to 230 ppm upon chilling. Photosynthetic responses of recombinant-inbred-lines (TX430 x SQR), showed a six-fold variation in internal CO2, with direct proportionality to transpiration efficiency, normalized by vapor pressure deficit. Precipitation mapping using radar signals from National Weather Service WSR-88D radar installations can support GIS models of soil water balance at regional scales. Precipitation amounts derived from Storm Total Precipitation images corresponded to ground observations with an average rank correlation of 0.77 for 44 precipitation events and 169 locations.

Impacts
Increasing crop use of available precipitation from 34 to 81% would conserve soil and water, reduce air-borne dust particles (and associated respiratory ailments) and sustain farm families by improving net farm income. Annual cropping systems have the potential to increase grain productivity by 33% and provide net returns of $8.25 to $20 per acre; potential benefits to 5 million acres cultivated as wheat-fallow in W. Kansas are in the order of $100 M annually.

Publications

• Charlet, L.D., R.M. Aiken, J.F. Miller, G.J. Seiler, K.A. Grady and R.F. Meyer. 2006. Prospects and challenges in developing sunflower with resistance to seed and stem infesting insects. Proc. 28th Sunflower Research Workshop, National Sunflower Assoc., Fargo, ND, 11-12 January 2006.
• Klocke, N., R. Aiken, R. Currie and L. Stone. 2006. Soil water evaporation as influenced by crop-residue management in sprinkler irrigation. In Report of Progress 961. SWREC 2006 Field Day. Kansas State University, AES and CES, August, 2006.
• Kozak, J.A., R. Aiken, G. Flerchinger, D. Nielsen, L. Ma and L. Ahuja. 2006 Comparison of Modeling Approaches to Quantify Residue Architecture Effects on Soil Temperature and Water. Soil and Tillage Research. (Accepted)
• Olson, B.L.S., J. Falk and R. Aiken. 2006. Sunflower yield as affected by strip-till. Proc. 28th Sunflower Research Workshop, National Sunflower Assoc., Fargo, ND, 11-12 January 2006.
• Olson, B., B. Gordon, J. Falk and R. Aiken. 2006. Dryland strip-till. Proceedings. Cover Your Acres Winter Conference. February 2, 2006. K-State Research and Extension. pp. 69-73.
• Aiken, R.M. 2006. Wheat productivity and water use in intensive cropping systems under drought. Agronomy Abstracts.
• Aiken, R.M. 2006. Cropping intensity, water use and productivity under drought conditions. Proceedings. Cover Your Acres Winter Conference. February 2, 2006. K-State Research and Extension. pp. 20-21.
• Aiken, R.M. and F.R. Lamm. 2006. Irrigation of oilseed crops. In Proceedings of the Central Plains Irrigation Conference. Colby, KS. Feb. 21-22, 2006. Available from CPIA 760 N. Thompson, Colby KS. pp. 162-172.
• Aiken, R.M. and F.R. Lamm. 2006. Irrigation guidelines for oilseed crops in the U.S. Central Great Plains. In Technical Conference Proceedings of the 27th Annual Irrigation Association. San Antonio, TX. Nov. 5-7 2006. pp. 14-24.
• Baltensperger, D., A. Pavlista, J. Krall, T. Nleva, E. Nielsen, J. Johnson, D. Nielsen, R. Aiken, M. Killon, G. Frickel, J. Margheim, J. Rickertsen, R. Meyer, L. Nelson, T. Isbell. 2006. Cultivar Performance of Canola, Brown Mustard and Camelina in the High Plains of Colorado, Kansas, Nebraska, South Dakota and Wyoming. Agronomy Abstracts.

Progress 01/01/05 to 12/31/05

Outputs
Wheat seed yields in two drought years were 66% lower when planted at sunflower or soybean harvest relative to planting after an eleven-month fallow period (4881 kg/ha). Wheat leaf area at anthesis was proportional to stored soil water at spring green-up and to water use during vegetative growth. Land productivity (annualized grain yield) in two drought years was greatest for wheat-fallow (2440 kg/ha) and wheat-grain sorghum-fallow (2358 kg/ha) crop sequences. Land productivity of seven continuous cropping sequences ranged from 866 to 1850 kg/ha. Sap flow heat gauges indicated daily transpiration of irrigated corn was 84% of potential evapotranspiration calculated from weather data. Under replicated field plot conditions, the devices could detect differences in transpiration rates of 30 W/m2 (about 10% of mid-day transpiration rates). Low-cost infrared thermometers indicated the apparent canopy-air temperature difference was proportional to vapor pressure deficit and similar for corn under full (7.6 mm/day) and limited (3.8 mm/day) irrigation capacities; apparent canopy temperatures for rain-fed crop exceeded ambient under radiation loading. The duration (thermal time) of sunflower achene development phase was correlated with daylength at floral initiation and floral bud appearance stages. Photoperiod altered thermal time to maturity as well as thermal time required for floral development. The result is most significant for crop grown at latitudes < 40 degrees, where growing season photoperiod is frequently < 15 h, an apparent threshold; and for double-cropped sunflower under limited irrigation. Control of stem weevil pests increased irrigated sunflower seed yield by 34% relative to non-control yields of 2524 kg/ha; planting after late May contributed to pest avoidance. Several pest resistant sunflower accessions (provided by the ARS Sunflower Research Unit) exhibited up to 90% reduction in number of stem weevil per stalk, relative to susceptible lines. Sorghum cold tolerance studies showed that both male and female parents affected thermal requirements (thermal time) for germination and meristematic growth. Studies indicated seedling growth is negatively related to release of CN upon chilling stress. Photosynthesis and CO2 assimilation responses to near-optimal (35C) and chilling (12C) temperatures were similar for grain sorghum lines adapted to cool temperate (Shan Qui Red, SQR) and warm tropical (TX 430) environments. The ratio of quantum efficiencies for PSII and CO2 flux was 13.4 (35C) and 13.1 (12C) though internal CO2 increased from 104 ppm to 230 ppm upon chilling. Photosynthetic responses of recombinant-inbred-lines (TX430 x SQR), showed a six-fold variation in internal CO2, with direct proportionality to transpiration efficiency, normalized by vapor pressure deficit. Precipitation mapping using radar signals from National Weather Service WSR-88D radar installations can support GIS models of soil water balance at regional scales. Precipitation amounts derived from Storm Total Precipitation images corresponded to ground observations with an average rank correlation of 0.77 for 44 precipitation events and 169 locations.

Impacts
Increasing crop use of available precipitation from 34 to 81% would conserve soil and water, reduce air-borne dust particles (and associated respiratory ailments) and sustain farm families by improving net farm income. Annual cropping systems have the potential to increase grain productivity by 33% and provide net returns of $8.25 to $20 per acre; potential benefits to 5 million acres cultivated as wheat-fallow in W. Kansas are in the order of $100 M annually.

Publications

• Aiken, R.M. and F.R. Lamm. 2005 Corn canopy temperature as a stress index with limited subsurface drip irrigation. In Report of Progress 956, pp. 26-32. Kansas State University, AES and CES.
• Aiken, R.M. and R.D. Stockton. 2005. Sunflower development, yield and water use: Mid-oleic and high-oleic isohybrids. In Report of Progress 956, pp. 14-17. Kansas State University, AES and CES.
• Aiken, R.M., M.R. Tuinstra and K.D. Kofoid. 2005. Assimilation and growth characteristics of kaoliang and tropical sorghum lines. Agronomy Abstracts [CD-ROM computer file].
• Charlet, L.D. and R.M. Aiken. 2005. Impact of planting date on sunflower stem weevil (Coleoptera: Curculionidae) larval density and parasitism in oilseed and confection sunflower in western Kansas. Crop Management. http://www.plantmanagementnetwork.org/cm/.
• Charlet, L.D. and R.M. Aiken. 2005. Management strategies for the sunflower stem weevil. Report of Progress 956, pp. 18-22. Kansas State University, AES and CES.
• Evans, P. and R. Aiken. 2004. National Winter Canola Variety Trial. C. Rife and C. LaBarge, eds. KSRE Publication No. SRP 937, pp. 34-35. Manhattan, KS. April, 2005.
• Klocke, N.L., R.M. Aiken and L.R. Stone. 2005. Soil water evaporation as influenced by crop residue management and plant transpiration in sprinkler irrigation systems. Report of Progress 945, pp 27-28. Kansas State University, AES and CES.
• Kofoid, K.D. and R.M. Aiken. 2005. Genetic control of grain fill rate and duration in sorghum. Agronomy Abstracts [CD-ROM computer file].
• Lamm, F.R. and R.M. Aiken. 2005. Effect of irrigation frequency for limited subsurface drip irrigation of corn. In Proc. Irrigation Assn. International Irrigation Technical Conf., 6-8 November 2005. Phoenix, AZ. Available from Irrigation Assn., Falls Church, VA. IA Paper No. IA05-1264.
• Olson, B.L.S and R. M. Aiken. 2005. Dryland Strip Till Production. Proc. 27th Sunflower Research Workshop, Natl. Sunflower Assoc., Fargo, ND, 11-13 January 2005.
• Schlegel, A., R. Aiken and L. Stone. 2005. Effect of tillage on soil water recharge and crop production. In Report of Progress 956, pp. 7-9. Kansas State University, AES and CES.

Progress 01/01/04 to 12/31/04

Outputs
A fourth year of drought conditions continued to limit crop productivity in 2004. Crop sequence altered wheat yields, likely due to reduced available soil water. Photosynthesis and CO2 assimilation response to near-optimal (35C) and chilling (12C) temperatures were similar for grain sorghum lines adapted to cool temperate (Shan Qui Red, SQR) and warm tropical (TX 430) environments. The ratio of quantum efficiencies for PSII and CO2 flux was 13.4 (35C) and 13.1 (12C), though internal CO2 increased from 104 ppm to 230 ppm upon chilling; both lines with similar results, which are consistent with published reports of C4 grass species. However, the leaf chlorophyll content of SQR was 24% less than that of TX 430 and apparent net assimilation rate at the whole-plant level averaged 26.2 g/m2 (SQR) in contrast to 16.8 g/m2 (TX 430); indicating rapid vegetative growth potential of SQR may be related to post-assimilation processes. The duration of sunflower seed fill (achene development) phase, in units of thermal time, was correlated with daylength at floral initiation and floral bud appearance stages. Photoperiod altered thermal time to maturity as well as thermal time required for floral development. The result is most significant for crop grown at latitudes < 40 degrees, where growing season photoperiod is frequently < 15 h, an apparent threshold. Thus, where heat units are adequate for late-planting (early July), double-cropping wheat and sunflower may provide a feasible alternative for irrigators with limited capacities. Sunflower accessions provided by the ARS Sunflower Research Unit (Fargo, ND) were screened for resistance to stem weevil and sunflower moth, continuing a fourth year of screening trials. Low-cost infrared thermometers were calibrated and deployed for a third year with automated data logger in corn plots irrigated by sub-surface driplines; results indicated the apparent canopy-air temperature difference was proportional to vapor pressure deficit and similar for crop under full (7.6 mm/day) and limited (3.8 mm/day) irrigation capacities; but apparent canopy temperatures for rain-fed crop exceeded ambient under radiation loading. Sap flow heat gauges, deployed on corn plants under sprinkler irrigation, quantified transpiration at 12-minute intervals, indicating a correspondence to potential evaporation calculated from weather data. A limited-irrigation (10, 20 or 30 cm of irrigation applied) two-year rotation sequence with double-cropped wheat-sunflower or wheat-soybean, followed by grain sorghum was continued (second year). Digital photographic procedures were applied (third year) to quantify effects of row spacing and geometry on plant canopy development and yield formation in soybean and grain sorghum. Precipitation mapping using radar signals from National Weather Service WSR-88D radar installations can support GIS models of soil water balance at regional scales. Precipitation amounts derived from Storm Total Precipitation images corresponded to ground observations with an average rank correlation of 0.77 for 44 precipitation events and 169 locations.

Impacts
Increasing crop use of available precipitation from 34 to 81% would conserve soil and water, reduce air-borne dust particles (and associated respiratory ailments) and sustain farm families by improving net farm income. Annual cropping systems have the potential to increase grain productivity by 33% and provide net returns of $8.25 to $20 per acre; potential benefits to 5 million acres cultivated as wheat-fallow in W. Kansas are in the order of $100 M annually.

Publications

• Aiken, R.M. 2004. Applying thermal time scales to sunflower development. Agron. J. In Press.
• Aiken, R.M., D. Inloes, and S. Hutchinson. 2004. Precipitation maps: Can they support a regional soil water balance? In Proc. High Plains Groundwater Resources: Challenges and Opportunities Conference, Dec. 7-9, 2004, Texas Tech University Water Resources Center, Lubbock, TX. Rainwater, K.A. and T.M. Zobeck, Eds. 4 pp.
• Aiken, R.M. and F.R. Lamm. 2004. Monitoring corn canopy temperature and soil water depletion under limited irrigation. Agronomy Abstracts. 6539 [CD-ROM computer file].
• Aiken, R.M., R.L. Vanderlip, L.R. Stone and R.D. Stockton. 2003. Can crop simulation models support sunflower production? National Sunflower Association Research Forum. Fargo, ND, Jan. 16-17, 2003.

Progress 01/01/03 to 12/31/03

Outputs
A third year of drought conditions continued to limit crop productivity in 2003 with crop failures for rain-fed corn, grain sorghum, soybean and sunflower. Crop sequence altered wheat yields, likely due to available soil water. Wheat seed yields, during two drought years, were 66% lower when planted immediately following sunflower or soybean harvest relative to yields following an eleven-month fallow period (4881 kg/ha). Land productivity (annualized grain yield) in two drought years was greatest for wheat-fallow (2440 kg/ha) and wheat-grain sorghum-fallow (2358 kg/ha) crop sequences. Land productivity of seven continuous cropping sequences ranged from 866 to 1850 kg/ha). Sub-surface tillage to alleviate soil compaction tended to reduce soil water recharge efficiency (change in stored soil water divided by cumulative precipitation), relative to no-till crop culture; sunflower yield response to tillage differed among three experimental sites. Sunflower development can be calculated as a continuous function of growing degree days from emergence and mid-vegetative photoperiod using a continuous time algorithm. Thus, where heat units are adequate for late planting (early July), double cropping wheat and sunflower may provide a feasible alternative for irrigators with limited capacities. Control of stem weevil pests by planting after late May increased irrigated sunflower seed yield. Sunflower accessions provided by the ARS Sunflower Research Unit (Fargo, ND) were screened for resistance to stem weevil and sunflower moth, continuing screening trials from 2002. Support for development of cold-tolerant sorghum germplasm included growth chamber studies showing that variation in the base temperature for thermal unit accumulation (germination and meristematic growth) is heritable and affected by both male and female parents. Studies also evaluated release of CN- upon chilling stress. Photosynthetic response of a population of sorghum recombinant-inbred-lines, grown under greenhouse and field conditions, showed a six-fold variation in internal CO2 concentration, with direct proportionality to transpiration efficiency, when normalized by vapor pressure deficit. Low-cost infrared thermometers were calibrated and deployed for a second year with automated data logger in corn plots irrigated by sub-surface driplines; preliminary results indicate similar canopy temperatures for full and limited irrigation, but higher canopy temperatures for the rain-fed crop. A limited-irrigation (10, 20 or 30 cm of irrigation applied) two-year rotation sequence with double-cropped wheat-sunflower or wheat-soybean, followed by grain sorghum was initiated. Digital photographic procedures were applied (second year) to quantify effects of row spacing and geometry on plant canopy development and yield formation in soybean and grain sorghum.

Impacts
Increasing crop use of available precipitation from 34 to 81% would conserve soil and water, reduce air-borne dust particles (and associated respiratory ailments) and sustain farm families by improving net farm income. Annual cropping systems have the potential to increase grain productivity by 33% and provide net returns of $8.25 to $20 per acre; potential benefits to 5 million acres cultivated as wheat-fallow in western Kansas are in the order of $100 M annually.

Publications

• Aiken, R. M., M. Tuinstra, K. Kofoid and R. Stockton. 2003. Components of cold tolerance in grain sorghum: male and female contributions to germination and early growth. KSU Agronomy Field Research, Report of Progress 913. pp. 105-108.
• Aiken, R. M. 2003. Transition from summer crop to winter wheat in the central High Plains. Proceedings: Four-State Cropping Systems Conference. PHREC 03-29. pp. 49-52.
• Aiken, R. M., M. R. Tuinstra, K. D. Kofoid, and R. D. Stockton. 2003. Cold tolerance components in grain sorghum seedlings: male and female contributions. Agronomy Abstracts. C02-aiken557267 [CD-ROM computer file].
• Aiken, R. 2003. Crop sequence effects on land productivity, water use and soil quality in semi-arid cropping systems. KSU Agronomy Field Research, Report of Progress 913. pp. 90-94.
• Aiken, R. M. and L. D. Charlet. 2003. Effects of insecticide timing and planting period on sunflower productivity in northwest Kansas. KSU Agronomy Field Research, Report of Progress 913. pp. 95-96.
• Aiken, R. M. and R. D. Stockton. 2003. Effects of planting period on sunflower productivity in northwest Kansas. KSU Agronomy Field Research, Report of Progress 913. pp. 97-98.
• Aiken, R. M. and R. D. Stockton. 2003. Effects of supplemental water on sunflower productivity in Northwest Kansas. KSU Agronomy Field Research, Report of Progress 913. pp. 99-101.
• Aiken, R. M. and W. B. Gordon. 2003. Soybean productivity under drought: Effects of planting dates and maturity groups in northwest Kansas. KSU Agronomy Field Research, Report of Progress 913. pp. 102-104.

Progress 01/01/02 to 12/31/02

Outputs
Drought conditions limited crop productivity in 2002 with crop failures for corn, grain sorghum, and early plantings of soybean and sunflower. Late-season rains supported yield formation in sunflower planted at the normal period (early June). Crop sequence altered wheat yields, likely due to available soil water. Wheat leaf area at anthesis was proportional to differences in stored soil water at spring green-up and to water use during vegetative growth. Wheat seed yields were 78% lower when planted immediately following sunflower or soybean harvest, relative to yield following an eleven-month fallow period. Leaf appearance and floral development in sunflower is proportional to cumulative heat units following emergence. Thus, where heat units are adequate for late-planting (early July), double-cropping wheat and sunflower may provide a feasible alternative for irrigators with limited capacities. Control of stem weevil pests increased irrigated sunflower seed yield by 34% relative to noncontrol yields of 2524 kg/ha; planting after late May contributed to pest avoidance. Sunflower accessions provided by the ARS Sunflower Research Unit (Fargo, ND) were screened for resistance to stem weevil and sunflower moth. Low-cost infrared thermometers were calibrated and deployed with an automated data logger in corn plots irrigated by subsurface driplines; preliminary results indicate similar canopy temperatures for full and limited irrigation, but higher canopy temperatures for rainfed crops. We developed digital photographic procedures to quantify effects of row spacing and geometry on plant canopy development and yield formation in soybean and grain sorghum. Soybean seed yield decreased 18% in paired rows (25-cm spacing) on 76-cm centers and 11% in solid seeding (25-cm spacing) with drill, relative to planting on 76-cm centers, when planted at 520,000 seeds/ha.

Impacts
Increasing crop use of available precipitation from 34 to 81% would conserve soil and water, reduce air-borne dust particles (and associated respiratory ailments) and sustain farm families by improving net farm income. Annual cropping systems have the potential to increase grain productivity by 33% and provide net returns of $8.25 to $20 per acre; potential benefits to 5 million acres cultivated as wheat-fallow in western Kansas are in the order of $100 M annually.

Publications

• Aiken, R. M., D. C. Nielsen, L. R. Ahuja and E. A. Walter-Shea. 2002. Scaling effects of standing crop residues on the wind profile. Agronomy Journal. "In Press"
• Flerchinger, G. N., T. J. Sauer and R. M. Aiken. 2002. Effects of crop residue cover and architecture on heat and water transfer at the soil surface. Geoderma. "In Press"
• Fjell, D. L., R. M. Aiken and A. J. Schlegel. Effect of tillering on dryland corn in the High Plains. Annual Meetings Abstracts 2002. [CD-ROM computer file]. ASA, CSSA, SSSA, Nov. 10-14, 2002, Indianapolis, IN.
• Aiken, R. M. 2001. NSI Variety Trial. Kansas performance test with sunflower hybrids. 2001 KAES Report of Progress 888.
• Aiken, R. M. 2002. Available soil water, sunflower canopy development and productivity. Proceedings, 24th Sunflower Research Workshop, National Sunflower Association, Jan. 17-18, 2002, Fargo, ND.
• Aiken, R. M., D. C. Nielsen and L. R. Ahuja. 2002. Scaling effects of standing crop residues on aerodynamic transfer processes. Proceedings of the 2002 International Conference on Wind Erosion and Aeolian Processes, July 22-25, 2002, Lubbock, TX.

Progress 01/01/01 to 12/31/01

Outputs
Greenhouse studies of cold tolerance in grain sorghum hybrids indicate both the seed parent and the male parent contribute beneficial trait(s). Planting multiple seeds together increased the germination fraction and root growth. Exponential seedling growth was correlated with cumulative growing degree-days. Shoot growth of inbred lines, under field conditions, was correlated with relative growth rate of seedlings raised in the greenhouse; best relative growth rates exceeded 0.075. Commercial, cold-adapted varieties could permit earlier planting (similar to planting dates for corn) which could help the crop avoid late-summer water stress and reach maturity before freezing fall conditions. Multiple field studies included crop rotations with cropping intensities ranging from 50 to 100%, planting date effects on soybean and sunflower productivity and water use, irrigation-timing effects on wheat and sunflower productivity and water use. Preliminary results in this dry year showed crop yields can vary dramatically with planting dates. The lowest yield of soybean was 28% relative to the highest yield; the lowest sunflower yields were 24% of the highest yields. Crops differed in productive use of water as well. Water use efficiency (kg of grain per hectare-cm of water) was lower in 2001 than in 2000 for both sunflower (44 and 67), and soybean (34 and 47), respectively; the value for grain sorghum was 165 in 2001. Annualized grain yield of wheat-grain sorghum-fallow crop sequence exceeded that of a wheat-fallow rotation by 31%. A wheat-grain sorghum-oilseed (canola, sunflower or soybean) sequence increased productivity by 12% relative to wheat-fallow. Field studies provided working experience with "water meters" for plants, an emerging tool for field research. These automated instruments provide a means to measure the flow of water through a plant stem under normal or stress conditions. Under replicated field plot conditions, the devices could detect differences in transpiration rates of irrigated corn treatments as low as 30 watts per square meter (about 10% of mid-day transpiration rates). Data on optimal planting dates, crop productivity and water use can guide growers seeking to increase use of available precipitation and reduce agronomic risk.

Impacts
Increasing crop use of available precipitation from 34 to 81% would conserve soil and water, reduce air-borne dust particles (and associated respiratory ailments) and sustain farm families by improving net farm income. Annual cropping systems have the potential to increase grain productivity by 33% and provide net returns of $8.25 to $20 per acre; potential benefits to 5 million acres of cultivated as wheat-fallow in W. Kansas are in the order of $100 M annually.

Publications

• Aiken, R. M., V. Thomas, and W. Waltman. 2001. AgriFACTs: Agricultural Farm Analysis and Comparison Tool. Proceedings: Geospatial Information in Agriculture Conference. July 17, 2001, Sydney, Australia.
• Aiken, R., F. Lamm, J. Ham, and T. Trooien. Detection Limits of Sap Flow Heat Gauges in Replicated Field Plots of Corn, Agronomy Abstracts 2001.
• Aiken, R. M. Sunflower Productivity under Agricultural Drought. Proceedings National Sunflower Association. Jan. 17-18, 2001, Fargo, ND.

Progress 01/01/00 to 12/31/00

Outputs
In this initial year, multiple field studies were established including crop rotation ranging from 50% to 100% cropping intensities, planting date effects on soybean and sunflower productivity and water use, irrigation timing effects on wheat and sunflower productivity and water use. Preliminary results in this drought year showed crop yields can vary dramatically with planting dates. The maximum yield of soybean was 335% relative to the poorest yield; the best sunflower yields were 245% of the poorest yields. Crops differed in productive use of water as well. Water use efficiency (kg of grain per hectare-cm of water) was greatest for corn (102 kg/ha-cm), less for sunflower (67 kg/ha-cm), and least for soybean (47 kg/ha-cm). Field studies provided working experience with "water meters" for plants, an emerging tool for field research. These instruments provide a means to measure the flow of water through a plant stem under normal or stress conditions. Field studies also demonstrated cold tolerance for several new grain sorghum lines. Adapted commercial varieties could permit earlier planting (similar to planting dates for corn) which could help the crop avoid late-summer water stress and reach maturity before freezing fall conditions. Data on optimal planting dates, crop productivity and water use can guide growers seeking to increase use of available precipitation.

Impacts
Increasing crop use of available precipitation from 34% to 81% would conserve soil and water, reduce air-borne dust particles (and associated respiratory ailments) and sustain farm families by improving net farm income. Annual cropping systems have the potential to increase grain productivity by 33% and provide net returns of $8.25 to $20 per acre; potential benefits to 5 million acres under wheat-fallow cultivation in western Kansas are in the order of $200 M annually.

Publications

• No publications reported this period