Irrigation and Tillage. Information Exchange Report

Transcription

1 Irrigation and illage Information Exchange Report, National Peanut Research Laboratory, Southeast Watershed Research Laboratory Georgia Soil & Water Conservation Commission Univ. of Georgia Extension Service errell County his report briefly details the applied research discussed at the Irrigation and illage Information Exchange Workshop that was held on December 6, at the Hooks Hanner Environmental Resource Center in.

2 Introduction Crop production in the Coastal Plain is generally water-limiting. Soils have been intensively cropped (cotton, peanuts), tend to be drought-prone, and susceptible to erosion. Rainfall in this region (~ inches per year) is poorly distributed, and producers commonly utilize supplemental irrigation to sustain crops during extended dry periods. A major problem facing producers in the region is maintaining crop yields, maximizing current water resources through efficient water use, while addressing soil and water quality concerns associated with sediment and agrichemical losses to off-site areas. Proper on-farm water management, especially irrigation scheduling, is critical to sustaining Coastal Plain farmers in the future. High fuel prices coupled with high production costs and low commodity prices require improved management of on-farm resources to improve profit margins and net returns to producers of this region. Surface residue management coupled with conservation tillage in the form of strip tillage is a viable management tool for producers in the Coastal Plain region of Georgia. Strip tillage and residue cover improves soil quality, promotes infiltration, increases soil and plant available water, and reduces runoff and erosion. Results presented at this workshop help producers maximize water use efficiency by reducing the amount of irrigation needed for sustaining crop production; thus increasing a producer s profit margin and net returns, while maintaining water supplies and minimizing off-site environmental contamination.

3 Conservation (Strip, S) tillage effects on soil quality, rainfall and irrigation partitioning, soil water, and erosion I. Strip tillage enhanced soil quality. Compared to conventional tillage: S increased organic carbon by 7% in the top / inch. S increased organic carbon by 6% in the / to / inch soil depth. S increased microbial biomass by -6% in the top 3 inches. S increases soil organic carbon and microbial biomass, thus improves soil quality. II. Strip tillage improved rainfall or irrigation infiltration into Coastal Plain soil thus increased plant available water and crop water use estimates. 8 6 Fall 99 Spr 3 6 Yr Avg. C S Spr Compared to conventional tillage (after year ): S increased infiltration by as much as 3%. S reduced runoff by as much as 3%. S increased the amount of soil water in the top inches of soil. S increased plant available water and crop water use estimates by as much as %. III. Strip tillage reduced soil erosion. Compared to conventional tillage (including year ): S reduced erosion by as much as 3%. S reduced sediment transported carbon by 36%. Key Question: Can the increased plant available water estimates be quantified? For more information, contact Clint ruman Southeast Watershed Research Lab.

4 Conservation (Strip, S) tillage effects on plant available water and crop water use Based on current research results on physiological responses to irrigation and drought, we provide producers with three essential pieces of information: I. Seasonal water use curves improve efficiency of irrigation. Irrigation and illage Workshop Water Use #: S easonal water use curves: improve irrigation scheduling Days After Planting Peanut Cotton Conventional ill Strip ill II. Accurate measures of crop water use for irrigation scheduling. Irrigation and illage Workshop #: Response to irrigation and rain show lag times: improve irrigation scheduling Ounces 3 rain = 3- day lag time Conventional ill Strip ill DaysAfter Planting Irrigation and illage Workshop Water Use 3 #3: Can pinpoint those times during the season that are the highest water use Days After Planting Peanuts: 8- DAP Cotton: 8- DAP Conventional ill Strip ill III. Water required to efficiently produce a given crop. Irrigation and illage Workshop #: How much total water does the crop use in an entire season? Conventional illage Peanut P () Cotton (3) Strip illage Peanut () Cotton (3) otal water use 8 inches inches 3 inches inches Strip ill Difference: Peanuts 9%, Cotton % Key Questions: Does increased plant available water and decreased crop water use increase crop yields? Which production practices help improve water use efficiency? For more information, contact Diane Rowland National Peanut Research Lab.

5 Conservation (Strip, S) tillage effects on irrigation amount and crop yields Cotton Corn Peanut % Peanut yield 3- Hooks-Hanner Environmental Research Center 66 % 38 Yield (lb/a) 36 Conventional tillage Moderate tillage Strip tillage 33 % 3 3 No statistical differences Dryland Irrigation level (%of recommended) Equivalent corn, cotton, and peanut yields may be obtained with /3 less water. S increased corn yield regardless of irrigation level. Yields for S cropped to cotton at 66% irrigation equaled those for C systems at % irrigation. Peanut yield response was minimal for both tillage and irrigation, thus yields should be maintained with less irrigation regardless of tillage. Corn yield 3- Hooks-Hanner Environmental Research Center Cotton yield 3- Hooks-Hanner Environmental Research Center Grain yield (bu/a) Conventional tillage Moderate tillage Strip tillage +/+ Lint yield (lb/a) 7 +3 Conventional tillage Moderate tillage Strip tillage Irrigation level (%of recommended) Irrigation level (%of recommended) Key Question: Can we predict water stress before it negatively affects crop yields? For more information, contact Wilson Faircloth National Peanut Research Lab.

6 Remotely Sensing Crop Water Demand Enhancing Drought olerance Cool (3 o C) Moderate (3 o C) Water Stress (> o C) Rapid Assessment of Crop Water Demand Rapid Assessment of Crop Water Demand Canopy Response C S With remote sensing, we can: Measure expected differences in crop water demand in real time. Measure relatively small differences in crop water use and drought tolerance. With remote sensing technology, we can detect spatial differences in crop water use and demand, thus fine-tuning current irrigation scheduling to limit drought-limiting crop yields. For more information, contact Dana Sullivan Southeast Watershed Research Lab.

7 Contributors Dr. Clint ruman Dr. Diane Rowland Southeast Watershed Research Lab. National Peanut Research Lab. POB 78, 37 Rainwater Rd. POB 9, Forrester Dr. S.E. ifton, GA (voice) (voice) Dr. Wilson Faircloth Dr. Dana Sullivan National Peanut Research Lab. Southeast Watershed Research Lab. POB 9, Forrester Dr. S.E. POB 78, 37 Rainwater Rd. ifton, GA (voice) (voice)