| Title |
Investigators | Department | Objectives | Approach Keywords | Progress Reports | Impact Statements | Publications | |
Project * COL00282 | |
| Title | Reducing Barriers to Adoption of Microirrigation |
| Investigator(s) | Berrada, A; Bartolo, ME; |
| Department | Soil and Crop Sciences |
| Objectives | 1) To identify and assess the significance of barriers to adoption of microirrigation. 2) To reduce technical barriers associated with microirrigation system design, performance, and maintenance. 3) To reduce existing water and nutrient management barriers associated with microirrigation. |
| Approach | Objective 1 will be met by conducting a survey in the Arkansas River Valley of Colorado to determine the acreage in microirrigation and assess the barriers to its adoption. Information will be gathered, which relates to soil type and topography, cropping systems, water availability, water quality; microirrigation installation procedure, design, operation, and maintenance; and system economics. Similar surveys could be conducted in other parts of Colorado depending on interest and resources. Objective 2 will be achieved through field research to determine the optimum drip line placement depth and spacing in relation to row-crop planting configuration (bed width, row spacing, etc.). Emphasis will be on vegetable crops grown in the Arkansas Valley such as onions, cantaloupe, watermelons, and peppers. Soil samples will be taken to a depth of three to four feet to monitor salt and nutrient concentration under the bed and furrow. Salt concentration in irrigation water will be monitored as well. The effects of drip line placement depth and spacing on plant germination and crop yield and quality will be assessed. Two studies will be conducted under Objective no. 3. The focus of the first study will be nitrogen management in onion production. Nitrate movement in the soil will be monitored under drip and furrow irrigation to determine leaching potential. Best management practices to maximize nitrogen use efficiency, enhance crop yield and quality, and minimize nitrate leaching in the Arkansas Valley will be developed and tested. The second study will focus on drip irrigation water management in corn and possibly onions. Irrigation application rates of 50, 75, 100, and 125% ET will be tested. Soil moisture will be monitored with a neutron probe. Salt concentration in the soil profile will be measured as well. The effect of irrigation application rate on crop yield and salt distribution will be assessed. |
| Keywords | drip irrigation, Arkansas River Valley, survey, movement of salts and nitrates, nitrogen fertilizer management, water use efficiency, best management practices under, drip irrigation |
| Progress Reports | |
| 2005 | Recent droughts and water transfers from agricultural to municipal and industrial uses have prompted interest in drip irrigation in the lower Arkansas River Valley. Not much is known about the movement of salts and nitrate-N under drip irrigation. Two field trials were conducted at the Arkansas Valley Research Center in 2005 to determine the effects of irrigation system on crop yield and salt and nitrate movement. In the first trial, four N fertilizer rates (0, 67, 134, and 201 kg N/ha) and four manure rates (22, 44, and 68 Mg/ha) were compared using subsurface drip irrigation and furrow irrigation under two irrigation scheduling regimes, full and deficit irrigation. Drip tapes were placed 20 cm below the soil surface at 152-cm lateral spacing. The results show no significant difference in corn yield between drip and furrow irrigation, even though 80% more water was applied with furrow (119 cm) than with drip (66 cm) irrigation. Deficit irrigation decreased corn yields since water was withheld during two critical growth stages, silking and milk. Corn did not respond to N fertilizer rates beyond 67 kg N/ha under deficit irrigation, while 68 Mg manure/ha depressed the yield due to stand loss. Under full irrigation, the highest yield was obtained with 201 kg N/ha which was more than the recommended rate of 134 kg N/ha. Manure application increased soil salinity levels, which contributed to the decrease in plant population with increasing manure rate. Higher electrical conductivity (ECe) values were observed at the 1.2- to 1.8-m soil depth under drip than under furrow irrigation, probably because of greater leaching with furrow irrigation. In the second trial, six N rates (0, 45, 90, 135, 180, and 225 kg N/ha) were applied to existing N plots previously cropped to corn (2000-2003) and chile pepper (2004). The N main plots were split in 2005 to allow irrigation by furrow (normal method) and by a drip system. Drip tapes were placed in the center of each 76-cm bed at 10-cm depth. Onion was grown in 2005. It is a high cash value crop with a very shallow rooting system that is frequently fertilized with high N rates (>225 kg N/ha) to maintain market quality. At the end of the season, a total of 69 cm of irrigation water had been applied with the drip system and 244 cm with the furrow system. Total marketable fresh onion yield increased with increasing N rate in both systems, with less response of onion to N with the drip system compared to the furrow irrigation system. Significantly higher onion yields were obtained with the drip system. The percentage of the onion crop that was of colossal size (greater than 10-cm diameter) increased from 5% to 14% with increasing N rate, jumbo size (7.6 to 10.0 cm diameter) which made up 80% of the yield was not affected by N rate, and medium size (5.1 to 7.6-cm diameter) decreased from 14% to 5% with increasing N rate. Adjusted gross economic returns were greater with drip irrigation than with furrow irrigation. Soil nitrate-N data was not available at this writing. |
| 2006 | Most cropland in the Arkansas River Valley of southeastern Colorado is furrow-irrigated, but drip irrigation is gaining in importance due to diminishing water supplies and other considerations. Two field trials were conducted at the Arkansas Valley Research Center in 2005 and 2006 to determine the effects of irrigation system and fertilizer rates on corn and onion yields, N dynamics, and salt accumulation in the soil profile. In the corn trial, four N fertilizer rates (0, 67, 134, and 201 kg N/ha) and four manure rates (22, 44, and 68 Mg/ha) were tested using subsurface drip irrigation (SDI) and furrow irrigation (FrI) under full- and deficit-irrigation. Drip tapes were placed 20 cm below the soil surface at 152-cm lateral spacing. There were no significant differences in grain yield between SDI and FrI in 2005 and 2006, even though 76% more water was applied with FrI in 2005 and 57% in 2006. Deficit irrigation decreased corn yield significantly in 2005 but not in 2006 due to more rainfall. Optimum yields were obtained with 67 kg N/ha and 22 Mg of manure/ha in both years, while 68 Mg manure/ha depressed corn yield, particularly with SDI and deficit irrigation. Manure application increased soil salinity early in the season, which led to significantly lower plant populations with 44 and 68 Mg/ha in 2005 and 68 Mg/ha in 2006. Some salt accumulation was observed at the 1.2- to 1.8-m soil depth under SDI compared to FrI in the fall of 2005. There was also more residual soil nitrate-N under SDI at 201 kg N/ha and 22 and 44 Mg manure/ha in the fall of 2005 but not in the spring of 2006. In the onion trial, six N rates (0, 45, 90, 135, 180, and 225 kg N/ha) were applied to furrow- (FrI) and drip-irrigated (SDI) plots in a split-plot arrangement with four replications. Drip tapes were placed in the center of each 76-cm bed at 10-cm depth. Onion was grown after corn in 2005 and after soybean (different field) in 2006. Significantly higher onion yields were obtained with SDI than with FrI in both years, even though substantially less water was applied with SDI. Total marketable fresh onion yield increased with increasing N rate in both systems, with less response of onion to N with SDI compared to FrI. Both the furrow and drip irrigated plots contained similar salt levels within the soil profile. Drip irrigation did not result in an increase in salt accumulation in the soil profile in the onion trial. Adjusted gross economic returns were greater with SDI than with FrI. |
| Impact | |
| 2005 | Corn yield was similar under furrow and drip irrigation even though 45% less water was applied with drip than with furrow irrigation. Significantly higher yield and substantial water saving (72%) were achieved with drip irrigation in the onion trial, compared to furrow irrigation. This work demonstrates the feasibility of drip irrigation for corn and particularly onion production in the Arkansas Valley. Manure in the corn trial increased soil ECe, which may have contributed to lower plant population compared to the non-manure treatments. Manure management and salinity issues will be addressed in more detail in 2006. |
| 2006 | This study shows that corn and onion can be grown successfully with drip irrigation in the Arkansas River Valley of southeastern Colorado. Corn yields were similar with drip- and furrow-irrigation in 2005 and 2006, while onion yields were significantly higher with drip irrigation in both years. Optimum corn and onion yields can be produced with drip irrigation and much less N fertilizer (100 kg N/ha or less) than is commonly used in the Arkansas Valley, often over 200 kg N/ha. Potential benefits of SDI include substantial water savings and reduced leaching of salts and nitrates. More and more vegetable crops are grown under SDI in the Arkansas Valley, often in rotation with corn. |
| Publications | |
| 2006 |
Berrada, A., Halvorson, A.D., Bartolo, M.E., Valliant, J. 2006. The effects of subsurface drip and furrow irrigation on the movement of salts and nitrate in the root zone. p. 1-13 In Proceedings of the 27th International Irrigation Show, 5-7 Nov. 2006, San Antonio, TX. The Irrigation Association. Berrada, A., Halvorson, A.D., Bartolo, M.E., Valliant, J. 2006. The effect of manure and N rates on corn yield and salt and nitrate movement in the soil under furrow and drip irrigation in the Arkansas River Valley. p. 264-269 In A.J. Schelegel (ed.) Great Plains Soil Fertility Conference Proceedings, vol. 11, March 7-8, 2006, Denver, CO. Halvorson, A.D., Bartolo, M., Reule, C.A., Berrada, A. 2006. Drip versus furrow irrigation for onion production in the Colorado Lower Arkansas River Valley. Soil and Water Conservation Society. Abstract. July 22-26-2006, Keystone, CO. J. Soil and Water Conserv. 61(3):229. Halvorson, A.D., Bartolo, M., Reule, C.A., Berrada, A. 2006. Onion Response to nitrogen fertilization under drip and furrow irrigation. p.73-78. Proceedings National Allium Research Conference. December 7-8, 2006, College Station, TX p. 73-78. Halvorson, A.D., Bartolo,M.E., Reule, C.R., Berrada, A. 2006. Onion response to nitrogen fertilization under drip and furrow irrigation. p. 7-12 In A.J. Schelegel (ed.) Great Plains Soil Fertility Conference Proceedings, vol. 11, March 7-8, 2006, Denver, CO. |