{"id":1562,"date":"2020-05-07T11:14:11","date_gmt":"2020-05-07T18:14:11","guid":{"rendered":"https:\/\/blogs.cdfa.ca.gov\/FREP\/?p=1562"},"modified":"2020-05-11T14:20:12","modified_gmt":"2020-05-11T21:20:12","slug":"research-assessing-nitrogen-content-improve-management","status":"publish","type":"post","link":"https:\/\/blogs.cdfa.ca.gov\/FREP\/index.php\/research-assessing-nitrogen-content-improve-management\/","title":{"rendered":"Research Update: Assessing Nitrogen Content to Improve Crop Management"},"content":{"rendered":"\n

Note: This is part of a Research\nUpdate series that highlights projects funded by the California Department\nof Food and Agriculture (CDFA) Fertilizer\nResearch and Education Program<\/a> (FREP).<\/em><\/p>\n\n\n\n

Read the first update\non this project<\/a>.<\/em> <\/em><\/em><\/p>\n\n\n\n

Project Title: <\/strong>Assessment\nof Harvested and Sequestered Nitrogen Content to Improve Nitrogen Management in\nCrops <\/p>\n\n\n\n

Project Leaders:<\/strong> Charlotte\nGallock, Dr. John Dickey and Dr. Ken Cassman<\/p>\n\n\n\n

Project Status:<\/strong> Year\n3 <\/strong><\/p>\n\n\n\n

Overview:<\/strong> This\nproject is refining nitrogen (N) removal rates for Central Valley crops so\ngrowers can plan their N management more accurately and better comply with\nregulatory requirements. Researchers are determining N removal values through\nthree approaches: field sampling of harvested crops, estimating N in perennial\ntissues with crop growth models, and integrating data from other research projects.\nThe culmination of these three approaches should refine N removal values for 23\ncrops. To date, over 900 samples have been collected and analyzed.\nAdditionally, the project leaders have disseminated information about this work\nat eight outreach events during the past two years.<\/strong><\/p>\n\n\n\n

Background:<\/strong> Through\nthe Irrigated Lands Regulatory Program (ILRP), the Central Valley Regional\nWater Quality Control Board (Regional Board) requires growers to implement\nmanagement practices that protect groundwater quality. To document the\neffectiveness of those practices, the Regional Board requires that coalitions provide\ninformation on growers\u2019 field N balances. These balances consist of N applied\n(A) minus removed (R) at harvest to gauge grower progress in reducing leachable\nN. To comply with these reporting requirements, growers and the ILRP coalitions\nneed reliable data about the amount of N removed from fields in harvested crop\nand sequestered in perennial (woody) tissues. Growers also use N crop removal\nrates to develop Irrigation and Nitrogen Management Plans (INMPs) to minimize\nthe risk of nitrate leaching below the root zone.<\/p>\n\n\n\n

The\nobjectives of this project include assessing N concentration of harvested\nmaterial for 23 major Central Valley crops. Additionally, work from this\nproject will establish values for N sequestered annually in standing biomass\nfor seven perennial crops. Based on the data collected, the researchers will refine\ncrop-yield-to-N-removal (Y-to-R) conversion factors and estimate\nN-sequestration rates. This information will expand knowledge and awareness of appropriate\nuses of N-removal coefficients and N-sequestration rates by growers, advisers,\nresearchers, and coalitions.<\/p>\n\n\n\n

Approach<\/strong>: <\/em>To achieve the objectives listed above, the project is using crop growth models for seven crops to determine N sequestration in perennial tissues. The crops included in this analysis are as follows: almond, English walnut, pistachio, orange, tangerine, peach, and pomegranate (Table 1). These estimates are complemented with whole-tree sampling from other studies for all except pomegranate and peaches. Additionally, the researchers have developed protocols for, and sampled, 11 crops to determine N removal rates for pomegranate, peach, plum, carrot, raisin, sunflower, safflower, processing tomato, pistachio, corn and sorghum silage (Table 1). They coordinated sample collection with grower\/packer\/shipper partners, and the samples are currently undergoing lab analysis. <\/p>\n\n\n\n

*Central Valley Irrigated Acreage Estimate<\/p>\n\n\n\n

Activity<\/td>Crops<\/td>No. of Crops<\/td>Percent CVIA*<\/td><\/tr>
Update and Remove Coefficients<\/strong><\/td><\/td><\/td><\/td><\/tr>
Crops for which N removed data are currently available and will be incorporated into an updated N-removed report. <\/td>Almond, English walnut<\/td>2<\/td>22%<\/td><\/tr>
Crops for which N removed data will be sampled and analyzed as a part of this investigation.<\/td>Pomegranate, peach, plum, carrot, raisin, sunflower, safflower, processing tomato, pistachio, corn silage, sorghum silage <\/td>11<\/td>19%<\/td><\/tr>
Crops for which N removed sampling and analysis are currently being funded by other sources. Results will be incorporated into the updated N-removed report<\/td>Pima cotton, prune, bok choy, ong choy, chives, lemongrass, orange, tangerine, daikon, table grape<\/td> 10 <\/td> 18% <\/td><\/tr>
Total<\/em><\/td><\/td>23<\/em><\/td>59%<\/em><\/td><\/tr>
Estimate N Sequestration on Perennial Tissues<\/strong><\/td><\/td><\/td><\/td><\/tr>
Crops for which data on N sequestration in perennial tissues are available or in development and results will be incorporated into the updated N-removed report. <\/td>Almond, English walnut, pistachio, orange, tangerine, pomegranate<\/td>6<\/td>29%<\/td><\/tr>
Crops for which N accumulation in perennial tissues will be estimated with growth models as part of this investigation.<\/td>Peach and all the previously listed perennial crops<\/td>1<\/td>1%<\/td><\/tr>
Total<\/em><\/td><\/td>7<\/em><\/td>30%<\/em><\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n