Research Project: Develop Water Management Strategies to Sustain Water Productivity and Protect Water Quality in Irrigated Agriculture

Location: Water Management Research

2021 Annual Report

Objectives
The San Joaquin Valley of California is one of the most productive regions in the world with annual agricultural output exceeding $30 billion. Irrigated agriculture faces severe competition for water from municipal, industrial, and environmental interests; therefore, management strategies must be developed to improve water use efficiency, particularly for perennial crops. Development of management alternatives will require characterization of crop water requirements and determination of levels of irrigation and water quality to sustain production. The overall goal of this multidisciplinary project is to develop new management strategies to increase water use efficiency of both good and poor quality waters and reduce impact on soil and water quality from agrochemicals. Objective 1: Develop crop water requirements and water management strategies using good quality water, and reuse strategies using poor quality waters, to maintain or improve water productivity. • Subobjective 1A: Determine effects of deficit irrigation on vegetable crops in biochar-amended soil and evaluate capacity of biochar to stabilize microbial community response to deficit irrigation. • Subobjective 1B: Determine effects of irrigation methods and deficit irrigation on growth and yield of nectarine budded to existing peach rootstock. • Subobjective 1C: Determine effects of deficit irrigation on table grape fruit yield and quality. • Subobjective 1D: Determine water requirements for a mature pomegranate orchard. • Subobjective 1E: Develop sustainable agricultural water reuse systems to protect soil/environmental health of drainage impacted soils when using poor quality water. Objective 2: Reduce the detrimental impacts of irrigated agriculture on water quality by developing practices to increase agrochemical use efficiency.

Approach
Objective 1, Subobjective 1A: The hypothesis for this research is that deficit irrigation in biochar-amended soil can increase crop water use efficiency and mediate changes in soil microbes. Plot experiments with different biochar and irrigation are planned for bulb onion. Crop yield, quality, and soil microbes will be determined and analyzed to assess the interactive effect of deficit irrigation and biochar. If the initial plan with bulb onion is not feasible, other crops will be used. Subobjective 1B: The hypothesis for this research is that grafted nectarine can grow well under different methods of irrigation and deficit irrigation can reduce total water use. This study will be conducted at an existing mature peach orchard that is having nectarine scions grafted to the existing trunks. Furrow, drip, and micro-sprinkler systems will be used under deficit irrigation to determine nectarine yield and quality. If the initial plan for the pre-selected deficit irrigation treatments are too high or too low, adjustments will be made. Subobjective 1C: The hypothesis for this research is that deficit irrigation will yield quantity and quality of grape products similar to a fully irrigated crop. Field experiments will be carried out at growers’ fields where two table grape varieties will be evaluated for performance under deficit irrigation. If the initial plan at the existing sites need to be changed, we will work with the California Table Grape Commission to find alternative cooperators. Subobjective 1D: The research goal for this study is that pomegranate water requirement can be determined using weighing lysimeters. This study will be conducted at an existing mature pomegranate orchard. Differential irrigation will be applied for comparison with the deficit treatments. It is not uncommon that there will be down times for the sophisticated mechanical and electronic components associated with the lysimeters. If that happens, we will use soil water content or nearby weather station data for irrigation scheduling. Subobjective 1E: The research goal for this investigation is that sustainable agronomic systems can be developed for managing soil selenium contributed by use or reuse of poor quality water. We will use drainage waters or poor quality soil and groundwater to grow mustard and canola for biofuel and seed meal production on the west side of the San Joaquin Valley. We will test forage, guayule, and cactus production using micro-plots containing high concentrations of soluble salts, selenium, and boron. If any of the planned research sites is lost, additional research plots can be initiated in areas containing high levels of salt and selenium. Objective 2: The research goal for this study is to develop feasible and sound management practices to use biochar and manure for irrigated crops to significantly increase nitrogen use efficiency and reduce environmental loss. Both laboratory and field experiments will be carried out for developing management strategies to increase agrochemical use efficiency. If selected biochar and manure do not meet the experimental needs, additional materials will be collected and added to the experiment.

Progress Report
Under Sub-objective 1A, a second-year experiment using processing tomatoes (rather than peppers) on the biochar plots was completed. The objective was to evaluate the effect of biochar and irrigation rates on tomato yield and growth responses, and on soil microbial, selenium (Se), and nitrogen (N) dynamics. Like in the previous year, three irrigation rates were applied to maintain soil moisture conditions at 100%, 75%, and 50% of crop water requirement. Soil moisture content and matric potential were monitored continuously during the growing season. Tomato plant leaf area and photosynthetic rates were measured during the flowering stage. Soil samples were collected after seedlings established, prior to differential irrigation treatments, and again five and 11 weeks after deficit irrigation commenced. Soil microbial biomass and bacterial community compositions were determined for these soil samples. During cultivation, different forms of Se treatments were applied to soils for a subset of tomato plants. Selenium treated and untreated (control) plant samples were collected at harvest and prepared for Se speciation analyses, which is ongoing. Nitrogen uptake, nitrate leaching, and carbon (C) and N changes in the soil profile were determined to evaluate the fate of N fertilizer and treatment effects. At harvest, tomato fresh weight in red, green, and rotten fruits were determined. Soluble solids, pH, and color were measured for red fruits as the quality parameters. Under Sub-objective 1B, research continued with the grafted nectarines to determine effect of irrigation methods on tree growth and fruit production. During the growing season, the orchard was irrigated to meet full water requirement according to evapotranspiration (ETc) demand. In addition, soil moisture content was measured continuously using time domain reflectometry sensors installed at multiple locations in the orchard. The real-time soil moisture data were used to make corrections on irrigation scheduling decisions so that the trees were not water stressed. Nectarine fruits were harvested from all 72 plots and fruits were picked from the middle six trees of each plot. A total of 432 trees were hand-harvested for the experiment. Fruit weight and number of fruits per tree were measured in the field during harvest. Sub-samples were collected for fruit quality analysis in the laboratory. Under Sub-objective 1C, data analysis was carried out on the table grape Scarlet Royal yield and quality parameters. Results from data analysis confirmed that irrigating the Scarlet Royal with the Vineyard-Soil Irrigation Model (VSIM) weekly recommendations based on a percentage of the previous week’s accumulated ETc did not affect its productivity or fruit quality. VSIM treatment did not reduce the berry size, weight, and color of the Scarlet Royal. After six weeks of cold storage, VSIM weekly recommendation did not increase the fruit decay, shattering, firmness, or the rachis browning. Under Sub-objective 1E, research continued on successfully growing and evaluating salt and boron (B) tolerant varieties of cactus, agretti, guayule, perennial grass species, mature and three-year-old pistachio trees for responses to irrigation with saline waters in saline soils and drainage sediment. In all studies, uptake and speciation of Se, B, sodium (Na) and chloride (Cl) were respectively analyzed and measurements were made to determine the amount of Se removed and accumulated by the different crops. Analyses showed that all plants tolerated the salinity, and accumulated Se, B and Na. Excessive accumulation of B and Na in the soil significantly contributed to slight decreases in yields in most crops, except in agretti. Approximately 15% net losses of soluble soil Se were accounted for in harvested plant material and less than 10% was assumed lost by leaching. Under Objective 2, a field experiment was conducted for two years that determined the effects of combinations of biochar with synthetic fertilizers and an organic N source (e.g., manure) on plant uptake and N losses. The experiment was conducted by growing processing tomato (Lycopersicon esculentum Mill.) for one year followed by a second year in a garlic variety used for dehydrated products (Allium sativum). Treatments included two biochar products from almond shell or softwood feedstocks at 20 or 40 tons per hectare (t ha-1), dairy manure compost at 20 t ha-1, combinations of the manure and the biochar (each at 20 t ha-1), and an unamended control. Data on surface soil organic C and N, crop yield, biomass, N uptake, and leaching loss were collected. A manuscript based on the data was submitted to a journal. Under Objective 2, field experiments were completed and summarized in the previous reporting cycle. Laboratory incubation experiments were conducted to evaluate the effects of biochar and associated variables on N transformation following urea addition to soil. Variables studied included: soil water content (5%, 10%, and 30%); three biochar products from different feedstocks - almond shell (AS), softwood (SW), and green waste (GW) that were produced at pyrolysis temperatures of 550 °C, 540 °C, and > 900 °C, respectively; soil type (sand, sandy loam, and loam), manure type (dairy manure compost and green manure compost); and combinations of the manure with SW biochar. Chemical analyses included mineral N species (nitrate, nitrite, and ammonium), soil pH, and total organic C and N. Biological analyses included quantitative polymerase chain reaction (qPCR)-based quantification of microbial denitrification genes [bacterial and archaeal ammonia monooxygenase (amoA) and nitrospira amoA genes utilized for complete ammonia oxidation to nitrate (commamox)]. The abundance of the total bacterial/archaeal community population was also approximated using qPCR to quantify 16S rRNA genes.

Accomplishments
1. Strawberry fruit production in substrate media under different irrigation regimes. Conventional strawberry fruit production is an intensive operation which requires significant inputs of fertilizers and pesticides. A potential alternative to reduce the chemical inputs is to grow strawberry plants in small troughs on field beds filled with disease and pathogen-free substrate media. However, irrigation requirements in these media under field conditions are unknown. ARS researchers in Parlier, California, carried out a multi-year field study in growers’ fields and tested five types of growing media and three irrigation rates. These substrate media produced a fruit yield of 50 – 55 ton per hectare, which was comparable to the grower standard soil beds and there was no significant yield difference between the different levels of irrigation. Findings from this research provide strawberry growers an alternative means of berry production without altering their current irrigation practices.

2. Organic amendments and deficit irrigation increase extracellular polysaccharide content in soil. Soil extracellular polysaccharides (EPSac), natural polymers secreted by soil microorganisms, can improve irrigation water productivity in agriculture by increasing soil aggregate stability and retaining water on and around plant roots. ARS researchers in Parlier, California, quantified soil aggregate stability, EPSac contents, and microbial community compositions and abundances in a field experiment by growing processing tomatoes under different levels of deficit irrigation and soil amendments with biochar and/or composts. Amending the soil with biochar, with or without composts, increased soil carbon and EPSac content per unit of microbial biomass, and shifted microbial community structures. Deficit irrigation treatments had higher quantities of soil EPSac per unit of microbial biomass. Indicators of microbial physiological stress and ubiquitous classes of soil bacteria were associated with soil EPSac production. These results can benefit tomato and other vegetable growers in adopting soil organic amendments and deficit irrigation to ameliorate impact of drought.

3. Alternative salt and boron tolerant crops grown under saline growing conditions. Marginal soils in California require unconventional plants that can grow under harsh conditions. ARS researchers in Parlier, California, conducted a number of field trials and tested a range of alternative plants, including cactus fruit, edible pistachio nuts, agretti and guayule biomass. All plants tolerated high saline- and soluble-boron growing conditions, and produced yields comparable to those under non-saline growing conditions. The selected plant species accumulated selenium (Se) and produced bio-based products, such as latex and edible Se-enriched plant products. The research showed that selected Se-accumulating plant species can accumulate high levels of Se and can be used to reduce soil Se from drainage-impacted soils in the arid Western United States by up to 20%.

4. Long-term organic amendment with biochar or manure can sustain soil productivity and crop yield. Soil amendment with biochar and manure is generally believed to be beneficial for improving overall soil property and nitrogen (N) management; however, a detailed understanding of carbon (C) and N dynamics is lacking. Based on three field experiments and laboratory examinations, ARS researchers in Parlier, California, found that biochar amendment increased soil C and N, but showed no significant effects on plant uptake, nitrate leaching, and ammonia or nitrous oxide emission losses in agricultural soils. Long-term incorporation of manure in soil increased soil aggregation in addition to soil C and N, while providing a significant source of nutrients for plants. These findings are beneficial to vegetable growers in balancing inorganic N fertilizer with the organic N sources for sustainable N management.

Review Publications
Intrigliolo, D., Wang, D., Pérez, M.B., Palou, L., Ayars, J.E., Puerto, H., Bartual, J. 2021. Pomegranate water requirements and responses to irrigation restrictions. In: Sarkhosh, A., Alimohammad M.Y, Zabihollah, Z., editors. The Pomegranate: Botany, Production and Uses. Oxfordshire, UK: CABI. p. 320-343.
Wang, D. 2021. Field production of strawberry fruit using growing media under different irrigation scheduling regimes. Acta Horticulturae. 1305:471-476. https://doi.org/10.17660/ActaHortic.2021.1305.62.
Niu, H., Hollenbeck, D., Zhao, T., Wang, D., Chen, Y. 2020. Evapotranspiration estimation with small UAVs in precision agriculture: A Review. Sensors. 20(20):6427. https://doi.org/10.3390/s20226427.
Rana Dangi, S., Wang, D. 2021. Soil microbial community characteristics in a vineyard ten years after fumigation. Soil Science Society of America Journal. 1-17. https://doi.org/10.1002/saj2.20186.
Farhangi-Abriz, S., Torabian, S., Qin, R., Lu, Y., Noulas, C., Gao, S. 2021. Biochar effects on yield of cereal and legume crops using meta-analysis. Science of the Total Environment. 775. https://doi.org/10.1016/j.scitotenv.2021.145869.
Duan, Y., Yang, H., Shi, T., Zhang, W., Xu, M., Gao, S. 2021. Long-term manure application to improve soil macroaggregates and plant-available nitrogen in a Mollisol. Soil and Tillage Research. 211:105035. https://doi.org/10.1016/j.still.2021.105035.
Yuan, J., Zhao, M., Zhao, J., Hale, L.E., Wen, T., Huang, Q., Vivanco, J.M., Zhou, J., Kowalchuk, G.A., Shen, Q. 2020. Root exudates drive soil-microbe-nutrient feedbacks in response to plant growth. Plant Cell and Environment. 44:613–628. https://doi.org/10.1111/pce.13928.
Azeem, M., Hale, L.E., Montgomery, J., Crowley, D., McGiffen, M. 2020. Biochar and compost effects on soil microbial communities and nitrogen induced respiration in turfgrass soils. PLoS ONE. 15(11). Article e0242209. https://doi.org/10.1371/journal.pone.0242209.
Wang, X., Zhu, H., Yan, B., Shutes, B., Banuelos, G.S., Wen, H., Cheng, R. 2021. Improving denitrification efficiency in constructed wetlands integrated with immobilized bacteria under high saline conditions. Environmental Pollution. 287. https://doi.org/10.1016/j.envpol.2021.117592.
Hale, L.E., Curtis, D., Azeem, M., Montgomery, J., Crowley, D., McGiffen, M. 2021. Influence of compost and biochar on soil biological properties under turfgrass supplied with deficit irrigation. Applied Soil Ecology. 168. Article: 104134. https://doi.org/10.1016/j.apsoil.2021.104134.
Bates, C., Escalas, A., Kuang, J., Hale, L.E., Wang, Y., Herman, D., Nuccio, E., Wan, X., Bhattacharyya, A., Fu, Y., Tian, R., Wang, G., Ning, D., Yang, Y., Wu, L., Pett-Ridge, J., Saha, M., Craven, K., Brodie, E.L., Firestone, M., Zhou, J. 2021. Conversion of marginal land into switchgrass conditionally accrues soil carbon and reduces methane consumption. The ISME Journal: Multidisciplinary Journal of Microbial Ecology. https://doi.org/10.1038/s41396-021-00916-y.
Wang, D., Ayars, J.E., Makus, D. 2021. White plastic and deficit irrigation improve pomegranate production. International Journal of Fruit Science. 21(1):868-882. https://doi.org/10.1080/15538362.2021.1939228.
Zhou, F., Dinh, Q.T., Yang, W., Xue, M., Banuelos, G.S., Liang, D. 2019. Assessment of speciation and in vitro bioaccessibility of selenium in Se-enriched Pleurotus ostreatus and potential health risks. Ecotoxicology and Environmental Safety. https://doi.org/10.1016/j.ecoenv.2019.109675.
Zhang, L., Banuelos, G.S., Wallis, C.M., Beede, R.H., Ferguson, L. 2019. Dust interferes with pollen-stigma interaction and fruit set in pistachio Pistacia vera cv. Kerman. HortScience. 54(11):1967-1971. https://doi.org/10.21273/HORTSCI14330-19.
Cai, Z., Wang, B., Zhang, L., Wen, S., Xu, M., Carswell, A.M., Gao, S. 2020. Striking a balance between N sources: mitigating soil acidification and accumulation of phosphorous and heavy metals from manure. Science of the Total Environment. 754. Article 142189. https://doi.org/10.1016/j.scitotenv.2020.142189.
Guo, X., Gao, Q., Yuan, M., Wang, G., Zhou, X., Feng, J., Shi, Z., Hale, L.E., Wu, L., Zhou, A., Tian, R., Liu, F., Wu, B., Chen, L., Jung, C., Niu, S., Li, D., Xu, X., Jiang, L., Escalas, A., Wu, L., He, Z., Van Nostrand, J.D., Ning, D., Liu, X., Yang, Y., Schuur, E.A., Konstantinidis, K., Cole, J.R., Penton, C., Luo, Y., Tiedje, J.M., Zhou, J. 2020. Gene-informed decomposition model predicts lower soil carbon loss due to persistent microbial adaptation to warming. Nature Communications. 11. Article 4897. https://doi.org/10.1038/s41467-020-18706-z.
Liang, Y., Ning, D., Lu, Z., Zhang, N., Hale, L.E., Wu, L., Clark, I.M., McGrath, S.P., Storkey, J., Hirsch, P.R., Sun, B., Zhou, J. 2020. Century long fertilization reduces stochasticity controlling grassland microbial community succession. Journal of Soil Biology and Biochemistry. 151. Article 108023. https://doi.org/10.1016/j.soilbio.2020.108023.
Tao, X., Feng, J., Yang, Y., Wang, G., Tian, R., Fan, F., Ning, D., Bates, C.T., Hale, L.E., Yuan, M.M., Wu, L., Gao, Q., Lei, J., Schuur, E.A., Yu, J., Bracho, R., Luo, Y., Konstantinidis, K.T., Johnston, E.R., Cole, J.R., Penton, C.R., Tiedje, J.M., Zhou, J. 2020. Winter warming in Alaska accelerates lignin decomposition contributed by Proteobacteria. Microbiome. 8(1):1-12. https://doi.org/10.1186/s40168-020-00838-5.