Potential amendments for improving productivity of low carbon semiarid soil

Authors: MAHARJAN, BIJESH - University Of Nebraska; PANDAY, DINESH - University Of Tennessee; BLANCO, HUMBERTO - University Of Nebraska; Mikha, Maysoon

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2021
Publication Date: 7/2/2021
Citation: Maharjan, B., Panday, D., Blanco, H., Mikha, M.M. 2021. Potential amendments for improving productivity of low carbon semi-arid soil. Agrosystems, Geosciences & Environment. 4(3):1-10. https://doi.org/10.1002/agg2.20171.
DOI: https://doi.org/10.1002/agg2.20171

Interpretive Summary: The soils in the semi-arid region of the Great Plains are characterized by low soil organic C (SOC) and low productivity due to intensive tillage, low precipitation, wind erosion, and frequent droughts. Organic amendments can be alternative to and/or complement inorganic fertilizer for enhancing soil productivity. The objective of this 3-yr field study was to evaluate the effects of organic amendments on soil C, soil chemical properties, crop nutrient uptake, and crop yields in a low C sandy loam soil near Scottsbluff, Nebraska. The field was planted to dry bean in 2017, maize in 2018, and sugar beet in 2019. Multiple organic amendments were incorporated into the soil at different rates as: Char at 22.3, 44.6, 66.9, 89.2, and 133.8 Mg ha-1; biochar at 5.6 and 11.2 Mg ha-1; composted manure at 33.6 and 67.2 Mg ha-1, and municipal compost at 33.6 and 67.2 Mg ha-1. After one year following the amendments, SOC level increased by 7-60 % compared to control. Our results suggest that locally available amendments including char, municipal compost or composted manure can increase productivity of low organic C (7 g kg-1) soils in semi-arid regions. Increased maize yield following these amendments could be related to increased micronutrient uptake and/or improved soil organic C. Biochar had limited effect on crop yields as rates of application were low (11.2 Mg ha-1). Long-term evaluation is required to determine effects of amendments on soil properties and crop yields. Production and transport cost can make some potential additives prohibitive for broader use in agriculture. Care need to be taken for preventing salt build-up and/or unwanted toxic material accumulation associated with different organic amendments.

Technical Abstract: Applying soil amendments with high C content can potentially improve soil properties and increase crop yields. The objective of this 3-yr field study was to evaluate the effects of organic amendments on soil organic C (SOC), chemical properties, crop nutrient uptake, and crop yields in a low C sandy loam soil near Scottsbluff, NE. The field was planted to dry bean (Phaseolus vulgaris L.) in 2017, maize (Zea mays L.) in 2018, and sugar beet (Beta vulgaris L.) in 2019. Char at 22.3, 44.6, 66.9, 89.2, and 133.8 Mg ha–1; biochar at 5.6 and 11.2 Mg ha–1; and composted manure and municipal compost each at 33.6 and 67.2 Mg ha–1 were applied and incorporated into the soil. In 1 yr after application, organic amendments increased SOC level in top 20 cm by 7–60%. In the second year, maize leaf tissue Fe was greater with char treatments and high biochar rate compared with the control. Greater Fe uptake in beet leaf tissue or trend for such was observed in amendment treatments at high rates compared with low rates and the control in the third year. Maize yield was enhanced with char, municipal compost, and high compost manure rate. Biochar was applied at lower rates than other amendments, and it had no effects on the parameters studied. Results suggest that locally available organic products can be potential soil amendments to increase SOC and enhance productivity. Care needs to be taken to prevent salt buildup and unwanted toxic material accumulation associated with amendments.