Location: Soil, Water & Air Resources Research
Project Number: 5030-12000-015-25-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Nov 1, 2017
End Date: Oct 31, 2019
1) Characterize the plant physiological and biochemical responses to humic amendments at multiple field sites and in a greenhouse study. Assess whether the crop growth enhancement is consistent with a hypothesized mechanism of plant-based bio-stimulation, and more broadly, whether the main outcome of humic amendments is increased plant vigor by alleviating local environmental stresses. 2) Determine whether long-term use of humic amendments improves soil physical properties, nutrient contents, biological activity, and other soil properties commonly associated with soil health.
This project will advance our knowledge of crop physiological responses to humic amendments under varying environmental stresses by analyzing plant samples from a coordinated set of field evaluations at sites in Kansas and Latin America and from a greenhouse study in Ames, IA. ARS will manage on-farm sites in Kansas devoted to corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) rotations, and they will collaborate with managers of field trials in Latin America, primarily Brazil and Mexico that will include corn, soybean, and sugar cane (Saccharum officinarum L.), and also local crops, tentatively citrus (Citrus L. sps.) and tomato (Solanum lycopersicum L.). To determine agronomic responses to humic treatments, local staff at each site will perform routine yet coordinated measurements in-season and at physiological maturity for crop biomass growth, yield components, and mechanized harvest. Specialized analyses of plant samples from all sites and from a local greenhouse study will be conducted to test the hypothesis that the primary mechanism for yield increases is enhanced crop alleviation of environmental stresses. In the greenhouse study, wheat (Triticum sp.) will be grown in a saline Kansas soil, and drought and nutrient stresses will be imposed. On plant samples from all sites, plant structural biochemical traits, including lignification, carbohydrate accumulation, leaf soluble sugars, and levels of amino acids and fatty acids will be measured. Additional analyses will be performed for plant hormones, genetic expression for corn, plant enzymes, vitamins and other anti-oxidants, plant stress enzymes and reactive oxygen species, and soil microbial activity.