VFRC Report 2013/1: Following the path of nutrients in the leaves 

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Plant roots absorb nutrients from the soil and transport them to the leaf, where they are assimilated by biological-chemical processes into proteins, fats, vitamins, hormones, etc., for plant growth. Soil is an extremely complex medium, and much of the fertilizer nutrients applied for plant uptake are actually not taken up and are consequently lost to the environment.

Interestingly, leaves can absorb nutrients also. This direct path of nutrients entering the plant near the assimilation point might enhance fertilizer efficiency. However, the efficacy of foliar fertilizer application is ambiguous because little is known about the plant processes governing uptake and utilization.

This paper describes paths of foliar nutrient absorption and outlines possible biochemical pathways of phosphorus (P) and iron (Fe) penetration, absorption and their translocation into various cell organelles where they engage in biochemical processes. This will help in identifying effective fertilizer nutrient composition and in developing next-generation foliar fertilizers.

Citation: Renu Pandey, Vengavasi Krishnapriya and Prem S. Bindraban. 2013. Biochemical nutrient pathways in plants applied as foliar spray: Phosphorus and iron. Washington, VFRC, VFRC Report 2013/1. 23 pp.; 6 figs.; 63 ref.


VFRC Report 2013/2: Fertilizer uptake through leaves – yet to be disentangled

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Nutrients are taken up by plant roots, but interestingly, leaves can absorb nutrients also. Research is not clear about the effectiveness of foliar fertilizers in agricultural crops and this initial study systematically analyzes the information to improve understanding about the matter.

Foliar fertilizers are applied for a variety of reasons, with greatly differing application methods and uptake efficiencies. Even after leaf penetration the relevance to plant growth and development remains ambiguous, e.g., because some nutrients are not remobilized to other organs once bound to permanent structures where deposited.

The interactions between physical, chemical, environmental and crop-physiological processes, along with metabolic processes, must be understood to arrive at effective foliar interventions.

Citation: Wim Voogt, Chris Blok, Barbara Eveleens, Leo Marcelis and Prem S. Bindraban. 2013. Foliar fertilizer application – Preliminary review. Washington, VFRC, VFRC Report 2013/2. 43 pp.; 9 tables; 2 figs.; 98 ref.


VFRC Report 2013/3: Methodology to assess the impact of fertilizer strategies on planetary boundaries

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Fertilizers affect plant growth fundamentally and are essential to feed the world population. Yet, fertilizer use also contributes to eutrophication and greenhouse gas emissions. Overuse will aggravate these side effects, but underuse leads to agro-ecosystem’s degradation, poverty and hunger.

The use of nitrogen and phosphorus fertilizers has been identified as one of the driving forces that push the Earth from its stable geological era of the Holocene into the Anthropocene with unknown implications for life on Earth. Curtailing nutrient losses will therefore have far reaching implications on the Earth’s ecosystem functioning and human health and well-being.

This report describes a methodology to quantitatively link global N and P cycles to four other drivers of global change, being land-system change, freshwater use, climate change and stratospheric ozone depletion. This will allow the assessment of the impact of fertilizer interventions on these drivers, revealing synergies and trade-offs with respect to food security and the environment.

Citation: J.G. Conijn, F.J. de Ruijter, J.J. Schröder and Prem S. Bindraban. 2013.Methodology to assess the impact of fertilizer strategies on planetary boundaries. VFRC Report 2013/3. Virtual Fertilizer Research Center, Washington, D.C. 21 pp.; 1 table; 3 figs.; 42 ref.


VFRC Report 2013/4: Early growth, a vital stage for P uptake

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Soils, either poor or fertile, contain much more P than is required for the yearly uptake. Yet, soil chemical processes fix most P, which leads to very low P concentrations in the soil solution. Crops can scavenge these low concentrations by exploring the soil profile with roots. The total length of the root system is then crucial as it is the constraining factor for P uptake, especially in the early crop stages. This report explores whether the uptake of P can be enhanced during this early stage, thereby stimulating the use of soil P reserves afterwards. Relevant literature is reviewed and reflected on possible measures like seed coating, P placement, foliar P application and the role of exudates to enhance early uptake.

Citation: A.L. Smit, M. Blom-Zandstra, and A. van der Werf and P.S. Bindraban, 2013. Enhancing early root growth to exploit indigenous soil P and fertilizer P. VFRC Report 2013/4. Virtual Fertilizer Research Center, Washington, D.C. 36 pp.; 4 tables; 6 figs.; 98 ref.