Ideal and saturated soil fertility as bench marks in nutrient management1. Outline of the framework

Janssen, B.H.; Willigen, P. de

doi:10.1016/j.agee.2006.03.014

Cited by 45 publications

(28 citation statements)

References 21 publications

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“…It implies that HC represents the fraction of plant biomass that can exactly turn into soil organic matter without causing net N mineralization or immobilization. Using N fractions of 0.005 in stover and 0.008 in roots (Janssen and De Willigen, 2006), 500 kg RSDM contains 3.76 kg of N. If this N is incorporated in soil organic matter, it corresponds to 37.6 kg SOC-C, which is 0.16711 (rounded 0.17) times the 225 kg C present in 500 kg of RSDM.…”

Section: Methodsmentioning

confidence: 99%

“…The estimate implies that 500 kg of RSDM approximately consist of 420 kg of roots and 80 kg of stover. The C fraction in crop DM usually is set at 0.45, and the value of HC of root biomass at 0.3 (Janssen and De Willigen, 2006). In the highland tropical environment of Kabete, HC of root biomass must be less than 0.3 found in temperate climates.…”

Section: Methodsmentioning

confidence: 99%

“…This was based on a maize biomass partitioning of 1000:1000:370 for grains, stover and roots (Janssen and De Willigen, 2006) and of 1000:2125:475 as used in Kabete (Kapkiyai et al 1999). The estimate implies that 500 kg of RSDM approximately consist of 420 kg of roots and 80 kg of stover.…”

Section: Methodsmentioning

confidence: 99%

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Simple models and concepts as tools for the study of sustained soil productivity in long-term experiments. I. New soil organic matter and residual effect of P from fertilizers and farmyard manure in Kabete, Kenya

Janssen

2010

Plant Soil

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The rough outcomes of a long-term experiment in Kenya were (re-)interpreted using simple models to find causes of success or failure with regard to sustained soil productivity. A two-pools model calculated the development of soil organic matter, and a practical equation estimated the residual effect of fertilizer P. Relative mineralization rate was 4 and 8% y −1 for original and newly formed soil organic carbon (SOC). Maize yielded 0.25 and 1.1 tha −1 per gkg −1 of original and new SOC, respectively. Yields of fertilized maize increased initially as a result of increasing residual effects of applied P, but decreased later presumably because SOC declined to below a critical level of 16 gkg −1. To maintain SOC above this level, about 10 tons of farmyard manure (dry matter) must be applied annually. Agronomic nutrient use efficiencies for fertilizer N and P were low, but the residual effect of P was high. The simple model outlined half a century ago adequately calculated build-up of new soil organic matter. The estimated residual effect of fertilizer P explained increasing crop responses to repeated P applications. The absence of data on nutrient uptake by the crop strongly limited the understanding of the experimental results.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Simple models and concepts as tools for the study of sustained soil productivity in long-term experiments. I. New soil organic matter and residual effect of P from fertilizers and farmyard manure in Kabete, Kenya

Janssen

2010

Plant Soil

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“…Various disciplines related to agronomy have proposed to characterize an 'ideal' soil either (i) according to individual parameters such as base-cation saturation ratio (Kopittke and Menzies 2007), moisture (Keen 1924), and capillary pull (Hackett and Strettan 1928), or (ii) through integrated parameters (De Orellana and Pilatti 1999;Janssen and de Willigen 2006;Pilatti and de Orellana 2000).…”

Section: Issues For Agronomistsmentioning

confidence: 99%

Redox potential (Eh) and pH as drivers of soil/plant/microorganism systems: a transdisciplinary overview pointing to integrative opportunities for agronomy

2012

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Background Oxidation-reduction and acid-base reactions are essential for the maintenance of all living organisms. However, redox potential (Eh) has received little attention in agronomy, unlike pH, which is regarded as a master variable. Agronomists are probably depriving themselves of a key factor in crop and soil science which could be a useful integrative tool. Scope This paper reviews the existing literature on Eh in various disciplines connected to agronomy, whether associated or not with pH, and then integrates this knowledge within a composite framework. Conclusions This transdisciplinary review offers evidence that Eh and pH are respectively and jointly major drivers of soil/plant/microorganism systems. Information on the roles of Eh and pH in plant and microorganism physiology and in soil genesis converges to form an operational framework for further studies of soil/plant/microorganism functioning. This framework is based on the hypothesis that plants physiologically function within a specific internal Eh-pH range and that, along with microorganisms, they alter Eh and pH in the rhizosphere to ensure homeostasis at the cell level. This new perspective could help in bridging several disciplines related to agronomy, and across micro and macro-scales. It should help to improve cropping systems design and management, in conventional, organic, and conservation agriculture.

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“…erosion and 'fixation', have to be compensated. Janssen and de Willigen (2006), however, reason that, in case of high soil P status, balanced P fertilisation should be enough to maintain the amount of P available for plant uptake and production.…”

Section: Introductionmentioning

confidence: 99%

Does balanced phosphorus fertilisation sustain high herbage yields and phosphorus contents in alternately grazed and mown pastures?

Middelkoop

Salm

Ehlert

et al. 2016

Nutr Cycl Agroecosyst

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Many soils of agricultural land in affluent countries have been enriched with phosphorus (P), because P application via fertilisers and manures was larger than P withdrawal via harvested biomass. This practice threatens the long-term availability of P fertilisers derived from finite rock phosphates, as well as surface water quality because of P leaching and runoff losses. In response, restrictions on P fertilisation have been implemented in some countries. The objective of this study is to examine the effects of balanced P fertilisation in comparison to a surplus P fertilisation on dry matter (DM) grass yield, grass quality, and soil P status. A 15 years' lasting field experiment was conducted on four permanent grassland sites, on sand (two sites), peat and young marine clay in the Netherlands. Fertilisation levels, including cattle slurry, were aimed to implement P surpluses of 0, 9, and 18 kg P ha -1 year -1 , and N surpluses of 180 and 300 kg ha -1 year -1 . Grasslands were alternately grazed and mown, and grass yields and soil P levels were measured. Annual DM yield, P content, and P yield of grazed grassland were lower at balanced P fertilisation than at a surplus of 9 or 18 kg P ha -1 -year -1 on sand and peat. Differences between P treatments remained constant over time. On the recently reclaimed marine clay, DM yield did not differ between P treatments, but P content and P yield did respond to different P surpluses. Differences between sites in the response to P surpluses were related to differences in soil P status, according to P-AL (capacity indicator) and P-CaCl 2 (intensity indicator). At balanced P fertilisation, P-AL tended to decrease, while P-CaCl 2 tended to remain constant. At surplus P, P-AL tended to increase and P-CaCl 2 tended to remain constant. Herbage yield and P uptake also strongly responded to N treatments. In conclusion, there is a risk that balanced P fertilisation reduces herbage yield and P content relative to surplus P fertilisation, even at relatively high soil P status. The risk of yield reduction seems to be related to the ratio between the P intensity indicator and P capacity indicator.Electronic supplementary material The online version of this article

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Ideal and saturated soil fertility as bench marks in nutrient management1. Outline of the framework

Cited by 45 publications

References 21 publications

Simple models and concepts as tools for the study of sustained soil productivity in long-term experiments. I. New soil organic matter and residual effect of P from fertilizers and farmyard manure in Kabete, Kenya

Simple models and concepts as tools for the study of sustained soil productivity in long-term experiments. I. New soil organic matter and residual effect of P from fertilizers and farmyard manure in Kabete, Kenya

Redox potential (Eh) and pH as drivers of soil/plant/microorganism systems: a transdisciplinary overview pointing to integrative opportunities for agronomy

Does balanced phosphorus fertilisation sustain high herbage yields and phosphorus contents in alternately grazed and mown pastures?

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