Environmental and economic benefits of variable rate nitrogen fertilization in a nitrate vulnerable zone

Nitrogen fertilization of silage maize in Central Italy is typically carried out with two applications at early stages of crop development: 2nd (V2) and 6th (V6) leaf respectively. In such conditions, the crop has not yet fully covered the soil and proximal or remote sensing of the canopy is hindered by the strong soil background signal. There is thus great interest in rapid and inexpensive approaches to N fertilization prescription. Therefore, an indirect method for inferring information on yield potential and soil variability, through a field-based clustering of multi-temporal satellite data, has been developed using archive Landsat images to identify temporally constant patterns. This method is potentially useful for the creation of prescription maps. The usefulness of the method was evaluated during an N fertilisation field trial in Maccarese (Central Italy), in 2016. At the V2 stage, both uniform and variable rate applications were performed and compared. A pseudo-cross variogram and a standardized ordinary co-kriging methodology was used to highlight spatially variable significant differences among the treatments.

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Nitrogen Consumption and Productivity of Cotton under Sensor‐based Variable‐rate Nitrogen Fertilization

Agronomy Journal ◽

10.2134/agronj2019.03.0197 ◽

2019 ◽

Vol 111 (6) ◽

pp. 3320-3328

Author(s):

Jianming Yu ◽

Xinhua Yin ◽

Tyson B. Raper ◽

Sindhu Jagadamma ◽

Daocai Chi

Keyword(s):

Nitrogen Fertilization ◽

Variable Rate ◽

Nitrogen Consumption

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On-Line Process Parameter Identification for Control of Variable Rate Nitrogen Fertilization

10.4271/932424 ◽

1993 ◽

Author(s):

Yu Li ◽

J. N. Wilson

Keyword(s):

Parameter Identification ◽

Nitrogen Fertilization ◽

Process Parameter ◽

Variable Rate ◽

On Line ◽

Line Process ◽

Identification For Control

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Economic Comparison of Satellite, Plane and UAV-Acquired NDVI Images for Site-Specific Nitrogen Application: Observations from Italy

Agronomy ◽

10.3390/agronomy11112098 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2098

Author(s):

Marco Sozzi ◽

Ahmed Kayad ◽

Stefano Gobbo ◽

Alessia Cogato ◽

Luigi Sartori ◽

...

Keyword(s):

Remote Sensing ◽

Decision Making ◽

Optical Properties ◽

High Resolution ◽

Economic Benefits ◽

Decision Making Process ◽

Variable Rate ◽

Nitrogen Application ◽

Sensing Platforms ◽

Medium Resolution

Defining the most profitable remote sensing platforms is a difficult decision-making process, as it requires agronomic and economic considerations. In this paper, the price and profitability of three levels of remote sensing platforms were evaluated to define a decision-making process. Prices of satellite, plane and UAV-acquired vegetation indices were collected in Italy during 2020 and compared to the economic benefits resulting from variable rate nitrogen application, according to a bibliographic meta-analysis performed on grains. The quality comparison of these three technologies was performed considering the error propagation in the NDVI formula. The errors of the single bands were used to assess the optical properties of the sensors. Results showed that medium-resolution satellite data with good optical properties could be profitably used for variable rate nitrogen applications starting from 2.5 hectares, in case of medium resolution with good optical properties. High-resolution satellites with lower optical quality were profitable starting from 13.2 hectares, while very high-resolution satellites with good optical properties could be profitably used starting from 76.8 hectares. Plane-acquired images, which have good optical properties, were profitable starting from 66.4 hectares. Additionally, a reference model for satellite image price is proposed.

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Variable-rate nitrogen fertilization of winter wheat under high spatial resolution

Precision Agriculture ◽

10.1007/s11119-017-9540-7 ◽

2017 ◽

Vol 19 (3) ◽

pp. 570-587 ◽

Cited By ~ 11

Author(s):

S. Stamatiadis ◽

J. S. Schepers ◽

E. Evangelou ◽

C. Tsadilas ◽

A. Glampedakis ◽

...

Keyword(s):

Winter Wheat ◽

Spatial Resolution ◽

Nitrogen Fertilization ◽

High Spatial Resolution ◽

Variable Rate

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A digital control system for variable rate nitrogen fertilization

Computers and Electronics in Agriculture ◽

10.1016/0168-1699(94)90044-2 ◽

1994 ◽

Vol 10 (3) ◽

pp. 245-258 ◽

Cited By ~ 1

Author(s):

Yu Li ◽

R.L. Kushwaha

Keyword(s):

Control System ◽

Nitrogen Fertilization ◽

Digital Control ◽

Variable Rate ◽

Digital Control System

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Variable and differential application of nutrients to a hill country farm

Journal of New Zealand Grasslands ◽

10.33584/jnzg.2017.79.565 ◽

2017 ◽

Vol 79 ◽

pp. 119-123

Author(s):

Jd Morton ◽

A. Gillingham

Keyword(s):

Financial Analysis ◽

Economic Benefits ◽

Early Spring ◽

Late Winter ◽

Variable Rate ◽

Hill Country ◽

Uniform Rate ◽

The Cost ◽

The Hill

Abstract Traditionally fertiliser has been aerially applied at a uniform rate to hill country, but the technology now exists to apply nutrients at a variable rate (VR) and each nutrient differentially, depending on the production potential and pasture composition of each part of the hill. A hypothetical case study of a sheep farm was modelled to show the economic benefits of VR application of phosphorus (P) and sulphur (S) and differential application of nitrogen (N), compared with application of a uniform rate of P and S. The financial analysis demonstrates that the VR strategy of less P and S to steeper slopes where there is low legume and more on easier slopes where there is more legume, costs less than the application of P and S at a uniform rate over all slopes. The cost saving could be used to apply N to steep land on both sunny and shady aspects and easy land on sunny aspects. This differential N application in late winter/early spring ensures better pasture cover for lactating ewes to improve ewe condition at weaning. When this gain in condition was maintained through to mating, lambing percentage increased in the following spring. The benefit from this increased lamb production was an increase in financial returns of $63/ha/year. A qualitative sensitivity analysis indicated that this value remains stable in response to changes in the proportion of each slope class, soil Olsen P level, the relative cost of fertiliser P and N and sheep to cattle ratio. Keywords: differential application, hill country, lamb production, nitrogen, phosphorus, aerial topdressing, variable rate

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Optical crop sensor for variable-rate nitrogen fertilization in corn: i - plant nutrition and dry matter production

Revista Brasileira de Ciência do Solo ◽

10.1590/s0100-06832013000500018 ◽

2013 ◽

Vol 37 (5) ◽

pp. 1288-1298 ◽

Cited By ~ 13

Author(s):

Jardes Bragagnolo ◽

Telmo Jorge Carneiro Amado ◽

Rodrigo da Silveira Nicoloso ◽

Joerg Jasper ◽

Junior Kunz ◽

...

Keyword(s):

Nitrogen Fertilization ◽

Plant Nutrition ◽

Dry Matter ◽

Vegetation Index ◽

N Uptake ◽

Climatic Conditions ◽

Dry Matter Production ◽

Variable Rate ◽

N Content ◽

Matter Production

Variable-rate nitrogen fertilization (VRF) based on optical spectrometry sensors of crops is a technological innovation capable of improving the nutrient use efficiency (NUE) and mitigate environmental impacts. However, studies addressing fertilization based on crop sensors are still scarce in Brazilian agriculture. This study aims to evaluate the efficiency of an optical crop sensor to assess the nutritional status of corn and compare VRF with the standard strategy of traditional single-rate N fertilization (TSF) used by farmers. With this purpose, three experiments were conducted at different locations in Southern Brazil, in the growing seasons 2008/09 and 2010/11. The following crop properties were evaluated: above-ground dry matter production, nitrogen (N) content, N uptake, relative chlorophyll content (SPAD) reading, and a vegetation index measured by the optical sensor N-Sensor® ALS. The plants were evaluated in the stages V4, V6, V8, V10, V12 and at corn flowering. The experiments had a completely randomized design at three different sites that were analyzed separately. The vegetation index was directly related to above-ground dry matter production (R² = 0.91; p<0.0001), total N uptake (R² = 0.87; p<0.0001) and SPAD reading (R² = 0.63; p<0.0001) and inversely related to plant N content (R² = 0.53; p<0.0001). The efficiency of VRF for plant nutrition was influenced by the specific climatic conditions of each site. Therefore, the efficiency of the VRF strategy was similar to that of the standard farmer fertilizer strategy at sites 1 and 2. However, at site 3 where the climatic conditions were favorable for corn growth, the use of optical sensors to determine VRF resulted in a 12 % increase in N plant uptake in relation to the standard fertilization, indicating the potential of this technology to improve NUE.

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