Agronomy

Editorial

Jump to: Research, Review

6 pages, 216 KiB

Open AccessEditorial

Site-Specific Nutrient Management

by Witold Grzebisz

Agronomy 2021, 11(4), 752; https://doi.org/10.3390/agronomy11040752 - 13 Apr 2021

Cited by 3 | Viewed by 2590

Abstract

The editorial introduces to a Special Issue entitled ”Site-Specific Nutrient Management. The concept of the nitrogen gap (NG) is as a core challenge for an effective realization of the so called “twin objectives” in sustainable agriculture. This special issue stresses on some hot [...] Read more.

The editorial introduces to a Special Issue entitled ”Site-Specific Nutrient Management. The concept of the nitrogen gap (NG) is as a core challenge for an effective realization of the so called “twin objectives” in sustainable agriculture. This special issue stresses on some hot spots in crop production, being responsible in the yield gap development, that farmers have to take control. The yield gap cannot be ameliorated without the synchronization of the in-season requirements of the currently grown crop for N with its three-dimensional variability in a supply on a field (temporal, spatial and vertical). A recognition of soil fertility status in the rooted zone, which includes availability of both mineral N and nutrients decisive for its uptake, is the first step in the NG amelioration. The sustainability in soil fertility, as a prerequisite of N fertilizer application, requires a wise strategy of organic matter management, based on farmyard manure, and/or cultivation of legumes. The soil fertility status, irrespectively of the World region determines ways of the N rate optimization. The division of a particular field into homogenous productive units is the primary step in the NG cover. It can be delineated, using both data on soil physico-chemical properties of the soil rooted zone, and then validated by using satellite spectral images of the crop biomass in a well-defined stage of its growth, decisive for yield. The proposed set of diagnostic tools is a basis for elaboration an effective agronomic decision support system. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

Research

Jump to: Editorial, Review

14 pages, 792 KiB

Open AccessArticle

The Effect of Farmyard Manure and Mineral Fertilizers on Sugar Beet Beetroot and Top Yield and Soil Chemical Parameters

by Lukáš Hlisnikovský, Ladislav Menšík, Kateřina Křížová and Eva Kunzová

Agronomy 2021, 11(1), 133; https://doi.org/10.3390/agronomy11010133 - 12 Jan 2021

Cited by 11 | Viewed by 3819

Abstract

In order to recommend the dose of fertilization for sugar beet under currently unstable weather conditions, we analysed beetroot and top yields, sugar content (SC), and the effect of fertilization on soil chemistry over a three-year period (2016–2018). All three years were characterized [...] Read more.

In order to recommend the dose of fertilization for sugar beet under currently unstable weather conditions, we analysed beetroot and top yields, sugar content (SC), and the effect of fertilization on soil chemistry over a three-year period (2016–2018). All three years were characterized by different weather conditions. The year 2016 was very warm and very dry. The year 2017 was warm with normal precipitation. The year 2018 was extraordinary warm and very dry. We compared the following ten fertilization treatments: unfertilized control, farmyard manure (FYM), mineral fertilizers NPK1–4, and FYM + NPK1–4. The applications of FYM, NPK, and FYM + NPK resulted in significantly higher yields of beetroots and tops as compared with the control, while no significant differences were recorded among FYM, NPK, and FYM + NPK treatments. The SC was not affected by the fertilization. The application of NPK resulted in a lower pH value, while the highest values were recorded for the control and FYM treatments. The application of FYM + NPK increased the content of organic carbon (Corg) in the soil, the total content of nitrogen (Ntot), and P and K concentrations. According to the results of the linear-plateau model, the recommended dose of N is 112 kg ha⁻¹, corresponding to a beetroot yield of 66 t ha⁻¹. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Figure 1

27 pages, 12889 KiB

Open AccessArticle

Spatial Variability of Yield and Nitrogen Indicators—A Crop Rotation Approach

by Remigiusz Łukowiak, Witold Grzebisz, Jakub Ceglarek, Adam Podolski, Cezary Kaźmierowski and Jan Piekarczyk

Agronomy 2020, 10(12), 1959; https://doi.org/10.3390/agronomy10121959 - 12 Dec 2020

Cited by 9 | Viewed by 2368

Abstract

The division of an arable field into zones of different productivity requires a reliable, discriminatory tool. This hypothesis was validated by analyzing the spatial variability of yield and N indicators in the crop rotation of winter oilseed rape (WOSR)/winter triticale (WTR) during 2016/2017 [...] Read more.

The division of an arable field into zones of different productivity requires a reliable, discriminatory tool. This hypothesis was validated by analyzing the spatial variability of yield and N indicators in the crop rotation of winter oilseed rape (WOSR)/winter triticale (WTR) during 2016/2017 and 2017/2018 in a field of 30 ha (Przebędowo, Poland). The direct, measurable variables were: yield, N accumulated in—seeds/grain and crop residues, mineral N in spring, and harvest. The basic N indicators were total N uptake (TN), N-partial factor productivity, and N balance (N_b). The attainable yields of WOSR and WTR were 4.93 and 6.51 t ha⁻¹, and a yield gap of −2.04 and −2.10 t ha⁻¹. The management of 50 kg of the non-used N by crops, i.e. nitrogen gap (NG) could cover 36% and 65% of the yield gap (YG), respectively. The N_b, based on N input (N_in = N_min + N_f) and TN, was the key field indicator, defining both yield and NG. Geostatic parameters, i.e., the nugget to sill ratio, spatial dependence range, and mean correlation distance, were very stable (≤0.2–0.17; 94–100 m; 28 m for WOSR and WTR). The spatial stability of N_b, irrespective of the crop and growing conditions, corroborates its suitability for discriminating high and low-productivity field zones. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Figure 1

16 pages, 302 KiB

Open AccessArticle

Effects of Landscape, Soils, and Weather on Yields, Nitrogen Use, and Profitability with Sensor-Based Variable Rate Nitrogen Management in Cotton

by James A. Larson, Melissa Stefanini, Xinhua Yin, Christopher N. Boyer, Dayton M. Lambert, Xia Vivian Zhou, Brenda S. Tubaña, Peter Scharf, Jac J. Varco, David J. Dunn, Hubert J. Savoy and Michael J. Buschermohle

Agronomy 2020, 10(12), 1858; https://doi.org/10.3390/agronomy10121858 - 25 Nov 2020

Cited by 3 | Viewed by 2054

Abstract

Farmers may be reluctant to adopt variable rate nitrogen (VRN) management because of uncertain profits. This study assessed field landscape, soil, and weather effects on optical sensing (OS)-based VRN on cotton (Gossypium hirsutum L.) N rates, yields, and net returns (NRs). Field [...] Read more.

Farmers may be reluctant to adopt variable rate nitrogen (VRN) management because of uncertain profits. This study assessed field landscape, soil, and weather effects on optical sensing (OS)-based VRN on cotton (Gossypium hirsutum L.) N rates, yields, and net returns (NRs). Field data were collected from 21 locations in Louisiana, Mississippi, Missouri, and Tennessee, USA, between 2011 and 2014. Data included yields, N rates, and NRs for the farmer practice (FP), OS-based VRN, and OS-based VRN supplemented with other information. Production data were augmented with landscape, soils, and weather data, and ANOVA and logistic regressions were used to identify field conditions where VRN was profitable, provided risk management benefits, and improved N efficiency. Key findings indicate that NRs were improved with VRN by applying additional N on more erodible soils. Higher organic matter soils also benefited from VRN through enhanced yields and NRs. VRN may also have provided risk management benefits by providing a lower probability of NRs below NRs for the FP on soils associated with greater water-holding capacity, higher organic matter levels, or deeper profiles. Results from this study may help identify farm fields with similar characteristics for adoption of VRN management. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

18 pages, 3010 KiB

Open AccessArticle

Within-Field Relationships between Satellite-Derived Vegetation Indices, Grain Yield and Spike Number of Winter Wheat and Triticale

by Ewa Panek, Dariusz Gozdowski, Michał Stępień, Stanisław Samborski, Dominik Ruciński and Bartosz Buszke

Agronomy 2020, 10(11), 1842; https://doi.org/10.3390/agronomy10111842 - 23 Nov 2020

Cited by 19 | Viewed by 3170

Abstract

The aims of this study were to: (i) evaluate the relationships between vegetation indices (VIs) derived from Sentinel-2 imagery and grain yield (GY) and the number of spikes per square meter (SN) of winter wheat and triticale; (ii) determine the dates and plant [...] Read more.

The aims of this study were to: (i) evaluate the relationships between vegetation indices (VIs) derived from Sentinel-2 imagery and grain yield (GY) and the number of spikes per square meter (SN) of winter wheat and triticale; (ii) determine the dates and plant growth stages when the above relationships were the strongest at individual field scale, thus allowing for accurate yield prediction. Observations of GY and SN were performed at harvest on six fields (three locations in two seasons: 2017 and 2018) in three regions of Poland, i.e., northeastern (A—Brożówka), central (B—Zdziechów) and southeastern Poland (C—Kryłów). Vegetation indices (Normalized Difference Vegetation Index (NDVI), Soil-Adjusted Vegetation Index (SAVI), modified SAVI (mSAVI), modified SAVI 2 (mSAVI2), Infrared Percentage Vegetation Index (IPVI), Global Environmental Monitoring Index (GEMI), and Ratio Vegetation Index (RVI)) calculated for sampling points from mid-March until mid-July, covering within-field soil and topographical variability, were included in the analysis. Depending on the location, the highest correlation coefficients (of about 0.6–0.9) for most of VIs with GY and SN were obtained about 4–6 weeks before harvest (from the beginning of shooting to milk maturity). Therefore, satellite-derived VIs are useful for the prediction of within-field cereal GY as well as SN variability. Information on GY, predicted together with the results for soil nutrient availability, is the basis for the formulation of variable fertilize rates in precision agriculture. All examined VIs were similarly correlated with GY and SN via the commonly used NDVI. The increase in NDVI by 0.1 unit was related to an average increase in GY by about 2 t ha⁻¹. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Figure 1

14 pages, 4474 KiB

Open AccessEditor’s ChoiceArticle

A Remote Sensing-Based Approach to Management Zone Delineation in Small Scale Farming Systems

by Davide Cammarano, Hainie Zha, Lucy Wilson, Yue Li, William D. Batchelor and Yuxin Miao

Agronomy 2020, 10(11), 1767; https://doi.org/10.3390/agronomy10111767 - 12 Nov 2020

Cited by 15 | Viewed by 3208

Abstract

Small-scale farms represent about 80% of the farming area of China, in a context where they need to produce economic and environmentally sustainable food. The objective of this work was to define management zone (MZs) for a village by comparing the use of [...] Read more.

Small-scale farms represent about 80% of the farming area of China, in a context where they need to produce economic and environmentally sustainable food. The objective of this work was to define management zone (MZs) for a village by comparing the use of crop yield proxies derived from historical satellite images with soil information derived from remote sensing, and the integration of these two data sources. The village chosen for the study was Wangzhuang village in Quzhou County in the North China Plain (NCP) (30°51′55″ N; 115°02′06″ E). The village was comprised of 540 fields covering approximately 177 ha. The subdivision of the village into three or four zones was considered to be the most practical for the NCP villages because it is easier to manage many fields within a few zones rather than individually in situations where low mechanization is the norm. Management zones defined using Landsat satellite data for estimation of the Green Normalized Vegetation Index (GNDVI) was a reasonable predictor (up to 45%) of measured variation in soil nitrogen (N) and organic carbon (OC). The approach used in this study works reasonably well with minimum data but, in order to improve crop management (e.g., sowing dates, fertilization), a simple decision support system (DSS) should be developed in order to integrate MZs and agronomic prescriptions. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Figure 1

27 pages, 2263 KiB

Open AccessArticle

Evaluation of Nitrogen Fertilization Systems Based on the in-Season Variability in the Nitrogenous Growth Factor and Soil Fertility Factors—A Case of Winter Oilseed Rape (Brassica napus L.)

by Witold Grzebisz, Remigiusz Łukowiak and Karol Kotnis

Agronomy 2020, 10(11), 1701; https://doi.org/10.3390/agronomy10111701 - 3 Nov 2020

Cited by 10 | Viewed by 2061

Abstract

Application of nitrogen (N) in contrastive chemical form changes availability of soil nutrients, affecting crop response. This hypothesis was evaluated based on field experiments conducted in 2015/16 and 2016/2017. The experiment consisted of three nitrogen fertilization systems: mineral-ammonium nitrate (AN) (M-NFS), organic-digestate (O-NFS), [...] Read more.

Application of nitrogen (N) in contrastive chemical form changes availability of soil nutrients, affecting crop response. This hypothesis was evaluated based on field experiments conducted in 2015/16 and 2016/2017. The experiment consisted of three nitrogen fertilization systems: mineral-ammonium nitrate (AN) (M-NFS), organic-digestate (O-NFS), ²/₃ digestate + ¹/₃ AN (OM-NFS), and N rates: 0, 80, 120, 160; 240 kg ha⁻¹. The content of nitrogen nitrate (N-NO₃) and available phosphorus (P), potassium (K), magnesium (Mg) and calcium (Ca) were determined at rosette, onset of flowering, and maturity of winter oilseed rape (WOSR) growth from three soil layers: 0.0–0.3, 0.3–0.6, 0.6–0.9 m. The optimum N rates were: 139, 171 and 210 kg ha⁻¹ for the maximum yield of 3.616, 3.887, 4.195 t ha⁻¹, for M-NFS, O-NFS, OM-NFS. The N-NO₃ content at rosette of 150 kg ha⁻¹ and its decrease to 48 kg ha⁻¹ at the onset of flowering was the prerequisite of high yield. The key factor limiting yield in the M-NFS was the shortage of Ca, Mg, O-NFS—shortage of N-NO₃. Plants in the OM-NFS were well-balanced due to a positive impact of the subsoil Mg and Ca on the N-NO₃ content and productivity. The rosette stage was revealed as the cardinal for the correction of WOSR N nutritional status. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Figure 1

27 pages, 1220 KiB

Open AccessArticle

Changes in Pisum sativum L. Plants and in Soil as a Result of Application of Selected Foliar Fertilizers and Biostimulators

by Hanna Sulewska, Alicja Niewiadomska, Karolina Ratajczak, Anna Budka, Katarzyna Panasiewicz, Agnieszka Faligowska, Agnieszka Wolna-Maruwka and Leszek Dryjański

Agronomy 2020, 10(10), 1558; https://doi.org/10.3390/agronomy10101558 - 13 Oct 2020

Cited by 10 | Viewed by 2591

Abstract

The aim of this study was to assess the effect of selected biostimulators and foliar fertilizers on plant development, plant yield, soil fertility and soil biochemical activity (dehydrogenases, phosphatases, catalases) during the cultivation of pea (Pisum sativum L.). A field experiment was [...] Read more.

The aim of this study was to assess the effect of selected biostimulators and foliar fertilizers on plant development, plant yield, soil fertility and soil biochemical activity (dehydrogenases, phosphatases, catalases) during the cultivation of pea (Pisum sativum L.). A field experiment was conducted between 2016 and 2018 at the Gorzyń Experimental and Educational Station, Poznań University of Life Sciences in Poland. The following treatments were tested: (1) control; (2) Titanit; (3) Optysil; (4) Metalosate potassium; (5) Rooter; (6) Bolero Mo; (7) Adob Zn IDHA; (8) Adob B and (9) Adob 2.0 Mo. Adob Zn IDHA stimulated yields, especially under average moisture conditions and less so in drought conditions, and the differences compared to control amounted 8.36 and 4.3%, respectively. The results showed a close relationship between the effects of the biostimulators and foliar fertilizers and weather conditions during the study. It was not possible to determine whether any of the biostimulators or foliar fertilizers had a positive effect on pea seed yield in any year. Similarly, it was difficult to clearly determine the effect of the biostimulators and fertilizers on biochemical activity in the soil, although soil enzyme activity was influenced most by application of the Bolero Mo fertilizer. In all study years, biological nitrogen fixation was always greater after the application of a biostimulator/fertilizer treatment. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Figure 1

27 pages, 1282 KiB

Open AccessArticle

Effect of Site Specific Nitrogen Management on Seed Nitrogen—A Driving Factor of Winter Oilseed Rape (Brassica napus L.) Yield

by Remigiusz Łukowiak and Witold Grzebisz

Agronomy 2020, 10(9), 1364; https://doi.org/10.3390/agronomy10091364 - 10 Sep 2020

Cited by 7 | Viewed by 2086

Abstract

It has been assumed that the management of both soil and fertilizer N in winter oilseed rape (WOSR) is crucial for N accumulation in seeds (N_se) and yield. This hypothesis was evaluated based on field experiments conducted in 2008/09, 2009/10, 2010/11 [...] Read more.

It has been assumed that the management of both soil and fertilizer N in winter oilseed rape (WOSR) is crucial for N accumulation in seeds (N_se) and yield. This hypothesis was evaluated based on field experiments conducted in 2008/09, 2009/10, 2010/11 seasons, each year at two sites, differing in soil fertility, including indigenous N (N_i) supply. The experimental factors consisted of two N fertilizers: N and NS, and four N_f rates: 0, 80, 120, 160 kg ha⁻¹. Yield, as governed by site × N_f rate interaction, responded linearly to N_se at harvest. The maximum N_se (N_semax), as evaluated by N input (N_in = N_i + N_f) to WOSR at spring regrowth, varied from 95 to 153 kg ha⁻¹, and determined 80% of yield variability. The basic reason of site diversity in N_semax was N_i efficiency, ranging from 46% to 70%, respectively. The second cause of N_se variability was a shortage of N supply from + 9.5 soil to −8.8 kg ha⁻¹ to the growing seeds during the seed filling period (SFP). This N pool supports the N concentration in seeds, resulting in both seed density and a seed weight increase, finally leading to a yield increase. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Figure 1

18 pages, 4267 KiB

Open AccessArticle

Economic Optimal Nitrogen Rate Variability of Maize in Response to Soil and Weather Conditions: Implications for Site-Specific Nitrogen Management

by Xinbing Wang, Yuxin Miao, Rui Dong, Zhichao Chen, Krzysztof Kusnierek, Guohua Mi and David J. Mulla

Agronomy 2020, 10(9), 1237; https://doi.org/10.3390/agronomy10091237 - 21 Aug 2020

Cited by 24 | Viewed by 3566

Abstract

The dynamic interactions between soil, weather and crop management have considerable influences on crop yield within a region, and should be considered in optimizing nitrogen (N) management. The objectives of this study were to determine the influence of soil type, weather conditions and [...] Read more.

The dynamic interactions between soil, weather and crop management have considerable influences on crop yield within a region, and should be considered in optimizing nitrogen (N) management. The objectives of this study were to determine the influence of soil type, weather conditions and planting density on economic optimal N rate (EONR), and to evaluate the potential benefits of site-specific N management strategies for maize production. The experiments were conducted in two soil types (black and aeolian sandy soils) from 2015 to 2017, involving different N rates (0 to 300 kg ha⁻¹) with three planting densities (55,000, 70,000, and 85,000 plant ha⁻¹) in Northeast China. The results showed that the average EONR was higher in black soil (265 kg ha⁻¹) than in aeolian sandy soil (186 kg ha⁻¹). Conversely, EONR showed higher variability in aeolian sandy soil (coefficient of variation (CV) = 30%) than in black soil (CV = 10%) across different weather conditions and planting densities. Compared with farmer N rate (FNR), applying soil-specific EONR (SS-EONR), soil- and year-specific EONR (SYS-EONR) and soil-, year-, and planting density-specific EONR (SYDS-EONR) would significantly reduce N rate by 25%, 30% and 38%, increase net return (NR) by 155 $ ha⁻¹, 176 $ ha⁻¹, and 163 $ ha⁻¹, and improve N use efficiency (NUE) by 37–42%, 52%, and 67–71% across site-years, respectively. Compared with regional optimal N rate (RONR), applying SS-EONR, SYS-EONR and SYDS-EONR would significantly reduce N application rate by 6%, 12%, and 22%, while increasing NUE by 7–8%, 16–19% and 28–34% without significantly affecting yield or NR, respectively. It is concluded that soil-specific N management has the potential to improve maize NUE compared with both farmer practice and regional optimal N management in Northeast China, especially when each year’s weather condition and planting density information is also considered. More studies are needed to develop practical in-season soil (site)-specific N management strategies using crop sensing and modeling technologies to better account for soil, weather and planting density variation under diverse on-farm conditions. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Graphical abstract

17 pages, 980 KiB

Open AccessArticle

The Development of Winter Wheat Yield and Quality under Different Fertilizer Regimes and Soil-Climatic Conditions in the Czech Republic

by Lukáš Hlisnikovský, Ladislav Menšík and Eva Kunzová

Agronomy 2020, 10(8), 1160; https://doi.org/10.3390/agronomy10081160 - 7 Aug 2020

Cited by 10 | Viewed by 3285

Abstract

Farmers must adapt to the changes brought about by the changing climate and market requirements. These adaptations are associated with fertilization—the availability of organic manures and mineral fertilizers and crop rotations. What is the effect of organic manures on wheat and soil? Is [...] Read more.

Farmers must adapt to the changes brought about by the changing climate and market requirements. These adaptations are associated with fertilization—the availability of organic manures and mineral fertilizers and crop rotations. What is the effect of organic manures on wheat and soil? Is it necessary to apply mineral phosphorus P and potassium (K) fertilizers to the wheat? These questions are frequently asked in workshops in different growing areas. To provide a relevant answer on this issue, we evaluated how farmyard manure (FYM), mineral nitrogen (N) applied without phosphorus (P) and potassium (K) fertilizers, and application of NPK affected grain yield, grain quality, and soil properties under different soil-climate conditions (Ivanovice—Chernozem, Caslav—Phaeozem, Lukavec—Cambisol) between 2015 and 2018. The FYM significantly increased grain yield even after three years since being applied and incorporated into the soil in all localities, but its application didnot affect grain quality. In the soil, the FYM significantly increased total nitrogen Nt, P, and K content in all localities and oxidable carbon Cox content in two localities. Mineral nitrogen significantly affected grain yield and quality and increased concentrations of soil N and C, but decreased pH in Caslav. Application of mineral P and K wasnot connected with a positive effect on grain yield and quality, but increased the concentration of these elements in the soil, preventing depletion of these elements from the soil. Maximal yields were recorded when 70–98 kg N ha⁻¹ was applied in Ivanovice, 55–72 kg N ha⁻¹ in Caslav, and 155 kg N ha⁻¹ in Lukavec. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Graphical abstract

Review

Jump to: Editorial, Research

24 pages, 2445 KiB

Open AccessEditor’s ChoiceReview

Nitrogen Gap Amelioration Is a Core for Sustainable Intensification of Agriculture—A Concept

by Witold Grzebisz and Remigiusz Łukowiak

Agronomy 2021, 11(3), 419; https://doi.org/10.3390/agronomy11030419 - 25 Feb 2021

Cited by 21 | Viewed by 2733

Abstract

The main reason for the development of the yield gap in crop production is the inefficient management of nitrogen (N). The nitrogen gap (NG) cannot be ameliorated without an indication and quantification of soil characteristics that limit N uptake by a crop plant. [...] Read more.

The main reason for the development of the yield gap in crop production is the inefficient management of nitrogen (N). The nitrogen gap (NG) cannot be ameliorated without an indication and quantification of soil characteristics that limit N uptake by a crop plant. The insufficient supply of N to a plant during its cardinal stages of yield formation is a result of two major-variabilities. The first is spatial variability in the soil characteristics responsible for water supply to a plant, also serving as a nutrient carrier. The second is a vertical variability in soil factors, decisive for pools of available nutrients, and their in-season accessibility to the grown crop. The long-term strategy for NG cover should focus first on soil characteristics (humus stock, pH, nutrient content) responsible for water storage and its availability to the currently grown plant. Diagnostics of plant nutrient availability should deliver data on their contents both in the topsoil and subsoil. The combined use of both classical diagnostic tools and spectral imagery is a way to divide a single field into units, differing in productivity. Remote-sensing techniques offer a broad number of tools to define the in-season crop canopy requirement for fertilizer N in homogenous field units. Full article

(This article belongs to the Special Issue Site-Specific Nutrient Management)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Site-Specific Nutrient Management

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (12 papers)

Editorial

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI