A Roadmap for Lowering Crop Nitrogen Requirement.

Increasing nitrogen fertilizer applications have sustained a growing world population in the 20th century. However, to avoid any further associated environmental damage, new sustainable agronomic practices together with new cultivars must be developed. To date the concept of nitrogen use efficiency (NUE) has been useful in quantifying the processes of nitrogen uptake and utilization, but we propose a shift in focus to consider nitrogen responsiveness as a more appropriate trait to select varieties with lower nitrogen requirements. We provide a roadmap to integrate the regulation of nitrogen uptake and assimilation into varietal selection and crop breeding programs. The overall goal is to reduce nitrogen inputs by farmers growing crops in contrasting cropping systems around the world, while sustaining yields and reducing greenhouse gas (GHG) emissions

Nitrogen Challenges and Opportunities for Agricultural and Environmental Science in India

In the last six decades, the consumption of reactive nitrogen (Nr) in the form of fertilizer in India has been growing rapidly, whilst the nitrogen use efficiency (NUE) of cropping systems has been decreasing. These trends have led to increasing environmental losses of Nr, threatening the quality of air, soils, and fresh waters, and thereby endangering climate-stability, ecosystems, and human-health. Since it has been suggested that the fertilizer consumption of India may double by 2050, there is an urgent need for scientific research to support better nitrogen management in Indian agriculture. In order to share knowledge and to develop a joint vision, experts from the UK and India came together for a conference and workshop on “Challenges and Opportunities for Agricultural Nitrogen Science in India.” The meeting concluded with three core messages: (1) Soil stewardship is essential and legumes need to be planted in rotation with cereals to increase nitrogen fixation in areas of limited Nr availability. Synthetic symbioses and plastidic nitrogen fixation are possibly disruptive technologies, but their potential and implications must be considered. (2) Genetic diversity of crops and new technologies need to be shared and exploited to reduce N losses and support productive, sustainable agriculture livelihoods. Móring et al. Nitrogen Challenges and Opportunities (3) The use of leaf color sensing shows great potential to reduce nitrogen fertilizer use (by 10–15%). This, together with the usage of urease inhibitors in neem-coated urea, and better management of manure, urine, and crop residues, could result in a 20–25% improvement in NUE of India by 2030

Model comparison and quantification of nitrous oxide emission and mitigation potential from maize and wheat fields at a global scale

This work was carried out by the International Maize and Wheat Improvement Center (CIMMYT) in collaboration with farmers and funded by the CGIAR research programs (CRPs) on Climate Change, Agriculture and Food Security (CCAFS). CCAFS' work is supported by CGIAR Fund Donors and through bilateral funding agreements. For details, please visit https://ccafs.cgiar.org/donors. The views expressed in this paper cannot be taken to reflect the official opinions of these organizations. The dataset associated with this manuscript will be available together with the supplementary materials of this manuscript.Peer reviewedPublisher PD

Spektralna analiza za praćenje porasta useva pomoću traktorskog spektroradiometra i ručnog senzora stanja useva u pamuku

Remotely sensed spectral vegetation indices are widely used and have benefited numerous disciplines interested in the assessment of biomass, water use, plant stress, plant health and crop production. Tractor mounted Spectroradiometer and hand held GreenSeeker were used to capture the spectral signatures of cotton crop canopy and to calculate NDVI which indicated the temporal changes in crop canopy, nutritional status and phenological conditions in cotton. The structural mechanism for mounting spectroradiometer on the tractor was prepared with various options of adjustments to use spectroradiometer infield. Spectral signatures of crop were measured using tractor mounted spectroradiometer and GreenSeeker at different growth stages in two cultivars of cotton. The relations between NDVI spectroradiometer (R650 and R770) and plant N, plant biomass and plant height at p=0.05 level of significance were found as quadratic, exponential and linear with maximum value of coefficient of determination (R2) of 0.806, 0.807 and 0.801 respectively. However, the relations between NDVI (Green- Seeker) and plant N, plant biomass and plant height at p=0.05 level of significance were found as quadratic, quadratic and linear with maximum R2 value of 0.828, 0.817 and 0.839 respectively. A close relationship between NDVI Spectro-radiometer (R650 and R770) and NDVI (GreenSeeker) was observed with R2 value of 0.833 at p=0.05 level of significance. The study suggested that NDVI at (R650 and R770) using spectroradiometer can be used as a reliable tool for fertilizer N management in cotton.Daljinska spektralna detekcija vegetacije se široko koristi u mnogim oblastima u kojima je potrebna procena biomase, korišćenja vode, stresa kod biljaka, zdravlja biljaka i biljne proizvodnje. Traktorski spektroradiometar i ručni sensor stanja useva su korišćeni za snimanje spektralnih potpisa useva pamuka i proračun NDVI indeksa, što je pokazalo povremene promene biljnog pokrivača, nutritivno stanje i fenološke uslove u kojima se pamuk nalazi. Konstrukcija za postavljanje pektroradiometra na traktor je izvedena sa različitim mogućnostima za podešavanje upotrebe uređaja na parceli. Spektralni potpisi useva mereni su spektroradiometrom postavljenim na traktoru i ručnim senzorom stanja useva u različitim fazama porasta kod dve sorte pamuka. Odnsoi između NDVI indeksa spektroradiometra (R650 i R770) i biljnog azota, biomase biljaka i visine biljaka na nivou značajnosti p=0.05 bili su kvadratni, eksponencijalni i linearni, sa maksimalnim vrednostima koeficijenta determinacije (R2) od 0.806, 0.807 i 0.801, redom. Pored ovoga, odnosi između NDVI (Green-Seeker) i biljnog azota, biomase biljaka i visine biljaka na nivou značajnosti p=0.05 bili su kvadratni, kvadratni i linearni, sa maksimalnom vredošću R2 od 0.828, 0.817 i 0.839, redom. Značajna zavisnost NDVI spektroradiometra (R650 i R770) i NDVI (GreenSeeker) bila je utvrđena sa vrednošću R2 od 0.833 na nivou značajnosti p=0.05. Istraživanje je pokazalo da NDVI kod (R650 i R770) upotrebom spektroradiometra može da se upotrebi kao pouzdano sredstvo za upravljanje đubrenjem azotom kod pamuka

Improving nitrogen use efficiency using precision nitrogen management in wheat (Triticum aestivum L.)

Background: Excessive application of nitrogen (N) fertilizer in cereal crops not only decreases the N use efficiency but also accelerates greenhouse gas (GHG) emission. Aim: To improve N use efficiency in wheat (Triticum aestivum L.) using precision N management and coating seeds with arbuscular mycorrhizal fungi (AMF). Methods: Field experiment laid out in split-plot design was conducted to study the role of AMF consortia (four species) seed coating and different precision N management strategies in rationalizing fertilizer N use. Results: The AMF seed coating improved mycorrhization but did not improve N assimilation, grain yield, root weight, N uptake, chlorophyll value, normalized difference vegetative index, and physiological efficiency (PEN) of applied N fertilizer. The benefits of AMF seed coating in improving N assimilation were not visible even in no-N treatment. Precision N management using leaf color chart (LCC), chlorophyll meter (SPAD), and GreenSeeker optical sensor (GS) sustained wheat grain yield equivalent to the soil-test based N fertilizer recommendation with the average savings of 20% N fertilizer. Precision N management strategies improved mean recovery efficiency (REN) and partial factor productivity (PFPN) of applied N fertilizer, respectively by 26.0% and 26.4% over the soil-test based N management. Spectral properties measured with LCC, SPAD and GS showed good correlation (R2 > 0.71) with grain yield, depicting great potential of optical sensing tools in predicting grain yield and inferring need-based fertilizer N topdressings decisions in wheat. Conclusions: Precision N management provides a potential solution to improve N nutrition in wheat while reducing nitrous oxide (N2O) and total GHG emissions by 23.2 and 23.6%, respectively, in comparison to soil-test based N application