A scoping review of side-dress nitrogen recommendation systems and their perspectives in precision agriculture

A scoping review of the relevant literature was carried out to identify the existing N recommendation systems, their temporal and geographical diffusion, and knowledge gaps. In total, 151 studies were identified and categorized. Seventy-six percent of N recommendation systems are empirical and based on spatialized vegetation indices (73% of them); 21% are based on mechanistic crop simulation models with limited use of spatialized data (26% of them); 3% are based on machine learning techniques with integration of spatialized and non-spatialized data. Recommendation systems started to appear worldwide in 2000; often they were applied in the same location where calibration had been carried out. Thirty percent of the studies use advanced recommendation techniques, such as sensor/approach fusion (44%), algorithm add-ons (30%), estimation of environmental benefits (13%), and multi-objective decisions (13%). Some limitations have been identified. Empirical systems need specific calibrations for each site, species and sensor, rarely using soil, vegetation and weather data together, while mechanistic systems need large input data sets, often non-spatialized. We conclude that N recommendation systems can be improved by better data and the integration of algorithms.

High intensity and red enriched LED lights increased growth of lettuce and endive

Changes in plant responses have been associated with different fractions of the visible spectrum and light intensity. Advances in light emitting diodes (LED) have enabled the study of the effect of narrow wavelengths on plant growth and antioxidant compound synthesis. LED technology also facilitates the incorporation of light sources in a controlled setting where light spectra and intensity can be regulated. The objective of this study was to compare the effect of two commercial light spectra (S1: standard white light with 32.8% blue, 42.5% green, 21.7% red and 2.4% far red;S2: AP67 spectrum, designed for horticultural growth, with 16.9% blue, 20.5% green, 49.7% red and 12.3% far red) at two light intensities [LI: low intensity (78 µmol·m-2s-1 of photons for S1 and 62 µmol·m-2s-1 for S2, and HI: high intensity (102 and 100 µmol·m-2s-1 for S1 and S2, respectively)] on growth and antioxidant compound contents in two leafy vegetables: endive (Cichorium endivia L.) and lettuce (Lactuca sativa L.). Fresh weight (FW), dry weight (DW), and DW% of plants were taken as growth indicators. Leaf number, SPAD index, leaf area (LA) and specific leaf area (SLA) were also evaluated. Antioxidant synthesis was measured as total phenol content (TPC), total flavonoid content (TFC) and antioxidant activity (AA). The results showed that S2 and HI increased the FW, DW, and LA in both species. On the other hand, antioxidant compound contents were significantly increased by HI but did not vary with the spectrum.

Cover crops as a weed seed bank management tool: A soil down review

This review explores ways that cover crops alter soil environmental conditions that can be used to decrease seed survival, maintain weed seed dormancy, and reduce germination cues, thus reducing above-ground weed pressures. Cover crops are grown between cash crops in rotation, and their residues persist into subsequent crops, impacting weed seeds both during and after cover crops’ growth. Compared to no cover crop, cover crops may reduce weed seedling recruitment and density via: i) reducing soil temperature and fluctuations thereof; ii) reducing light availability and altering light quality; and iii) trapping nitrogen in the cover crop, thus making it less soil-available to weeds. In addition, cover crops may provide habitat for above- and below-ground fauna, resulting in increased weed seed predation. The allelopathic nature of some cover crops can also suppress weeds. However, not all effects of cover crops discourage weeds, such as potentially increasing soil oxygen. Furthermore, cover crops can reduce soil moisture while actively growing but conserve soil moisture after termination, resulting in time-dependent effects. Similarly, decaying legume cover crops can release nitrogen into the soil, potentially aiding weeds. The multiplicity of cover crop species and mixtures, differing responses between weed species, environmental conditions, and other factors hampers uniform recommendations and complicates management for producers. But, cover crops that are managed to maximize biomass, do not increase soil nitrogen, and are terminated at or after cash crop planting will have the greatest potential to attenuate the weed seed bank. There are still many questions to be answered, such as if targeting management efforts at the weed seed bank level is agronomically worthwhile. Future research on cover crops and weed management should include measurements of soil seed banks, including dormancy status, predation levels, and germination. Highlights - Cover crops alter the weed seed bank environment, influencing survival, dormancy, and germination. - Weed seed germination may be reduced by decreased temperature and fluctuations thereof, light, and soil nitrogen. - Weed seed germination may be increased by greater soil moisture, soil nitrogen, and oxygen. - Management should maximize cover crop biomass, decrease soil nitrogen, and delay termination for the greatest potential. - Future research should include measurements of weed seed banks, including dormancy status, predation, and germination.

Evaluation of the mulch films biodegradation in soil: a methodological review

Plastic mulch films are widely used in agriculture, but most are not biodegradable in soil. Biodegradable mulch films are blends of different polymers whose composition-ratios vary notably from one product to another. Their degradation rates vary greatly according to the physio-chemical characteristics of the product and according to the properties of the soil and its microbial activity. The objective of this review is to provide an overview of the methods used to estimate the biodegradation performances of biodegradable plastics in the soil. In line with this objective, 80 papers were selected and systematically analyzed to extract information on the characteristics of the soil used in the experiments, the type of polymer analyzed, and the methods used to estimate biodegradation in soil environment. Our systematic analysis showed that studies were carried out under both laboratory-controlled and open-field conditions, with different approaches involving visual analysis, mass loss measurements, spectroscopy, and CO2 measurements. A linear estimation of biodegradation performance for four of the most common biodegradable polymers (i.e., polybutylene succinate, polybutylene succinate-co-adipate, polylactic acid, and polybutylene adipate-co-terephthalate), either pure or blended, showed a very wide range of results that appear only partially comparable. Many of the analyzed papers did not report soil characteristics at all, despite soil being one of the most important factors in the biodegradation process. Although methodologies for estimating biodegradation are well developed, at least under laboratory-controlled conditions, there is a need for a shared methodology to make results comparable among different experiments. Within such a shared methodology, visual analysis or mass loss measurements, despite not being able to scientifically prove the biodegradation of polymers, should not be discarded a priori as they might be useful indicators especially for open field experiments. When using indirect biodegradation indicators such as visual analysis or mass loss, it is necessary to couple them with CO2 measurements or to use materials whose biodegradability in the soil environment has already been tested.

Genetic variability of some agronomic traits in a collection of wheat (Triticum turgidum L. ssp) genotypes under South Mediterranean growth conditions

Genetic variability of some agronomic traits were investigated in 60 tetraploid wheat accessions (Triticum turgidum L. ssp) under rainfed conditions. The results indicated the presence of sufficient variability for all measured traits.The highest phenotypic and genotypic coefficient of variation was recorded for yield and awn length. High heritability coupled with high genetic advance and high expected response to selection recorded for thousand-grain weight, awn length, and the number of grains per spike. Cluster analysis grouped the 60 wheat genotypes into five clusters. Clusters are relatively formed according to the geographical origin of the genotypes. Cluster III carried entries having the best combinations for all the traits; in which genotypes PI 127106, PI 192658, PI 29051 and PI67343 can represent an important reservoir of useful genes for the development of new wheat cultivars. Thousand-grain weight, biomass, awn length and harvest index could be used as a selection criterion for hybridization programs in the future. Highlights - The genetic variability of 9 traits of 60 wheat varieties was investigated. - There was great variability among wheat genotype for all measured traits. - There were wheat varieties shows highest phenotypic and genotypic coefficient of variation. - Some wheat genotypes may be desired allele reservoirs. - Some traits can be an alternative in wheat selection.

Variation in quality traits of newly developed Serbian wheat cultivars under different environmental conditions of Pannonian plain

Introduction of new high-yielding wheat cultivars and intensification of high year-to-year variability require an additional update of information about environmental effects on main wheat quality parameters that is lacking for newly released cultivars in Serbia. The aim of this study was to determine the effect of growing seasons on the technological properties of new Serbian wheat cultivars, and to examine the relationships among the quality traits in different growing seasons. The experiment was set up in three growing seasons (2016-17, 2017-18 and 2018-19). A total of 13 recently developed wheat cultivars in Serbia and five most widespread local cultivars were evaluated to compare differences in end-use quality. Also, the influence of climatic conditions on the technological quality was examined as well as relations among them. Modern Serbian cultivars have improved grain yield but lower technological quality than the widespread Serbian cultivars. Changes in farinograph resistance and degree of softening were related to the differences growing seasons, cultivars and their interaction, while growing seasons had the highest effect on bread volume and extensograph parameters energy and ratio resistance and extensibility variation. Moreover, a strong positive correlation was found between protein content, sedimentation value, wet gluten content and water absorption with extensograph extensibility, and negative correlation with the second parameter of extensograph, ratio of resistance and extensibility.

Integrated weed management: Tools and strategies in a world of pesticide restriction

Not available.

Predictive phytotoxic value of water-soluble allelochemicals in plant extracts for choosing a cover crop or mulch for specific weed control

Cover crops and mulches have become an alternative for soil management in vineyards due to the agronomic, environmental, and economic advantages, especially the possibility of weed control. Implicitly to this objective lies the idea of assessing the potential herbicide effect of the allelochemicals released by different cover crop and mulch species. With this objective, the present work evaluated the phytotoxic effects of 12 aqueous extracts of selected species with potential use as a cover crop or mulch: a Bromus species mixture (B. hordeaceus L. and B. rubens L.), Festuca arundinacea Schreb., Hordeum murinum L., H. vulgare L., Vulpia ciliata Dumort., Medicago rugosa Desr., M. sativa L., Trifolium subterraneum L., T. incarnatum L., Phacelia tanacetifolia Benth., Sinapis alba L., and Pinus sylvestris L.,on the germination and early growth of three troublesome weeds (Conyza bonariensis (L.) Cronquist, Aster squamatus (Spreng.) Hieron, and Bassia scoparia (L.) A. J.). The different in vitro bioassays showed that aqueous extracts of some species significantly inhibited or reduced germination and root and shoot growth of the target weed species in a dose-response manner. Germination of A. squamatus and C. bonariensis was reduced by 100-80% by the different extracts applied at 50% concentration, and completely blocked at 100% concentration, except for M rugosa extract to which both species showed less sensitivity. Root elongation of A. squamatus was absolutely inhibited under every extract and concentration, whereas C. bonariensis root growth showed only some tolerance to the crude extracts of F. arundinaceaand P. sylvestris. Bassia scoparia was relatively tolerant to the aqueous plant extracts, except for T. subterraneum crude extract, which reduced total germination by 80%; otherwise, B. scoparia showed higher general sensitivity of shoot growth than the other two weed species. The chemical profiles of phenolic compounds of the aqueous extracts were obtained and identified by HPLC-DAD, the phenolic profiles of H. murinum, V. ciliata, and M. rugosa being reported in this work for the first time. Using stepwise regression, the influence of certain phenolic compounds from the aqueous extracts on the germination and early growth of weeds was predicted. Among other significant compounds, the flavonoid naringenin identified in T. subterraneumaqueous extract at 8.09 µg·mL-1 was predicted to underlie its specific phytotoxicity on B. scoparia germination. These results support the use of cover crops and mulches in weed management and can help to select the most suitable species to adopt according to the target weed species. Highlights The phytotoxic nature of the aqueous extracts of twelve conventional and novel cover crops and mulch species was demonstrated on three troublesome weed species in vineyards. Phenolic acids and flavonoids of the twelve aqueous extracts were identified and quantified by HPLC-DAD, and, by regression analysis, some allelochemicals were postulated as responsible for the phytotoxic effects. The water-soluble phenolic profiles of three potential cover crops, namely Hordeum murinum, Vulpia ciliata, and Medicago rugosa, are reported for the first time. In vitro germination and early root growth of Conyza bonariensis and Aster squamatus were almost entirely restricted by any of the twelve plants' aqueous extracts and presumably by the joint action of their particular allelopathic compounds. Bassia scoparia germination was relatively much less sensitive to the extracts, except for Trifolium subterraneum, for which the flavonoid naringenin was predicted to underlie its specific phytotoxicity.

Retraction: Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model

To: Pier Paolo Roggero, Editor-in-Chief, Italian Journal of Agronomy, and Michele Moscato, PAGEPress Publications, Publisher We take note of your communication following the report by Dr. Paolo Bazzoffi regarding the copyright infringement of the paper ‘Effectiveness of the GAEC cross-compliance standard short-term measures for runoff water control on sloping land (temporary ditches and grass strips) in controlling soil erosion’ (Authors: Bazzoffi, Ciancaglini, Laruccia), that can be found at the following address: https://www.agronomy.it/index.php/agro/ article/view/ija.2011.6.s1.e3. The title of the retracted publication is: ‘Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model’ (Authors: Francaviglia, Neri), that can be found at the following address: https://www.agronomy.it/index. php/agro/article/view/1762). The undersigned authors thoroughly agree with the points raised by Dr. Paolo Bazzoffi in relation to the copyright infringement. In particular, we agree that the original paper ‘Effectiveness of the GAEC cross compliance standard short-term measures for runoff water control on sloping land (temporary ditches and grass strips) in controlling soil erosion’ was not clearly indicated as original data source in the paper ‘Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model’. We also recognize that we did not give credit to Dr. Paolo Bazzoffi of the original methodology, particularly: i) the original materials and methods; ii) the GIS elaboration; and iii) the original data and results. The authors declare that: - they considered the opportunity to review the data published by Dr. Bazzoffi et al. shown in Table 7 of their original publication after a data re-elaboration, as shown in Table 3 of the publication to be retracted, with the aim to provide a statistical comparison of erosion in hilly agricultural land among the Italian Regions, as well as introducing an evaluation of the weight of the parameters implemented in the RUSLE model using a multiple regression technique; - they are aware of not having adequately recognized the copyrights of Dr. Bazzoffi and co-authors Ciancaglini and Laruccia. For these reasons, and as requested, we retract the paper ‘Temporary ditches are effective in reducing soil erosion in hilly areas. An evaluation with the RUSLE model’ from publication. We apologize to Dr. Bazzoffi, Dr. Ciancaglini and Dr. Laruccia for the unpleasant inconvenience caused. We also take the opportunity to thank Dr. Paolo Bazzoffi for coordinating the EFFICOND and MONACO projects, in which we participated in various work packages, offering the possibility of a valuable and constructive work experience. Sincerely, Rosa Francaviglia and Ulderico Neri

Discovering genetic diversity of Changmaogu, a rice landrace, for conservation and rural development

Changmaogu is a very rare and endangered rice landrace cultivated in a very limited area by Lama people, a branch of Bai ethnic group in Lanping County, Yunnan, China. No study on this precious landrace had been reported. This study was intended to explore the genetic diversity so as to develop strategy for conserving Changmaogu. The Changmaogu samples were compared with other three varieties (Hejing 16, Nipponbare and Hongxiangmi), using 24 pairs of SSR markers. Among all varieties, Changmaogu showed the richest genetic diversity. Cluster analysis also showed that Changmaogu can be distinguished in the genetic distance of 0.68. These data suggested that landrace is of great significance for the selection of rice varieties under the harsh environment and the acquisition of parents in the breeding work. The high altitude, low temperature and complex microbial community may be the important factors of genetic diversity in Changmaogu. The influence of ‘agriculture-processing-marketing’ mode of landraces should be continuously tracked. The strategy for conservation and sustainable development of Changmaogu was proposed in the present paper. Highlights - Changmaogu, a very rare and endangered rice landrace cultivated in a very limited area by Lama people, has more abundant genetic diversity than the three compared cultivars-Hejing 16, Nipponbare and Hongxiangmi, which enables it to adapt to changing environmental conditions, ensures local food supply and agricultural economic development, and makes it an effective supplement to the rice gene pool. - The result of UPGMA clustering analysis based on genetic distance led to the formation of three clusters, which Changmaogu had further genetic distance compared with hybrid rice Hejing 16 and rice parents Nipponbare, further revealing the utilization potential of Changmaogu in crop breeding. - The genetic diversity of Changmaogu and Hongxiangmi was compared to reveal the important position of Changmaogu in the protection of landrace, and to explore the potential impact of commercial activities on the genetic diversity of landrace. - According to the case of Changmaogu, this paper puts forward reasonable and effective strategies for the protection, which can be derived and applied to the protection of other landraces.