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Grasslands, a vital ecosystem and component of the global carbon cycle, play a significant role in evaluating ecosystem health and monitoring the global carbon balance. In this study, based on the Carnegie–Ames–Stanford Approach (CASA) model, we estimated the Net Primary Productivity (NPP) of grasslands in northern Shaanxi from 2000 to 2020. Employing trend analysis, stability analysis, multiple regression analysis, and residual analysis, the research examined the dynamic changes of grassland NPP and its response to climatic and human factors. Key findings include: (1) Grassland NPP showed a significant increasing trend during 2000–2020, with high-coverage grasslands showing a higher rate of increase than medium and low-coverage grasslands. (2) Most grasslands (>90%) exhibited unstable growth and high NPP fluctuation. (3) While temperature, precipitation, and radiation undulate, the trends were not significant. Rainfall and radiation emerged as dominant factors affecting NPP, with temperature suppressing NPP increase to some extent. (4) Policies like returning farmland to grassland had a positive impact on grassland recovery, vegetation productivity, and regional ecosystem health. [ABSTRACT FROM AUTHOR]

Grasslands, a vital ecosystem and component of the global carbon cycle, play a significant role in evaluating ecosystem health and monitoring the global carbon balance. In this study, based on the Carnegie–Ames–Stanford Approach (CASA) model, we estimated the Net Primary Productivity (NPP) of grasslands in northern Shaanxi from 2000 to 2020. Employing trend analysis, stability analysis, multiple regression analysis, and residual analysis, the research examined the dynamic changes of grassland NPP and its response to climatic and human factors. Key findings include: (1) Grassland NPP showed a significant increasing trend during 2000–2020, with high-coverage grasslands showing a higher rate of increase than medium and low-coverage grasslands. (2) Most grasslands (>90%) exhibited unstable growth and high NPP fluctuation. (3) While temperature, precipitation, and radiation undulate, the trends were not significant. Rainfall and radiation emerged as dominant factors affecting NPP, with temperature suppressing NPP increase to some extent. (4) Policies like returning farmland to grassland had a positive impact on grassland recovery, vegetation productivity, and regional ecosystem health.

Soybean (Glycine max (L.) Merr.) is a typical short-day and thermophilic crop. This study aimed to reveal the required accumulative day length (ADL) and accumulative active temperature (AAT) for DSF (days of sowing to flowering) and DFM (days of flowering to maturity) in global soybeans. A sample consisted of 354 varieties from 27 countries in five geographic regions, which were tested in Nanjing, China in two spring-sowing and two summer-sowing seasons. The ADL and AAT were calculated from the climatological data provided by the Public Service of Nanjing Meteorological Bureau. The results showed that the average DSF and DFM of global soybeans were 41.0 d and 83.3 d, which required ADLDSF of 606.6 d·h and AATDSF of 1185.9 d·°C, ADLDFM of 1126.7 d·h and AATDFM of 2145.1 d·°C, respectively, all with a wide variation among/within geographic and MG(maturity-group)-set subpopulations. From the multiple regression of DSF and DFM on required ADL and AAT, the ADL, AAT and ADL×AAT contributed 38.5%, 44.79% and 17.10% to DSF variation and 86.98%, 11.42% and 0.54% to DFM variation, respectively, and their relative importance to DSF and DFM varied among the geographic and MG subpopulations. The geographic subpopulations matched only partially with the genomic marker clusters, indicating multiple genetic sources of each subpopulation and that genetic exchange happened among subpopulations. [ABSTRACT FROM AUTHOR]

Soybean (Glycine max (L.) Merr.) is a typical short-day and thermophilic crop. This study aimed to reveal the required accumulative day length (ADL) and accumulative active temperature (AAT) for DSF (days of sowing to flowering) and DFM (days of flowering to maturity) in global soybeans. A sample consisted of 354 varieties from 27 countries in five geographic regions, which were tested in Nanjing, China in two spring-sowing and two summer-sowing seasons. The ADL and AAT were calculated from the climatological data provided by the Public Service of Nanjing Meteorological Bureau. The results showed that the average DSF and DFM of global soybeans were 41.0 d and 83.3 d, which required ADLDSF of 606.6 d·h and AATDSF of 1185.9 d·°C, ADLDFM of 1126.7 d·h and AATDFM of 2145.1 d·°C, respectively, all with a wide variation among/within geographic and MG(maturity-group)-set subpopulations. From the multiple regression of DSF and DFM on required ADL and AAT, the ADL, AAT and ADL×AAT contributed 38.5%, 44.79% and 17.10% to DSF variation and 86.98%, 11.42% and 0.54% to DFM variation, respectively, and their relative importance to DSF and DFM varied among the geographic and MG subpopulations. The geographic subpopulations matched only partially with the genomic marker clusters, indicating multiple genetic sources of each subpopulation and that genetic exchange happened among subpopulations.

Economic and environmental concerns limit peat use for substrate production, promoting interest in alternative materials. Hence, in this study, 16 substrates were obtained by mixing, in a factorial combination, eight substrates with different ratios of peat, rice hulls (RH), and anaerobic digestion residues (ADR) and two types of RH: whole (WRH) or ground RH (GRH). Substrates were physically and chemically characterized and then tested as potting substrates for Pelargonium peltatum ‘Ville de Paris’ and Rosa × hybrida ‘La Sevillana’ production. Physical characteristics worsened the increasing RH content. This problem was partly solved using GRH and adding ADR to the substrates. As for chemical characteristics, RH increased P and K, reducing cation exchange capacity, NO3-N, and Ca, thus causing a possible nutritional imbalance. ADR addition increased all nutrients, restoring the nutritional balance. Geranium and rose plants were negatively affected by an increasing rate of RH. In both species, the use of GRH improved the considered parameters, whereas ADR improved some parameters but only in geranium. It was possible to partly substitute peat with 33% RH, but GRH plus ADR is necessary for geranium production, and facultative for rose. The multiple regression method and principal component analysis appear to be useful tools to understand which substrate parameters, and to what extent, influence the growth of ornamental plants.

Through field experiments and empirical analysis methods, this study determined the dependence of plant residue removal on the row cleaner’s settings in strip-tillage. The main research object of this study is row cleaners. By changing the slip angles (10, 15, and 22.5°), the gap between row cleaner discs in parallel (165, 180, and 195 mm), and the driving speed (1.3, 1.9, 2.5, and 3.1 m s−1), we determined what percentage of wheat residue was removed from the strip on the surface of the soil and what distance it was moved. The percentage of removed plant residue was determined by evaluating the differences between the masses of the plant residue taken from non-removed and removed strips. Empirical analysis of the results of the field experiments showed that both the amount of the removed plant residue and the distance it is moved to were the best when the slip angle was 15°, the gap between the discs of row cleaner was 180 mm, and the driving speed was 2.5 m s−1. With these parameters, up to three-quarters of the plant residue was removed from the soil surface of the strip, which was relocated 308 mm from the middle of the strip. If the slip angle and the driving speed are increased further, even more plant residue can be removed; however, if the plant residue is relocated too far away, it may fall into the zone of the adjacent strip.

This work presents quantitative changes of nickel in soil and plants under the influence of compost and fly ash. The research was carried out in a 3-year experiment on medium soil fertilised with compost or fly ash. The plants: narrow leaf lupine (Lupinus angustifolius L.), camelina (Camelina sativa L.), and oat (Avena sativa L.) were planted in consecutive years. The soil from the experiment was subjected to extraction by sequential analysis with the Community Bureau of Reference (BCR) method, and single extractions using 1 mol·dm−3 HCl and DTPA solutions, obtaining the amount of nickel in various combinations with the soil solid phase. Total contents of the metal in soil and cultivated plants were determined. On the basis of Ni contents in the soil and cultivated plants, the bioconcentration factors and the risk assessment code were calculated. The type of amendments had a significant impact on the nickel content in lupine, for camelina and oat was the greatest in the control conditions. The differences between the amounts of Ni determined for bioconcentration factors were significant and depended on the amendments and nickel obtained by different methods. Regardless of the experimental conditions, the amount of Ni in the exchangeable bonds (Fr. I) had the greatest impact on the content of Ni in lupine and oat, whereas NiDTPA in the case of camelina. [ABSTRACT FROM AUTHOR]

Economic and environmental concerns limit peat use for substrate production, promoting interest in alternative materials. Hence, in this study, 16 substrates were obtained by mixing, in a factorial combination, eight substrates with different ratios of peat, rice hulls (RH), and anaerobic digestion residues (ADR) and two types of RH: whole (WRH) or ground RH (GRH). Substrates were physically and chemically characterized and then tested as potting substrates for Pelargonium peltatum 'Ville de Paris' and Rosa × hybrida 'La Sevillana' production. Physical characteristics worsened the increasing RH content. This problem was partly solved using GRH and adding ADR to the substrates. As for chemical characteristics, RH increased P and K, reducing cation exchange capacity, NO3-N, and Ca, thus causing a possible nutritional imbalance. ADR addition increased all nutrients, restoring the nutritional balance. Geranium and rose plants were negatively affected by an increasing rate of RH. In both species, the use of GRH improved the considered parameters, whereas ADR improved some parameters but only in geranium. It was possible to partly substitute peat with 33% RH, but GRH plus ADR is necessary for geranium production, and facultative for rose. The multiple regression method and principal component analysis appear to be useful tools to understand which substrate parameters, and to what extent, influence the growth of ornamental plants. [ABSTRACT FROM AUTHOR]

Through field experiments and empirical analysis methods, this study determined the dependence of plant residue removal on the row cleaner's settings in strip-tillage. The main research object of this study is row cleaners. By changing the slip angles (10, 15, and 22.5°), the gap between row cleaner discs in parallel (165, 180, and 195 mm), and the driving speed (1.3, 1.9, 2.5, and 3.1 m s−1), we determined what percentage of wheat residue was removed from the strip on the surface of the soil and what distance it was moved. The percentage of removed plant residue was determined by evaluating the differences between the masses of the plant residue taken from non-removed and removed strips. Empirical analysis of the results of the field experiments showed that both the amount of the removed plant residue and the distance it is moved to were the best when the slip angle was 15°, the gap between the discs of row cleaner was 180 mm, and the driving speed was 2.5 m s−1. With these parameters, up to three-quarters of the plant residue was removed from the soil surface of the strip, which was relocated 308 mm from the middle of the strip. If the slip angle and the driving speed are increased further, even more plant residue can be removed; however, if the plant residue is relocated too far away, it may fall into the zone of the adjacent strip. [ABSTRACT FROM AUTHOR]