Leaf Photosynthetic Characteristics of High-Yield Soybean[Glycine max(L.)Merr.]Under Different Planting Densities,Different Fertilization Rates,and Single/Mixed Planting Patterns

Understanding the photosynthetic characteristics of high-yield soybean[Glycine max(L.)Merr]cultivar(HYC)would aid research aiming at investigating the soybean high yield formation mechanism and optimization of cultivation system.To assess the photosynthesis of HYC,a pot experiment was conducted to quantify the differences in photosynthetic characteristics between HYC and common-yield soybean cultivar(CC)under different planting densities,fertilization rates,and single/mixed planting patterns.The leaf greenness(Lg),net photosynthetic rate(Ph),stomatal conductance(St)and transpiration rate(Tr)were significantly higher in HYC than CC mainly in seed-filling stages.HYC was more tolerant to dense and mixed planting because the decreases of Ph and St under high planting density and those of Ph,St,and Tr under mixed planting were lower in HYC than CC.The Lg and Ph in HYC were more superior to those in CC at high fertilization rate.Thus,the HYC has a superior performance in photosynthetic characteristics under the varied cultivation practices,which may contribute to the greater seed yield in HYC than CC.

Improving Soil Fertility with Different Planting Patterns in Rocky Desertification Areas

[Objectives]This study was conducted to investigate the effect of different planting patterns on soil improvement in rocky desertification areas.[Methods]The one-way ANOVA analysis method was used to statistically analyze the soil physical and chemical properties,enzyme activity,microbial quantity,CEC,ECEC,and aggregate content distribution with different planting patterns.[Results]The walnut+sesame+mung bean planting pattern showed the highest soil available phosphorus,available potassium,porosity,non-capillary porosity,and contents of free living nitrogen-fixing bacteria,organophosphate-dissolving bacteria,bacteria,fungi and actinomycetes,at 63.2 mg/kg,178.8 mg/kg,22.85%,6.89%,10.0×10^6 bacteria/g,18.0×10^6 bacteria/g,21.0×10^5 CFU/g,5.7×10^3 CFU/g and 7.9×10^5 CFU/g,respectively,and it reduced soil bulk density(the same as treatment F and treatment E)compared with other planting patterns.The walnut+American chicory+sweet potato planting pattern had the highest alkali-hydrolyzale nitrogen,organic matter,CEC,ECEC,water-air ratio and moisture content,which were 227.9 mg/kg,46.30 g/kg,36.38 cmol/kg,24.00 cmol/kg,8.13,and 32.89%,respectively,and it reduced soil bulk density,increased capillary porosity,acid phosphatase,and contents of bacteria and actinomycetes compared with single cropping of walnut.[Conclusions]Interplanting crops under walnut forests is an effective measure to improve the ecological environment of rocky desertification farmland.

Elevational patterns of warming effects on plant community and topsoil properties: focus on subalpine meadows ecosystem

Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.

From statistics to grids:A two-level model to simulate crop pattern dynamics

Crop planting patterns are an important component of agricultural land systems.These patterns have been significantly changed due to the combined impacts of climatic changes and socioeconomic developments.However,the extent of these changes and their possible impacts on the environment,terrestrial landscapes and rural livelihoods are largely unknown due to the lack of spatially explicit datasets including crop planting patterns.To fill this gap,this study proposes a new method for spatializing statistical data to generate multitemporal crop planting pattern datasets.This method features a two-level model that combines a land-use simulation and a crop pattern simulation.The output of the first level is the spatial distribution of the cropland,which is then used as the input for the second level,which allocates crop censuses to individual gridded cells according to certain rules.The method was tested using data from 2000 to 2019 from Heilongjiang Province,China,and was validated using remote sensing images.The results show that this method has high accuracy for crop area spatialization.Spatial crop pattern datasets over a given time period can be important supplementary information for remote sensing and thus support a wide range of application in agricultural land systems.

Effects of Planting Methods on Levels of Common Pesticides and Heavy Metals in Dendrobium officinale

The levels of common pesticides and heavy metals in Dendrobium officinale grown from 2012 to 2014 were measured, and three planting methods were used in 2014. The quality of plant husbandry improved during the study period. Thirteen types of pesticides were detected in D. officinale grown in 2014 and antimicrobials, including carbendazim, difenoconazole and azoxystrobin, were evident in 61.53% of plants. These three pesticides constituted 72.33% of all the antimicrobials detected. Planting methods affected the levels of pesticides and heavy metals. Trellising in plastic sheds was optimal, being associated with the lowest amounts of both pesticides and heavy metals. Both cadmium(Cd) and lead(Pb) levels were high in treed plants, whereas Cr, As and Cu levels were the highest in potted plants.

Impacts of Rice Field Winter Planting on Soil Organic Carbon and Carbon Management Index

To tackle with the problem of prevailing farmland abandonment in winter,5 treatments includes Chinese milk vetch-double cropping rice(CRR),rape-double cropping rice(RRR),garlic-double cropping rice(GRR),winter crop multiple cropping rotation(ROT),winter fallow control(WRR)were set up.By measuring soil total organic carbon,active organic carbon and its components and calculating the soil carbon pool management index in 0~15 cm and 15~30 cm soil layers in the early and late rice ripening stage.The effects of different winter planting patterns on the changes of soil organic carbon and carbon pool management index were discussed.In order to provide theoretical basis for the optimization and adjustment of winter planting pattern of double cropping rice field in the middle reaches of Yangtze River.The results showed that soil total organic carbon,active organic carbon and its components in different winter cropping patterns were increased,and ROT and CRR treatments were more beneficial to the accumulation of soil total organic carbon,active organic carbon and its components as well as the improvement of soil carbon pool management index,which should be preferred in the adjustment of cropping patterns.