Comparative study of pyrochar and hydrochar on peanut seedling growth in a coastal salt-affected soil of Yellow River Delta, China.

Biochar (i.e., pyrochar and hydrochar) application is a promising strategy to improve soil quality and productivity. However, the comparison of biochars with different carbonization methods and feedstocks for the plant growth in the coastal salt-affected soil remains limited. In this study, a 30-day microcosmic experiment was conducted to compare the effects of pyrochars and hydrochars derived from reed straw (RPC and RHC) and cow manure (CPC and CHC) on the peanut (Arachis hypogaea L.) seedling growth in a coastal salt-affected soil of Yellow River Delta, China. The results showed that RPC, CHC and CPC significantly elevated fresh shoot weight by 67.77%-89.37%, whereas the RHC amendment showed little effect. The malondialdehyde contents in peanut seedling leaves were significantly declined by 25.28%-35.51% with pyrochar and hydrochar amendments, which might be associated with the enhanced proline contents and K/Na ratios. The stimulation of certain phytohormones (i.e., indole-3-acetic acid, zeatin riboside, gibberellic acid 3) in peanut seedlings with pyrochar and hydrochar amendments might be attributed to the growth enhancement. RPC, CPC and CHC improved the soil properties and fertility such as cation-exchange capacity (CEC), total nitrogen, and available potassium and water holding capacity (WHC) of the coastal salt-affected soil. However, RHC not only significantly decreased soil CEC and WHC, but also increased soil exchangeable sodium percentage. The abundances of soil beneficial bacteria, such as f_Gemmatimonadacea, Sphingomonas, Blastococcus and Lysobacter were enhanced by RPC, CHC and CPC amendments, which were mainly associated with the increased WHC and CEC. Fungal community was less sensitive to pyrochar and hydrochar amendments than bacterial community according to the relative abundance and diversity, and beneficial fungi, such as Oidiodendron and Sarocladium were enriched in the CHC soil. Overall, the application of RPC, CHC and CPC showed greater potentials for the enhancement of peanut growth in a coastal salt-affected soil.

Effect of biochar and hydrochar from cow manure and reed straw on lettuce growth in an acidified soil.

Soil acidification has become a major environmental and economic concern worldwide. Char materials (e.g biochar, hydrochar) have attracted considerable attention as soil amendments to restore degraded soil. However, the comparative study of biochar and hydrochar on plant growth in acidified soil is limited. In this study, a microcosmic experiment was used to compare the effect of biochar and hydrochar from cow manure (CBC, CHC) and reed straw (RBC, RHC) on the growth of lettuce in the acidified soil. CBC and RHC significantly increased and decreased the biomass of lettuce by 18.7% and 32.5% in the acidified soil, respectively. The increase of the lettuce growth by CBC primarily attributed to the enhancement of soil properties (SOM and pH) and soil nutrient content (Olsen-P, K, Ca, Mg, Zn, Fe and Mn). Moreover, CBC enhanced the microbial activity and complexity and increased the abundance of beneficial genera like Gemmatimonas, Ramlibacter and Haliangium, which improved soil health and might indirectly benefited the lettuce growth. Our findings highlighted the priority of char materials feedstock and preparation technology for remediating the acidified soil.

Preparation and characterization of biochar derived from co-pyrolysis of Enteromorpha prolifera and corn straw and its potential as a soil amendment.

Single biomass feedstock approach may not meet the requirements for developing biochar with desired characteristics for use as soil amendment. In this study, biochars were prepared by co-pyrolysis of nutrients-rich Enteromorpha prolifera and lignocellulose-rich corn straw (CPECs) at different mass ratios (3:7, 1:1, and 7:3). CPECs presented higher water-soluble N/P contents than corn straw biochar, and exhibited larger surface area, low Na content, and slower nutrient release rate than Enteromorpha prolifera biochar. The modification in physicochemical and properties of CPECs enhanced its potential application as a soil amendment. A pot experiment showed that CPECs derived from co-pyrolysis of appropriate ratios of Enteromorpha prolifera and corn straw (1:1, 7:3) significantly increased the biomass of cherry tomato plant by 64.05%, 40.03% and 81.88%, 55.25%, when compared with corn straw biochar and Enteromorpha prolifera biochar, respectively. The positive effects of CPECs were primarily attributed to improved soil properties (e.g., water holding capacity, soil organic matter, pH, soil nutrients content) and increased total N/P uptake by plants. The results of this work provided potentials of developing "designer" biochars to meet the multiple soil requirements by co-pyrolysis.

Biochar decreased enantioselective uptake of chiral pesticide metalaxyl by lettuce and shifted bacterial community in agricultural soil.

A 35-day microcosmic experiment was conducted with lettuce (Lactuca sativa L.) and two metalaxyl (MET) enantiomers (R-MET and S-MET) to understand the roles of biochar in the enantioselective fate of chiral pesticides in soil-plant ecosystems. Wood waste-derived biochar (WBC) amendment effectively decreased the shoot concentrations of R-MET/S-MET and their metabolites R-MET/S-MET acid by 57.7-86.3% and 13.3-32.5%, respectively. The reduced uptake was mainly attributed to the decreased bioavailability of R-MET and S-MET. A lower fraction of R-MET was accumulated by the lettuce in the WBC-amended soils relative to the control, suggesting a decrease in the enantioselective uptake of the chiral pesticide MET in the presence of biochar. Regardless of the WBC amendment, no enantiomerization of MET or MET acid occurred. The application of WBC stimulated soil bacterial diversity, shifted the bacterial community, and enhanced the abundance of pesticide degrading bacteria (e.g., Luteimonas, Methylophilus, and Hydrogenophaga), which were responsible for the enantioselective degradation of MET in the soil. This work expands our understanding of the enantioselective fate of chiral pesticides in the biochar-amended soil ecosystems. These findings can be used to develop biochar-based technologies to remediate soils contaminated with these chiral pesticides to ensure food safety.

Biochar and fertilizer improved the growth and quality of the ice plant (Mesembryanthemum crystallinum L.) shoots in a coastal soil of Yellow River Delta, China.

Coastal soil is an important land reserve that may be used to alleviate the shortage of cultivated land; however, this soil is stressed by saline conditions and nutrient deficiency. Biochar offers the potential to reclaim coastal soil, but the response of plant growth to biochar addition in salt-affected soil is species-dependent. In this study, the response of ice plant (Mesembryanthemum crystallinum L.), an economically valuable halophyte that grows in the coastal soil of the Yellow River Delta, to wood chip biochar (WBC) either alone or in combination with chemical fertilizer was investigated using a 90-day pot experiment. The WBC enhanced the growth of ice plants in the coastal soil, but combining it with chemical fertilizer did not increase its effect. The nutritional quality of the plants was improved by the addition of WBC, regardless of whether chemical fertilizer was applied; moreover, WBC amendment enhanced photosynthesis and reduced the oxidative stress of the plants. The ameliorated soil properties (e.g., soil organic matter and water holding capacity) and increased contents of available macronutrients (e.g., P and K) and micronutrients (e.g., Mg, Mn, B and Zn) resulting from soil amendment with WBC may have contributed to the enhanced growth and quality of the ice plants. Additionally, in soil modified with WBC, an increased abundance of beneficial taxa (e.g., Erythrobacter, Sphingomonas and Lysobacter) and a shift in the microbial community may also have helped to improve the growth and quality of the ice plants. The results of our study provide useful information for developing a biochar-based technology to use in combination with valuable halophytes to reclaim degraded coastal soil and enhance food security.

The Effect of Grain Position on Genetic Improvement of Grain Number and Thousand Grain Weight in Winter Wheat in North China.

Genetic improvements have significantly contributed to wheat production. Five wheat cultivars-widely grown in north China in the 1950s, 1990s, or 2010s-were grown in field experiments conducted in the 2014-2015 and 2015-2016 growing seasons. This study evaluated the genetic progress in wheat grain yield and its related traits in north China and explored how breeding and selection have influenced grain numbers and weights within spikelets in the past 60 years. The results showed that the significant increases in grain yield in the past 60 years were mainly due to increases in grain number per spike and grain weight, while spike number per m2 has not changed significantly. Improvements in thousand grain weight (TGW) from the 1950s to 2010s have occurred at four grain positions (G1 to G4). The relative contribution of G4 to TGW increased over time, but was much less than the contributions of G1, G2, and G3. Indeed, the average grain weight at G4 was much less than that of 1000 grains. The increase in grain number per spike since the 1950s was mainly due to an increase in grain number at G1, G2 and G3, with the relative contribution of grain position to grain number being G1 > G2 > G3 > G4. Dwarfing genes increased grain number per spike and grain number at G3 and G4, but not TGW. In future, yields could be boosted by enhancing grain weight at G4 and grain number at G3 and G4, while maintaining those at G1 and G2.