Wei Ren

Soil phosphorus (P) limitation in karst areas has severely constrained soil quality and land productivity. To enhance silage maize yield and quality and alleviate and/or balance the low phosphorus availability in the karst areas of China, the experiment investigated the effects of different tillage and residue retention practices on silage maize yield and quality and soil phosphorus in this region. The treatment set included: conventional tillage (CT), conventional tillage and root stubble retention (CTH), conventional tillage and mulch (CTM), conventional tillage and crushing and incorporation of hairy vetch by tillage (CTR), no tillage (NT), no tillage and root stubble retention (NTH), no tillage and mulch (NTM), and no tillage and living mulch (NTLM). The results showed that CTM, NTM, CTR, and NTLM significantly increased the height and LAI of silage maize compared with the CT, NT, and NTH treatments. CTM, CTR, and NTM significantly enhanced maize yield. Compared with conventional tillage, not tilling had a more pronounced improvement in silage quality, whereas residue retention hardly affected corn quality. In addition, although not tilling does not significantly increase acid phosphatase activity, it appeared to be advantageous in increasing soil microbial phosphorus and available phosphorus content when combined with cover crop measures. Ultimately, we concluded that NTM and NTLM are beneficial for silage maize yield and quality and soil phosphorus content in karst areas and verified the advantages of combining no tillage and residue retention practices for silage maize production and soil phosphorus improvement in the karst areas of China.

Cyperus esculentus is highly adaptable to extremely arid conditions and functions of oil extraction and sand fixation. Numerous studies have investigated the influence of row spacing on traditional crop growth and soil physicochemical traits but have not determined how cultivation affects C. esculentus growth and soil properties. Therefore, we conducted a field experiment in a sandy land to explore the responses of the organ yields of C. esculentus, soil wind erosion, and soil properties to row spacing (30, 60, or 90 cm), and bare land was used as the control. The highest plant height, plant density, number of tillers, and organ yields were observed at 30 cm row spacing. However, the lowest degree of soil erosion was also observed at 30 cm row spacing, and the coverage of C. esculentus facilitated soil fixation and conservation. The levels of soil wind erosion in the control plot were 11.7, 3.1, and 4.9 times those at 30, 60, and 90 cm row spacing, respectively. The percentages of clay and silt increased, whereas sand particles decreased with decreasing levels of soil wind erosion. Soil texture improved, and soil nutrients and plant growth were altered. Soil nutrient concentrations, yields, and root nutrient concentrations were positively related to clay percentage and negatively related to sand particles. In addition, the microbial biomass carbon and nitrogen significantly increased in the C. esculentus treatment groups, suggesting that planting C. esculentus promotes the survival and development of microorganisms. Overall, this study indicated that planting C. esculentus can decrease the level of soil wind erosion and improve soil quality. Narrow row spacing (30 cm) has the highest crop yield and soil amelioration and produces optimal ecological and economic benefits.

Carex laevissima Nakai 1914 (Cyperaceae) is vital for ecological conservation and land virescence, and has high ornamental value. Here the chloroplast genome of Carex laevissima was assembled and systematically analyzed for further genetic research of Carex plants. The chloroplast sequence of Carex laevissima was 188,029 bp in length, including two inverted repeat (IR) regions of 36,699 bp each, a large single-copy (LSC) region of 106,171 bp and a small single-copy region (SSC) of 8460 bp. The overall GC content is 34.0%. It contains 133 genes, including 89 protein-coding, 36 tRNA, and eight rRNA genes. Phylogenetic analysis showed that Carex laevissima is most closely related to Carex neurocarpa.

Tiger nut (Cyperus esculentus L.) has recently attracted increasing interest from scientific and technological communities because of its potential for serving as additional source of food, oil, and feed. The present study reports morphology and biochemical characterization of 42 tiger nut accessions collected from China and other counties performed in the 2020 and 2021 growing seasons at Nongan, Jilin Province. Assessment of variability of 14 agronomic traits including plant height, maturation, leaf width, tilling number, color, size, and shape: 100-tuber weight showed a wide range of phenotypic variation. The color, size, and shape and maturation of the tubers, as well as the leaf width, were the most distinct characteristics describing variation among the accessions. Compositional analyses of major nutritional components of the tubers reveals that this crop could be a source of high-value proteins, fatty acids, and carbohydrates. Specifically, tiger nut tubers contained high levels of starch, oil, and sugars, and significant amounts of fiber, Ca, P, and Na. Furthermore, the tubers appeared to be a good source of proteins as they contain 16 amino acids, including the essential ones. Amino acid profiles were dominated by aspartic acid followed by glutamic acid, leucine, alanine, and arginine. Overall, these results demonstrated that tiger nut is well adapted to the temperature and light conditions in the north temperate zone of China, even with a shorter growth season. The tiger nut accessions collected here exhibited wide variations for agronomical and biochemical traits, suggesting potential for potential for breeding improvement by maximizing the fresh tuber and grass yield based on the optimal selection of genetic characteristics in climate and soil conditions of northern China.

Cyperus esculentus produces large amounts of oil as one of the main oil storage reserves in underground tubers, making this crop species not only a promising resource for edible oil and biofuel in food and chemical industry, but also a model system for studying oil accumulation in non-seed tissues. In this study, we determined the chloroplast genome sequence of the cultivated C. esculentus (var. sativus Boeckeler). The results showed that the complete chloroplast genome of C. esculentus was 186,255 bp in size, and possessed a typical quadripartite structure containing one large single copy (100,940 bp) region, one small single copy (10,439 bp) region, and a pair of inverted repeat regions of 37,438 bp in size. Sequence analyses indicated that the chloroplast genome encodes 141 genes, including 93 protein-coding genes, 40 transfer RNA genes, and 8 ribosomal RNA genes. We also identified 396 simple-sequence repeats and 49 long repeats, including 15 forward repeats and 34 palindromes within the chloroplast genome of C. esculentus. Most of these repeats were distributed in the noncoding regions. Whole chloroplast genome comparison with those of the other four Cyperus species indicated that both the large single copy and inverted repeat regions were more divergent than the small single copy region, with the highest variation found in the inverted repeat regions. In the phylogenetic trees based on the complete chloroplast genomes of 13 species, all five Cyperus species within the Cyperaceae formed a clade, and C. esculentus was evolutionarily more related to C. rotundus than to the other three Cyperus species. In summary, the chloroplast genome sequence of the cultivated C. esculentus provides a valuable genomic resource for species identification, evolution, and comparative genomic research on this crop species and other Cyperus species in the Cyperaceae family.