The effect of tillage systems on phosphorus distribution and forms in rhizosphere and non-rhizosphere soil under maize (Zea mays L.) in Northeast China

Effects of Rotary and Deep Tillage on Soil Environment and Melon Root Development

Tillage practices significantly influence crop yield and soil quality. This study investigated the impact of rotary tillage (RT) and deep tillage (DT) on soil properties, microbial diversity, and melon (Cucumis melo L.) root growth and yield. RT involved breaking up the topsoil to a depth of 15 cm using a rotary tiller, while DT employed a rotary tiller followed by a moldboard plow to turn the soil layer over to a depth of 35 cm. The melon variety "Nasimi" was used as the material. Our findings revealed a remarkable response of soil phosphorus to tillage practices. High-throughput sequencing results revealed a significant impact of tillage practices on the soil fungal composition, richness, and diversity but little impact on the bacterial communities. Compared to RT, DT markedly enhanced melon root length, root surface area, root volume, and mean root diameter by 47.42%, 56.70%, 58.83%, and 27.28%, respectively. Additionally, DT treatments significantly increased melon yield (53.46%) compared to RT. The results indicate that DT improves soil nutrient availability, affects soil fungal community characteristics, and optimizes root distribution in soil, thereby improving melon yield. The findings offer valuable theoretical insights for the implementation of effective tillage practices in open-field melon cultivation.

Influence of tillage and residue management practices on productivity, sustainability, and soil biological properties of rice-barley cropping systems in indo-gangetic plain of India

Introduction

Conservation agriculture is a sustainable system of farming that safeguard and conserves natural resources besides enhancing crop production. The biological properties of soil are the most sensitive indicator to assess the short term impact of management practices such as tillage and residue incorporation.

Methods

Nine treatments of tillage and residue management practices [Reduced till direct seeded rice-zero till barley (RTDSR–ZTB); RTDSR–ZTB–green gram residue (Gg); Zero till direct seeded rice–zero till barley–zero till green gram (ZTDSR–ZTB–ZTGg); RTDSR–ZTB + rice residue at 4 t ha 1 (RTDSR–ZTBRR4); RTDSR–ZTBRR6; un-puddled transplanted rice (UPTR)–ZTB–Gg; UPTR–ZTBRR4; UPTR–ZTBRR6, and puddled transplanted rice (PTR)–RTB] executed under fixed plot for five years on crop productivity and soil biological properties under rice-barley production system.

Results

The shifting in either RTDSR or ZTDSR resulted in yield penalty in rice compared to PTR. The PTR recorded highest pooled grain yield of 3.61 ha−1. The rice grain yield reduced about 10.6% under DSR as compared to PTR. The ZTB along with residue treatments exhibited significantly higher grain yield over ZTB, and the RTDSR-ZTBRR6 registered highest pooled grain yield of barley. The system productivity (12.45 t ha−1) and sustainable yield index (0.87) were highest under UPTR-ZTBRR6. Biological parameters including microbial biomass carbon, soil respiration, microbial enzymes (Alkaline phosphatase, nitrate reductase and peroxidase), fluorescein diacetate hydrolysis, ergosterol, glomalin related soil proteins, microbial population (bacteria, fungi and actinobacteria) were found to be significantly (p < 0.05) effected by different nutrient management practices. Based on the PCA analysis, Fluorescein diacetate hydrolysis, microbial biomass carbon, soil respiration, nitrate reductase and fungi population were the important soil biological parameters indicating soil quality and productivity in present experiment. The results concluded that UPTR-ZTBRR6 was a more suitable practice for maintaining system productivity and soil biological health.

Discussion

The understanding of the impact of different tillage and residue management practices on productivity, soil biological properties and soil quality index under rice-barley cropping system will help in determining the combination of best conservation agriculture practices for improved soil quality and sustainable production.

Role of Agricultural Management in the Provision of Ecosystem Services in Warm Climate Vineyards: Functional Prediction of Genes Involved in Nutrient Cycling and Carbon Sequestration

(1) Background: Maintaining soil fertility and crop productivity using natural microbial diversity could be a feasible approach for achieving sustainable development in agriculture. In this study, we compared soils from vineyards under organic and conventional management by predicting functional profiles through metagenomic analysis based on the 16S rRNA gene. (2) Methods: The structure, diversity and predictive functions of soil bacteria related to the biogeochemical cycle of the soil were analyzed, including oxidative and hydrolytic C-cycling enzymes, N-cycling enzymes and P-cycling enzymes. The inter-row spontaneous vegetation in the organic vineyards was also characterized. (3) Results: A clear effect of the farming system (organic vs. conventional) and cover management (herbicides plus tillage, mowing only and mowing plus tillage) on bacterial beta diversity and predicted functions was evidenced. While conventional viticulture increased the potential capacity of the soil to regulate the cycling of inorganic forms of N, organic viticulture in general enhanced those functions involving organic N, P and C substrates. Although the soil bacterial community responded differently to contrasting soil management strategies, nutrient cycling and carbon sequestration functions remained preserved, suggesting a high bacterial functional redundancy in the soil in any case. However, most of the predicted bacterial functions related to soil organic matter turnover were enhanced by organic management. (4) Conclusions: We posit the potential for organic viticulture to adequately address climate change adaptation in the context of sustainable agriculture.

Agricultural soil physico-chemical parameters and microbial abundance and diversity under long-run farming practices: A greenhouse study

The growth of agriculture led to indiscriminate use of synthetic pesticides or fertilizers and unsustainable crop management farming practices which can aggravate harmful impacts on the microbial population and physical and chemical characteristics of soil ecosystem. Based on this fact, the present study was planned to evaluate the effect of long run farming practices on different soil physico-chemical parameters and soil microbial abundance and diversity within different soil depth (0–20 cm and 20–40 cm) at Quzhou Experimental Station of China Agricultural University, Hebei, China during October and December, 2016. The effect of farming practices on soil microbial abundance and diversity was studied by phospho-lipid fatty acid (PLFA) and DNA high-throughput sequencing methods. The findings revealed that soil is neutral to slightly alkaline in nature with highest water content under organic farming (ORF) at 0–20 cm and least under conventional farming at 20–40 cm depth. It was found that the ORF significantly increased the contents of total organic carbon (TOC), total carbon (TC), ammonium nitrogen, available nitrogen (AN), total nitrogen (TN), total phosphorus (TP), and available phosphorus (AP) followed by low input and conventional farming modes in both October and December soil samples. The correlation analysis showed significantly (at p ≤ 0.05 and 0.01) strong positive relationship within different physical and chemical properties of the soil under study. ANOVA and MANOVA analysis indicated significant effect of interaction between soil depth and farming modes on soil parameters. PCA analysis showed the most significant correlation between most of the bacterial types (G + bacteria, G− bacteria, actinomycetes) and soil AP, total available nitrogen, TOC and soil WC. Pearson correlation analysis revealed a significant correlation between microbial phylum groups (Proteobacteria, Bacteroidetes, and Latescibacteria) and microbial class group (Alphaproteobacteria, Sphingobacteriia, Flavobacteriia) with most of the soil physicochemical properties.

Diversity of Phosphate Chemical Forms in Soils and Their Contributions on Soil Microbial Community Structure Changes

In many soils, the bioavailability of Phosphorus (P), an essential macronutrient is a limiting factor for crop production. Among the mechanisms developed to facilitate the absorption of phosphorus, the plant, as a holobiont, can rely on its rhizospheric microbial partners. Therefore, microbial P-solubilizing inoculants are proposed to improve soil P fertility in agriculture. However, a better understanding of the interactions of the soil-plant-microorganism continuum with the phosphorus cycle is needed to propose efficient inoculants. Before proposing further methods of research, we carried out a critical review of the literature in two parts. First, we focused on the diversity of P-chemical forms. After a review of P forms in soils, we describe multiple factors that shape these forms in soil and their turnover. Second, we provide an analysis of P as a driver of microbial community diversity in soil. Even if no rule enabling to explain the changes in the composition of microbial communities according to phosphorus has been shown, this element has been perfectly targeted as linked to the presence/absence and/or abundance of particular bacterial taxa. In conclusion, we point out the need to link soil phosphorus chemistry with soil microbiology in order to understand the variations in the composition of microbial communities as a function of P bioavailability. This knowledge will make it possible to propose advanced microbial-based inoculant engineering for the improvement of bioavailable P for plants in sustainable agriculture.

Identification and Analysis of Zinc Efficiency-Associated Loci in Maize

Zinc (Zn) deficiency, a globally predominant micronutrient disorder in crops and humans, reduces crop yields and adversely impacts human health. Despite numerous studies on the physiological mechanisms underlying Zn deficiency tolerance, its genetic basis of molecular mechanism is still poorly understood. Thus, the Zn efficiency of 20 maize inbred lines was evaluated, and a quantitative trait locus (QTL) analysis was performed in the recombination inbred line population derived from the most Zn-efficient (Ye478) and Zn-inefficient inbred line (Wu312) to identify the candidate genes associated with Zn deficiency tolerance. On this basis, we analyzed the expression of ZmZIP1-ZmZIP8. Thirteen QTLs for the traits associated with Zn deficiency tolerance were detected, explaining 7.6-63.5% of the phenotypic variation. The genes responsible for Zn uptake and transport across membranes (ZmZIP3, ZmHMA3, ZmHMA4) were identified, which probably form a sophisticated network to regulate the uptake, translocation, and redistribution of Zn. Additionally, we identified the genes involved in the indole-3-acetic acid (IAA) biosynthesis (ZmIGPS) and auxin-dependent gene regulation (ZmIAA). Notably, a high upregulation of ZmZIP3 was found in the Zn-deficient root of Ye478, but not in that of Wu312. Additionally, ZmZIP4, ZmZIP5, and ZmZIP7 were up-regulated in the Zn-deficient roots of Ye478 and Wu312. Our findings provide a new insight into the genetic basis of Zn deficiency tolerance.