Spatial Distribution Of Roots Research Articles

WITHDRAWN: Design and experiment of a deviation information detection mechanism for sugar beet harvesters based on agricultural machinery and agronomy integration

To address large geometric shape differences, poor ridge distribution straightness and the uncertain spatial distribution of beet roots during the harvesting period, as well as damage caused by the inaccurate row correction detection mechanisms of combine harvesters, this study conducts a design analysis and performance tests of deviation information detection mechanisms based on the integration of agricultural machinery and agronomy. The agronomic process of mechanized sugar beet production was analyzed, the geometric dimensions of root tubers under typical planting patterns of typical varieties in main sugar beet production areas were measured, and a three-dimensional geometric model of beet root tubers was established. A device for measuring ridge shape and root tuber distribution was designed, and agronomic parameters during the harvesting period, such as plant spacing, ridge height, unearthed height, and deviation distance of beet root tubers, were measured and analyzed. A spatial model of ridge shape and beet root tuber growth distribution on the ridge during harvesting was established. The overall structure of the deviation information detection mechanism was analyzed and designed, and the structural forms and key parameters of key mechanisms, such as left‒right swing detection and up‒down floating profiling, were designed on the basis of agronomic parameter analysis. Using the missed detection rate as the evaluation index, field performance tests of the deviation information detection mechanism were conducted. The results revealed that when the average forward speed of the harvester was 0.84 m/s, the average missed detection rate of the deviation information detection mechanism was 0.56%. This method has high adaptability and detection accuracy and achieves a high level of integration for agricultural machinery (detection spatial region of the detection mechanism) and agronomy (beet root distribution spatial region). This study provides a technical basis and methodological reference for improving the quality and efficiency of automatic row correction combined with harvesting operations for crops such as sugar beets.

Application of Nitrate–Ammonium Nitrogen Fertilization Reduced Nitrogen Loss in Surface Runoff and Infiltration by Improving Root Morphology of Flue-Cured Tobacco

Nitrogen loss in water from farmland has become an environmental issue. Nitrogen fertilizer is the main cause of agricultural non-point source pollution in the Lake Basin, Yunnan. However, it is unclear how different nitrogen fertilizer forms affect water loss from farmland and how the root systems of crops respond. We established five nitrogen fertilizer treatments (100–0% [T1], 75–25% [T2], 50–50% [T3], 25–75% [T4], and 0–100% [(T5)] nitrate–ammonium) and performed an investigation to determine nitrogen loss in water and root morphological parameters of tobacco in Mile County and Chengjiang County. Compared with in the T1, T4, and T5 treatments, the total nitrogen loss in surface runoff was reduced by 4.67%, 11.85% and 9.56% in the T2 treatment and 27.32%, 23.20%, and 31.43% in the T3 treatment, respectively. Similar results were observed for the nitrogen loss due to infiltration. The root biomass was negatively correlated with nitrogen loss. There was greater root biomass, root surface area, and root spatial distribution in T2 and T3 compared with in T1, T4, and T5. These results indicate that 50–50% nitrate–ammonium nitrogen fertilizer can facilitate the root growth of tobacco and reduce nitrogen loss, which provides a reference for agricultural sustainable development.

Spatial Distribution of Fine Roots in Pinus tabuliformis and Populus tomentosa and Their Competition in Soils Response to Nutrient Availability and Proximity

Developing high-efficiency mixed forests or converting low-efficiency pure forests into near-natural mixed forests with optimal structure and function is a crucial aspect of forest management. In the initial stages of afforestation or stand improvement, fertilization and planting distance significantly influence the formation and development of mixed forests. This study investigated how nutrients and planting distance affect root competition between five-year-old Chinese pine (Pinus tabuliformis) and one-year-old Chinese white poplar (Populus tomentosa) and identified the factors influencing the competitive ability of these two species. Field planting experiments used three fertilization gradients (63 g·m−2, 125 g·m−2, and 250 g·m−2) of Stanley compound fertilizer with an N:P:K ratio of 2:1:1 and two planting distances (25 cm and 50 cm). Each experimental group was planted in circular plots with a radius of 0.5 m, yielding a total of nine plots. The effects of different fertilization concentrations and planting distances on root distribution were analyzed both horizontally and vertically. Pearson correlation analysis was used to assess the relationship between roots and soil nutrients, while Levins’ niche overlap formula evaluated the differences in root competition between the species. Furthermore, principal component analysis quantified the relationships between impact factors and the root competitiveness of the two species. Results indicated that both species primarily allocated their fine root biomass to the shallow 0–10 cm layer. Pinus tabuliformis primarily extended to the southwest, while Populus tomentosa predominantly grew to the north. Both species exhibited enhanced root growth at moderate nutrient concentrations of 125 g·m−2. At a planting distance of 50 cm from Pinus tabuliformis, Populus tomentosa seedlings demonstrated superior root growth compared to those planted 25 cm apart. Pinus tabuliformis demonstrated greater competitive ability in the deeper 10–30 cm soil layers compared to Populus tomentosa, which showed the opposite pattern in the shallow 0–10 cm layers. Furthermore, available phosphorus (contribution rate of one impact factor on the competitiveness indexes, CR: −0.998), organic matter (CR: −0.978), total nitrogen (CR: −0.947), and alkali-hydrolysable nitrogen (CR: −0.937) significantly negatively impacted the competitiveness indexes of Pinus tabuliformis. The fine root surface area, volume, and length of Populus tomentosa also significantly negatively affected its competitiveness indexes, with all contribution rates exceeding an absolute value of 0.847. Results indicated that the root distributions of Pinus tabuliformis and Populus tomentosa overlapped spatially, with each species exhibiting advantages in different regions. Therefore, in future plantation reconstruction and forest management, it is essential to thoroughly evaluate root, soil, and fertilizer factors, adjusting planting distances accordingly, to effectively mitigate competition between the two species and successfully establish a mixed forest.

Soil Physical Properties, Root Distribution, and “Ponkan” Tangerine Yield Across Different Rootstocks in a Deep Tillage Ultisol

Deep soil tillage and proper rootstock selection mitigate the root development limitations in Ultisol’s Bt horizon, enhancing the citrus yield potential. This study evaluates the root spatial distribution of three Ponkan tangerine rootstocks in Ultisol under deep tillage alongside the physical-hydric attributes and plant measurements. The experimental area underwent furrow creation, subsoiling, and hole opening for planting. The treatments included three rootstocks: “Cravo Santa Cruz” (CSC), “Sunki Tropical” (ST), and “Citrandarin Índio” (CI). Under the Ultisol preparation, these rootstocks were compared to a native forest area (FA). Three years post-initial tillage, soil samples were collected at depths of 0–0.05, 0.35–0.40, and 0.45–0.50 m from the pre-established positions. The evaluation encompassed soil dispersive clay, available water, crop water use, plant measurement, and crop yield. The root evaluation utilized the crop profile method and 2D images, with subsequent surface mapping of the root variables, number (NR), and diameter (RD) analyzed via kriging geostatistical analysis. The Ultisol showed significant changes in its physical-hydric attributes regarding structural change and more excellent clay dispersion, with a considerable contribution to the micropore volume. Deep tillage effectively improved the root spatial distribution, especially concerning the number and diameter of roots, and enhanced the water use, reflected in the vegetative growth and yield, with the rootstock CSC standing out.

Integrated deep banding and fertigation of phosphorus improves cotton yield by regulating root spatial distribution and growth

Context or problemTraditionally, 100 % phosphorus (P) fertilizer application as a band at various depths before sowing significantly influenced crop root growth and yield by reducing P fixation and optimizing its spatial distribution. However, with the advent of drip fertigation in Xinjiang, China, P fertilization practices have shifted from 100 % basal to a combination of basal and fertigation for enhanced P nutrition in cotton. Despite this, the impact of pre-sowing P band application on cotton growth under drip fertigation remains unclear. Objective or research questionThis study aimed to determine the optimal P fertilizer banding depth for cotton under a drip fertigation system. MethodsField trials were conducted comparing different basal P fertilizer application depths (5 cm, 15 cm, and 25 cm, denoted as D5, D15, and D25, respectively) with 50 % of the P rate and the remaining 50 % applied as topdressing via drip fertilization. A control (CK) involving 50 % broadcasted P fertilizer and 50 % topdressed P was included. The study focused on the effects of P application depth on soil P availability, root growth patterns, P utilization, and cotton yield. ResultsAt the boll opening stage, the D15 treatment exhibited a significant 18.69 %-49.76 % increase in available phosphorus in the 10–40 cm soil layer compared to the CK. During the peak boll to boll opening stage, the D15 treatment significantly outperformed the CK in terms of total root biomass density (11.62 %-17.54 %), total root length (16.75 %-24.81 %), total root surface area (23.07 %-37.59 %), and total root volume (20.69 %-26.23 %). Moreover, root activity and growth parameters were notably higher in the D15 treatment within the 10–40 cm soil layer. ConclusionsApplying 50 % of the P fertilizer as a band at a 15 cm depth before planting drip-irrigated cotton is optimal. This practice enhances soil P availability, stimulates root growth and distribution, and ultimately improves P utilization and cotton yield. Implications or significanceBanding P fertilizer at a 15 cm depth in combination with drip fertigation demonstrates superior yield benefits. This technology offers a novel approach to fertilizer application, enhancing nutrient use efficiency and crop productivity in drip-irrigated systems.

Effects of phosphorus fertilizer type and dripline depth on root and soil nutrient distribution, nutrient uptake, and maize yield under subsurface drip fertigation

ContextSubsurface drip irrigation can potentially increase nutrient uptake by altering the spatial distribution of nutrients and roots, but the efficiency enhancement potential of different phosphorus (P) sources combined with varying dripline depths still requires further evaluation. MethodsWe established a 2-year field experiment with spring maize in 2021 and 2022 to determine the regulatory effects of three P sources [P1, monoammonium phosphate (MAP); P2, ammonium polyphosphate (APP); and P0, no P] and three dripline depths (D0, surface drip irrigation, 0 cm; D15, subsurface at 15 cm depth; and D30, subsurface at 30 cm depth) on the soil NO3-N, NH4-N and Olsen-P distribution, root distribution, nitrogen (N) fertilizer partial factor productivity (PFPN) and P use efficiency (PUE), and grain yield. ResultsWe found a significant coupling effect between the P source and dripline depth, both of which significantly impacted soil nutrients and root distribution, grain yield, PFPN, and PUE. In P1D15 and P2D15, the highest soil NO3-N and Olsen-P contents were observed at soil depths of 0–30 and 10–20 cm and at 0–30 and 10–30 cm, respectively. Similarly, in P1D30 and P2D30, which were 20–40 and 20–40 cm, and 20–40 and 30–60 cm, respectively. Compared to the other treatments, P2D15 and P1D30 exhibited considerable increases in root length density at the 30–60 cm soil depth of 37∼52 % and 28∼58 %, respectively. Regardless of the dripline depth, P0 resulted in the lowest yield during both growing seasons. P1D30 and P2D15 were found to be the optimal combinations for achieving higher grain yield, PFPN, and PUE, as they were able to achieve a high degree of coordination between soil available N and Olsen-P, as well as root distribution. ConclusionsThe recommended approach for optimizing nutrient and root spatial distributions under subsurface drip irrigation systems involves the use of poly-P fertilizer (APP) in conjunction with shallow dripline depth and ortho-P fertilizer (MAP) paired with deep dripline depth, which provides valuable guidance for co-fertigation practices involving N and P fertilizers.

Improving the productivity of intercropping through above and below ground separation: A case study on photosynthetic characteristics and root distribution

Soybean and maize have important industrial applications, as their yield and production distribution plays an important role in supporting the global agricultural industries. In maize and soybean intercropping system, yield optimization relies on a comprehensive understanding of the complex interactions between above-ground and below-ground processes. Therefore, to investigate the impacts of various planting and separation methods on the spatial distribution of roots, soil moisture, nutrient uptake, photosynthetic physiology of leaves at different positions as well as yield advantages in soybean and maize intercropping, a two-year field experiment was conducted. The results indicted that maize root length density (RLD) increased by 24.3 %-25.5 % in non-separated maize rows and by 25.5 %-30.2 % in 10 cm from the maize rows as compared to the below-ground separated. While soybean RLD was reduced by 13.2–16.5 % in soybean rows and by 34.5 %-36.5 % in 10 cm from soybean rows. The change of the above parameters resulted in a noteworthy decrease in soil water content within the rows of maize, which was effectively mitigated by the below-ground separation. The photosynthetic rate (Pn) in middle and lower leaves of maize increased by 51.1 % and 39.2 % in above and below-ground separation, while less in upper leaves. Above-ground separation can alleviate the decrease of Pn in the upper and middle leaves of soybean, which was only decreased by 2.7 % and 3.0 % as compared with monocropping. The main constraint on maize production is the Pn of the middle and lower leaves, the upper leaves being secondary factors. Intercropping enhanced chlorophyll fluorescence parameters, while below-ground separation decreased it in the middle and lower leaves of maize. However, above-ground separation increased fluorescence characteristics in soybeans across all leaves. Intercropped maize benefited more from the below-ground than above-ground advantages, while the opposite was true for soybeans. The above-ground separation improves the overall LER and contributes the most to the yield advantages.

Coordination between degree of isohydricity and depth of root water uptake in temperate tree species

In an increasingly dry environment, it is crucial to understand how tree species use soil water and cope with drought. However, there is still a knowledge gap regarding the relationships between species-specific stomatal behaviour, spatial root distribution, and root water uptake (RWU) dynamics.Our study aimed to investigate above- and below-ground aspects of water use during soil drying periods in four temperate tree species that differ in stomatal behaviour: two isohydric tracheid-bearing conifers, Scots pine and Norway spruce, and two more anisohydric deciduous species, the diffuse-porous European beech, and the ring-porous Downy oak. From 2015 to 2020, soil-tree-atmosphere-continuum parameters were measured for each species in monospecific forests where trees had no access to groundwater. The hourly time series included data on air temperature, vapor pressure deficit, soil water potential, soil hydraulic conductivity, and RWU to a depth of 2 m. Analysis of drought responses included data on stem radius, leaf water potential, estimated osmotically active compounds, and drought damage.Our study reveals an inherent coordination between stomatal regulation, fine root distribution and water uptake. Compared to conifers, the more anisohydric water use of oak and beech was associated with less strict stomatal closure, greater investment in deep roots, four times higher maximum RWU, a shift of RWU to deeper soil layers as the topsoil dried, and a more pronounced soil drying below 1 m depth. Soil hydraulic conductivity started to limit RWU when values fell below 10−3 to 10−5 cm/d, depending on the soil. As drought progressed, oak and beech may also have benefited from their leaf osmoregulatory capacity, but at the cost of xylem embolism with around 50 % loss of hydraulic conductivity when soil water potential dropped below −1.25 MPa.Consideration of species-specific water use is crucial for forest management and vegetation modelling to improve forest resilience to drought.

Study on the Root Characteristics and Effects on Soil Reinforcement of Slope-Protection Vegetation in the Chinese Loess Plateau

The Loess Plateau region of China suffers from severe soil erosion, and the selection of effective slope-protection vegetation is essential to prevent soil and water loss. This study focused on individual plants of common species in the Loess Plateau, such as Caragana korshinski Kom., Hippophae rhamnoides Linn., Pinus tabuliformis Carr., Robinia Pseudoacacia Linn., Populus tomentosa Carr., Prunus armeniaca Lam. The root spatial distribution, geometric morphology, and fractal characteristics of these plants were measured using the whole-root-excavation method, and the vertical pull-out force of their root systems was quantified using the in situ whole-plant root-pulling method. The results showed that H. rhamnoides dominates in the vertical spatial distribution of its root system through a larger number of inclined roots. C. korshinskii, P. tomentosa, R. pseudoacacia, and P. armeniaca dominate in the horizontal spatial distribution of their root systems through a greater number of horizontal roots. P. tabuliformis, on the other hand, achieves a relatively balanced distribution in both horizontal and vertical spaces through its well-developed taproot and numerous lateral roots. In terms of the geometric morphology and fractal characteristics of their root systems, H. rhamnoides and C. korshinskii exhibit a larger number of fine roots and complex branching, resulting in a higher total-root length, total-root surface area, and root fractal dimension. The soil-stabilizing ability of H. rhamnoides, C. korshinskii, and R. pseudoacacia was stronger, mainly influenced by their total-root length, total-root surface area, and inclined root quantity, and these species can be prioritized as typical vegetation for soil and water conservation in the construction of Loess Plateau vegetation. From the perspective of slope stabilization and soil conservation alone, we strongly recommend planting shrub vegetation in the Chinese Loess Plateau.

Water Uptake Characteristics of Stipa bungeana Trin: Affected by Subsidence in the Coal Mining Areas of Northwest China

Revealing the water use pattern of plants influenced by coal-mining-caused land subsidence is crucial to understand plant–water interactions and guide ecological restoration. However, available information on herbaceous plants, the dominant species in most arid and semi-arid regions with abundant coal resources, remains inadequate. We investigated the water use patterns of Stipa bungeana Trin. by measuring soil water content, root distribution, and stable isotopes of hydrogen (δ2H) and oxygen (δ18O) of soil water and plant stem water both before and after a rainfall event. The results revealed that prior to rainfall, both areas exhibited a low soil water content with no discernible difference in soil drought. However, the soil waters δ2H and δ18O were found to be more enriched at varying depths within the subsidence area, indicating a heightened level of soil evaporation. Both soil water content and soil water isotopic composition responded sensitively to rainfall, with rainfall primarily replenishing the shallow layer (0–20 cm), thereby reflecting an infiltration mode dominated by piston flow. More water seeped into deeper soil layers in the subsidence area compared to the non-subsidence area, with more preferential flow. Before rainfall, the sources of plant water uptake were consistent both at shallow and deep soil layers, implying that the proportion of water uptake gradually decreased with increasing depth. After rainfall, the sources of plant water uptake differed slightly between the two soil layers. The plants in non-subsidence and subsidence areas dominantly extracted soil water at depths greater than 10 cm and 20 cm, respectively. The root system in the subsidence area was more developed than that in the non-subsidence area. Plant water uptake was primarily influenced by the spatial distribution of roots, as well as the post-rainfall water distribution, regardless of whether they were in the subsidence area or not. Although land subsidence affected soil water transport, the water uptake pattern of Stipa bungeana Trin. was similar before and after rainfall, indicating the adaptive growth of plants through their roots in the subsidence area. The high adaptability of herbs such as Stipa bungeana Trin. makes them a viable option for vegetation restoration in subsidence areas. This study has significant implications for evaluating plant–water relationships in subsidence areas due to coal mining, thereby providing a fundamental basis and valuable reference for ecological restoration and management strategies within such affected regions.

Effects of water-nitrogen coupling on water and salt environment and root distribution in Suaeda salsa.

Understanding the spatial distribution of crop roots is crucial for effectively managing crop water and fertilizer. We investigate the effects of water-nitrogen coupling on the water-salt environment and root distribution in the root zone of S. salsa. Three irrigation levels were established, calculated according to 0.35 (W1), 0.50 (W2), and 0.65 (W3) of local ET0. The three nitrogen levels were 150 (N1), 250 (N2), and 350 (N3) kg·hm-2 in a complete combination design. With the augmentation of irrigation water and nitrogen application, the total root weight density of the root system of Suaeda salsa increased from 17.18×10-3 g·cm-3 to 27.91×10-3 g·cm-3. The distribution of soil water suction significantly influences the root distribution of Suaeda salsa in saline soil, causing a transition from a narrow deep type to a wide shallow type. Under the W2 irrigation level, soil water suction ranges from 1485.60 to 1726.59 KPa, which can provide water for S. salsa.it becomes feasible to attain the necessary water and salt environment for the growth and development of S. salsa, resulting in the attainment of maximum biomass, ash content, and salt uptake. No significant differences in the biomass, ash content, and salt uptake of S. salsa was noted between N2 and N3 nitrogen application levels (p > 0.05).The optimal irrigation volume and nitrogen application level were 0.50 ET0 and 250 kg·hm-2, respectively. The results of this study provide a scientific basis for the large-scale planting of S. salsa in extreme arid areas to improve and utilize saline wastelands.

Root spatial distribution and belowground competition in an apple/ryegrass agroforestry system

CONTEXTForestry and fruit industry is a unique and advantageous industry in Xinjiang, China, and it is an important channel for farmers to increase income. With limited land resources and a shortage of forage in southern Xinjiang, farmers began to establish a fruit-grass interplanting model to improve the comprehensive economic benefits of orchards. OBJECTIVEThe objective of this study was to explore the effects of apple/ryegrass intercropping system on root spatial distribution and competition, and to evaluate the performance of field microclimate, soil physical properties and productivity under intercropping. METHODSIn the study, three different planting patterns were designed: sole-cropped apple (The spacing of the rows of apple trees was 4.0 m, and the plant spacing was 1.0 m), sole-cropped ryegrass (Strip sowing, row spacing was 0.25 m), and apple/ryegrass intercropping (The distance from apple row to ryegrass row was 1.0 m). Two-year field experiments were conducted to measure the root length density (RLD), specific root length (SRL), interspecific competitiveness index, soil moisture content, organic matter content, air temperature, relative humidity, wind speed, yield, land equivalent ratio (LER) and aggressivity. RESULTS AND CONCLUSIONCompared with sole cropping, intercropping reduced the RLD of apple and ryegrass and increased the SRL of ryegrass. The competition space between apple and ryegrass was concentrated in the soil area of 100 cm horizontally and 0–20 cm vertically, and apple was more competitive than ryegrass. Intercropping increased the content of soil moisture and organic matter and improved the microclimate of farmland, decreased the air temperature, increased the relative humidity of an orchard, and decreased wind speed. Although intercropping reduced ryegrass and apple yield, land equivalent ratio (LER) was 1.27–1.30, indicating that intercropping improved land use efficiency. Root competition led to an uneven distribution of root length density (RLD) and specific root length (SRL). The plasticity of root morphology and root spatial distribution was key to adapting to competition and maximizing the absorption of water and nutrients in apple/ryegrass agroforestry systems. SIGNIFICANCEApple/ryegrass intercropping system maximizes resource utilization and reduces interspecies resource competition. It improved land use efficiency, improved the comprehensive benefits of fruit and grass production.

Effects of soil physicochemical environment on the plasticity of root growth and land productivity in maize soybean relay strip intercropping system.

Soil is a key foundation of crop root growth. There are interactions between root system and soil in multiple ways. The present study aimed to further explore the response of root distribution and morphology to soil physical and chemical environment under maize (Zea mays L.) soybean (Glycine Max L. Merr.) relay strip intercropping (MS) An experiment was carried out aiming to examine the effects of nitrogen (N) applications and interspecific distances on root system and soil environment in MS. The two N application levels, referred to as no N application (NN) and conventional N application (CN), were paired with different interspecific distances: 30, 45 and 60 cm (MS30, MS45 and MS60) and 100 cm of monoculture maize and soybean (MM/SS100). The results demonstrated that MS45 increased the distribution of soil aggregates (> 2 mm) near the crop roots and maize soil nutrients status, which increased by 20.3% and 15.6%. Meanwhile, MS reduced soil bulk density, increased soil porosity and improved soil oxygen content. Optimization of the soil environment facilitated root growth. The MS45 achieved a better result on root distribution and morphology than the other configuration and also increased land productivity. Relay intercropped soybean with maize in interspecific row spacing of 45 cm, improved soil physicochemical environment, reshaped root architecture and optimized root spatial distribution of crops to achieve greater land productivity. © 2024 Society of Chemical Industry.

Exploring spatial distribution characteristics of Populus simonii Carr coarse roots using ground penetrating radar

A comprehensive root database holds paramount importance for agro-forestry endeavours, providing valuable insights into the ecological characteristics and stability of plant species. However, the creation of such databases presents a formidable challenge. This study is devoted to shedding light on the spatial distribution characteristics of coarse roots (diameter ≥1 cm) in Populus simonii trees, which naturally flourish in Tongde County, Thanh Hai province, China. Ground-penetrating radar (GPR) technology was employed to investigate the distribution of these coarse roots, while tree root diameters were estimated through controlled experiments involving buried objects. A total of 40 P. simonii trees were meticulously selected for data collection, and the coarse roots of these trees were categorized into three diameter classes: 1-2 cm, 2-3 cm, and ≥3 cm. The study findings have unveiled a robust correlation between the density of coarse roots and the diameter at breast height (dbh) of the trees. Moreover, the total coarse root density moderately correlates with canopy width and tree height within a horizontal plane extending 3-5 m from the tree base and a vertical plane at a soil depth of 20-40 cm. This study underscores the effectiveness of GPR in elucidating the spatial distribution of tree roots and accurately estimating root diameters. This underscores the potential of GPR to significantly enhance investigations related to root ecology and below-ground biomass estimation.

Root Distribution, Agronomic Performance, and Phosphorus Utilization in Wheat as Mediated by Phosphorus Placement under Rainfed Coastal Saline Conditions

Rainfall variations between seasons could affect phosphorus translocation from rainfed saline soil to wheat plants. Whether deep-banded P application increases wheat yield compared to traditional P placement under rainfed coastal saline conditions remains a question. This study investigated the impact of season, P placement, and genotype on root distribution, agronomic performance, and P utilization in wheat grown under rainfed coastal saline conditions. Four wheat genotypes (two tall genotypes (Alice and Shavano) and two dwarf genotypes (AK58 and LX99)) were grown in a saline field with five P placement treatments (Top-dressed High P input (TopHP), Deep-banded High P input (DeepHP), Top-dressed Reduced P input (TopRP), Deep-banded Reduced P input (DeepRP), and no P supply (No P)) for two consecutive seasons. Root length density (RLD), agronomic traits, nutrient concentrations in grain and straw, and P utilization efficiency were determined. Statistical analysis was employed to compare the P utilization across treatments. TopHP increased RLD at a 0–20 cm depth, while deep-banded P increased RLD at a 20–40 cm depth. The wet season (2021–2022) resulted in higher grain yields, more fertile spikelets, and fewer non-fertile spikelets in all four genotypes than the dry season (2020–2021). The highest 1000-kernel weights occurred in DeepHP or TopHP. Deep-banded P outperformed top-dressed P placement in terms of P utilization efficiency for LX99, Shavano, and AK58 (not Alice) in both seasons. Nutrient concentrations/accumulations showed inconsistent patterns due to significant genotype × P placement interactions. PCA analysis revealed that first two PCs accounted for 56.19% and 60.13% of the variance in the 2020–2021 and 2021–2022 seasons, respectively. The first component (PC1) represented root spatial distribution and straw weight, while the second component (PC2) represented 1000-kernel weight, grain number per head, and grain yield. Altered P utilization efficiency mediated by P placement was associated with changes in wheat root distribution, agronomic traits, and nutrient concentrations in straw and grain. The increased wheat yield in the wet season (2021–2022) was attributed to higher rainfall.

Efficient Utilization Mechanism of Soil Moisture and Nutrients with Ridge Film Furrow Seeding Technology of Sloping Farmlands in Semi-Arid and Rain-Fed Areas

How to improve the utilizations of water and nutrient is a research hotspot of sloping farmland in semi-arid and rain-fed areas. In this study, the spatial changes of soil moisture, nutrients, and roots under different tillage modes, as well as the efficient utilization mechanism of soil moisture and nutrients from rain-fed maize on three mulching treatments (no surface covering, ridge film and straw mulch and ridge film mulch) and two slope treatments (5° slope and 10° slope) of sloping farmlands were studied at the Nationally Agricultural Environment Fuxin Observation and Experiment Station in China through a micro-zone simulation and a long-term positioning experiment. The results indicated that ridge film mulch and furrow seeding significantly improve the water use efficiency and partial factor productivity of the plants in sloping farmlands, with the highest increases being 51.33% and 45.05%. By analyzing the coordinated relationship between water, nutrients, and roots, it was found that ridge film furrow seeding technology can significantly affect the spatial distribution of water, nutrients, and roots in different soil layers, and improves the effective coefficient of soil water and nutrients. The effective coefficient of ridge film and straw treatment was 2.53, while the average value of the effective coefficient of ridge film treatment was 1.39. Further analysis found that the degree of consistency between the root system, water, and nutrient barycenter was highly correlated with the effective coefficients of water and nutrients. Visual radar map analysis revealed that root development limits the improvement availability of the efficient use of water and nutrients in the soil. Promoting root development indicators and root spatial distribution through ridge film coverage was an effective way to improve the efficient use of maize water and nutrients. The ridge film mulching promoted the root development index and root spatial distribution, thus improving the efficient use of water and nutrients in maize. Overall, the ranking of the regulation effect was as follows: ridge film and straw mulch > ridge film mulch > no mulch, and 5° slope > 10° slope. This research provided a theoretical basis for the enhancement of use efficiency in water and nutrients in sloping farmlands.

Intercropping and weed cover reduce sugarcane roots colonization in plant crops as a result of spatial root distribution and the co-occurrence of neighboring plant species

Intercropping and weed cover reduce sugarcane roots colonization in plant crops as a result of spatial root distribution and the co-occurrence of neighboring plant species

Coupling non‐invasive imaging and reactive transport modeling to investigate water and oxygen dynamics in the root zone

AbstractOxygen (O2) availability in soils is vital for plant growth and productivity. The transport and consumption of O2 in the root zone is closely linked to soil moisture content, the spatial distribution of roots, as well as structure and heterogeneity of the surrounding soil. In this study, we measure three‐dimensional root system architecture and the spatiotemporal dynamics of soil moisture (θ) and O2 concentrations in the root zone of maize (Zea mays) via non‐invasive imaging, and then construct and parameterize a reactive transport model based on the experimental data. The combination of three non‐invasive imaging methods allowed for a direct comparison of simulation results with observations at high spatial and temporal resolution. In three different modeling scenarios, we investigated how the results obtained for different levels of conceptual complexity in the model were able to match measured θ and O2 concentration patterns. We found that the modeling scenario that considers heterogeneous soil structure and spatial variability of hydraulic parameters (permeability, porosity, and van Genuchten α and n), better reproduced the measured θ and O2 patterns relative to a simple model with a homogenous soil domain. The results from our combined imaging and modeling analysis reveal that experimental O2 and water dynamics can be reproduced quantitatively in a reactive transport model, and that O2 and water dynamics are best characterized when conditions unique to the specific system beyond the distribution of roots, such as soil structure and its effect on water saturation and macroscopic gas transport pathways, are considered.

Phenotypic quantification of root spatial distribution along circumferential direction for field paddy-wheat.

Plant roots are essential for water and nutrient absorption, anchoring, mechanical support, metabolite storage and interaction with the surrounding soil environment. A comprehensive understanding of root traits provides an opportunity to build ideal roots architectural system that provides improved stability and yield advantage in adverse target environments caused by soil quality degradation, climate change, etc. However, we hypothesize that quantitative indicators characterizing root system are still need to be supplemented. Features describing root growth and distribution, until now, belong mostly to 2D indicators or reflect changes in the root system with a depth of soil layers but are rarely considered in a spatial region along the circumferential direction. We proposed five new indicators to quantify the dynamics of the root system architecture (RSA) along its eight-part circumferential orientations with visualization technology which consists of in-situ field root samplings, RSA digitization, and reconstruction according to previous research based on field experiments that conducted on paddy-wheat cultivation land with three fertilization rates. The experimental results showed that the growth space of paddy-wheat root is mainly restricted to a cylinder with a diameter of 180 mm and height of 200 mm at the seedlings stage. There were slow fluctuating trends in growth by the mean values of five new indicators within a single volume of soil. The fluctuation of five new indicators was indicated in each sampling time, which decreased gradually with time. Furthermore, treatment of N70 and N130 could similarly impact root spatial heterogeneity. Therefore, we concluded that the five new indicators could quantify the spatial dynamics of the root system of paddy-wheat at the seedling stage of cultivation. It is of great significance to the comprehensive quantification of crop roots in targeted breeding programs and the methods innovation of field crop root research.

Field traffic-induced soil compaction under moderate machine-field conditions affects soil properties and maize yield on sandy loam soil.

Soil compaction due to field trafficking involves a complex interplay of machine-soil properties. In contrast to previous studies simulating worst field scenarios, this two-year field experiment investigated the effects of traffic-induced compaction involving moderate machine operational specifications (axle load, 3.16 Mg; mean ground contact pressure, 77.5 kPa) and lower field moisture contents (< field capacity) at the time of trafficking on soil physical properties, spatial root distribution, and corresponding maize growth and grain yield in sandy loam soil. Two compaction levels, i.e. two (C2) and six (C6) vehicle passes, were compared with a control (C0). Two maize (Zea mays L.) cultivars, i.e. ZD-958 and XY-335, were used. Results showed topsoil (< 30cm) compaction with increases in bulk density (BD) and penetration resistance (PR) up to 16.42% and 127.76%, respectively, in the 10-20cm soil layer in 2017. Field trafficking resulted in a shallower and stronger hardpan. An increased number of traffic passes (C6) aggravated the effects, and the carryover effect was found. Higher BD and PR impaired root proliferation in deeper layers of topsoil (10-30cm) and promoted shallow horizontal root distribution. However, XY-335, compared with ZD-958, showed deeper root distribution under compaction. Compaction-induced reductions in root biomass and length densities were respectively up to 41% and 36% in 10-20cm and 58% and 42% in the 20-30cm soil layer. Consequent yield penalties (7.6%-15.5%) underscore the detriments of compaction, even only in topsoil. In crux, despite their low magnitude, the negative impacts of field trafficking under moderate machine-field conditions after just two years of annual trafficking foreground the challenge of soil compaction.