Soil Nutrient Status Research Articles

Aboveground antagonists mitigate belowground plant–antagonist interactions but not affect plant–mutualist interactions

Species interactions exert important influences on biodiversity and ecosystem stability. In complex natural communities, species interactions have gone beyond pairwise mechanisms, as interactions between two species can be regulated by one or more other species (higher-order species interactions). However, few studies consider higher-order interactions among organisms that are indirectly contacted, particularly under high soil nutrient conditions. Here, we performed a common garden experiment to investigate how natural herbivory (aboveground weevil) and simulated herbivory (leaf clipping) affect plant (Triadica sebifera) interactions with soil antagonists (root-knot nematodes) and mutualists (arbuscular mycorrhizal fungi; AMF) under nitrogen and phosphorus addition. We also tested the effects of nitrogen, phosphorus, and herbivory-stimuli on T. sebifera leaf extrafloral nectary (EFN) production. We found that T. sebifera can compensate for biomass loss caused by clipping or weevil feeding, moreover, high nitrogen availability caused plant biomass to outpace herbivory-stimuli. Plant–antagonist (root-knot nematodes) interactions were not affected by clipping or weevil feeding under ambient nitrogen condition but were reduced by clipping or weevil feeding under high nitrogen supply, however, we did not find the same pattern under phosphorus addition. Aboveground herbivory-stimuli did not affect plant–mutualist (AMF) interactions, whether fertilized or not. In addition, nitrogen addition stimulated plants to secrete more EFN against clipping but did not increase EFN production against weevil feeding. Clipping and weevil feeding exhibited consistent effects on both plant–antagonist (root-knot nematodes) interactions and plant–mutualist (AMF) interactions. These results suggest that aboveground antagonists mainly mitigate belowground plant–antagonist interactions but not affect plant–mutualist interactions, and higher-order species interactions depend on nitrogen addition but not phosphorus addition.

Survival Status of Young Plants in Paluwatar Plantation Site of Udayapur District, Nepal

Forests provide multitude of benefits, including carbon sequestration, biodiversity conservation, timber production, and recreational opportunities. However, these valuable ecosystems are facing severe threats due to deforestation and land degradation. To counter this, plantation has emerged as a key strategy to restore degraded lands and ensure a continuous supply of ecosystem services. Yet, the success of these plantation sites remains uncertain due to a lack of systematic assessment of their survival status. Therefore, this study focuses on evaluating the survival status of young plantations on degraded riverbanks in Udayapur District, Nepal. Through systematic sampling at 0.5% intensity, 30 plots, each spanning 25 m², were established for regeneration inventory. Soil samples were collected using soil augers to a depth of 30cm for nutrient analysis. Nitrogen (N), Phosphorus (P), and Potassium (K) levels were determined using soil testing kits, while organic matter (OM) content was assessed using the Loss-on-Ignition (LOI) method. The results revealed an encouraging overall seedling survival rate of 95% at the research site. Notably, Dalbergia sissoo (Sissoo) and Tectona grandis (Teak) exhibited the highest survival rates at 100%, whereas Phyllanthus emblica (Amala) and Delonix regia (Gulmohar) showed lower survival rates at 40%. The site demonstrated low levels of N, P, and K, alongside high organic matter content. Unexpected high survival rate (95%) despite presence of a low level of nutrients raises intriguing questions about the adaptive mechanisms of the planted tree species. Further replication of similar studies as well as investigation of factors playing crucial role in seedling survival and growth beyond soil nutrient status is recommended.

Response of integrated nutrient management on growth, yield, and soil nutrient status in chili (Capsicum annuum L.)

Response of integrated nutrient management on growth, yield, and soil nutrient status in chili (Capsicum annuum L.)

Struvite as P Fertilizer on Yield, Nutrient Uptake and Soil Nutrient Status in the Rice–Wheat Rotation System: A Two-Year Field Observation

Long-term large inputs of phosphorus (P) fertilizer in China have caused serious soil P accumulation, low P use efficiency (PUE) and high risk of P loss. Controlling the amount of P fertilizer applied presents an inevitable choice for improving the PUE. Struvite recycled from agricultural wastewater rich in N and P concentrations are capable of slow nutrient release, improving nutrient uptake and enabling the reuse of nutrients from environmental sources when applied to agricultural land. A two-year field experiment was conducted to investigate the effects of struvite combined with P reduction under a rice–wheat rotation system in eastern China. A total of five treatments were set up, including conventional fertilization (FP), a struvite substitution of 100% P fertilizer (SP), a 50% P reduction with struvite substitution (RSP), no application of N fertilizer (N0) and no application of P fertilizer (P0). Grain yield, crop N and P uptake, N and P use efficiency (NUE and PUE) and soil nutrient status were assessed. Under the same P application rate, the yield and aboveground biomass of the SP treatment were slightly higher than those of FP treatment, but the crop P uptake, PUE and soil available P content were significantly increased. The RSP treatment did not reduce yield with 50% P reduction, and significantly improved the PUE and soil available P content. Crop N uptake and NUE were also found to be increased in SP and RSP treatments with struvite substitution. The P apparent balance showed that both the SP and FP treatments had a P surplus, but the RSP treatment had a P break-even, and the soil available P content remains stable compared with the initial value. The results indicate that struvite application could improve the soil P availability and crop nutrient uptake then promote the crop yield. To increase the nutrient use efficiency of crops while ensuring crop yield and soil fertility, appropriate P reduction combined with struvite as a P fertilizer could be sustainable in the rice–wheat rotation system in the long run.

Effect of Integrated Nutrient Management on Productivity and Quality of Aonla

The field experiment was conducted at the Horticulture Research CRC Farm – 1 of the Department of Horticulture, School of Agriculture, ITM University Gwalior (M.P. during the year 2019 and 2020 to study the effect of Integrated Nutrient Management on fruit yield and quality of aonl. The experiment was laid out in the randomized block design with three replications and eleven treatments viz. (control - RDF (1000: 500:1000 g/ tree, 3/4thof RDF + FYM, 3/4thof RDF + FYM + Azotobacter (100g, 3/4thof RDF + FYM+ Azospirillum (100g, 3/4thof RDF + FYM+ PSB (100g, 3/4thof RDF + FYM+ Azotobacter + Azospirillum + PSB(100g/tree each, ½ of RDF + FYM, 1/2 of RDF + FYM+ Azotobacter (100g, 1/2 of RDF + FYM + Azospirillum(100g, ½ of RDF + FYM + PSB(100g, ½ of RDF + FYM + Azotobacter + Azospirillum + PSB (100g/tree, each. The results revealed that among different treatments, application of ½ of RDF + FYM + Azotobacter + Azospirillum + PSB recorded higher fruit yield, TSS, Total sugar, Ascorbic acid which was followed by application of ¾th of RDF+ FYM + Azotobacter + Azospirillum + PSB except acidity. Thus, application of ½ of RDF + FYM + Azotobacter + Azospirillum + PSB was found to best for improving the soil nutrient status which will in turn help in improving the yield of Aonla.

“Three-strip management”: introducing a novel mowing method in perennial flower strips and grass margins to increase habitat complexity and attractiveness for pollinators

Flower margins are widely adopted as agri-environment measure (AEM) to enhance farmland biodiversity. However, perennial flower margins need appropriate mowing schemes to manage succession, especially in regions with high nitrogen depositions, and current schemes inadequately address the needs of arthropods, including pollinators. Effective management should provide floral diversity with staggered flowering times, creating varied sward structures for diverse habitats that support shelter, nesting, and mating sites. To address these challenges, a novel mowing method, called 'Three-strip management,' is proposed. This method involves dividing the margin into three strips using curved instead of straight mowing lines. During each cycle, one third remains unmown for shelter, while clippings are removed to lower soil nutrient status and reduce succession. The use of overlapping curved mowing lines aims to maximize variety in patterns, fostering spatio-temporal variation in the (re)growth of perennials and swards. Unlike Regular rotational management, multiple uneven parts are kept unmown over winter, increasing the number of subzones in different mown states over successive years. In this study, field trials comparing Three-strip management with Regular rotational management reveal positive effects especially during the second year, including higher bee abundance and diversity. Plant-pollinator networks also demonstrate increased interactions. While the study focuses on bees, the potential of the Three-strip management to support other beneficial insects is discussed. Given declining insect populations in agricultural landscapes, this paper offers insights into enhancing perennial flower margins as AEM to support pollinator populations. The novel Three-strip management presents a promising strategy for balancing management needs with diverse insect requirements, contributing to sustainable biodiversity conservation in agricultural settings.

Effect of Organic Manures and Phosphorus on Soil Nutrient Status in Kharif Rice

Field experiments were conducted at Agricultural College Farm, Bapatla during Kharif and Rabi seasons of 2017-2018 and 2018-2019 to study the Phosphorus dynamics in relation to nutrient management in rice- blackgram cropping sequence with respect to changes in soil nutrient status. Results of two years (2017-2019) experimentation revealed that at all growth stages of rice, significantly highest available nitrogen, phosphorus and potassium in soil were recorded with application of RDNK+Dhaincha @ 10t ha-1 (M3) and this was on par with RDNK+ Sunhemp @ 10t ha-1(M2), whereas lowest was recorded in RDNK (M0) alone in both seasons of study. Among the P levels the available nutrient status (N, P and K) were increased with the increasing level of P from 0 (P1) to 120 kg P2O5 (P5) ha-1, irrespective of the nutrients imposed to rice crop. Significantly highest was recorded in P5 (120 kg P2O5 ha-1) and this was on par with P4 (90 kg P2O5 ha-1), whereas the lowest was recorded in treatment P1 that received 0 kg P2O5 ha-1.

Integrated Application of Inorganic, Organic Sources and Biofertilizers on Nutrient Status of Soil and Aonla Leaves under Sub-Tropics of Madhya Pradesh, India

The field experiment was conducted at the Horticulture Research CRC Farm – 1 of the Department of Horticulture, School of Agriculture, ITM University Gwalior (M.P.) during the year 2019 and 2020 to study the Influence of Integrated Nutrient Management on nutrient status of soil and aonla leaves under sub-tropics of Madhya Pradesh. The experiment was laid out in the randomized block design with three replications and eleven treatments viz. (control) - RDF (1000: 500:1000 g/ tree), 3/4thof RDF + FYM, 3/4th of RDF + FYM + Azotobacter (100 g), 3/4th of RDF + FYM+ Azospirillum (100 g), 3/4th of RDF + FYM+ PSB (100 g), 3/4thof RDF + FYM+ Azotobacter + Azospirillum + PSB(100 g/tree each), ½ of RDF + FYM, 1/2 of RDF + FYM+ Azotobacter (100 g), 1/2 of RDF + FYM + Azospirillum(100 g), ½ of RDF + FYM + PSB(100 g), ½ of RDF + FYM + Azotobacter + Azospirillum + PSB (100 g/tree, each. The results revealed that among different treatments, application of ½ of RDF + FYM + Azotobacter + Azospirillum + PSB recorded higher microbial population, available nitroge, phosphorus, potassium and available soil zinc, copper and boron which was followed by application of 1/2 of RDF + FYM+ Azotobacter (100 g). Thus, application of ½ of RDF + FYM + Azotobacter + Azospirillum + PSB was found to best for improving the soil nutrient status which will in turn help in improving the yield of Aonla.

The Response of Plants to Soil Pb Stress

The problem of soil heavy metal pollution is becoming increasingly serious, and Pb is one of the main causes of soil heavy metal pollution due to its toxicity. Phytoremediation technology can reduce the content of heavy metal pollutants and improve soil nutrient conditions, and thus, it is more widely used. Pb in the soil affects the physiological and biochemical processes of plants, which in turn have a toxic effect on plants, causing severe wilting and death. Similarly, Pb also affects plant photosynthesis to varying degrees. This paper details the progress of research on the effects of soil Pb contamination on plants, with the aim of finding directions for further study.

Impact of Crude Oil Contamination on Soil Physicochemical Properties around the Sildubi Oil Spill, Borhola, Assam

Crude oil contamination can affect the soil physicochemical properties and it is a serious constraint on the rice ecosystem near the oil drilling sites. The objective of this study was to identify the effects of crude oil contamination through oil exploration on soil health and the horizontal distribution of soil nutrients in rice field soils in the Sildubi area, Jorhat district, Assam. Soil samples were collected at a depth of 0–15 cm from the drilling site and from the four directions (East, West, South and North) in a circular mode with a radius of 500 and 1000m away from the oil spill. Each sample was mounded with four replications. Samples were analyzed for physicochemical properties by using standard methods that reflect soil nutrient status.
 The percentage of organic carbon, organic matter and soil pH are found to be higher at the drilling site compared to the results obtained in the rice field soils, apart by 500 and 1000m from the central zone. Similarly, bulk density, moisture percentage and electrical conductivity were found to be lowest in the soils of the drilling site. In our study, considerable variation in the horizontal distribution of soil nutrients was also observed. The highest P, Ca and nitrogen contents were recorded in the oil-contaminated soils compared to soils collected from 500 and 1000m radius. The total soil Fe was significantly higher in the samples collected at 1000m. Spilled crude oil is certainly responsible for alterations in soil physicochemical properties and the horizontal distribution of some plant-specific nutrients. High concentrations of Fe and P observed due to crude oil contamination have been developing Fe stress situations reducing crop production in nearby agricultural lands.

Conservation Agriculture System Impact on Soil Nutrient Status in Eastern Dry Zone of Karnataka, India

Tillage is the physical manipulation of soil into optimum conditions, which enhance the soil health for better crop productivity. A field investigation was carried out to evaluate conservation agriculture effect on soil nutrient conservation and set up in spilt plot design. Zero tillage (M3) witnessed significantly (P<0.05) greater nitrogen availability (288.17, 251.39 and 239.70 kg ha-1), K2O (229.04, 209.80 and 193.73 kg ha-1) than conventional tillage (M1) at soil depths 0-7.5, 7.5-15 and 15-30 cm, respectively. In green manuring practices, horse gram (C3) recorded OC (0.53, 0.51 and 0.47 %), available sulphur (23.38, 20.61 and 18.10 mg kg-1) followed by sun hemp. The interaction combination of M3C3 recorded highest soil nutrient status. Significantly lowest microbial population were found in M1, was due to faster decomposition organic matter resulted in unfavourable condition for survival. Overall adopting M1 alone (1 Ploughing + 2 harrowing + 1 intercultural operation) adversely affect soil health.

Effect of Nitrogen and Sulphur Fertilization on Growth, Yield, Quality, and Nutrient Status of Soil of Wheat (Triticum aestivum) var. HD3086 (Pusa Gautami) Crop

Effect of Nitrogen and Sulphur Fertilization on Growth, Yield, Quality, and Nutrient Status of Soil of Wheat (Triticum aestivum) var. HD3086 (Pusa Gautami) Crop

Impact of manures and fertilizers on yield and soil properties in a rice-wheat cropping system.

The use of chemical fertilizers under a rice-wheat cropping system (RWCS) has led to the emergence of micronutrient deficiency and decreased crop productivity. Thus, the experiment was conducted with the aim that the use of organic amendments would sustain productivity and improve the soil nutrient status under RWCS. A three-year experiment was conducted with different organic manures i.e. no manure (M0), farmyard manure @ 15 t ha-1 (M1), poultry manure @ 6 t ha-1(M2), press mud @ 15 t ha-1(M3), rice straw compost @ 6 t ha-1(M4) along with different levels of the recommended dose of fertilizer (RDF) i.e. 0% (F1), 75% (F2 and 100% (F3 in a split-plot design with three replications and plot size of 6 m x 1.2 m. Laboratory-based analysis of different soil as well as plant parameters was done using standard methodologies. The use of manures considerably improved the crop yield, macronutrients viz. nitrogen, phosphorus, potassium and micronutrients such as zinc, iron, manganese and copper, uptake in both the crops because of nutrient release from decomposed organic matter. Additionally, the increase in fertilizer dose increased these parameters. The system productivity was maximum recorded under F3M1 (13,052 kg ha-1) and results were statistically identical with F3M2 and F3M3. The significant upsurge of macro and micro-nutrients in soil and its correlation with yield outcomes was also observed through the combined use of manures as well as fertilizers. This study concluded that the use of 100% RDF integrated with organic manures, particularly farmyard manure would be a beneficial resource for increased crop yield, soil nutrient status and system productivity in RWCS in different regions of India.

Effect of residue and weed management practices on weed flora, yield, energetics, carbon footprint, economics and soil quality of zero tillage wheat

A two-year field study was conducted during Rabi 2018–2019 and 2019–20 to find out the influence of different residue and weed management practices on weed dynamics, growth, yield, energetics, carbon footprint, economics and soil properties in zero-tilled sown wheat at Research Farm, AICRP-Weed management, SKUAST-Jammu. The experiment with four rice residue management practices and four weed management practices was conducted in a Strip-Plot Design and replicated thrice. The results showed that residue retention treatments recorded lower weed density, biomass and higher wheat growth, yield attributes and yields of wheat as compared to no residue treatment. The magnitude of increase in wheat grain yield was 17.55, 16.98 and 7.41% when treated with 125% recommended dose of nitrogen + residue + waste decomposer (RDN + R + WD), 125% RDN + R, and 100% RDN + R, respectively, compared to no residue treatment. Further, all three herbicidal treatments decreased weed density and biomass than weedy treatments. Consequently, a reduction of 29.30, 28.00, and 25.70% in grain yield were observed in control as compared to sulfosulfuron + carfentrazone, clodinafop-propargyl + metasulfuron, and clodinafop-propargyl + metribuzin, respectively. Moreover, 125% RDN + R + WD obtained significantly higher energy output (137860 MJ ha−1) and carbon output (4522 kg CE/ha), but 100% RDN had significantly higher net energy (101802 MJ ha−1), energy use efficiency (7.66), energy productivity (0.23 kg MJ−1), energy profitability (6.66 kg MJ−1), carbon efficiency (7.66), and less carbon footprint (7.66) as compared to other treatments. Despite this, treatments with 125% RDN + R + WD and 125% RDN + R provided 17.58 and 16.96% higher gross returns, and 24.45% and 23.17% net outcomes, respectively, than that of control. However, compared to the control, sulfosulfuron + carfentrazone showed considerably higher energy output (140492 MJ ha−1), net energy (104778 MJ ha−1), energy usage efficiency (4.70), energy productivity (0.14 kg MJ−1), energy profitability (3.70 kg MJ−1), carbon output (4624 kg CE ha−1), carbon efficiency (4.71), and lower carbon footprint (0.27). Furthermore, sulfosulfuron + carfentrazone, clodinafop-propargyl + metasulfuron, and clodinafop-propargyl + metribuzin recorded 29.29% and 38.42%, 27.99%, and 36.91%, 25.69% and 34.32% higher gross returns and net returns over control treatment, respectively. All three herbicides showed higher gross returns, net returns, and benefit cost ratio over control. The soil nutrient status was not significantly affected either by residue or weed management practices. Therefore, based on present study it can be concluded that rice residue retention with 25% additional nitrogen and weed management by clodinafop-propargyl + metasulfuron herbicide found suitable for zero tillage wheat.

The Effects of Partial Substitution of Fertilizer Using Different Organic Materials on Soil Nutrient Condition, Aggregate Stability and Enzyme Activity in a Tea Plantation.

Fertilization plays a crucial role in enhancing tea production. However, it has been demonstrated that the long-term single application of chemical fertilizer will reduce soil nutrient content and the formation of soil aggregates, which is not conducive to the sustainable development of soil and agriculture. Many studies have shown that partial substitution of chemical fertilizer with organic fertilizer can improve soil physicochemical properties and soil nutrient content. This study compared the effects of different organic materials as substitutes for chemical fertilizer. We partially replaced chemical fertilizer with rabbit manure, wine lees and rapeseed cake, amounting to 30% of the total annual nitrogen application in the field experiment, and we set nine different fertilization methods to assess and analyze the soil nutrient condition, aggregate stability and enzyme activity. The results showed that the experimental soil aggregate mean weight diameter (MWD) and geometric mean diameter (GMD) were significantly increased compared with control (p < 0.05); the aforementioned fertilization methods also decreased the soil aggregate fractal dimension (D), disruption rate (PAD), average weight-specific surface area (MWSSA) and soil erodibility factor (K). The application of the fertilizer containing organic materials and microbial agent increased soil organic carbon (SOC) by 20.7% to 22.6% and total nitrogen (TN) by 34.6% to 38.1%; it also significantly promoted sucrase, urease and protease activities in all aggregate sizes (p < 0.05) and increased the 2-5 mm aggregate content. The correlation coefficients between the SOC and the enzyme activities were 0.18-0.95, and most of them showed an extremely significant positive correlation (p < 0.01). In conclusion, the application of fertilizers containing organic materials and microbial agents can improve soil aggregate stability, aggregate enzyme activity and soil structural stability.

Determination of Soil Fertility Characteristics and Heavy Metal Health Risks Using the Camellia oleifera Planting Base in Guizhou Province, China

To clarify the soil nutrient status and identify the safety risks of heavy metals in Camellia oleifera planting regions, the integrated soil fertility status was assessed using the improved Nemero composite index method, weighted average method, and coefficient of variation (CV) method, and the impact of heavy metals in the soil on human health was evaluated with a health risk assessment model using the Qianyu C. oleifera planting base in Yuping County, Guizhou Province, as the study object. The results showed the following: (1) The soil pH levels were 4.12–6.17, with CV values of 0.04–0.66, and no significant differences were observed among the plots. The soil was rich in organic matter, alkali-hydrolyzed nitrogen, and available phosphorus, with a high total potassium content, total phosphorus content, and rapidly available potassium, indicating a high level of comprehensive soil fertility. (2) The total carcinogenic risk (CR) index of the arsenic (As), cadmium (Cd), and chromium (Cr) in the soil was 1.92 × 10−7, and among these elements, the CR index of the As was the highest (1.3–8.0 × 10−7), but all were below the highest acceptable level (10−6) recommended by the United States Environmental Protection Agency (USEPA). (3) The redundancy analysis (RDA) between the soil fertility and trace elements revealed that the soil organic matter content was positively correlated with the contents of lead (Pb), manganese (Mn), and Cr and negatively correlated with the contents of zinc (Zn), iron (Fe), Cd, mercury (Hg), As, and copper (Cu). The soil pH was positively correlated with the contents of Cr, Fe, and Cu and negatively correlated with the contents of Mn, Pb, Zn, Cd, Hg, and As. In the study area, the soil was slightly acidic with overall high fertility without any CR. The quality of the C. oleifera was degraded by soil acidification, but the slightly acidic soil facilitated the absorption of trace elements by C. oleifera. Soil acidification could be relieved by taking appropriate measures, such as the addition of biochar or CaCO3. This study determined the soil fertility of the Qianyu C. oleifera planting base and assessed the health risk of heavy metals in the soil, providing a theoretical reference for enhancing C. oleifera quality, preventing the excessive accumulation of soil heavy metals, and improving the soil in this planting base.

Effects of Enclosure Succession on the Morphological Characteristics and Nutrient Content of a Bamboo Whip System in a Moso Bamboo (Phyllostachys edulis) Forest on Wuyi Mountain, China

To investigate the morphological characteristics and nutrient content of bamboo whip systems in the Wuyi Mountain Moso bamboo (Phyllostachys edulis) forest in response to enclosure succession. The mixed Moso bamboo forests in the Wuyi Mountain Nature Reserve with 0, 4, 6, 11, 16, and 41 enclosure years were taken as the object of investigation. All the bamboo whips in the 2 m × 2 m sample plots were excavated layer-by-layer according to the soil layers of 0–20 cm, 20–40 cm, and 40–60 cm, and a total of 54 plots were dug. The morphological characteristics and nutrient contents of the Moso bamboo whips in the different soil layers were analyzed and evaluated. Enclosure management measures can not only effectively improve vegetation coverage, biodiversity, and biomass, but also improve soil moisture and nutrient status, indirectly affecting the vegetation, which is of great significance for preventing soil erosion. The results showed that the whip number, whip diameter, flagella number, whip length, and whip weight in the 0–20 cm soil layer were significantly increased by 169.2%, 11.0%, 197.5%, 113.7%, and 109.0% (p &lt; 0.05), respectively, compared with CK after 41 years of enclosure. The average internode length was significantly decreased by 27.9% (p &lt; 0.05) compared to CK after 41 years of enclosure. In the 20–40 cm soil layer, the whip diameter increased by 9.7% after 41 years of enclosure compared with CK, but the whip number, flagella number, whip length, and whip weight were significantly reduced after 16 and 41 years of enclosure compared to CK (p &lt; 0.05). In the 40–60 cm soil layer, the whip number, number of flagella, and whip length increased significantly after 6 and 11 years of enclosure compared with CK (p &lt; 0.05). In the 0–20 cm soil layer, the contents of total nitrogen, total phosphorus, and total potassium in CK were higher than those in other enclosure years, and the soluble sugar content in CK was significantly higher than that in the enclosures of 4, 6, 11, and 41 years by 39.8%, 37.9%, 34.4%, and 34.0% (p &lt; 0.05). The organic carbon content was significantly increased by 14.8%, 12.7%, 7.2%, and 7.1% (p &lt; 0.05) after 4, 6, 11, and 41 years of enclosure compared with CK, respectively. The starch content was significantly increased by 34.1%, 23.0%, and 62.7% (p &lt; 0.05) after 6, 16, and 41 years of enclosure compared with CK, respectively. In the 20–40 cm and 40–60 cm soil layers, the total nitrogen content and soluble sugar content in CK were significantly lower than that in the enclosures of 4 years (p &lt; 0.05), the total phosphorus and total potassium content in CK were significantly higher than that in the enclosures of 41 years (p &lt; 0.05), and the organic carbon content and starch content in CK were significantly higher than that in the enclosures of 6 years (p &lt; 0.05). In summary, enclosure measures were implemented for Moso bamboo forests in the Wuyi Mountain Nature Reserve, which promote the growth of Moso bamboo whips and optimize the structure of bamboo whips.

Exclosure effects on soil physicochemical properties and woody species diversity in the south Rift valley basin of Ethiopia

Establishing exclosures has become common rehabilitation and restoration of degraded lands in Ethiopia. This study examined the effects of exclosure on identified soil physical and chemical properties, and woody diversity at the Wamole sub-watershed. Representative soil samples were taken from the open grazing land and eight-year-old exclosure. Six transects and 18 plots, with an area of 20 m × 20 m and containing nine from each open grazing ground and nine from the exclosure, were constructed alongside to sample the vegetation. From every plot, by ‘X’ design, composite soil samples were collected for investigation of total nitrogen (TN), available phosphorus, cation exchange capacity (CEC), soil pH and soil organic carbon content (SOC), and the bulk density (BD) of the soil, 18 undisturbed soil samples were taken from 0 to 20 cm deep. 34 and 28 woody species belonging to 25 and 20 families were registered between exclosure and adjacent open grazing land respectively. Significantly (P < 0.05) higher Index Shannon-Wiener (3.36) in the exclosure indicated better species diversity in the exclosure than in the open grazing land (3.13). Soil properties such as available phosphorus, pH, OC, TN, and CEC showed significant differences (p < 0.05) across different land uses. Exclosures facilitated to reclaim of degraded lands by re-establishing vegetation and improving soil nutrient status in a comparatively short period. It suggests that further research on socio-economic aspects of exclosures has to bring livelihood improvement in the locality to establish additional degraded open grazing lands in the research sub-watershed.

Linking the rhizosphere effects of 12 woody species on soil microbial activities with soil and root nitrogen status

The rhizosphere effect depicts the changes in soil physical, chemical, and biological properties due to altered microbial activity in response to root activity, which has important implications for soil carbon and nutrient cycling. However, how the plant-induced changes in rhizosphere soil microbial activity correlate with root and soil nutrient status remains uncertain. Here we targeted 12 woody species of distinct growth forms, i.e., tree vs. shrub, in an urban park on a university campus in Beijing, China. We measured root carbon and nitrogen concentrations and soil properties of paired rhizosphere and bulk soils for each plant. We investigated how the rhizosphere effects on microbial properties, as indicated by microbial biomass and potential activity of soil extracellular hydrolases, varied among the 12 woody species and between trees and shrubs, as well as how they were regulated by bulk soil and root nitrogen status. In general, across the 12 species, root nitrogen content, which is a potential indicator of plant life span and nutrient acquisition strategy, was positively correlated with the rhizosphere effect on potential enzyme activity, while the inverse was true for root carbon: nitrogen ratio, which further verified the role of root functional traits in controlling soil nutrient cycling through the rhizosphere effect. Moreover, soil organic carbon, total nitrogen, and available nitrogen concentrations were all found to be negatively correlated with the rhizosphere effect on microbial properties, which highlighted the stimulation of rhizosphere microbial activity for nitrogen acquisition (the nitrogen-mining hypothesis). Trees and shrubs exhibited no significant differences in their rhizosphere effects, and there was a potential difference in the role of rhizosphere effect in regulating soil nitrogen cycling between legumes and non-legumes. Overall, our study highlights the role of plant nutrient acquisition strategy and soil nutrient status in regulating the rhizosphere effect of woody species on microbial-driven soil processes, which is essential for a better understanding of mechanisms by which plants sustain their nutrient supply.

Impact of Herbicides on Soil Fertility and Nutrient Uptake by Transplanted Rice (Oryza sativa L.) in Eastern U.P, India

A field experiment was carried out at Agricultural Research Farm, Institute of Agricultural Sciences, Varanasi during kharif 2017 and 2018 to evaluate the nitrogen intake by transplanted rice (Oryza sativa L.) and the available nutrient status of soil under ten weed control treatments. The treatment bispyribac-Na 9.1% (24.57 g/ha) + metsulfuron-methyl 1.2% (3.24 g/ha) + chlorimuron ethyl 1.2% (3.24 g/ha) recorded higher Organic carbon (0.47%), pH (7.38), EC(0.18 dS m-1), available N193.48 kg/ha, P22.46 kg/ha, and K 221.56 kg/ha in soil, higher nutrient (N, P and K) content in grain 1.14, 0.33, 0.38%, and straw 0.74, 0.12, 1.74% and protein content 6.81 &amp; 4.42% in grain and straw, respectively. improved N, P, K uptake in grain 58.57, 17.06, 19.23 kg/ha and straw 71.00, 11.36, 166 kg/ha, respectively over weedy check (grain 46.09, 13.35, 15.10 kg/ha and straw 58.58, 9.38 and 137.65 N, P and K respectively). This treatment exhibited positive performance of soil fertility and N, P and K uptake by transplanted rice.