Improve Soil Physical Properties Research Articles

Wildflowers and compost amendment can improve infiltration in soils impacted by construction

AbstractVegetation is an important component of stormwater control measures, as vegetation can reduce erosion and runoff. While grass is typically used in stormwater control measures, wildflowers can be planted to reduce maintenance and improve pollinator habitat. Previous studies have established that tillage followed by establishment of a vigorous vegetation stand can increase infiltration relative to compacted soils. Compost can also improve soil physical properties and fertility. The goal of this study was to evaluate potential improvements in infiltration using tillage together with compost and either grass or wildflowers. Wildflowers or grass were planted on tilled soil with or without compost at three sites in North Carolina. Bulk density, infiltration rate, root mass density, and penetration resistance were measured every 6 months over a 30‐month period. A subset of plots received wheel traffic from a mower. Compost application reduced bulk density compared to tillage alone. Compost improved infiltration at two sites (46%–50%). Wildflowers improved infiltration at all sites (30%–43%) compared to grass. Few differences were observed in root mass and penetration resistance. Mower traffic reduced soil improvements more in grassed plots than wildflower plots due to higher mowing frequency. Results suggest compost and/or wildflowers together with tillage (at establishment) provide viable options to improve soil conditions and infiltration rate in construction impacted soils.

Assessing the effectiveness of cover crops on ecosystem services: a review of the benefits, challenges, and trade-offs

ABSTRACT While it is crucial to consider the ecological trade-offs of cover crop effects to promote sustainable agricultural production, there has been limited analysis of the combined effects of cover crops on various ecosystem services. For this purpose, we synthesized 43 meta-analysis and review studies comparing cover crops to monocropping in order to investigate benefits, challenges, and trade-offs among ecosystem services under cover crop implementation. We summarized the current state of knowledge of cover crops effectiveness across 11 ecosystem services in three categories (regulating, provisioning and supporting). We identified the factors influencing the relative benefits and risks of integrating cover crops into crop production systems. These factors include farm practices, planting and termination season, species of cover and main crop, climatic zone and soil properties, cover crop biomass, and residue management. Our findings highlight that compared to monocropping, in general, cover cropping enhances soil biodiversity and nutrient cycling, prevents runoff and Nitrogen leaching, improves soil physical properties and carbon sequestration over the long term, and suppresses pests and weeds. However, trade-offs comprise inconsistencies in primary crop yields and soil water provision. Overall, our result highlighted that a multifunctional cover crop implementation provides substantially more regulating and supporting than other ecosystem services.

Short‐term effects of double‐layer ploughing reduced tillage on soil structure and crop yield

AbstractSoil tillage is widely acknowledged to affect soil characteristics and agricultural productivity. This research investigates the short‐term effects of various tillage methods on soil physical properties and crop yields at a Central German field site with a dry climate (mean temperature 9.5°C; annual precipitation 470 mm). Three tillage approaches were evaluated: conventional plough tillage (25 cm depth), cultivator tillage (18 cm depth), and double‐layer plough tillage (15 and 30 cm depth). We assessed soil physical properties through standard laboratory analyses, compression tests, soil pore structure via X‐ray computed tomography (X‐ray CT) and crop yields over 3 years. The results indicate that cultivator tillage approach increased soil bulk density relative to conventional tillage, especially in the second year, though this effect diminished over time. Double‐layer plough tillage emerged as a viable short‐term alternative to conventional tillage, achieving comparable soil bulk density. Saturated hydraulic conductivity values were generally higher for soils under conventional tillage or double‐layer plough tillage than for cultivator tillage, highlighting their soil loosening effect. Classical soil analysis methods combined with X‐ray computed tomography provided valuable insights into tillage induced changes to soil structure. Cultivator tillage resulted in a distinct pore structure with reduced macroporosity and pore connectivity. Despite notable soil property variations, crop yields remained consistent across the tillage methods. Overall, double‐layer plough tillage presents a sustainable option, moderately improving soil physical properties while maintaining crop yields. This study highlights the need to assess the short‐term effects of tillage on soils and contributes to the broader dialogue on optimizing tillage strategies for effective soil management and crop production.

Converted paddy to upland in saline-sodic land could improve soil ecosystem multifunctionality by enhancing soil quality and alleviating microbial metabolism limitation

Soil salinization is one of the major soil degradation threats worldwide, and parameters related to soil quality and ecosystem multifunctionality (EMF) are crucial for evaluating the success of reclamation efforts in saline-sodic wasteland (WL). Microbial metabolic limitation is also one of the main factors that influences EMF in agricultural cropping systems. A ten-year localization experiment was conducted to reveal the key predictors of soil quality index (SQI) values, microbial metabolic characteristics, and EMF in different farmland cropping systems. A random forest model showed that the β-glucosidase (BG), cellobiosidase (CBH) and saturated hydraulic conductivity (SHC) of the SQI factors were the main driving forces of soil EMF. Compared to monoculture models, such as paddy field (PF) or upland field (UF), the converted paddy field to upland field (CF) cropping system was most effective at improving EMF in reclaimed saline-sodic WL, increasing this metric by 275.35 %. CF integrates practices from both PF and UF planting systems, improved soil quality and relieves microbial metabolic limitation. Specifically, both CF and PF significantly reduced soil pH (by 16–23 %) and sodium adsorption ration (SAR) (by 65–83 %) and significantly reduced the abundance of large macroaggregates. Moreover, CF significantly improved soil saturated hydraulic conductivity relative to PF and UF (p < 0.05), indicating an improvement in soil physical properties. Overall, although reclamation improved SQI compared to WL (0.25), the EMF of CF (0.56) was significantly higher than that of other treatments (p < 0.05). Thus, while increasing SQI can improve soil EMF, it was not as effective alone as it was when combined with more comprehensive efforts that focus on improving various soil properties and alleviating microbial metabolic limitations. Therefore, our results suggested that future saline-sodic wasteland reclamation efforts should avoid monoculture systems to enhance soil EMF.

Long‐term organic management: Mitigating land use intensity drawbacks and enhancing soil microbial redundancy

AbstractBackgroundSoils under organic farming systems exhibit better quality and higher biological activity than conventional systems. Manure addition, especially coupled with reduced or no tillage, significantly enhances microbial biomass and activity by improving soil physical properties and providing carbon (C) and nitrogen (N) sources. While several studies have examined the effects of transitioning from conventional to organic farming on soil chemistry and biochemistry, limited research has explored the influence of land use variations on soil fertility within long‐term organic farming systems.AimsTherefore, the aim of this study was to assess how three different land uses—pasture, vegetable crops, and orchard—affected soil fertility under a long‐term organic farming system.MethodsSoil samples were collected from the 0 to 15 cm layer of plots used for pasture, vegetable crops and orchard, being the latter cover cropped with legumes, and analyzed to determine chemical and biochemical soil parameters.ResultsContrary to expectations, high land use intensity (vegetable crops and orchard soils) resulted in increased soil organic C and total N, compared to low intensity (pasture). Such an increase was ascribed to farmyard manure addition that counteracted the negative impact of tillage. Consequently, microbial biomass C and activity also increased. The greatest availability of organic substrates favored bacteria, particularly gram‐positive strains, shaping the microbial community. However, despite changes of microbial biomass and of the main microbial groups, microbial activity was only slightly affected, suggesting high functional redundancy of microorganisms in long‐term organic farming soil.ConclusionsResults suggested that if land use intensification provides for organic supply, its negative impact on soil fertility may be mitigated.

Application of Clay and Rice Husk Biochar and its effect on Soil Pore Distribution of Psamment and Corn Yield

Abstract The effect of clay and rice husk biochar application under minimum soil tillage on soil pore distribution of psamment and corn yield was conducted in Batang Anai District, Padang Pariaman Regency. Plot experiment consisting of four treatment (without clay or biochar; 20 ton clay/ha; 20 ton biochar/ha; and 20 ton biochar/ha + 20 ton clay/ha) with 3 replications. Soil samples were analyzed at the soil laboratory, Faculty of Agriculture, Andalas University Padang and Soil Laboratory, Bogor Soil Research Institute. Soil physical properties were categorized by soil criteria, while crop growth and yield data were statistically analyzed using F test and DNMRT at 5% level. Results showed that application of 20 ton/ha of clay and rice husk biochar improved soil physical properties of psamment namely: decreasing soil bulk density, increasing total soil porosity, aeration pores, and available water pores. The application of biochar and clay has also increased the growth and yield of corn.

Root-derived carbon stocks in formerly deep-ploughed soils – A biomarker-based approach

Roots can add significant amounts of carbon (C) to the subsoil, which improves soil physical properties and can mitigate climate change. About 5% of croplands in Germany have been deep-ploughed (30–120 cm) at least once. This can provide better root access to the subsoil and may increase yields, but little is known on the fate of root-derived C in the subsoil (at depth greater than 30 cm) after deep-ploughing. We hypothesized that five decades after deep-ploughing, root-derived C stocks were higher than conventionally ploughed treatments due to better root development. We analysed suberin and cutin monomers as tracers for root- and shoot-derived C at three former deep-ploughed sites in Northern Germany with different soil textures and deep-ploughing depths. Concentrations of suberin monomers in the soil positively correlated with root biomass; this was most pronounced at one sandy site, but had higher variability at the other two sites due to crops with different root systems in the crop rotation, lower root development, and more favourable conditions for C decomposition. Suberin contributed more to the bulk soil organic carbon (SOC) stocks than cutin throughout the soil profile at all sites. The contribution of suberin monomers to the bulk SOC stock at silty site Banteln and the sandy site Essemühle was 38% higher in the deep-ploughed plots than at the reference plot, respectively, these differences were most visible in the subsoil of Essemühle. We conclude that as C stocks and root development increase, suberin SOC stocks also increase, especially in sandy subsoils with low pH.

Effects of Different Tillage Depths on Soil Physical Properties and the Growth and Yield of Tobacco in the Mountainous Chongqing Region of China

Tobacco (Nicotiana tabacum L.) is the most important cash crop in the mountainous Chongqing region, where mini rotary tillers are widely used for land preparation. The decline in tobacco yields has been partially attributed to deteriorating soil physical properties and the formation of plough pans as a result of the repeated use of the mini rotary tiller. The objective of this study was to evaluate the effects of different tillage depths on soil physical properties and the growth and yield of tobacco. Three tillage depths were evaluated: mini rotary tillage to 15 cm (T15) as a control, medium-deep tillage to 25 cm (T25), and deep tillage to 35 cm (T35). Total porosity, capillary porosity, and soil water content were measured for each treatment, and the root distribution, agronomical traits, and dry matter accumulation were monitored at different growing stages. Tobacco yield and output value were determined following the harvest. Compared to T15, T35 significantly increased total porosity and capillary porosity in the 10–40 cm soil layer and soil water content in the 0–40 cm soil layer, while T25 improved soil physical properties but not significantly. T35 significantly promoted dry matter accumulation and root, stem, and leaf growth compared to T15, while differences in some agronomic traits between T25 and T15 were not significant. Compared to T15, T35 and T25 increased the tobacco yield by 17.2–18.9% and 8.0–10.1%, respectively, and increased the output value by 44.4–46.4% and 29.2–32.6%, respectively. The results indicate that deep tillage improves soil physical properties, breaks plough pans, stimulates root growth, and increases tobacco yield and output value.

Influence of tillage methods combined with mulching on soil physical properties and potato yield in dry farming area under different precipitation years.

We conducted a field experiment in the dry farming area in south Ningxia from 2018 to 2021, to explore the influence of tillage methods combined with mulching on soil bulk density, aggregate content, soil water storage and potato yield under different precipitation years. There were four tillage methods (15 cm depth ploughing, and 30 cm, 40 cm and 50 cm depth subsoiling) and three mulching measures (mulching with oat straw, plastic film and no mulching), with the ploughing depth of 15 cm without mulching as control. The results showed the combination of tillage and mulching effectively reduced soil bulk density in 0-60 cm layer after three years of farming compared with that prior to the experiment. Under the same tillage mode, the best effect was achieved in mulching with oat straw under different precipitation years. To be specific, the best effect in 20 cm and 40 cm soil layers was achieved in mulching with oat straw for 30 cm depth subsoiling, in 60 cm soil layer for 15 cm ploughing in wet year, and for 40 cm depth subsoiling in 20 cm, 40 cm and 60 cm soil layers in normal and dry years. In 0-20 cm soil layer, the content of >0.25 mm soil aggregate was the highest for 40 cm depth subsoiling with oat straw mul-ching in all the three years. In 20-40 cm soil layer, the content was the highest for 15 cm depth ploughing with oat straw mulching in wet year, and for 40 cm depth subsoiling with oat straw mulching in normal and dry years. In 40-60 cm soil layer, content was the highest for 15 cm depth ploughing with plastic film mulching, 30 cm depth subsoiling with plastic film mulching, and 30 cm depth subsoiling with oat straw mulching in wet, normal and dry years, which was increased by 18.8%, 27.0%, and 35.8%, respectively, compared with the control. In the key growth stage (from squaring to tuber expansion) of potatoes, soil water storage in 0-100 cm layer was optimal for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling with oat straw mulching in normal and dry years, with an increase of 19.4%, 19.5%, and 23.7%, respectively. Potato yield was the highest for 30 cm depth subsoiling with oat straw mulching in wet year and for 40 cm depth subsoiling in normal and dry years, with an increase of 84.6%, 81.7%, and 106.3%, respectively. The correlation analysis showed that improved soil physical properties played a significant role in increasing potato yield, with the most significant role of soil bulk density and soil water storage at the squaring stage. Potato yield was high at a tillage depth of 34.67-36.03 cm. We concluded that the combination of tillage method and mulching could effectively improve soil physical pro-perties and increase soil water storage in the growth stage of potatoes, thereby significantly increa-sing potato yield. Potato yield in dry farming area could be enhanced through 30 cm depth subsoiling with oat straw mulching in wet years, and 40 cm depth subsoiling with oat straw mulching in normal and dry years.

Humic acid application on soil stability indices and enzyme activity at different bell pepper water requirements

Use of organic materials helps in reducing the consumption of chemical fertilizers, contributing to the sustainability of agricultural ecosystems. Humic acid can improve soil structure, especially in soils with low clay content, aiding in water retention and enhancing water absorption by plants. This characteristic has led to the attention of humic acid application in drought stress, particularly in arid soil regions. The present study aimed to investigate the simultaneous effects of humic acid and plant water requirements on the physical and biological properties of soil under bell pepper cultivation. The factorial experiment was conducted in a completely randomized block design with three levels of humic acid: 0 (HA0), 2 (HA2), and 4 (HA4) g/Kg of soil and four levels of plant water requirements: 60 (L60), 80 (L80), 100 (L100), and 120 % (L120), with four replications under greenhouse conditions. Bell pepper seedlings were transferred to 10 Kg pots after applying humic acid treatments and after the establishing of seedlings, plant water requirement treatments were applied for 80 days. During this period, plants were maintained at a temperature of 25 degrees Celsius during the day, 18 degrees Celsius at night, and a relative humidity of 75%, with a carbon dioxide concentration of 80 milligrams per liter. The results of this study showed that treatments L80HA4, L100HA4, and L120HA4 had the most significant impact on improving soil physical properties, such as normal stability index, total soil stability index, mean weight diameter of soil particles, soil particle stability, geometric mean diameter of soil particles, and reduction in soil particle destruction percentage. The highest values of wet and dry weight diameter of soil particles were observed in treatment L100HA4, which were 42.92%, 74%, and 67.01% higher, respectively, compared to the control (L60HA0). In contrast, the highest percentage of soil particle destruction was observed in treatment L60HA0, showing a 32.90% increase compared to treatment L100HA4. Furthermore, the best performance of bell pepper yield was observed in treatments L80HA4, L100H4, and L120HA4, although the differences between treatments were not statistically significant. The application of humic acid, in addition to improving bell pepper yield, increased water use efficiency and reduced water use. The lowest yield (3283 Kg/ha) and the lowest water consumption (3584 cubic meters/ha) were observed in treatments L60HA0 and L60HA4, respectively. Additionally, the results showed that the highest water use efficiency observed in L80HA4 treatment (7.45 Kg/m³), while the lowest was in L60HA0 treatment (0.80 Kg/m³). Moreover, humic acid significantly influenced the activity of soil enzymes, including soil phosphatase and urease. With more application of humic acid, soil moisture retention, microbial biomass carbon, urease, phosphatases activities increased. However, in treatments with full water requirements and 20 percent more than plant water requirements, enzyme activities decreased.

Biochar modifies soil physical properties mostly through changes in soil structure rather than through its internal porosity

AbstractBesides its carbon sequestration potential, biochar application generally improves soil physical properties, but the magnitude of its impact and the underlying mechanisms remain debated and depend on soil type, biochar application rate, and age. The objective was therefore to determine the effect of biochar application rate and age on physical properties of agricultural soils in a temperate climate. On a silt loam and a sandy loam soils, we compared the physical properties of fresh biochar (1% and 2% w/w) or century‐old biochar (0.5%–1% w/w; 19th‐century kiln sites)‐enriched soil samples with biochar‐free soil samples. Biochar pore network characteristics were determined using helium pycnometry, mercury intrusion porosimetry, scanning electron microscopy observation, and electron dispersive X‐ray spectrometry, whereas location of biochar particles within soil structure was analyzed using optical microscopy observations. Fresh biochar application decreased bulk density by 16.8% and increased saturated water content by 16.0% and macroporosity by 78.8%. These effects were attributed to soil structure improvement rather than to biochar porosity. Soil type and biochar application rate had a limited impact. In the long‐term, biochar effects were mostly nonsignificant, which might result from its fairly low content in kiln sites and from the clogging of its internal porosity by clay particles. Biochar was thus able to improve some soil physical properties in the short‐term, but these effects could no longer be detected in the very long‐term. Further investigating the time rate of change in soil physical properties over several decades following biochar additions to soil would therefore seem particularly relevant.

Short-term effects of brassica cover crops on soil quality indicators in organic production in high tunnels

The use of cover crops is aimed at sustaining soil health and productivity in the context of agricultural intensification and accompanying soil degradation. While cover crops have been extensively studied in field production systems, limited research has been conducted concerning their application in high-tunnel vegetable production. This study aimed to assess the effects of turnip (Brassica napus subsp. napobrassica (L.) Jafri) and swede Brassica rapa subsp. Rapifera Metzg) cover crops (CCs) on soil physicochemical and biological properties in an organic high tunnel system in southern Poland in 2017–2019. The planting sequence was as follows: winter cover crops/pumpkin/romaine lettuce/broad bean/chilli pepper. Soil analyses included measurements of bulk density, water capacity, soil aggregation, soil organic carbon (SOC), available soil nutrients, as well as microbial abundance and diversity. Rape crops produced a higher aboveground dry biomass (4.11 t ha−1) than swede (2.85 t ha−1), and the N content in their biomass was 101 kg N ha−1 and 75 kg N ha−1, respectively. The results presented that CC residue significantly contributed to soil organic carbon stock, retention of plant-available nitrogen, and improvement of soil physical properties, especially wet aggregate stability. Soils with the highest SOC concentrations were associated with the highest bacterial and fungal abundance. The most significant number of mesophilic bacteria was detected in the soil where turnip was grown as a cover crop (7.6 × 107 cfu g−1 DM soil). Moreover, a higher abundance of the tested nitrogen cycle bacteria was found in the soils after CC cultivation compared to the control soils, particularly bacteria reducing NH4 +-N and NO₃⁻-N. These findings highlight the importance of cover crop management practices in high tunnels, as they influence the composition of the total bacterial community and the abundance of N-cycling microbial guilds.

Do organic farming practices improve soil physical properties?

AbstractOrganic farming (OF) is a reemerging system that could address food security and adverse environmental footprints of conventional farming (CF). However, how OF affects the soil physical environment, an essential pillar for soil ecosystem service delivery, is not well understood. This paper (1) reviews published global literature up to 13 July 2023 regarding the impacts of OF on soil physical properties compared with CF and (2) underlines research needs. Literature indicates OF improves some soil physical properties relative to CF although studies on some properties were few. Specifically, OF increased wet aggregate stability, saturated hydraulic conductivity, and plant available water in 55% of studies. OF also increased mesoporosity (5–500 μm) and cumulative water infiltration. However, OF had mixed or no effects on soil compaction indicators (i.e. bulk density, penetration resistance). Not all studies reported both soil physical properties and soil organic C to assess how amendment‐induced increase in soil organic C affected physical properties. Based on studies reporting both properties, physical properties such as wet aggregate stability were not significantly correlated (r = 0.12; p &gt; .10) with soil organic C. Variability in data and frequent tillage under OF likely obscured this relationship. Factors tended to affect OF impacts on physical properties in this order: amendment type &gt; duration &gt; others. Most OF studies (1) used animal manure amendments, (2) were long‐term (&gt;10 years), and (3) were conducted in medium textured soils, highlighting the need for more comprehensive assessments of OF and soil physical properties under different management conditions. In general, OF improves some soil physical properties, which can contribute to OF sustainability.

Mode and experiments of a straw ditch-burying returning and maturing in cold region of Northeast China

The current agronomic model of returning straw litter to soil (straw returning) involves crushing and mixing the straw with soil, which leads to shallow burial and ineffective decomposition of the straw. To address this issue in the cold region of Northeast China, this study proposed a method of burying and composting rice straw in furrows for returning to the field, and developed a matching machinery. Based on long-term experiments of burying straw in soil in spring and autumn, in this study, the operating parameters, postoperative straw decomposition effects, and influence of soil bulk density were analyzed. The results showed that the straw returning rate was inversely proportional to the forward speed and proportional to the furrow opening rotation speed and exhibited an increasing-then-decreasing trend with increasing collecting rotation speed. Taking into account both straw returning rate and operational efficiency, the recommended optimal operating parameters for the machinery unit were a forward speed of 0.4 m s−1, a raking speed of 180 r min−1, and a ditching speed of 420 r min−1. Under the spring model of burying straw in soil, straw treated with the composting agent was more likely to be fully decomposed in a short period, with a maximum total decomposition rate of up to 97.23%. Burying straw in soil effectively reduced soil bulk density, and straw returning in spring was more conducive to improving soil physical properties than straw returning in autumn. The value of this research lies in the integration of agricultural machinery and agronomy, providing insights for the development and design of related equipment, as well as offering a new approach for the effective treatment and utilization of straw in cold regions.

Minor millets based agroforestry of multipurpose tree species of Bhimal (Grewia optiva Drummond J.R. ex Burret) and Mulberry (Morus alba L.) for resource conservation and production in north western Himalayas – 10-year study

In a long term study 2009–2018 at ICAR-IISWC, Dehradun, the uniqueness of minor millets based agroforestry systems (AFSs) for effective soil water conservation and biomass production in foot hills of Himalayas were evaluated. The Morus alba (Ma) based AFS was found to be the most productive and profitable system producing 1.1 and 1.8 t ha−1yr−1 of finger millet and wheat grain, respectively besides carbon stocks of 22.9 t ha−1. Morus based agroforestry system produced the highest yield of green fodder and dry fuel wood at 5.1 and 4.5 t ha−1yr−1, respectively after 10 years of planting. The reduction in minor millets yield was offset by the additional production of tree fodder and dry fuel wood by the Multiparous trees (MPTs) in the AFSs.The minimum soil loss was recorded inMa + barnyard millet (BM) based AFS followed byMa + finger millet (FM) at 15.4 and 16.4 t ha−1yr−1 in comparison to cultivated fallow at 25.6 t ha−1. The traditional millets recorded the identical soil loss of 19.7 t ha−1 during the period. The MPTs land use recorded the soil loss of 22.4–22.8 t ha−1. Similarly, the lowest run off was recorded in millet-AFSs ranging from 23.0% to 25.6% than cultivated fallow without crops (38.9%). The highest soil and runoff conservation efficiency was observed in order of AFSs> sole millets > MPTs > cultivated fallow.Millet based AFS led to the improvements in soil physical properties and fertility status significantly.Ma + FM based AFS recorded favourable changes in bulk density (B.D.), water stable aggregates and organic carbon, OC, 0.73%. Grewia optiva + BM recorded the highest OC (0.75%) besides plant nutrients P (183.2%) and K (51.1%) over the cultivated fallow. Agroforestry systems of Ma+FM-wheat and Ma+FM-toria were the most productive and robust systems economically in respect of benefit: cost ratio and net present value.

Could continuous rice cropping increase soil fertility and rice productivity by rice straw carbonized utilization in cold areas? - A 6-year field-located trial.

Biochar amendment can benefit rice growth, but the long-term effects of rice straw carbonized utilization (RSCU, biochar, and biochar-based fertilizer) on rice production in cold areas are still unclear. Herein, we conducted a field experiment over 6 years with four treatments: F (conventional fertilization) as the control, RB1 (biochar, 3 t·ha-1), RB2 (biochar, 6 t·ha-1), and RBF (biochar-based fertilizer, 0.75 t·ha-1). We found that rice straw biochar significantly improved soil physical properties by reducing soil bulk density, increasing soil porosity and liquid and gas phases ratio, and enhancing soil aggregate stability. RSCU also increased soil fertility by improving soil organic carbon (SOC), active organic carbon, and soil nutrients (N, P, K) and their availability, as indicated by an increase in soil C:N and a decrease in soil N:P. Moreover, biochar increased soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and enzyme activities. As a result, RSCU increased rice yield, which was positively correlated with soil total porosity, total phosphorus, available potassium, dissolved organic carbon (DOC), easily oxidizable carbon (EOC), labile fraction of organic carbon (LFOC), and urease activity. RB2 had the highest rice yield (5.94% higher than F). Our study suggests that RSCU can synergistically improve the rice straw utilization rate, soil fertility, and rice productivity in cold areas.

Effect of Inorganic Fertilizers and Organic Manures on Physical Properties of Soil: A Review

Deterioration of physical properties of soil and there after depletion the soil fertility are the main constrains in food and environment security of any country. This review paper summarizes the current knowledge and information on the effect of inorganic fertilizers and organic manures on soil physical properties. The use of inorganic fertilizer or organic fertilizer alone has both positive and negative effects on soil properties, plant growth and nutrient availability. Most of earlier investigators confirmed that combined application of inorganic fertilizers and organic manures improved the physical properties and available nutrient status in soils. Organic manures improve physical properties of soil but they are comparatively low in nutrient content, addition of larger quantity of manures is required for successful plant growth. However, inorganic fertilizers is contain all the essential nutrients which are early accessible for plants. Due to continuous use of inorganic fertilizers alone causes soil organic matter degradation, soil acidity or alkalization, soil deterioration and environmental pollution, so integrated or mixed inorganic and organic nutrient management system is an alternative system for the sustainable and cost effective management of soil and the result is improve in soil properties and raising soil fertility without affecting environment. The objective of the review is to assess the effect of inorganic fertilizer and organic manure on physical properties of soil. The study revealed that appropriate application of inorganic fertilizers with organic manures improves soil physical properties and increases the productivity without negative effect on soil health than the values obtained by organic or inorganic fertilizers separately.

Mixture of winter cover crops improves soil physical properties under no-tillage system in a subtropical environment

The monocrop of winter cover crops is a common practice under no-tillage system (NTS) in subtropical environment but increase diversity of cover crop species can be an alternative to improve soil physical quality, with positive effects on crop production. This study evaluated whether using a greater diversity of cover crop species affects soil physical properties, as well as grain yield of soybean (Glycine max L.) and common bean (Phaseolus vulgaris L.) under NTS in three growing seasons. The experimental design was in randomized blocks with four replications. The treatments were monocrop of black oat (Avena strigosa Schreb.); intercropping of black oat and turnip (Brassica napus L.); and a mixture of black oat, turnip, white oat (Avena sativa L.), rye (Secale cereale L.), white lupine (Lupinus albus L.), and common vetch (Vicia sativa L.). Cover crop biomass yield, soil physical properties, and grain yield of summer crops were evaluated. Using a mixture of cover crops improved soil physical properties by decreasing soil bulk density up to 5 %, increasing soil air-filled porosity at –100 hPa (0.0–0.2 m) up to 27 % and saturated hydraulic conductivity (0.0–0.2 m) up to 300 %. Common bean grain yield and 1000-grain weight in succession to the mixture of cover crops increased by 15 % and 4 %, respectively. Soybean yield components were not affected by treatments. The increased diversity of winter cover crops improved soil physical properties in relation to monocrop in NTS, as well as improved crop yield of common bean, which is a shallower root growth specie, more sensitive to soil constraints.

IMPACT OF POTENTIALLY SOIL MINERALIZABLE NITROGEN (PMN) ON SOIL HEALTH AND CROP PRODUCTION

Potentially Soil Mineralizable Nitrogen (PMN) is critical in soil health and crop production. This review paper explores the impact of PMN on soil health, crop production, different soil types, and mitigation strategies. It highlights the importance of PMN in enhancing nutrient availability, crop yield, and quality. The paper discusses the role of PMN in promoting soil organic matter accumulation, supporting microbial activity, and improving soil physical properties. Case studies illustrate the influence of PMN on different soil types and associated crops. Mitigation and management strategies are discussed, such as soil organic matter management, precision nutrient management, and crop rotation/diversification. The review also identifies future research directions, including refining PMN measurement techniques, integrating into nutrient management decision support systems, and exploring PMN interactions with other soil properties and environmental factors. Overall, effective PMN management is crucial for sustainable agriculture, and further research and collaboration are needed to advance our understanding and develop practical strategies for its implementation.

Forest soil inoculation with Bacillus subtilus reduces soil detachment rate to mitigate rill erosion

Rill erosion is one of the most important types of soil erosion that has caused the destruction of many lands in recent decades, and its management has become an essential issue in world research. This study has evaluated the effects of soil physical properties induced by Bacillus subtilis OSU 142 (B. subtilis) on the soil detachment rate (Dc) and rill erodibility (Kr) in the inoculated soil, compared to the uninoculated soil in rill erosion-prone areas of Northern Iran. For measuring Dc, a hydraulic flume was used at 5 slopes (from 4.3% to 34.2%) and 5 water discharges (from 0.31 l m−1 s−1 to 0.67 l m−1 s−1) with 7 replications. Moreover, three physical properties of soils including the bulk density, mean weight diameter and total porosity of soils were measured before and after inoculation. Dc was found to be significantly lower (on average - 52% for the average slopes) in the inoculated soil with the B. subtilis (IB) compared to the uninoculated soil (UB). Rill erodibility (Kr), also was notably reduced in the IB soil (−70%) relative to the UB soil. The variability of Dc in the two studied soils showed a positive correlation to bulk density (R2 = 0.87), and a negative correlation to mean weight diameter (P < 0.01) (R2 = 0.89). The clustering of soils in two distinct classes (inoculated and uninoculated) by agglomerative hierarchical cluster analysis (AHCA) revealed a clear difference based on the physical properties of the treated and control soils. Based on the findings of present study, direct inoculation of B. subtilis can be proposed as a new and suitable technique for the improvement of soil physical properties and the reduction of soil detachment rate, especially in rill erosion-prone areas.