Straw Incorporation Research Articles

Enhancement of Fertilizer Efficiency Through Chinese Milk Vetch and Rice Straw Incorporation

The incorporation of rice straw (RS) and Chinese milk vetch (CMV) with reduced chemical fertilizers (CFs) is a viable solution to reduce the dependency on CF. However, limited research has been conducted to investigate the impact of CMV and RS with reduced CF on rice production. A field trial was conducted from 2018 to 2021 with six treatments: CK (no fertilizer), F100 (100% NPK fertilizer (CF)), MSF100 (100% CF+CMV and RS incorporation), MSF80 (80% CF+CMV+RS), MSF60 (60% CF+CMV+RS), and MSF40 (40% CF+CMV+RS). The results revealed that compared with the F100, the MSF80 treatment maintained a significantly higher mean grain yield over the four years, with an increase of 5.8~24.5%. MSF80 treatment also improved nitrogen (N), phosphorus (P), and potassium (K) use efficiencies, sustainable yield index, and partial factor productivity. Soil organic matter (SOM), total nitrogen (TN), ammonium N (NH4+-N), nitrate N (NO3−-N), available phosphorus (AP), and available potassium (AK) contents were significantly enhanced under MSF80 across different growth stages in both 2020 and 2021 seasons over F100. Pearson correlation analysis revealed a strong positive correlation among SOM, TN, NH4+-N, AP, AK, and rice yield. Additionally, Partial Least Squares Path Modeling (PLS-PM) demonstrated significant relationships between organic amendments, soil nutrients, nutrient uptake, and yield. The above findings suggest that combining RS returning with CMV incorporation is a long-term sustainable strategy for maintaining soil health, and it could reduce fertilizer addition by 20% without prejudicing rice grain yield under a rice-green manure rotation system.

Legacy Effects of Long-term Straw Returning on Straw Degradation and Microbial Communities of the Aftercrop

Straw incorporation can improve soil fertility and soil structure. While numerous studies have explored the immediate impacts of straw return on soil properties and crop production, the legacy effects of long-term straw return remain less understood. In this study, the straw returning soil of a continuous 15 years （SS） and non-straw returning soil （NS） were collected from Dahe Experimental Station of Hebei Academy of Agriculture and Forestry Sciences in China. The simulation experiments of subsequent straw return were carried out in pots by adding straw to the two types of soil （SS and NS）, in which the degradation rate of straw was determined using the sandbag method, the number of culturable microorganisms was counted through a dilution coating plate, and microbial communities were characterized using high-throughput sequencing. The findings revealed that compared with that in NS, SS significantly increased the degradation rate of 15 d and 30 d straw by 14.16% and 26.57%； the number of soil culturable fungi in 0-60 days by 43.10%-185.92%； and the number of cellulose-degrading bacteria by 55.12%-92.04% at 0 d, 42 d, and 56 d. Additionally, after straw returning for seven days, the bacterial ACE index, fungal ACE index, and Chao1 index in SS were lower than those in NS, indicating that the microbial community richness in SS was significantly reduced. At the phylum level of bacteria, the relative abundances of Acidobacteria, Rokubacteria, and Planctomycetes in SS increased observably, with an increase of 25.92%-45.17%. The relative abundances of the phyla of fungi such as Olpidiomycota, Zoopagomycota, and Glomeromycota increased markedly, with an increase of 12.09%-176.00%. At the genus level of bacteria, the relative abundances of uncultured_bacterium_c_Subgroup_6 and uncultured_bacterium_o_Rokubacteriales in SS increased significantly, with an increase of 28.91%-31.26%, and at the genus level of fungi, the relative abundances of Paecilomyces, Penicillium, and Moesziomyces were significantly increased by 2.98%-8.79%. Network analysis showed the SS bacterial network had a higher interaction degree and network connection, and the fungal network structure was more complex and stable than that of the NS. RDA results showed that soil microbial community composition was significantly correlated with straw degradation rate. SS showed obvious legacy effects on straw degradation, the number of soil culturable microorganisms, and population structure in a certain period, and the microbial flora of SS was more conducive to the degradation of the straws.

Soil Greenhouse Gas Emissions and Nitrogen Dynamics: Effects of Maize Straw Incorporation Under Contrasting Nitrogen Fertilization Levels

Straw is widely incorporated into conservation agriculture around the world. However, its effects on greenhouse gas emissions (GHGs) and nitrogen dynamics under soils formed by the long-term application of different amounts of nitrogen (N) fertilizer are still unclear. An incubation experiment was conducted on soils collected from a field study after 6 years of contrasting N fertilization of 0 (low N), 187 (medium N), and 337 kg N ha−1 (high N), with and without maize straw. Straw amendment significantly stimulated both nitrous oxide (N2O) and carbon dioxide (CO2) fluxes (p < 0.05), and increased cumulative emissions by 0.8 and 19.0 times on average compared to those without straw incorporation. Medium-N soil observably weakened N2O emissions (23.8 μg kg−1) compared to high-N soil (162.7 μg kg−1), and increased CO2 emissions (1.9 g kg−1) compared to low-N soils (2.3 g kg−1) with straw amendment. Soil NH4+-N and NO3−-N invariably increased with rising soil N level, whereas straw promoted the turnover of mineral N by enhancing soil N fixation capacity. From the first day until the end of incubation, NH4+-N decreased by 79.0% and 24.7%, while NO3−-N showed a decrease of 58.8% or an increase of 75.2%, depending on whether straw was amended or not, respectively. Moreover, partial least squares path modeling and random forest mean predictor importance were used to find that straw affected GHGs by altering the N turnover capacity. Straw amendment increased GHGs and diminished the risk of losing mineral N by enhancing its turnover. Combining straw with medium-N soil could mitigate the greenhouse effect and improve the N and carbon (C) balance in farming systems compared to low- and high-N soils. This is recommended as a farmland management strategy in Northeast China.

Design and Testing of a Low-Speed, High-Frequency Straw Chopping and Returning Machine Using a Constant Breath Cam Mechanism

Straw incorporation offers significant advantages in agricultural crop cultivation systems. Mechanized methods constitute the predominant approach, potentially reducing yield costs and enhancing operational efficiency. The imperative to enhance the quality of straw chopping within the field is of particular significance, as suboptimal chopping quality can engender a cascade of issues, particularly seeding blockages. The straw chopping pass rate (CPR) is a pivotal metric for assessing the quality of straw chopping. Therefore, enhancing the CPR during the straw chopping process is necessary. This study introduces a novel maize-straw-chopping device with the ground as its supporting base. This device facilitates the rapid vertical chopping of maize straw through a constant breath cam transmission mechanism. Critical parameters were determined to optimize the performance of the chopping device by establishing mathematical models and kinematic simulation analysis methods. With the help of Rocky 2022.R2 software, the influence of the rotational velocity of the draft, tractor velocity, and blade edge angles on the CPR during the operation of the device was analyzed. The Box–Behnken test methodology was used to carry out a three-factor, three-level orthogonal rotation test to obtain the optimal working parameter combination. The results indicated that the maximum CPR value was achieved with a draft rotational velocity of 245 rpm, a tractor velocity of 3.8 km/h, and a blade edge angle of 20.75°. Finally, field validation experiments were conducted under these optimized conditions, with the average CPR of maize straw reaching an impressive 91.45%. These findings have significant implications for enhancing crop production practices.

Effects of Different Straw Incorporation Amounts on Soil Organic Carbon, Microbial Biomass, and Enzyme Activities in Dry-Crop Farmland

The direct input of straw to the field can increase the source and supply of soil carbon and nitrogen, change the soil microbial biomass and enzyme activity, and affect the soil organic carbon sequestration, which in turn affects soil fertility and quality. In this study, a three-year field orientation experiment was conducted to investigate the effects of straw input on soil microbial biomass, enzyme activity, and soil organic carbon at different straw incorporation amounts (0, 3000, 7000, and 14,000 kg/hm2). The results showed that soil microbial biomass, enzyme activity, and organic carbon content increased with the increase in straw amount, and the increase in 4-fold straw input (T4) treatment was significantly larger than that of other treatments; the microbial biomass, enzyme activity, and SOC (soil organic carbon) in different soil layers were 0–10 cm > 10–20 cm > 20–30 cm; and straw incorporation amounts had a significant effect on soil microbial biomass, enzyme activity, and SOC. The amount of straw input to the field had a highly significant positive effect on soil microbial carbon and nitrogen and SOC (p < 0.001). In conclusion, four times the amount of straw input to the field had the most obvious effect on enhancing soil organic carbon content, microbial biomass, and enzyme activity. This has important implications for the development of sustainable agriculture.

Straw Returning Methods Affects Macro-Aggregate Content and Organic Matter Content in Black Soils: Meta-Analysis and Comprehensive Validation.

Straw returning into the soil is a crucial method for boosting soil carbon levels. To research the influence of straw return practices on soil aggregates and organic matter content within the farmlands of the Northeast Black Soil Region, the objective was to clarify the varying impacts of these practices on soil carbon enhancement. In this study, 89 pertinent papers were acquired through a rigorous literature compilation. Meta-analysis and the linear regression method were employed to analyze the influence of field return methods, their duration on soil water-stable aggregates, and their organic matter content. Furthermore, the study delved into the trends in the variation of aggregates and organic matter in relation to mean annual temperature and precipitation. Our results showed that the straw-returning method has been discovered to predominantly bolster soil organic matter by altering the proportions of macro-aggregate content. Specifically, straw incorporation has led to a notable enhancement in the content of macro-aggregates (57.14%) and micro-aggregates (20.29%), in addition to augmenting the content of macro-, small, and micro-aggregate organic matter by 13.22%, 16.43%, and 15.08%, respectively. The most significant increase in large agglomerates was witnessed in straw return over a period of more than 5 years (115.17%), as well as shallow mixing return (87.32%). Meanwhile, the highest increase in the organic matter content of large agglomerates was recorded in straw return over 5 years (12.60%) and deep mixing return (8.72%). In the field validation experiment, a period of seven years of straw return significantly boosted the macro-aggregate content across various soil layers, ranging from 11.78% to 116.21%. Furthermore, among the various climatic factors, the primary determinants of disparities in study outcomes were the average annual temperature and average annual precipitation. Specifically, lower precipitation and higher temperatures were conducive to the enhancement of macro-aggregate formation and organic matter content.

Response characteristics of soil Cd availability to microbes in paddy soil with long-term fertilization and its impact on Cd uptake in rice

Long-term fertilization contributes to the accumulation of cadmium (Cd) in soils and crops, yet the effects of different fertilization regimes on soil Cd dynamics and its uptake in rice remain poorly understood. This long-term field experiment aimed to elucidate how different fertilization regimes influence Cd bioavailability and mobility in soil, thereby affecting Cd accumulation in rice. Four fertilization treatments were tested, including chemical fertilizer (CF), rice straw incorporation (RF), and low (LM) and high (HM) rates of manure fertilizers. Results revealed that manure fertilizers treatments (LM and HM) significantly reduced Cd concentrations in brown rice compared to other fertilization regimes, with levels falling below 0.2 mg kg−1. Compared to CF, the average Cd concentrations in brown rice under LM and HM were significantly reduced by 33.14 % and 15.88 %, respectively, and which was significantly reduced by 42.53 % and 27.70 % compared with RF. Additionally, the concentration of Cd in brown rice was significantly higher under HM than LM treatment. Partial least squares path model revealed that reductions in Avail-Cd and AciCd, coupled with the formation of low-crystalline iron plaque (IP-Feh and IP-Feh-Cd), were critical factors in decreasing Cd concentration in brown rice. Manure fertilizers reduced the availability of Cd in soil by increasing soil organic matter (SOM), pH, and the abundance of microbial phyla such as Latescibacterota and Gemmatimonadota. Manure application also increased cation exchange capacity (CEC) and Fe2+ concentrations in soil, promoting IP formation on rice roots and effectively preventing Cd2+ uptake. In conclusion, the application of manure fertilizers at low rates, particularly in combination with chemical fertilizer, is recommended to ensure the safe production of rice by mitigating Cd uptake.

Effects of different straw return methods on soil properties and yield potential of maize

Long-term continual straw return can enhance soil quality and increase crop yields by perpetually altering the soil environment. However, little is known about how different straw return methods affect soil physicochemical properties, enzymatic processes, and crop yields. The study aims to determine how different straw return practices improve soil structure, nutrients, enzyme activities, and maize yields. In this experiment, a field trial was conducted in 2021–2022 in the irrigated area of the Tumochuan Plain Irrigation District to determine the effects of four different straw returns on soil structure, nutrients, enzyme activities, soil quality, and maize yields. The four types of straw return included straw incorporation with deep tillage (DPR), straw incorporation with subsoiling (SSR), no-tillage mulching straw return, and farmer’s shallow rotation (CK). Our results showed that DPR and SSR enhanced water retention capacity by reducing the bulk weight of the 0–45 cm soil layer. DPR and SSR significantly increased soil organic C (12.76%), total nitrogen (25.32%), and available nutrients (i.e. AP, NO3−–N) in the 0–45 cm soil layer compared to CK, whereas there were no differences between straw-returned treatments in the 0–15 cm soil layer. Finally, maize yield was significantly increased by 13.14% and 11.41% in the second year of DPR and SSR, respectively, compared to CK. This study demonstrated that DPR and SSR are effective at enhancing the agricultural utilization of crop residues and represent feasible strategies for improving physical, chemical, and biological processes in continuous maize cropping systems, leading to increased crop productivity.

Trade-off of greenhouse gas emissions from double-cropped rice due to straw retention and zero tillage practices

CONTEXTZero tillage and straw retention have been presented large scale to curb the menace of straw burning and sustaining soil health in rice production systems. At the same time, we know rice cultivation particularly double rice cropping system is an anthropogenic source of atmospheric greenhouse gas (GHGs) emissions, mainly, Methane (CH4), Nitrous oxide (N2O), and Carbon dioxide (CO2). Thus, it is important to know how straw retention and zero tillage affect the GHGs emissions in the rice-rice system. OBJECTIVEThe study, we made an effort to assess the straw retention/incorporation and zero-tillage (ZT) practices on GHGs emissions, yield, and soil labile carbon pools in rice, to identify sustainable practices that reduce GHG emissions, improve soil health, and at the same time addresses the issue of straw burning. METHODSA two-year field study was conducted with four (04) treatments; (i) Immediate incorporation of rice straw after harvesting of previous crop (IIRS); (ii) Zero-tillage (with straw retention) with glyphosate spray (ZT); (iii) Spreading of rice straw over field (SRS); and (iv) Zero-tillage (with straw retention) without glyphosate application (ZT + SR). The GHGs fluxes were measured during both straw decomposition (before rice transplanting) as well as rice growing periods during both wet and dry seasons of the two consecutive years. RESULTS AND CONCLUSIONSThe average seasonal Methane (CH4), Nitrous oxide (N2O), and Carbon dioxide (CO2) emissions and global warming potential (GWP) were significantly higher in IIRS followed by SRS, ZT, and ZT + SR during straw decomposition as well as rice growing periods. Similarly, the soil labile carbon pools and enzymatic activities were also higher in IIRS as compared to other treatments. Moreover, the increased percentage of SOC from initial to final was higher in IIRS (25.8 %), followed by SRS (23.3 %), ZT (20.7 %), and ZT + SR (17.9 %). However, the crop yield was not significantly influenced by the straw incorporation/retention and tillage practices. So, it is evident there is a trade-off of soil carbon improvement & GHGs emissions in zero tillage (ZT) and straw retention/ incorporation practices. Straw retention/incorporation in soil on one hand increased carbon storage but at the same time also enhanced GHGs emissions. Zero tillage (with straw retention) without glyphosate spray could be recommended for sustainable straw management. SIGNIFICANCEThe study identifies zero-tillage with straw retention without glyphosate spray (ZT + SR) for sustainable straw management, which increases the carbon build-up and decreases the GHGs emissions while addressing the issue of straw burning.

Effects of Straw Addition on Soil Priming Effects Under Different Tillage and Straw Return Modes.

This study aims to investigate the impact of straw addition on soil activation effects under different tillage practices, providing a scientific basis for establishing reasonable straw return measures in the southern Northeast Plain, thus enhancing soil fertility, and mitigating greenhouse effects. Soil samples were collected from various straw return practices that were conducted continuously for two years as follows: rotary tillage without straw return (RTO), deep tillage combined with straw incorporation (PT), rotary tillage with straw incorporation (RT), and no-till with straw cover (NT). The samples were incubated in the dark at 25 °C for 70 days. We measured the CO2 release rate and cumulative release, apparent activation effect, soil organic carbon, active microbial biomass organic carbon, soluble organic carbon, and easily oxidizable organic carbon to clarify the effects of straw addition on soil activation under different tillage practices. The results indicate that a straw addition promotes the mineralization of soil organic carbon while also increasing the content of active organic carbon components. The CO2 release rates and cumulative release under different tillage practices were as follows: PT > NT > RT. The contents of the active microbial biomass organic carbon, soluble organic carbon, and easily oxidizable organic carbon increased by 16.62% to 131.88%, 4.36% to 57.59%, and 12.10% to 57.97%, respectively, compared to the control without the straw addition. Except for the RT practice, the addition of straw significantly enhanced the instability of soil organic carbon in the PT, NT, and RTO practices, with increases of 51.75%, 48.29%, and 27.90%, respectively. Different straw return practices altered the physical and chemical properties of the soil, resulting in significant differences in the strength of the apparent activation effect. Notably, the apparent activation effect of RT was reduced by 86.42% compared to RTO, while that of NT was reduced by 36.99% compared to PT. A highly significant positive correlation was observed between the apparent activation effect and the unstable carbon components in the soil, indicating that higher levels of easily decomposable organic carbon corresponded to stronger apparent activation effects. In conclusion, it is recommended that in this region, rotary tillage should be adopted for straw return in the first 2 to 3 years, as this practice is beneficial for the formation and stabilization of organic carbon in the short term. As the duration of straw return increases, adjustments can be made based on the degree of soil organic carbon retention and soil fertility status.

Growth and yield responses of maize to different tillage practices and straw incorporation under different levels of gypsum in a saline-sodic soil

Soil salinity is one of the significant issues in crop production and its adverse effects have been noticed at various stages of a crop life cycle therefore to assess the remedies for mitigation of soil salinity, the present study was conducted in Khipro district, Sanghar, Sindh, Pakistan during 2018-19. The experiment was laid out in Randomized Complete Block Design (RCBD), to evaluate the growth and yield responses of maize to different tillage practices and straw incorporation under different levels of gypsum in a saline-sodic soil. The factorial study was consisted of three factors including: Tillage practices (shallow tillage [ST] and deep tillage [DT], Wheat straw incorporation (3, 7, and 10 ton. ha-1) and gypsum rates (13.5, 9 and 4.5-ton ha-1). The comparative results showed that Deep Tillage DT with wheat straw incorporation at 10-ton ha-1 (DTWS10) had significantly higher result in term of growth and yield traits followed by shallow tillage ST at 10-ton ha-1 (STWS10). Moreover, the lowest results regard growth and yield attributes were observed in Shallow tillage ST with no wheat straw incorporation (STCK) Additionally, It was also observed that gypsum application did not have significant effect (P > 0.05) on maize growth and yield, but it mitigated soil salinity and sodicity, contributing to improved crop growth and yield. Therefore, incorporating straw into saline-sodic soils can significantly (P < 0.05) enhance maize yield and its attributes, with notable effects observed after two years of treatment.

Wheat Straw Incorporation Coupled With Direct Seeding Method Influence Nitrogen Uptake and Translocation in Rice

ABSTRACTOn‐farm trials were performed to investigate the nitrogen (N) uptake, N translocation, and grain yield of rice planted via different direct seeding methods into a field after wheat straw incorporation. The study conducted using two direct seeding methods, dry direct seeding of rice (DDSR) and wet direct seeding of rice (WDSR), in a field without or with straw incorporation demonstrated that straw incorporation negatively influenced both grain yield and N uptake in direct‐seeded rice. Compared with WDSR, DDSR suffered significant negative effects, with a 7.2% decrease in grain yield and an 8.0% decrease in N uptake. Additionally, N uptake in direct‐seeded rice with straw addition decreased by 6.5% at the middle stage and 9.5% at the late stage compared with that without straw incorporation. Straw incorporation prolonged the initial phase of growth and thus shortened the N uptake days in the last two phases. Moreover, the total N uptake of rice was positively associated with the uptake rate and the uptake days during the latter stages. Specifically, WDSR exhibited a higher N uptake rate, N uptake days, and N translocation ability than DDSR, which increased the N uptake in stem and panicle, total N uptake, and grain yield at maturity. These results indicated that straw incorporation decreased grain yield and N uptake, which was related to the fewer N uptake days in the latter stages caused by the prolonged early growth stage for direct‐seeded rice. Nevertheless, using WSDR in a field incorporated with straw alleviated the losses in N uptake and grain yield.

Application of crop straw with different C/N ratio affects CH4 emission and Cd accumulation in rice (Oryza sativa L.) in Cd polluted paddy soils

Return straw to field is a common practice for straw utilization. However, effects of crop straw with different C/N ratio incorporation on the CH4 emission and Cd phytoavailaility in Cd-contaminated paddy soils have not been simultanously evaluated. Here, we investigated the impacts of rice straw (RS) and pea straw (PS) incorporation on CH4 emission and rice Cd available in heavily Cd polluted soil (HP) and lightly polluted soil (LP) through a pot experiment. Results showed that RS and PS significantly increased CH4 emission in the two soils (p ​< ​0.05). CH4 emission in PS treatment were greater than that in RS treatment. PS with lower C/N ratio favored to increase soil DOC and SOM (p ​< ​0.05), and promote dominant methanogens of Methanobacterium uliginosum and uncultured Methanocellales archeaon growth (p ​< ​0.05), which mainly contributed to higher CH4 emisison. The significant influences of straw application on soil chemical parmeters subsequently affected soil different Cd fractions (p ​< ​0.05). Specifically, straw significantly decreased water soluble ​+ ​exchangeable Cd and manganese oxides Cd, but significantly increased other Cd fractions in HP soil (p ​< ​0.05); whereas there were nearly opposite trendancies in LP soil. Thus, roots Cd was mainly determined by soil soluble ​+ ​changeable Cd in HP soil, while it was more likely affected by other Cd fractions except for the soluble ​+ ​exchangeable Cd in LP soil, thereby reduced Cd transport from roots to stems in both soils. Greater effects of PS were displayed in inhibiting rice growth and reducing organs Cd than RS in HP soil, while higher efficiency of RS treatment on improving rice growth than that of PS was found in LP soil (p ​< ​0.05). The results can provide a basis for scientific straw returning in Cd contaminated paddy field, achieving safe rice production and reducing carbon emission.

Straw incorporation: A more effective coastal saline land reclamation approach to boost sunflower yield than straw mulching or burial

In coastal lands, soil salinity greatly impedes crops growth and severely affects the agricultural productivity. Returning the crop straw and residual to soil was considered an important land reclamation method; however, the approach of straw return varied, including mulching (SM), burial (SB), and incorporation (SI). This study aimed to determine which approach was most effective to ameliorate coastal saline land and boost crop yield. Field experiments were conducted under different straw amelioration treatments on dry farming sunflowers (Helianthus annuus Linn.) in Bohai coastal land of Northern China. The results indicated that SM and SB changed the soil salt profile and significantly reduced the topsoil (0–0.2 m) salt content mainly by their direct effects on soil water transport, with little impacts on soil structure changes. Differently, SI significantly increased 21.8 % soil organic carbon and 52.3 % soil mean weight diameter in straw incorporated layer. The improvement on soil aggregates and porosity reduced 24.1–38.9 % of topsoil salt content, by limiting soil salt accumulation and promoting salt leaching. Furthermore, SI significantly boosted the sunflower fine root (d< 1.0 mm) growth and resulted in the highest sunflower yield (4.7 t/ha in 2020 and 4.6 t/ha in 2021) among those straw treatments. Compared to SM and SB, the net revenues of two-years sunflower cultivation under SI were improved by 40.68 % and 31.22 %, respectively. Therefore, it concluded that straw incorporation was more effective to reclaim coastal saline soil than straw mulching or burial. In addition, a back propagation artificial neural network model was developed to predict the dynamic of sunflower yield. This outcome provides an insight into the management of coastal farmland by establishing an easily desalinized and fertile topsoil profile structure.

Short-Term Effects of Incorporation Depth of Straw Combined with Manure During the Fallow Season on Maize Production, Water Efficiency, and Nutrient Utilization in Rainfed Regions

Diminishing soil fertility and crop productivity due to traditional intensive cultivation has prompted the use of straw and manure to improve soil health in Northeast China. However, few comparative studies have explored the influence of varying straw and manure incorporation depths on crop growth. A field experiment in the rainfed black soil regions of Gongzhuling and Keshan assessed the effects of deep (30 cm) and shallow (15 cm) incorporations of straw and manure on soil fertility, maize root growth, and maize productivity. Deep incorporations, via subsoiling tillage (DST) and deep-plow (DDT) tillage, enhanced soil water storage of 30–100 cm soil layer during periods of low rainfall, improved the availability of nutrients (nitrogen, phosphorus, and potassium) and soil organic matter content, especially in deeper soil, compared to shallow incorporation using rotary tillage (SRT). Both DST and DDT induced a larger rooting depth and a higher fine root (diameter class 0–0.5 mm) length density by 31.0% and 28.9%, respectively, accompanied by reduced root turnover. Furthermore, the sub-surface foraging strategies of roots under the DST and DDT treatments boosted the total nitrogen, phosphorus, and potassium uptake (6.5–17.9%) and achieved a higher dry mass accumulation during the later growth period, thus leading to notable improvements in the 100-kernel weight and yield (16.1–19.7%) and enhancing water- and nutrient-use efficiencies by 2.5–20.5%. Overall, compared to shallow incorporation, deep incorporation of straw and manure significantly enhances root growth and spatial distribution of soil water and nutrients, which has great potential for increasing maize yield in rainfed agricultural areas.

Influence of rice straw incorporation and recommended dose of primary nutrients on growth, productivity and nutrient use efficiency of Rabi maize (Zea mays L.)

Rice-maize-based cropping system is one of the important agricultural practices in India. Maize has a wider range of adaptability to various climatic and soil conditions, which allows the farmers to cultivate the crop at various locations throughout the year. During the present days, straw handling after rice crop harvesting has become a major problem to the farmers and the burning of rice straw is considered as a serious environmental threat causing air pollution. In this scenario, incorporation of rice straw in succeeding maize cultivation can be beneficial in various aspects like soil health improvement, increased productivity and proper waste management. Considering these, the present field study was conducted at the Post Graduate Research Farm of Centurion University of Technology and Management, Gajapathi, Odisha, India. The experiment was laid out in randomized complete block design with 8 treatments and each treatment was replicated 4 times. The details of the treatment are as follows, T1: absolute control, T2: 100 % RDF, T3: 100 % RDF + rice straw incorporation (RSI) at 2 t/ha, T4: 100 % RDF + RSI at 4 t/ha, T5: 100 % RDF + RSI at 6 t/ha, T6: 100 % RDF + RSI at 8 t/ha, T7: 75 % RDF + RSI at 2 t/ha and T8: 75 % RDF + RSI at 4 t/ha. The experimental results found that the superior values of growth attributes were obtained highest in treatments T2: 100 % RDF, T3: 100 % RDF + RSI at 2 t/ha. Further, the incorporation of rice straw at the rate of 2 t/ha (T3) accounted for maximum grain yield (6354 kg/ha), stover yield (8429 kg/ha) and biological yield (14783 kg/ha) of maize and this treatment remained at par with T2: 100 % RDF. The experiment concludes that application of the optimum dose of fertilizers (100 % RDF) along with the incorporation of 2 t/ha of rice straw can be recommended for better growth, yield and nutrient use efficiency of Rabi maize.

Effect of Different Kharif Paddy Straw Management Options and Different Levels of Nitrogen on Soil Dehydrogenase and Urease Activity

A field experiment was conducted during rabi 2020-21, at Regional Agricultural Research Station, Polasa, Jagtial, PJTSAU to study soil dehydrogenase and urease activity as influenced by different kharif paddy straw management options and nitrogen levels. The results reveal that dehydrogenase and urease activity of soil was significantly influenced by paddy straw management options and activity was increased with crop duration up to 60 DAT and decreased after harvest. Dehydrogenase activity was reduced after burning (1.93 mg TPF produced g-1 soil d-1) as compared to the initial values (2.34 mg TPF produced g-1 soil d-1). The highest dehydrogenase activity of 3.74 and 3.54 mg TPF produced g-1 soil d-1 was recorded at 60 DAT in paddy straw incorporation with phosphorus and incorporation without phosphorus and decreased to 3.36 and 3.03 mg TPF produced g-1 soil d-1 after harvest respectively. Soil urease activity was showed an increasing trend with crop duration up to 60 DAT and then declined. Maximum activity of 3.05, 4.84, 5.17 mg NH4+ released g-1 soil h-1 was observed at 60 DAT under paddy straw burning, paddy straw incorporation with phosphorus incorporation without phosphorus respectively. Paddy straw incorporation with phosphorus recorded higher urease activity and paddy straw burning recorded lower urease activity at all the intervals of crop growth. The effect of nitrogen levels on soil urease activity was found to be significant. Soil urease was highest with 120% RDN followed by 115% RDN, followed by 110% RDN, followed by 100% RDN and the similar trend was observed at all the intervals of crop growth.

Evaluating crop nitrogen status in maize leaves: A predictive modelling approach using chlorophyll fluorescence parameters

The consumption of chemical fertilizers has increased eight-fold since the 19th century, outstripping crop yields increases and, emphasizing the need for precise nitrogen (N) assessment in crops to optimize fertilization and mitigate environmental impacts. This study developed a model using chlorophyll fluorescence technology to accurately evaluate the N status in maize leaves while addressing the limitations of current labor-intensive and environmentally sensitive methods. Based on a long-term experiment initiated in 2011, maize hybrid Fumin 985 was sampled in 2021 and 2022 under two crop-straw management strategies (SM: no tillage with surface straw mulch, SP: plough tillage with straw incorporation) and six N application rates. Partial least squares regression (PLSR) models were formulated using chlorophyll fluorescence parameters (ChlF) to assess leaf N content (N leaf). The results indicated that a N application rate of 270 kg ha−1 sufficed to meet crop N requirements. Leaf characteristics such as N leaf, total pigment content (TP), and leaf dry weight (DW leaf) changed significantly with increasing N application rates, influencing rapid chlorophyll fluorescence (OJIP) dynamics. Principal component analysis (PCA) reduced ChlF from 35 to 21, and four models were developed, among which, the model using ChlF and TP was more accurate than the model using DW alone. Key ChlF parameters for PLSR model performance included ABS/RC, φ(Eo), ETo/CSm, and δ(Ro)/(1–δ(Ro)). Although non-destructive N leaf detection using chlorophyll fluorescence technology proved feasible, additional leaf characteristics, such as TP, are necessary to improve model accuracy. Considering local field conditions is essential for the application of this technology at a larger scale. Precise evaluation of N status using chlorophyll fluorescence is beneficial for a more efficient N management and sustainable agriculture.

Plant-Soil Feedback Combined with Straw Incorporation Under Maize/Soybean Intercropping Increases Heavy Metals Migration in Soil-Plant System and Soil HMRG Abundance Under Livestock Wastewater Irrigation

Plant-Soil Feedback Combined with Straw Incorporation Under Maize/Soybean Intercropping Increases Heavy Metals Migration in Soil-Plant System and Soil HMRG Abundance Under Livestock Wastewater Irrigation

Biochar and Straw Amendments over a Decade Divergently Alter Soil Organic Carbon Accumulation Pathways

Exogenous organic carbon (C) inputs and their subsequent microbial and mineral transformation affect the accumulation process of soil organic C (SOC) pool. Nevertheless, knowledge gaps exist on how different long-term forms of crop straw incorporation (direct straw return or pyrolyzed to biochar) modifies SOC composition and stabilization. This study investigated, in a 13-year long-term field experiment, the functional fractions and composition of SOC and the protection of organic C by iron (Fe) oxide minerals in soils amended with straw or biochar. Under the equal C input, SOC accumulation was enhanced with both direct straw return (by 43%) and biochar incorporation (by 85%) compared to non-amended conventional fertilization, but by different pathways. Biochar had greater efficiency in increasing SOC through stable exogenous C inputs and inhibition of soil respiration. Moreover, biochar-amended soils contained 5.0-fold greater SOCs in particulate organic matter (POM) and 1.2-fold more in mineral-associated organic matter (MAOM) relative to conventionally fertilized soils. Comparatively, although the magnitude of the effect was smaller, straw-derived OC was preserved preferentially the most in the MAOM. Straw incorporation increased the soil nutrient content and stimulated the microbial activity, resulting in greater increases in microbial necromass C accumulation in POM and MAOM (by 117% and 43%, respectively) compared to biochar (by 72% and 18%). Moreover, straw incorporation promoted poorly crystalline (Feo) and organically complexed (Fep) Fe oxides accumulation, and both were significantly and positively correlated with MAOM and SOC. The results address the decadal-scale effects of biochar and straw application on the formation of the stable organic C pool in soil, and understanding the causal mechanisms can allow field practices to maximize SOC content. These results are of great implications for better predicting and accurately controlling the response of SOC pools in agroecosystems to future changes and disturbances and for maintaining regional C balance.