Effects Of Residue Management Research Articles

Nitrogen and residue management effects on productivity and profitability of happy seeder wheat in Indian Punjab

Development of a suitable nitrogen (N) management strategy in wheat sown under residue retained conditions will go a long way in maintaining its sustainability. The reason for this is the variable concentration of N in rice residues and complexity of crop N demand. The present experiment was conducted at Punjab Agricultural University, Ludhiana during rabi2016–17 and 2017–18 to study the infuence of different residue and nitrogen management practices on productivity and proftability of Happy Seeder sown wheat. Experiment was conducted in randomized block design (RBD) consisting of eleven residue and N management treatments in four replications. The results revealed that yield attributes and grain yield of Happy Seeder sown wheat varied signifcantly with different residue and N management practices. Yield attributes (effective tillers, spike length & number of grains/spike) and grain yield (54.2 & 53.6 q/ha) were maximum in treatment where 150 kg N (30 kg at chopping of straw and 120 kg as per recommendation) was applied along with 5 t farmyard manure (FYM)/ha, which was signifcantly better than NC + N125, C + N125, C + FYM5 + N125 and C + N20+105 treatments but statistically at par with rest of the treatments. Highest gross (Rs. 1, 18, 155 & 1, 28, 011/ha) and net (Rs. 85, 120 & 94, 466/ha) returns were obtained with C + FYM5 + N30+120 during 2016–17 and 2017–18, respectively. But highest beneft cost ratio (2.59 & 2.87) was reported in treatment C + FYM5 + N30+95 during both years. It may be concluded that application of 20/30 kg N/ha at the time of chopping of straw improved grain yield of Happy Seeder wheat as compared to recommended schedule of N application.

Conservation Agriculture Practices Can Improve Earthworm Species Richness and Abundance in the Semi-Arid Climate of Eastern Cape, South Africa

Earthworms play a pivotal role in the regulation of soil health. Studies that explore the effects of conservation agriculture (CA) principles on earthworms under the semi-arid climate of the central Eastern Cape (EC) of South Africa (SA) are limited. Therefore, this study investigated the effects of tillage, crop rotations, and residue management on earthworms’ abundance and species richness. The study design followed a split-split plot with three replicates. The main plot was allocated to tillage treatment, which had conventional tillage (CT) and no-tillage (no-till) as factors. Crop rotation treatment was allocated to a subplot, and had maize (Zea mays)–fallow–maize (MFM), maize–fallow–soybean (Glycine max) (MFS), maize–wheat (Triticum aestivum)–maize (MWM), and maize–wheat–soybean (MWS). Residue management was in the sub-subplot with residue retention and residue removal. The study was carried out over four cropping seasons: summer 2015–2016, winter 2016, spring 2016, and summer 2016–2017. The results showed that the genera Amynthas and Lumbricus, both belonging to the anecic group, and Dendrobaena, belonging to the epigeic group, were present. Earthworm species diversity and density were highest under no-till than under CT. Residue retention improved earthworm density regardless of tillage management. Rotations that had fallow periods recorded lower earthworm numbers as compared to continuous cropping systems where wheat was grown in winter. The study concluded that maize–wheat–soybean (MWS) rotation with residue retention results in the highest earthworm abundance and species richness.

Conservation Tillage, Residue Management, and Crop Rotation Effects on Soil Major and Micro-nutrients in Semi-arid Vertisols of India

Due to declining soil quality and increasing climate change, resource conservation technologies are often advocated for the food production system. Conservation agriculture (CA) is one of the technologies that increase soil nutrient status without jeopardizing the soil health and quality. The effects of conservation tillage, residue retention, and cropping systems on soil physical, chemical, and biological properties within the irrigated agricultural system are well established. However, scanty information is available on the combined impact of tillage, residue, and cropping system available on the major and micro-nutrient in the rainfed farming systems. Thus, a field experiment was conducted to measure the short-term effect of CA practices on soil properties and major (N, P, and K) and micro (Fe, Mn, Zn, and Cu)-nutrients in a Vertisol of Central India. The field experiment was laid out in a split-plot design consisting of two tillage systems (TS), conventional tillage (CT) and reduced tillage (RT), as the main plots and six cropping systems (CS) as subplots. A total of 144 soil samples were collected after four crop cycles to assess soil properties and nutrient (major and micro-nutrient) status. Results demonstrated that in the surface soil layer (0–5 cm), the major and micro-nutrient concentrations were higher than subsurface layers, regardless of TS and CS. In the surface soils, soil organic carbon (SOC) varied from 0.58 to 0.60% under CT and from 0.60 to 0.62% under RT. Tillage and cropping systems had a significant effect (p < 0.05) on major available nutrients (N, P, and K) at 0–5-cm depth. The DTPA extractable Fe, Mn, Cu, and Zn concentrations exhibited decreasing trends with increasing depth. At 0–5-cm depth, the DTPA-Fe, Mn, Cu, and Zn under CT varied from 7.56 to 9.58 mg kg−1, 15.04 to 15.91 mg kg−1, 1.37 to 1.80 mg kg−1, and 0.57 to 0.62 mg kg−1 and under RT varied from 8.25 to 11.16 mg kg−1, 15.65 to 17.73 mg kg−1, 1.54 to 1.80 mg kg−1, and 0.59 to 0.67 mg kg−1, respectively. We concluded that RT practices, coupled with crop residue retention, positively affected major and micro-nutrient distribution and availability in this soil. Results highlight the importance of nutrient dynamics under different tillage and cropping systems and thus improve the nutrient recommendation in the semi-arid eco-region of Central India.

Less efficient residue‐derived soil organic carbon formation under no‐till irrigated corn

AbstractSoil organic carbon (SOC) stores a large portion of terrestrial C, yet the mechanisms that affect its formation efficiency under different residue management in irrigated systems are still not well understood. No‐till (NT) increases SOC concentrations in topsoil compared with conventional tillage (CT) but there is uncertainty surrounding the stability of these gains in irrigated systems. We investigated the effect of NT and CT residue management on CO2 loss and SOC formation by applying isotopically (13C) labeled residues on the surface or incorporated in the mineral soil of disturbed (i.e., CT) or undisturbed (i.e., NT) soil in a semiarid, NT, sprinkler‐irrigated, continuous corn (Zea mays L.) field. We measured residue‐derived C in CO2, bulk soil, dissolved organic C, particulate organic matter (POM), and silt‐ and clay‐sized mineral‐associated organic matter (MAOM) fractions. Twelve months after residue addition, soils with surface‐applied residue produced 19% more CO2 and formed 41% less SOC than residue‐incorporated soils. Across all treatments, 62% of residue‐derived C was recovered in POM, and 38% in the MAOM fractions. Residue‐derived bulk soil C formation was more efficient when the residue was incorporated (0.60) rather than surface‐applied (0.42), suggesting that mixing and burial of residue within the soil matrix is a key pathway of SOC formation. During the growing season, surface residue under NT management in irrigated systems is particularly vulnerable to decomposition and will require additional conservation strategies to generate long‐term C sequestration.

Effect of tillage, residue and nitrogen management on soil physical properties, root growth and productivity of wheat (Triticum aestivum)

A study was conducted on a semi-arid climate and sandy loam soils of Indian Agricultural Research Institute farm, New Delhi to evaluate the short-term (5 years) interactions of tillage, residue and nitrogen management on soil physical properties, root growth and yield of wheat (Triticum aestivum L.) in a maize-wheat cropping system in a split-split plot design comprising two tillage (No tillage and conventional tillage), two residue levels (no residue, maize residue @ 5 t ha-1) and three nitrogen doses (N60, N120 and N180) as the main plot, sub plot and sub subplot treatments, respectively. It was observed that bulk density (up to 45 cm), penetration resistance (10-27 cm depth) reduced under no tillage and residue applied plots while the porosity (15-60 cm), mean weight diameter (0-15 cm), organic carbon (0-15 cm) improved in these treatments. The hydraulic conductivity was significantly enhanced due to residue applications in the surface layers (0-15cm). Root growth parameters were improved under no tillage and crop residue mulching. Although neither tillage nor residue mulching could significantly influence the grain and biomass yield of wheat on two years of study (2017-18, 2018-19), yield increased significantly with increasing nitrogen doses. Thus no tillage, residue mulching with 150% recommended dose of nitrogen can be practised for maintaining a better soil physical health, root growth without any significant reduction in crop productivity compared to conventional tillage.

Tillage and residue management effects on irrigated maize performance and water cycling in a semiarid cropping system of Eastern Colorado

Residue removal from maize (Zea mays) fields offers an opportunity to increase farmer profits, but potential tradeoffs for water dynamics and crop performance merit further evaluation. This study, established in 2014, compared the effects of two tillage practices (no-till and conventional) and two residue management practices (harvested vs. kept in place) on maize grain yields, water infiltration, evapotranspiration, and soil physical attributes. On average, maize grain yields under limited irrigation increased with residue retention by 1.1 Mg ha−1 year−1 between 2016 and 2018, but tillage had no significant effect. Total infiltration (over 30 min) was higher with residue retention. Neither tillage nor residue management had a significant impact on evapotranspiration during the vegetative growth stage. However, there was a significant residue by tillage interaction where vegetative evapotranspiration was reduced by no-till and residue retention. Conversely, penetrometer resistance was significantly reduced by both tillage and residue retention. Volumetric water content in the soil profile at planting was higher with residue retention. These results suggest that plots with residue removal would on average require 60 mm year−1 of additional irrigation to attain the same yields as fields with residue retention. In summary, our findings suggest that high rates of crop residue removal under limited irrigation in a semiarid environment can negatively affect water conservation and yields, and that tradeoffs surrounding residue export need to be fully considered in land management and policy decisions.

Effects of residue management and nitrogen fertilizer rates on accumulation of soil residual nitrate and wheat yield under no-tillage system in south-west of Iran

Conservation tillage, residue management and optimizing nitrogen (N) fertilization are important strategies for soil and water conservation and sustainability of agricultural systems. In order to evaluate the effects of various residue management methods and N fertilizer rates on some soil quality indicators, accumulation of residual soil nitrate, and wheat yield under no till system, a split-plot experiment was arranged in a randomized complete block design with three replications. Main plots were three residue management methods, including retaining (R.M1), removing (R.M2) and shredding (R.M3) of corn residues. The subplots consisted of four N fertilizer rates, 100 (N1), 150 (N2), 200 (N3), and 250 (N4) kg N ha−1 from urea source. The results showed that soil organic carbon and total N in R.M1 and R.M3 treatments increased at the depth of 0–15 cm as compared to R.M2. The maximum accumulation of soil nitrate was observed in R.M1 × N4 and R.M3 × N4 interactions at the soil depth of 60-cm. The results of this study showed that R.M1 × N3 and R.M3 × N3 interactions had a greater impact on wheat yield than the sole effect of R.M1 or R.M3. According to our findings, application of 200 kg N ha−1 in combination with R.M1 which had once less tractor passing for mechanical shredding than R.M3, can contribute effectively to improve soil quality indicators, control soil residual nitrate and subsequently produce more wheat grain yield in the south-west of Iran.

Biochemical signatures reveal positive effects of conservation tillage on arbuscular mycorrhizal fungi but not on saprotrophic fungi and bacteria

Since tillage can reduce the amount of organic C stored in soils, the use of conservation tillage practices, which exclude soil inversion, or include it less frequently, is often promoted. Soil microorganisms are closely linked to soil organic C (SOC), and they are assumed to respond quicker to management changes than SOC. Using two Swedish long-term tillage experiments, our aim was to determine whether (i) continuous conservation tillage (harrowing, H) increase microbial biomass (indicated by fatty acid signatures) compared to plowing (P), and if occasionally tilled soil (HP) was more like H or P. Also, the aim was to determine whether (ii) crop residue management has different effects on microbial biomass depending on tillage management, and whether (iii) conservation tillage and residue return increase SOC. We found that arbuscular mycorrhizal fungi (AMF) were stimulated by the H treatment compared to P treatment in the upper soil layer, and that occasional plowing resulted in intermediate amounts of AMF. The amount of microbial saprotrophs, on the other hand, was not affected by tillage treatment, and neither was the SOC concentration. Whether crop residues were returned in the autumn or not, had no direct effect on the microbial saprotrophs or the SOC after the winter, but crop residue removal stimulated AMF close to the surface in the P treatment. Although more research is needed to fully understand agricultural tillage and residue management effects on SOC dynamic, our study suggests that reducing or omitting plowing influence soil microbes, but does not necessarily result in more SOC.

Carbon Dioxide Fluxes and Carbon Stocks under Conservation Agricultural Practices in South Africa

Understanding the impacts of agricultural practices on carbon stocks and CO2 emission is imperative in order to recommend low emission strategies. The objective of this study was to investigate the effects of tillage, crop rotation, and residue management on soil CO2 fluxes, carbon stock, soil temperature, and moisture in the semi-arid conditions in the Eastern Cape of South Africa. The field trial was laid out as a split-split-plot design replicated three times. The main plots were tillage viz conventional tillage (CT) and no-till (NT). The sub-plots were allocated to crop rotations viz maize–fallow–maize (MFM), maize–oat–maize (MOM), and maize–vetch–maize (MVM). Crop residue management was in the sub-sub plots, viz retention (R+), removal (R−), and biochar (B). There were no significant interactions (p &gt; 0.05) with respect to the cumulative CO2 fluxes, soil moisture, and soil temperature. Crop residue retention significantly increased the soil moisture content relative to residue removal, but was not different to biochar application. Soil tilling increased the CO2 fluxes by approximately 26.3% relative to the NT. The carbon dioxide fluxes were significantly lower in R− (2.04 µmoL m−2 s−1) relative to the R+ (2.32 µmoL m−2 s−1) and B treatments (2.36 µmoL m−2 s−1). The carbon dioxide fluxes were higher in the summer (October–February) months compared to the winter period (May–July), irrespective of treatment factors. No tillage had a significantly higher carbon stock at the 0-5 cm depth relative to CT. Amending the soils with biochar resulted in significantly lower total carbon stock relative to both R+ and R−. The results of the study show that NT can potentially reduce CO2 fluxes. In the short term, amending soils with biochar did not reduce the CO2 fluxes compared to R+, however the soil moisture increases were comparable.

Effect of crop residue management on damage by Diatraea saccharalis (Lepidoptera: Crambidae), its egg parasitoids and the ants associated with sugarcane.

In the American continent, the sugarcane borer Diatraea saccharalis (F.) is the main pest in sugarcane producing areas. The objective of this study was to assess the effect of crop residue management on damage by D. saccharalis, its egg parasitoids and the ants associated with sugarcane. The study was carried out during 2011-2012, 2012-2013 and 2013-2014 crop cycles, in three commercial fields located in different regions of Tucumán state, Argentina. Two types of crop residue management (= treatments) were compared: conservation of trash at the soil surface (CT) and trash burning (TB). In 'trash conservation' treatment, crop residue was allowed to remain over the soil surface during the whole sugarcane growing season, while the second treatment consisted of complete burning of trash blanket approximately 2 weeks after harvest. The injury level was measured by recording the number of stalks bored and internodes bored. Parasitism was estimated by counting the total number of eggs and number of black eggs (which indicates the occurrence of egg parasitoids). Ants (Formicidae) richness was calculated by two estimators; abundance-based coverage estimator and incidence-based coverage estimator, using the non-parametric richness estimators: Chao 2 and Jackknife. Finally, the indicator value was estimated through the measurement of specificity and fidelity. In all the parameters studied no significant difference was found between TB and CT treatments.

Tillage, Crop Rotation and Crop Residue Management Effects on Nutrient Availability in a Sweet Sorghum-Based Cropping System in Marginal Soils of South Africa

The low soil fertility status of South African marginal soils threatens sustainable production of biofuel feedstock in smallholder farmers. It is therefore imperative to development sustainable and optimal management practices that improve soil fertility. The objective of this study was to determine the effect of tillage, rotation and crop residue management on nutrient availability in a bioenergy sweet sorghum-based cropping system in marginal soils. Two tillage levels, no-till (NT) and conventional tillage (CT); two crop rotations, sweet sorghum–grazing vetch–sweet sorghum (SVS) and sweet sorghum–fallow–sweet sorghum (SFS); and three crop residue retention levels, 0%, 15% and 30%, were tested. No-till enhanced total nitrogen, total organic nitrogen (TON), magnesium (Mg) and sodium (Na) by 3.19% to 45% compared to CT. SVS rotation increased ammonium (NH4+-N) and nitrate (NO3−-N) by 3.42% to 5.98% compared to SFS. A 30% crop residue retention increased NH4+-N, NO3−-N, available phosphorus (Available P), cation exchange capacity (CEC), calcium (Ca), Mg and potassium (K) by 3.58% to 31.94% compared to crop residue removal. In the short term, a 30% crop residue retention was the main treatment that enhanced soil fertility. The application of NT−30% was a better practice to enhance soil fertility. However, research on inclusion of crop diversity/intercropping can add more value to the NT–30% practice in enhancing soil fertility.

Carbon Input and Maize Productivity as Influenced by Tillage, Crop Rotation, Residue Management and Biochar in a Semiarid Region in South Africa

Conservation agriculture (CA) as a system is still evolving on many of the smallholder farms in sub-Saharan Africa (SSA) and questions on the impact of individual components and pathways toward adoption still require answers. A short-term study was conducted to investigate the effect of tillage, crop rotation, and crop residue management, including maize residue biochar on above ground biomass, cumulative carbon (C) input, soil organic carbon (SOC), and maize grain yield. A split–split plot design was used to evaluate two tillage operations (conventional tillage (CT) and no-till (NT)), three crop rotations (maize–fallow–maize (MFM), maize–oat–maize (MOM), and maize–vetch–maize (MVM)), and three-crop residue management (retention (R+), removal (R−), and biochar (B)). The cumulative above ground biomass produced in the MOM rotation was significantly higher by 78.9% and 88.7% relative to MVM and MFM rotations, respectively. The cumulative C input under residue management treatments ranged from 10.65 to 12.16 Mg ha−1. The highest SOC was observed under R+ (1.10%) followed by B (1.0%) and the lowest was in R− (0.96%). Crop residue management significantly affected grain yields in 2015/2016 (p &lt; 0.05) and 2016/2017 (p &lt; 0.01) summer seasons. Biochar did not result in an obvious improvement in both C input and crop yield. Smallholder farmers can potentially switch from CT to NT without any significant yield penalty, as well as adopt MOM and R+ practices for increased biomass and C input.

Evaluation of residue management practices on barley residue decomposition.

Optimizing barley (hordeum vulgare L.) production in Idaho and other parts of the Pacific Northwest (PNW) should focus on farm resource management. The effect of post-harvest residue management on barley residue decomposition has not been adequately studied. Thus, the objective of this study was to determine the effect of residue placement (surface vs. incorporated), residue size (chopped vs. ground-sieved) and soil type (sand and sandy loam) on barley residue decomposition. A 50-day(d) laboratory incubation experiment was conducted at a temperature of 25°C at the Aberdeen Research and Extension Center, Aberdeen, Idaho, USA. Following the study, a Markov-Chain Monte Carlo (MCMC) modeling approach was applied to investigate the first-order decay kinetics of barley residue. An accelerated initial flush of residue carbon(C)-mineralization was measured for the sieved (Day 1) compared to chopped (Day 3 to 5) residues for both surface incorporated applications. The highest evolution of carbon dioxide (CO2)-C of 8.3 g kg-1 dry residue was observed on Day 1 from the incorporated-sieved application for both soils. The highest and lowest amount of cumulative CO2-C released and percentage residue decomposed over 50-d was observed for surface-chopped (107 g kg-1 dry residue and 27%, respectively) and incorporated-sieved (69 g kg-1 dry residue and 18%, respectively) residues, respectively. There were no significant differences in C-mineralization from barley residue based on soil type or its interactions with residue placement and size (p >0.05). The largest decay constant k of 0.0083 d-1 was calculated for surface-chopped residue where the predicted half-life was 80 d, which did not differ from surface sieved or incorporated chopped. In contrast, incorporated-sieved treatments only resulted in a k of 0.0054 d-1 and would need an additional 48 d to decompose 50% of the residue. Future residue decomposition studies under field conditions are warranted to verify the residue C-mineralization and its impact on residue management.

Crop yield after 5\xa0decades of contrasting residue management

The benefits of soil organic input on crop yields have long been discussed, yet details of their relationship remain controversial. This study considers the effects of different residue management on crop performance as assessed by yield and nitrogen use efficiency (NUE). Three residue management (residue removal, residue incorporation, and residue incorporation + added poultry manure), combined with five levels of N application, were studied in a long-term experiment starting in 1966. Crop residue incorporation improved maize yield by 12% (nutritional effect) and sugar beet yield by 16% (non-nutritional), and the combination of crop residue incorporation with added poultry manure increased both winter wheat and sugar beet yields by 8% (nutritional effect). The NUE values of mineral fertiliser were almost three-fold those of residues and the combination of residue with poultry manure, except in sugar beet and maize, where NUE of mineral fertilizer approached those observed for residues (0.44 vs 0.45, on average). In wheat, NUE for residue incorporation with added poultry manure was nearly double the NUE for residues alone. Residue management effects depended on crop type; spring-sown crops showing stronger effects than those sown in autumn. Residues primarily produced a nutritional effect, suggesting that they decomposed within 1 year. While residue use offers little potential for soil improvement, it does reduce the need for fertilisers.

Effect of harvest residue management on soil properties of Eucalyptus hybrid and Acacia mangium plantations planted on steep slopes in northern Vietnam

Burning harvest residues during site preparation can compromise the soil-nutrient stock in short-rotation plantations, but this practice remains common in northern Vietnam. This study compared the effect of two contrasting harvest-residue treatments (burning vs retention) on soil total carbon (TC), total nitrogen (TN), extractable P (ext-P), exchangeable K (exch-K) and bulk density (BD) of two adjacent randomised complete-block trials, one of Eucalyptus hybrid (Eucalyptus urophylla × E. pellita) and the other of Acacia mangium planted on steep slopes. Harvest-residue management had no effect on soil properties of either E. hybrid or A. mangium two years after planting. Soil pH in E. hybrid increased and exch-K in A. mangium decreased during the first year; ext-P decreased over time in both species though this was only significant in the residue-retention treatment in A. mangium. Slope significantly influenced pH and TC of E. hybrid and TC and TN of A. mangium. It appeared that slope position and correlative factors such as surface runoff and erosion had led to the observed distribution of some soil properties along the steep slope.

Tillage, Crop Residue and Nitrogen Management Effects on Nitrogen Uptake, Nitrogen Use Efficiency and Yield of Rice

Field experiment was conducted in three factorial strip split plot design to evaluate the effect of two establishment methods (EM) i.e. transplanted in puddled soil (Pu-TPR) and direct seeded in zero tillage (ZT-DSR), two residue levels i.e. residue kept at 3 t ha -1 (RK) and no residue (RR) with two nitrogen doses i.e. recommended dose (100 kg N ha -1) (RD) and farmers' dose (50 kg N ha-1) (FD) with six replications with individual plot size of 5.4 m × 6.3 m on rice variety Ram-Dhan during the year 2016. Nitrogen uptake, nitrogen use efficiencies and yield of rice were recorded. Straw nitrogen uptake was significantly higher in ZT-DSR than Pu-TPR. Similarly, grain straw and total nitrogen uptake were significantly higher in residue applied and recommended dose of nitrogen than no-residue applied and farmers-nitrogen dose treatments respectively. Nitrogen efficiency ratio and physiological efficiency index were significantly higher in Pu-TPR and no-residue applied treatments while partial factor productivity was higher in residue applied treatment. All nitrogen use efficiencies like partial factor productivity, nitrogen efficiency ratio and physiological efficiency index were significantly influenced by nitrogen dose and seen higher in recommended dose of nitrogen. Establishment methods had no significant effect on grain yield but straw yield was significantly higher in ZT-DSR but harvest index was seen higher in Pu-TPR. Grain yield and straw yield were significantly higher in residue applied treatment and recommended nitrogen but harvest index was higher in farmers-nitrogen dose.

Effect of conservation agriculture and residue management on yield and economics of cotton – maize cropping system

Effect of conservation agriculture and residue management on yield and economics of cotton – maize cropping system

Effect of rice residue management and crop diversification on growth and yield of rice

RWCS is the most dominant and extensive cropping system across South Asian Indo-Gangetic Plains. It has the deleterious effects on the soil physical properties and leads to ample amount of residue generation. Residue managements is the biggest question that arises thereby to overcome these problems and to maintain the sustainability an experiments was held during the Kharif season of 2017 at N. E. Borlaug Crop Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar, US Nagar, Uttarakhand situated at 29◦N, 79◦29E and at an altitude of 243.86 above mean sea level, to evaluate the effect of crop diversification and residue management techniques through organics on rice growth and productivity. It has been observed that diversification of RWCS as rice-yellow sarson-groundnut and rice-vegetable pea-maize along with 30% residue management through organics viz., vermicompost @ 2 t ha-1, FYM @ 5 t ha-1 and biogas slurry @ 2 t ha-1 can be advocated for enhancing the growth and productivity of rice and the 30% residue management through organics viz., vermicompost @ 2 t ha-1 and rice-yellow sarson-groundnut perform best among them with the grain yield of 7.12 t ha-1 and 6.44 t ha-1, respectively.

Analytical method validation, dissipation and safety evaluation of combination fungicides fenamidone + mancozeb and iprovalicarb + propineb in/on tomato

Dissipation behavior and degradation kinetics of fenamidone + mancozeb (Sectin 60 WG) and iprovalicarb + propineb (Melody Duo 66.75 WP) in tomato were studied at recommended dose (RD) and double dose (DD) of application. The analysis of the field samples were carried out by employing liquid chromatography tandem mass spectrometry (LC-MS/MS) for fenamidone and iprovalicarb residues and gas chromatography mass spectrometry for mancozeb and propineb residues after thorough validation of the extraction methods. The dissipation of residues best followed 1st + 1st order for all the test fungicides. The half-life period for fenamidone, mancozeb, iprovalicarb and propineb were 2, 2, 1.5 and 2days for RD and 3, 2.5, 2 and 3days for DD, respectively. The pre-harvest intervals were not applicable for iprovalicarb, fenamidone and mancozeb (at RD) as the residues at 0day were below maximum residue limit set by European Union, and it was 1day for DD of iprovalicarb, 3.5days for DD of fenamidone, 3days for DD of mancozeb, 3 and 7days for propineb at RD and DD, respectively. A PHI of 4 and 7days are proposed for fenamidone + Mancozeb and iprovalicarb + propineb, respectively. Dietary exposure calculated for all the pesticides were safe on all the sampling days except for propineb residues for which it was safe after first day of the double dose application. The study will be useful for promoting effective residue management and safe use of these chemicals for controlling fungal diseases in tomato crop.

Arbuscular mycorrhizal fungal community was affected by tillage practices rather than residue management in black soil of northeast China

Arbuscular mycorrhizal (AM) fungi are one of the most important soil microbes in an agrarian ecosystem, and consequently affected by various agricultural practices. To elucidate the effects of tillage practices and residue management on AM fungi, a field trial was conducted on the Songnen Plain, Northeast China. We examined the effects of different tillage practices including no-tillage (NT), rotary tillage (RT), subsoil tillage (ST) and deep tillage (DT) on the AM fungal biomass, diversity and community under residue removal and residue retention. AM root colonization and extraradical hyphal (ERH) density were significantly higher in DT treatment compared with NT treatment, whereas an opposite trend was observed for AM fungal spore density. Structural equation modeling indicated that AM fungal spore density was directly affected by tillage practices. Albeit, the effect of tillage practices on ERH density was mainly mediated through root length of maize. By Miseq sequencing of 18S rDNA, 66 AM fungal operational taxonomic units (OTUs) were identified and Glomeraceae was the most abundant group in this study. AM fungal OTU richness was highest in treatment NT, and significantly higher than that in treatment DT. Non-metric multidimensional scaling analysis indicated that treatment DT and ST induced a distinct AM fungal community composition compared with treatment NT. On the other hand, residue did not significantly influence AM fungal biomass, OTU richness and community composition. Overall, our findings indicated that tillage practice is a stronger determinant than residue management in AM fungal development and community composition in black soil on the Songnen Plain.