Residue Incorporation Treatments Research Articles

Effect of Paddy Straw Incorporation and Nitrogen Levels on Yield and Nutrient Uptake by Mustard (Brassica juncea L.)

Burning of crop residues results in immense loss to soil fertility, in addition to this burning causes greenhouse gas emissions into atmosphere thereby disturbs the environment. A Field experiment was conducted to ascertain the crop residue and fertilizer management practices on yield and nutrient uptake of mustard at Regional Agricultural Research Station (RARS), Polasa, Jagtial situated in Northern Telangana Zone of Telangana State during rabi, 2020-21. Grain yield, nutrient content and nutrient uptake were significantly influenced by crop residue and fertilizer management practices. Highest grain and stover yield of 1194 and 2654 kg ha-1 were recorded, when 20 % excess nitrogen was applied than RDN along with residue incorporation. Nutrient uptake was significantly higher in burning treatment during initial stages of crop growth later more uptakes were observed in residue incorporation treatments. Among the treatments lowest yields and nutrient contents (N and P) were recorded in residue burning treatments. This study concluded that, instead of burning, paddy straw was to be incorporated along with 20% excess nitrogen to obtain better yields and nutrients uptake in succeding mustard crop.

Influence of Different Moisture Conservation Practices and Crop Sequence on Direct Seeded Rice based Cropping System in Rainfed Ecosystem of Assam, India

Background: Land configuration decides the effectiveness of crop management practices and major land configuration practice includes raised bed preparation, ridges and furrows, broad bed furrows etc. The farmers’ practice of sowing in flatbed without proper land configuration, leads to poor growth and development of crops. A large portion of crop residues is burnt by the farmers in the fields to clear the left-over straw and stubbles. Conservation agriculture involving crop residue management can give new direction for sustaining productivity. The development issue of rainfed agriculture assumes critical importance in India due to slow growth and its impact on livelihood security of rural poor in India. Changes in crop establishment method in rice have significant implications in performing farm operations like tillage, seedbed preparations, transplanting, weeding and other intercultural operations including water management. The current study aimed to study the BF methods as land configuration including crop residue management in rainfed eco system in direct seeded rice based cropping system. Methods: In the field experiment during 2016-17 and 2017-18, different size of bed of Broad bed Furrow (BBF) including Flatbed was made manually consisting four replication. After final land preparation the experimental field was divided into four blocks and each block was divided in to six main plots to allocate the six soil moisture conservation practices randomly, for growing summer (direct seeded ahu rice), kharif (green gram) crops. The main plots were again divided in to four sub-plots to allocate the rabi crops randomly following a split-plot design. Incorporation of crop residues was done in the plots as per treatments. Result: The investigation resulted better performance of both the size of BBF beds as compared to flatbed method in respect of yield attributes and yield of the crops studied. Among the BBF, 60-30 cm size bed showed better than the BBF 120-30 cm size beds. The residue incorporation plots were shown comparatively better result than no residue incorporation treatments. The present study will be a contribution to the study of BBF particularly in pulse crops due to heavy rainfall received during kharif season in Assam.

Effects of short‐term tillage managements on rhizosphere soil‐labile organic carbon fractions and their hydrolytic enzyme activity under a double‐cropping rice field regime in Southern China

AbstractThe soil‐labile organic carbon (C) fractions and their hydrolytic enzyme activity play an important role in maintaining or increasing soil quality and soil fertility, which are affected by adopting various tillage managements. But there is still limited information about how rhizosphere soil‐labile organic C fractions and their hydrolytic enzyme activity respond to different tillage managements under a double‐cropping rice (Oryza sativa L.) (early rice and late rice) in a field in Southern China. We hypothesized that rhizosphere soil‐labile organic C fractions and their hydrolytic enzyme activity in the double‐cropping rice field were modified by combined application of tillage with crop residue incorporation. Therefore, the main objectives of this study were to explore change in rhizosphere SOC content, soil‐labile organic C fractions [mineralizable C (Cmin), microbial biomass C (MBC), dissolved organic C (DOC), particulate organic C (POC), light fraction organic C (LFOC), permanganate oxidizable C (KMnO4‐C)] and their hydrolytic enzyme activity during 6‐years tillage management in a double‐cropping rice system in Southern China by using the fluorometric method. The relationship between proportion of each labile organic C fraction to SOC content were analysis using the redundancy analysis (RDA) method. The experiments included four tillage treatments: rotary tillage with all crop residues removed as a control (RTO), conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), and no‐tillage with crop residue retention (NT). The results showed that combined application of tillage with crop residue incorporation managements significantly increases rhizosphere SOC content and soil‐labile organic C fractions compared without crop residue input treatment. Compared with RTO treatment, rhizosphere soil Cmin, KMnO4‐C, POC, DOC, LFOC, and MBC contents with CT treatment increased by 170.97%, 37.22%, 52.53%, 14.46%, 20.29%, and 27.35%, respectively. The proportion of labile C with CT, RT, and NT treatments was higher than that of RTO treatment. This results demonstrated that rhizosphere soil hydrolytic enzyme activity with CT, RT, and NT treatments were higher than that of RTO treatment. Compared with RTO treatment, rhizosphere soil polyphenol oxidase and peroxidase activities with NT treatment increased by 75.80% and 40.90%, respectively. They had significantly positive correlation between rhizosphere soil hydrolytic enzyme activity and SOC content and its labile organic C fractions. Rhizosphere soil polyphenol oxidase and peroxidase activities had significantly positive correlation with labile organic C fractions. The RDA results indicated that CT and RT treatments were significantly different from NT and RTO treatments, and all of them were clearly separated from each other. As a result, combined application of tillage with crop residue incorporation is a beneficial nutrient management for improving rhizosphere soil‐labile organic C fractions and their hydrolytic enzyme activity in the double‐cropping rice fields of Southern China.

Effects of Short-Term Tillage Managements on CH4 and N2O Emissions from a Double-Cropping Rice Field in Southern of China

Soil carbon (C) content plays an important role in maintaining or increasing soil quality and soil fertility. However, the impacts of different tillage and crop residue incorporation managements on greenhouse gas (GHG) emissions from paddy fields under the double-cropping rice (Oryza sativa L.) system in southern China still need further study. Therefore, a field experiment was conducted to determine the impacts of different short-term (5-years) tillage and crop residue incorporation managements on soil organic carbon (SOC) content, SOC stock, and GHG emissions from paddy fields under the double-cropping rice system in southern China. The field experiment included four tillage treatments: rotary tillage with all crop residues removed as a control (RTO), conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), and no-tillage with crop residue retention (NT). These results indicated that SOC stock in paddy fields with CT, RT, and NT treatments increased by 4.64, 3.60, 3.50 Mg ha−1 and 4.68, 4.21, and 4.04 Mg ha−1 in 2019 and 2020, respectively, compared with RTO treatment. The results showed that early rice and late rice yield with CT treatment increased by 7.22% and 19.99% in 2019 and 6.19% and 6.40% in 2020, respectively, compared with RTO treatment. A two-year (2019–2020) investigation of GHG results indicated that methane emissions from paddy fields with NT treatment were decreased, but nitrous oxide emissions from paddy fields were increased. The lowest mean global warming potential (GWP) and per yield GWP carbon dioxide were found with NT treatment, compared to RT and CT treatments. Therefore, it was a beneficial practice for maintaining SOC stock and decreasing GHG mitigation under the double-cropping rice system in southern China by applying no-tillage with crop residue retention management.

Impacts of short-term tillage and crop residue incorporation managements on soil microbial community in a double-cropping rice field

Soil microbial community were usually reconsidered as a sensitive indicator in soil quality and soil environment change of paddy field. However, the effects of different tillage and crop residue incorporation managements on soil bacterial community under the double-cropping rice cropping system were still need to further investigated. Therefore, the impacts of different tillage and crop residue incorporation managements on soil bacterial community under the double-cropping rice cropping system in southern of China were studied by using phospholipid fatty acids (PLFAs) profile method in the present paper. The experiment included four different tillage treatments: rotary tillage without crop residue input as a control (RTO), no-tillage with crop residue retention (NT), rotary tillage with crop residue incorporation (RT), and conventional tillage with crop residue incorporation (CT). Compared with RTO treatment, grain yield of rice with NT, RT and CT treatments increased by 1.21%, 3.13% and 6.40%, respectively. This results showed that soil aC15:0, C16:0, iC17:0, C19:0c9, 10 fatty acids with CT and RT treatments were higher than that of RTO treatment, while soil C16:1ω6c and C18:1ω9t fatty acids with NT treatment were higher than that of RTO treatment, respectively. Soil G+ and G− bacteria PLFAs contents with CT treatment were higher than that of NT, RT and RTO treatments, while the value of soil G+/G− bacteria PLFAs with NT treatment were higher than that of CT, RT and RTO treatments. This results indicated that Richness and McIntosh indices with CT treatment were significantly higher than that of RTO treatment. Principal component analysis (PCA) results showed that the first and second principal components (PC1 and PC2) were explained 93.2% of total variance with all tillage treatments. Except C12:0, C14:0 2OH and C18:2ω6, all unsaturated and cyclopropyl PLFAs contents were belong to PC1. PC1 and PC2 were explained 88.4% of total variance with all tillage treatments. There had significantly positive correlation between soil Richness, Shannon indices and soil PLFAs, G+ bacteria, G− bacteria, fungi contents. As a result, it were benefit practices for increasing soil bacterial community structure in the double-cropping rice field of southern China by combined application of rotary, conventional tillage with crop residue incorporation managements.

Effects of different short-term tillage managements on rhizosphere soil autotrophic CO2 -fixing bacteria in a double-cropping rice paddy field.

Soil autotrophic bacteria community plays an important role in carbon (C) cycling process in soil, but there is still limited information about how the rhizosphere soil microbe that drives this process respond to combined application of tillage with crop residue incorporation managements under a double-cropping rice (Oryza sativa L.) paddy field in southern China. Therefore, the 6-years short-term tillage treatment on rhizosphere soil autotrophic bacteria community [RubisCO gene (cbbL)] under the double-cropping rice paddy field in southern China was studied using the high-throughput sequencing method in the present article. The field experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT) and rotary tillage with all crop residues removed as a control (RTO). The results showed that abundance, composition and activity of rhizosphere soil cbbL-carrying bacteria were obviously influenced by application of different tillage treatments. The rhizosphere soil abundant cbbL and 16S rRNA genes as well as RubisCO activity with CT, RT and NT treatments were higher than that of RTO treatment. The cbbL sequences in rhizosphere soil with CT, RT andNTtreatments mainly included Azoarcus_sp._KH33C,Ralstonia_pickettii, Thermomonospora_curvata, Variovorax_paradoxus and uncultured_proteobacterium. Meanwhile, the results indicated that cbbL-carrying bacterial composition was significantly affected by soil organic carbon, microbial biomass carbon, dissolved organic carbon contents and soil bulk density. There had an obvious difference in characteristics of rhizosphere soil autotrophic bacteria community between CT, RT, NT treatments and RTO treatment. Therefore, it was a beneficial practice for improving rhizosphere soil autotrophic bacteria community in the double-cropping rice paddy field in southern China by combined application of tillage with crop residue incorporation practices.

Effects of different tillage management on rhizosphere soil nitrogen mineralization and its extracellular enzyme activity in a double‐cropping rice paddy field of southern China

AbstractSoil extracellular enzyme activity plays an important role in regulating the process of nitrogen (N) mineralization in the paddy field. However, there is still limited information about how rhizosphere N mineralization and its extracellular enzyme activities respond to different tillage treatments in a double‐cropping rice paddy fields of southern China. Therefore, the effects of 6‐year (short‐term) tillage management on rhizosphere soil acid hydrolysable N and its fractions, N mineralization, and its extracellular enzyme activities in a double‐cropping rice paddy fields of southern China were studied and reported in this article. The field experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no‐tillage with crop residue retention (NT), and rotary tillage with crop residue removed as a control (RTO). The results showed that rhizosphere soil total acid hydrolysable N and its fractions with CT, RT and NT treatments were higher than those with RTO treatment. Compared to RTO treatment, the rhizosphere soil total acid hydrolysable N content with CT and RT treatments was increased by 19.17% and 17.74%, respectively. Compared to RTO treatment, the rhizosphere soil aerobic and anaerobic N mineralization rates with CT and RT treatments were increased by 100.00% and 80.65%, and 43.02% and 33.72%, respectively. Rhizosphere soil extracellular enzyme activities with CT and RT treatments were higher than those with NT and RTO treatments. There was a positive correlation between rhizosphere soil amino sugar N, amino acid N, total acid hydrolysable N contents, L‐glutaminase activity and N mineralization rate. The principal component analysis results indicated that rhizosphere soil organic carbon, amino sugar N, amino acid N and total acid hydrolysable N contents, soil β‐glucosaminidase, β‐glucosidase and L‐glutaminase activities were the main factors affecting rhizosphere soil aerobic and anaerobic N mineralization rates. As a result, rhizosphere soil acid hydrolysable N and its fractions, N mineralization, and its extracellular enzyme activities were significantly increased under the combined application of conventional tillage and rotary tillage with the crop residue incorporation condition.

Effects of short-term soil tillage practice on activity and community structure of ammonia-oxidizing bacteria and archaea under the double-cropping rice field.

The potential nitrification activity (PNA), population size and community composition of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in paddy soil from a short-term (5years) tillage field experiment conducted at tillering stage of late rice were investigated using the shaken slurry method and quantitative real-time polymerase chain reaction. The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue returning (NT) and rotary tillage with all crop residues removed as a control (RTO). The results showed that PNA in paddy soil of CT, RT and NT treatments was higher than that of RTO treatment, and the abundance of AOA and AOB was much higher in paddy soil of CT, RT and NT treatments than RTO treatment. Meanwhile, PNA and the abundance of AOB and AOA in paddy soil were greatly enhanced by combined application of tillage and crop residue, whereas PNA and the abundance of AOB and AOA in paddy soil were decreased by combined application of no-tillage and crop residue. Moreover, PNA was closely correlated with the abundance and community structure of AOB rather than AOA. The results also showed that PNA and the population sizes of AOB and AOA in crop incorporation treatments were higher than that of crop residue removed treatment. Cluster and redundancy analyses indicated that crop residue effect played a more important role in shaping AOA community structure compared to short-term tillage management. The results indicated that AOB rather than AOA functionally dominated ammonia oxidation in the double-cropping rice paddy soil, the activities of AOB and AOA were increased and the community structure was also changed under the combination of conventional tillage, rotary tillage and crop residue condition. The activity and community structure of AOB and AOA, which were affected by the combination of tillage and crop residue managements, play an important role in cycling of nitrogen.

Carbon Mineralization Rates and Kinetics of Surface-Applied and Incorporated Rice and Maize Residues in Entisol and Inceptisol Soil Types

Mineralization of carbon (C) is a burning issue that is regulated by soil attributes. It has direct impacts on crop productivity and quantification of organic residue addition in soil. For better understanding and achievement of potential tillage benefits, a comprehensive scientific understanding of C mineralization is very important. Therefore, a laboratory incubation experiment was conducted to investigate the C mineralization rates and kinetics of crop residues (rice and maize) when applied on the surface (as zero-tillage, ZT) and incorporation (as conventional tillage, CT) in four different soil types (S1 and S2 of Entisol; S3 and S4 of Inceptisols) of West Bengal state, India. Results showed that after 7 days of incubation, there was a rapid phase of decrease in CO2-C fluxes. It continued up to day 14 followed by a sluggish nature of CO2 emission up to day-42, and after that almost levelling off in all subsequent periods up to the end of 126 days of incubation. There was a progressive release of cumulative total C from the soils with an increase in time till the last day of incubation. For every 10% increase in C loss, there was about 0.376 mg/g C mineralization from the applied residue C. It was evident from the kinetic models that C mineralization from the residues followed the exponential model: C = Co(1 − e−kt). Similar rate constant (k) values were recorded in both placement methods, but the rate of maximum potential mineralizable (C0k) residue C was higher under residue incorporation treatments for both rice and maize residue. However, the rice and maize residues showed almost similar amounts of C mineralized over time when applied on the surface. The future prediction analysis using the equation C = Co(1 − e−kt) suggested that the residues incorporated into the soil releases a maximum C irrespective of residue type. We conclude that the residues when incorporated into the soil significantly increases the C footprints through maximum C mineralization; leaving the crop residue on the soil surface reduces the C footprints which helps in achieving sustainability from an environmental perspective.

Functional soil organic matter fraction in response to short-term tillage management under the double-cropping rice paddy field in southern of China.

Soil organic matter (SOM) and its fraction play an important role in maintaining and improving soil fertility of paddy field. However, there is still limited information about how SOM fraction response to carbon (C) sequestration with different short-term tillage practices under the double-cropping rice paddy field in southern of China. Therefore, the effects of 5-year short-term tillage treatments on different SOM fractions (physically protected, physico-chemically protected, physico-biochemically protected, chemically protected, biochemically protected, and unprotected) under the double-cropping rice paddy field in southern of China were studied in this paper. The field experiment included four different tillage treatments: rotary tillage with crop residue removed as a control (RTO), conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), and no-tillage with crop residue retention (NT). The results showed that soil unprotected (cPOM), biochemically (NH-dSilt), physically-biochemically (NH-μSilt), and chemically protected (H-dSilt) fractions with different tillage treatments were the mainly C storage fraction in paddy field. The soil organic carbon (SOC) content in unprotected (cPOM and fPOM), physically protected (iPOM), and physico-chemically protected (H-μClay) fractions with CT treatment was increased by 1.45, 2.13, 1.91, and 1.42 times higher than that of RTO treatment, respectively. The results showed that largest proportion of fraction to SOC content was biochemically protected, followed by unprotected and physically-biochemically protected, and physically protected was the lowest. These results indicated that soil physically protected, physically-chemically protected, and physically-biochemically protected fractions with CT and RT treatments were higher than that of NT and RTO treatments. In summary, it was a benefit practice for increasing SOM fraction under the double-cropping rice paddy field in southern of China by combined application of conventional tillage and rotary tillage with crop residue incorporation management.

Microbial carbon source utilization in rice rhizosphere soil with different tillage practice in a double cropping rice field

Carbon (C) plays an important role in maintaining soil fertility and increasing soil microbial community, but there is still limited information about how source utilization characteristics respond to soil fertility changes under double-cropping rice (Oryza sativa L.) system in southern China paddy field. Therefore, the effects of different short-term (5-years) tillage management on characteristics of C utilization in rice rhizosphere and non-rhizosphere soils under double-cropping rice field in southern China were investigated by using 18O incorporation into DNA. Therefore, a field experiment were included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), rotary tillage with crop residue removed as control (RTO). The results showed that soil microbial biomass C content with CT, RT, NT treatments were increased by 29.71–47.27% and 3.77–21.30% in rhizosphere and non-rhizosphere soils, compared with RTO treatment, respectively. Compared with RTO treatment, soil microbial basal respiration and microbial growth rate with CT treatment were increased 30.56%, 30.94% and 11.91%, 12.34% in rhizosphere and non-rhizosphere soils, respectively. The soil microbial C utilization efficiency were promoted with NT treatment. Compared with RTO treatment, the metabolic capacity of soil microorganism to exogenous C source with CT, RT and NT treatments were increased. The largest type of exogenous C source was saccharides, followed by amino acid and polymers, and complex compounds was the smallest. The redundancy analysis results indicated that tillage treatments significantly changed the utilization characteristics of soil microorganism to exogenous C source. Compared with RTO treatment, the grain yield of early rice and late rice with CT treatment were increased by 409.5 kg ha−1 and 387.0 kg ha−1, respectively. Therefore, the CT and RT treatments could significantly increase soil microbial biomass C content, but the NT treatment promote microbial C utilization efficiency in the double-cropping paddy field of southern China.

Soil properties of rhizosphere under maize based cropping system

This field experiment was conducted for two consecutive years during 2014-15 and 2015-16 on loamy sand soil of Agronomy Main Research Farm, Department of Agronomy, Central Research Station of the Odisha University of Agriculture and Technology, Bhubaneswar. The treatments consisted of three legumes as main plot treatments taken up during the kharif season and two residue management practices as sub-plot treatments and four nitrogen levels as sub-sub plot treatments. It shows that soil microbial population increased linearly over the initial level by taking a legume-cereal sequence. Further the incorporation of legume residues improved the microbial population over no residue incorporation treatments. Decreased trend of the total microbes was seen after the harvest of maize. An increase in available N, P and K was noticed with increase in nitrogen levels during both the years of study. After the harvest, cowpea recorded the highest available soil nitrogen values of 278 and 284 kg ha-1 in the first and second year respectively as well as highest total bacterial count of 228 x 104 g-1 of soil was recorded with cowpea residue incorporation with nitrogen application at 180 kg ha-1.

Effect of different short-term tillage management on nitrogen-fixing bacteria community in a double-cropping paddy field of southern China.

Soil nitrogen (N)-fixing bacteria community plays an important role in the N cycling process in soil, but there is still limited information about how the soil microbes that drive this process to respond to combined application of tillage and crop residue management under the double-cropping rice (Oryza sativa L.) paddy field in southern of China. Therefore, the effects of 6-years short-term tillage treatment on soil N-fixing bacteria community under the double-cropping rice paddy field in southern China were studied by using the polymerase chain reaction-denaturing gradient gel electrophoresis method. The field experimentincluded four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), rotary tillage with crop residue removed as control (RTO). The results showed that the diversity index and richness index of cbbLR and nifH genes with CT, RT, and NT treatments were increased, compared with RTO treatment. Compared with RTO treatment, the abundance of cbbLR gene with CT, RT, and NT treatments were increased by 6.54, 4.73, and 2.78 times, respectively. Meanwhile, the abundance of nifH gene with CT, RT, and NT treatments were 5.32, 3.71, and 2.45 times higher than that of RTO treatment. The results also indicated that soil autotrophic Azotobacter and nitrogenase activity with CT and RT treatments were significantly higher (p < .05) than that of RTO treatment. There was an obvious difference in characteristic of soil N-fixing bacteria community between the application of crop residue and without crop residue input treatments. In summary, the results indicated that the abundance of N-fixing bacteria community in the double-cropping rice paddy field increased with conventional tillage and rotary tillage practice.

Effects of Short-Term Soil Tillage Management on Activity and Community Structure of Denitrifiers under Double- Cropping Rice Field.

Soil physical and chemical characteristics, soil potential denitrification rates (PDR), community composition and nirK-, nirS- and nosZ-encoding denitrifiers were studied by using MiSeq sequencing, quantitative polymerase chain reaction (qPCR), and terminal restriction fragment polymorphism (T-RFLP) technologies base on short-term (5-year) tillage field experiment. The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), and rotary tillage with crop residue removed as control (RTO). The results indicated that soil organic carbon, total nitrogen and NH4+-N contents were increased with CT, RT and NT treatments. Compared with RTO treatment, the copies number of nirK, nirS and nosZ in paddy soil with CT, RT and NT treatments were significantly increased. The principal coordinate analysis indicated that tillage management and crop residue returning management were the most and the second important factors for the change of denitrifying bacteria community, respectively. Meanwhile, this study indicated that activity and community composition of denitrifiers with CT, RT and NT treatments were increased, compared with RTO treatment. This result showed that nirK, nirS and nosZ-type denitrifiers communities in crop residue applied soil had higher species diversity compared with crop residue removed soil, and denitrifying bacteria community composition were dominated by Gammaproteobacteria, Deltaproteobacteria, and Betaproteobacteria. Therefore, it is a beneficial practice to increase soil PDR level, abundance and community composition of nitrogen-functional soil microorganism by combined application of tillage with crop residue management.

Impact of Cropping Systems and Resource Conservation Techniques on Productivity and Profitability of Systems

Background: A suitable cropping system seem to be the possible solution to meet the continuous increase in demand for food, stability of income and diverse requirement of food grains. Selection of suitable cropping system for conservation of resources has prime importance now a day. The cropping systems selected in study have higher potential of production along with incorporable residues during winter. The residues of cotton, castor and mustard crops (Crops in selected cropping systems) have more potential to feed nutrients to soil as compared to burning. So incorporation of such crop residues in to soil helps to recycle the nutrients to correct their deficiencies. Farmyard manure is being used as major source of organic manure in field crops. Thus to maintain the soil health, integrated nutrient management approaches involving FYM and mineral source need to be standardized. So there is need to find out agronomically efficient and economically viable cropping system which can perform better for increasing productivity and profitability with association of conservation of natural resources. Methods: The experiment was laid out in split plot design with three replications. Sixteen treatment combinations comprising of four cropping system treatments viz, C1 : Cotton- Summer Pearlmillet, C2 : Greengram + Kharif Castor (Relay), C3 : Greengram - Mustard - Summer Pearlmillet and C4 : Greengram - Rabi Castor and two residue incorporation treatments viz, R0 : No residue incorporation and R1 : Residue incorporation as well as two fertilizer doses viz, F1 : 100% RDN through inorganic fertilizer and F2 : 75% RDN through inorganic fertilizer + 25% RDN through FYM were evaluated in the study. Result: Cotton - summer pearlmillet cropping system found significantly superior by recording higher pearlmillet equivalent yield, system productivity and system profitability while, total weed count/m2 and total weed dry weight were found the lowest under greengram- kharif castor (relay) cropping system. Residue incorporation secured top position by recording significantly the highest pearlmillet equivalent yield, system productivity and system profitability as well as lowest total weed count/m2 and total weed dry weight. Application of 75% RDN through inorganic fertilizer + 25% RDN through FYM recorded significantly highest pearlmillet equivalent yield, system productivity and system profitability. In case of weed count and weed dry weight, 100% RDN through inorganic fertilizer found significantly superior by recording lowest total weed count/m2 and total weed dry weight.

Tillage and crop residue incorporation effects on soil bacterial diversity in the double-cropping paddy field of southern China

ABSTRACT There is still limited information about the influence of different tillage and crop residue management on soil bacterial communities in the paddy field. Therefore, the short-term effects of tillage and incorporated crop residue management on soil properties and bacterial communities in a double-cropping rice system of southern China were studied. The experiment included four tillage treatments: conventional tillage with crop residue incorporation (CT), rotary tillage with crop residue incorporation (RT), no-tillage with crop residue retention (NT), and rotary tillage without crop residue as control (RTO). The results indicated that soil invertase, urease and catalase activities with CT treatment were increased 11.5%, 82.6% and 43.9%, compared with RTO treatment. Meanwhile, the results showed that genetic diversity indices of soil microbial communities increased by application of crop residue treatments, compared to without crop residue treatment. The value of Richness indices and McIntosh indices with CT treatment were increased by 10.8% and 35.4%, compared with RTO treatment. CT and RT treatments increase the abundance of phylum Alphaproteobacteria, Firmicutes and Gammaproteobacteria, compared to RTO treatment. Therefore, the combined application of tillage and crop residue management could significantly increase the abundance of profitable functional bacteria species in the double-cropping paddy field of southern China.

Functional diversity of rhizosphere soil microbial communities in response to different tillage and crop residue retention in a double-cropping rice field.

Microbial community functional diversity is a sensitive indicator of soil quality, soil management such as tillage and crop residue which can affect the microbial community functional diversity of paddy field. However, there is still limited information about the influence of different tillage and crop residue management on rhizosphere soil microbial community functional diversity in a double-cropping rice (Oryza sativa L.) field. Therefore, four tillage treatments were set up in paddy field, tillage treatments were included: conventional tillage with residue incorporation (CT), rotary tillage with residue incorporation (RT), no-tillage with residue retention (NT), and rotary tillage with residue removed as control (RTO). And the effects of CT, RT, NT, and RTO treatments on the average well color development (AWCD), genetic diversity indices and carbon source utilization of rhizosphere soil were studied in the present paper. The results showed that the values of AWCD with CT, RT and NT treatments were higher than that of RTO treatment. It was implied that application of crop residue management resulted in the variation of the carbon utilization efficiency of rhizosphere soil microbial communities. At maturity stages of early and late rice, the Richness indices, Shannon indices and McIntosh indices with CT treatment were significantly higher than that of RTO treatment, and with the order as CT>RT>NT>RTO. Principal component analysis (PCA) results indicated that there were significant differences in carbon substrate utilization patterns among different tillage treatments. Carbohydrates and amino acids were the main carbon resources utilized by rhizosphere soil microbes. Therefore, the combined application of tillage with crop residue management could significantly increase the rhizosphere soil microbial community functional diversity in the double-cropping paddy field of southern China.

Effects of Different Soil Tillage Systems on Soil Carbon Management Index Under Double‐Cropping Rice Field in Southern China

Core Ideas SOC and AOC were higher in CT and RT treatments than RTO at 0 to 5, 5 to 10, and 10 to 20 cm. Lability, LI, and CMI in the CT treatment were higher than NT treatment at 0 to 5 and 10 to 20 cm. SOC stocks were significantly higher in NT at 0 to 5 cm than under the RTO treatment. SOC stocks were significantly higher in CT and RT at 5 to 10 and 10 to 20 cm than under RTO. Interactions between tillage and soil organic carbon (SOC) impact soil structure, soil quality, and the calculated soil carbon management index (CMI). However, the effects of different tillage and residue management systems on the dynamics of SOC remain unclear under double‐cropping rice (Oryza sativa L.). Therefore, the effects of soil tillage and incorporated residues on soil bulk density, SOC, soil active organic carbon (AOC), and the CMI were studied in a southern China double‐cropped rice system. The experiment included four tillage treatments: conventional tillage with residue incorporation (CT), rotary tillage with residue incorporation (RT), no tillage with residue retention (NT), and rotary tillage with residue removed as a control (RTO). The results indicated that soil bulk density increased under NT in the 0‐ to 20‐cm layer, SOC was higher under NT than that of other treatments, and SOC in the 5‐ to 20‐cm layer was higher under CT and RT than under NT and RTO. The greatest SOC and AOC contents were observed under CT at the 5‐ to 10‐cm and 10‐ to 20‐cm layers. The CMI was used to assess the soil quality change with different soil tillage practices. The application of residue combined with conventional tillage or rotary tillage was more effective for increasing soil carbon pool index (CPI) and CMI than was rotary tillage with the residue was removed. The CMI for the 0‐ to 10‐cm depth under RT and CT were higher (P &lt; 0.05) than the NT treatment. Meanwhile, RT significantly enhanced the SOC stocks over the RTO treatment at three different depths. As a result, based on soil CMI and C storage, double‐cropping rice using a no‐tillage system where crop residues are not removed could increase SOC in the surface 5 cm.

Crop residue incorporation and nitrogen fertilizer effects on greenhouse gas emissions from a subtropical rice system in Southwest China

Crop residue incorporation has been widely accepted as a way to increase soil carbon (C) sequestration and sustain soil fertility in agroecosystems. However, effect of crop residue incorporation on greenhouse gas (GHG) emissions in rice paddy soils remains uncertain. A field experiment was conducted to quantify emissions of CH4 and N2O and soil heterotrophic respiration (RH) from a paddy rice field under five different crop residue treatments (i.e., 150 kg N ha-1 of synthetic N fertilizer application only [NF], 150 kg N ha-1 of synthetic N fertilizer plus 5.3 Mg ha-1 wheat residue [NF-WR1], 150 kg N ha-1 of synthetic N fertilizer plus 10.6 Mg ha-1 wheat residue [NF-WR2], 75 kg N ha-1 of synthetic N fertilizer plus 10.6 Mg ha-1 wheat residue [50%NF-WR2] and 150 kg N ha-1 of synthetic N fertilizer plus 21.2 Mg ha-1 wheat residue [NF-WR3]) in southwest China. Our results showed that crop residue incorporation treatments (NF-WR1, NF-WR2, 50%NF-WR2, NF-WR3) significantly increased CH4 emissions by at least 60%, but N2O emissions were not enhanced and even suppressed by 25% in the NF-WR3 treatment as compared to the NF treatment. Soil RH emissions were comparable among experimental treatments, while crop residue incorporation treatments significantly increased soil carbon sequestrations relative to the NF treatment. Overall, CH4 emissions dominated total global warming potentials (GWP) across all experimental treatments. The average yieldscaled GWPs for the NF and NF-WR1 treatments were significantly lower than for the NF-WR2, 50%NFWR2 and NF-WR3 treatments. Given the comparable yield-scaled GWPs between the NF and NF-WR1 treatments, the NF-WR1 treatment could gain net carbon sequestration as compared with the NF treatment with net soil carbon loss. Our findings suggest that the NF-WR1 treatment should be an effective option to sustain rice production while mitigating GHG emissions from the rice field in China.

English

This study was carried out to investigate the prospects of using methanolic extracts and residue of wheat (Triticum aestivum&nbsp;L.) for the management of parthenium (Parthenium hysterophorus&nbsp;L.), one of the world&rsquo;s worst weeds. In a laboratory bioassay, the effect of methanol extracts of 1, 2, 3, 4 and 5% (w/v) concentrations of four wheat varieties namely: AS 2002, Inqalab 91, Ufaq and Uqab was studied against the germination and seedling growth of parthenium. Extracts of all the four wheat varieties suppressed germination as well as root and shoot growth of the seedlings. In soil amendment bioassay, dried and chopped wheat straw of the four test wheat varieties was thoroughly mixed in pot soil at 0.5, 1.0 and 1.5% (w/w). Pots were irrigated with tap water and left for one week followed by sowing of seeds in these pots. The effect of residue incorporation of all the wheat cultivars was insignificant on germination of parthenium seeds. However, all the residue incorporation treatments significantly reduced the survival percentage of the parthenium seedlings. Root and shoot growth in terms of length, and fresh and dry biomass were also significantly suppressed by residues of all the four test wheat cultivars. This study concludes that parthenium weed can effectively be managed by amending the soil with wheat residue. &nbsp; Key words:&nbsp;Non-chemical weed control, parthenium, wheat residue.