An investigation was undertaken to screen, select and evaluate a set of bacterial and cyanobacterial isolates from the wheat rhizosphere for their role as biofertilizers in wheat. From an initial set ...of 23 cyanobacterial strains and 110 bacterial isolates from wheat rhizospheric soil, 3 bacterial and 3 cyanobacterial strains were selected based on their plant growth promoting potential under laboratory and controlled greenhouse conditions. In vitro compatibility studies revealed positive interactions among the six strains. Pot experiments were conducted with wheat variety HD 2687, with a total of 51 treatments, along with recommended fertilizer controls. Various combinations of the selected set of three bacterial (PW1, PW5 and PW7) and three cyanobacterial isolates (CW1, CW2 and CW3) were used along with 1/3 N and full dose of P and K fertilizers. Significant enhancement in the soil microbiological (Dehydrogenase activity, FDA hydrolase, Alkaline phosphatase and microbial biomass) and plant growth/yield parameters were recorded. Observations revealed a two-fold increase in panicle weight in selected combinations (PW1+PW7+CW3; PW1+ CW1+CW2/CW1+CW3; CW2+CW3), as compared to control treatment involving full dose of chemical fertilizers. Such combinations, which also provided N savings of 40-80 kg N/ha are being further evaluated in field experiments. This study for the first time illustrated the positive and dynamic interactions among bacterial and cyanobacterial strains and their promise in integrated nutrient management of wheat crop.
Delayed sowing of maize hybrids could exacerbate the capability of maximizing the yield potential through poor crop stand, root proliferation, nutrient uptake, and dry matter accumulation coupled ...with the inadequate partitioning of the assimilates. This study appraised the performance of five recent maize hybrids viz., PMH-1, PJHM-1, AH-4158, AH-4271, and AH-8181 under timely and late sown conditions of the irrigated semi-arid ecologies. Timely sowing had the grain and stover yields advantage of 16-19% and 12-25%, respectively over the late sown maize hybrids. The advanced hybrids AH-4271 and AH-4158 had higher grain yields than the others. During the post-anthesis period, a greater dry matter accumulation and contribution to the grain yield to the tune of 16% and 10.2%, respectively, was observed under timely sown conditions. Furthermore, the nutrient acquisition and use efficiencies also improved under the timely sown. The nutrient and dry matter remobilization varied among the hybrids with AH-4271 and PMH-1 registering greater values. The grain yield stability index (0.85) was highest with AH-4158 apart from the least yield reduction (15.2%) and stress susceptibility index (0.81), while the maximum geometric mean productivity was recorded with the AH-4271 (5.46 Mg ha
). The hybrids AH-4271 and PJHM-1 exhibited improved root morphological traits, such as root length, biomass, root length density, root volume at the V5 stage (20 days after sowing, DAS) and 50% flowering (53 DAS). It is thus evident that the timely sowing and appropriate hybrids based on stress tolerance indices resulted in greater yields and better utilization of resources.
Field experiments were conducted to evaluate eight different integrated crop management (ICM) modules for 5 years in a maize-wheat rotation (M
); wherein, ICM
-'business-as-usual' (conventional ...flatbed maize and wheat, ICM
-conventional raised bed (CT
) maize and wheat without residues, ICM
-conservation agriculture (CA)-based zero-till (ZT) flatbed maize and wheat with the residues, and ICM
CA-based ZT raised bed maize and wheat with the residues. Results indicated that the ICM
produced significantly (p < 0.05) the highest maize grain yield (5 years av.) which was 7.8-21.3% greater than the ICM
. However, across years, the ICM
gave a statistically similar wheat grain yield and was 8.4-11.5% greater than the ICM
. Similarly, the CA-based residue retained ICM
modules had given 9.5-14.3% (5 years av.) greater system yields in terms of maize grain equivalents (M
) over the residue removed CT-based ICM
. System water productivity (S
) was the highest with ICM
, being 10.3-17.8% higher than the ICM
. Nevertheless, the highest water use (T
) was recorded in the CT flatbed (ICM
), ~ 7% more than the raised bed and ZT planted crops with or without the residues (ICM
). Furthermore, the ICM
had produced 9.54% greater variable production costs compared to the ICM
, whereas, the ICM
gave 24.3-27.4% additional returns than the ICM
. Also, different ICM modules caused significant (p < 0.05) impacts on the soil properties, such as organic carbon (S
), microbial biomass carbon (S
), dehydrogenase (S
), alkaline phosphatase (S
), and urease (U
) activities. In 0.0-0.15 m soil profile, residue retained CA-based (ICM
) modules registered a 7.1-14.3% greater S
and 10.2-17.3% S
than the ICM
. The sustainable yield index (S
) of M
was 13.4-18.6% greater under the ICM
compared to the ICM
Hence, this study concludes that the adoption of the CA-based residue retained ICMs in the M
could sustain the crop yields, enhance farm profits, save water and improve soil properties of the north-western plans of India.
Improving nutrient use efficiency and system productivity with a positive nutrient balance in rice-wheat cropping system (RWCS) is vital for long-term food security. Two-year field trials were ...conducted with the objective of computing the effect of different rates, time, method, and source of potassium (K) fertilization on nutrient recovery efficiency, nutrient balance, and system productivity in a dry direct-seeded RWCS with eight treatments. The two-split (half basal and half at panicle initiation) application of 60 kg K
2
O/ha resulted in 37.5% and 19.2% increase in recovery efficiency of K in rice and wheat, respectively over basal application of 60 kg K
2
O/ha. Besides, the split-application of K increased the nitrogen recovery efficiency in rice and wheat by 11.2% and 10.8%, respectively. Similarly, the phosphorus recovery efficiency was increased by 3.6% and 7.4% in rice and wheat, respectively. The split application of 60 kg K
2
O/ha also increased the K harvest index (% of the total K absorbed is transferred to grain) by 0.7% and 2.7% in rice and wheat, respectively over applying entire K at basal. Similarly, the system productivity (11.26 t/ha) was increased by 8% over applying entire K at basal. In the absence of top-dressing of K (30 kg/ha), two foliar-sprays of 2.5% K provide equal benefits of top dressing. Application of 90 kg K
2
O/ha lowered the K negative balance (−99 kg/ha/year) considerably compared to two-split application of 60 kg K
2
O/ha (−152.5 kg/ha/year). Thus, optimization of K fertilization in RWCS will increase the system productivity, nutrient use efficiency, and sustainability.
Healthy soils are the foundation for producing healthy food and creating a healthy environment. Therefore, we assessed the changes in the physical and chemical properties of soil, and their long-term ...impact on yield, quality, and nutritional status of rice grains in an organic
basmati
rice-based cropping system in a typic Ustchrept Soil of India. The experiment was laid out in a strip plot design with three replications. The vertical strips consisted of two rice-based cropping systems, namely,
basmati
rice-wheat-mung bean (RWM) and
basmati
rice-wheat-
sesbania
(RWS), whereas seven combinations of different organic materials and biofertilizers (BF) were assigned to horizontal strips,
viz.
, control (no manure application), farmyard manure (FYM), vermicompost (VC), FYM + crop residues (CR), VC + CR, FYM + CR + BF, and VC + CR + BF. The results revealed that soil moisture content (SMC), soil organic carbon (SOC), soil total N, and soil available P, Fe, Zn, Mn, and Cu were significantly higher under the RWS system than in RWM. The application of organic manures either alone or in conjunction with CR and BF significantly lowered the soil pH (∼3.0%), EC (43.1%–45.8%), and BD (3.3%–9.2%) as compared to the control. Water holding capacity (WHC), SMC, and SOC were increased by 5.7%–14.7%, 8.7%–49.3%, and 35.3%–76.5%, respectively under single or co-application of FYM/VC with CRs and BFs as compared to control. Similarly, sole or conjoint application of organic manures, CR, and BF significantly enhanced the soil available macro (N, P, and K) and micro (Fe, Zn, Mn, and Cu) nutrients over the control. Grain yield, protein content, N uptake, and cooking quality parameters were significantly higher under the RWS system than under RWM. However, the Zn concentration and its uptake by grains were significantly higher under the RWM system over RWS. The grain yield was significantly increased by 25.8%–49.2% under different organic nutrient management options over control. The single or conjoint application of FYM/VC with CR and BF increased the hulling, milling, head rice recovery, and protein concentration in grain by 9.4%–9.8%, 23.2%–28.4%, 22.7%–25.5%, and 9.6%–10.7%, respectively over control. The concentration of N, P, K, Fe, Zn, Mn, and Cu was significantly improved by 9.7%–11.3%, 45.5%–63.6%, 16.7%–20.8%, 66.9%–74.1%, 72.9%–81.9%, 87.1%–97.0%, and 48.9%–67.2%, respectively under co-application of FYM/VC with CR and BF compared to control. Thus, our results indicate that improved soil properties could significantly increase the physical and nutritional quality of
basmati
rice grain. Therefore, adopting
basmati
rice-based cropping systems with different organic nutrient sources can sustain soil health, end global hunger, produce nutritious food, and create a healthy environment.
Due to higher microbial activity and diversity, organic farming serves as a sustainable alternative in preventing several soil-borne plant diseases. However, there are limited studies that have shown ...direct relationship between soil bacterial composition and its effect on disease suppressive potential under different farming systems. Thus, the objective of the study was to understand the effect of farming practices on disease suppressive ability of the soil using a long-term (managed since 18 years) field experiment under organic and conventional farming management. Amplicon sequencing revealed higher abundance of several biocontrol genera in organic field compared to conventional field. The diversity indices for bacterial communities were significantly higher in soil from organic field. Subsequently, the comparative disease suppressive potential of the two management practices was validated in planta against two model phytopathogens, Rhizoctonia solani and Fusarium oxysporum. The disease severity was less in plants treated with microbiome from organic field compared to that of conventional field. The study revealed the key taxa such as Flavobacterium, Bacillus, Pseudomonas, Planctomycetes etc. with potential to impart disease suppressiveness in organic field. This can serve as the basis for generation of synthetic microbial community to induce suppressiveness in otherwise conducive soil.
•Long-term field experiment under organic and conventional farming practices•Differences in the prokaryotic microbiome characterised by amplicon sequencing•Disease suppressive potential of the agri-management practices compared in planta•Delineation of the key taxa rendering disease suppressiveness in organic field•Correlation between prokaryotic community structure and disease suppressiveness
Efficient nutrient and water use are two important considerations to obtain good harvests of wheat. This necessitates the development of an effective nutrient management technique that not only ...increases yield, but simultaneously can save nutrient and water use. In this context, a field experiment was conducted at Indian Agricultural Research Institute, New Delhi, India to evaluate the residual effect of sesbania and rice bean (in-situ), subabul (ex-situ) green manuring and Zinc (Zn) fertilization, using chelated Zn-ethylenediaminetetraacetic acid (Zn-EDTA) on nutrient use, yields and water productivity of wheat under rice-wheat cropping system. Among residual effects of green manure crops and Zn fertilization, sesbania and foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 days after sowing (DAS) recorded significantly higher nutrient content and uptake and yields than other green manure crops and Zn treatments. Residual effect of sesbania saved about 46.5 × 10
3
and 30.5 × 10
3
L irrigation water per tonne of wheat over subabul and rice bean, respectively. Foliar spray of 0.5% chelated Zn-EDTA at 20, 40, 60 and 80 DAS saved about 55.5 × 10
3
, 47 × 10
3
and 13 × 10
3
L irrigation water per tonne wheat over residual effect of 5 kg Zn ha
−1
through chelated Zn-EDTA as soil application, 2.5 kg Zn ha
−1
through chelated Zn-EDTA as soil application + 1 foliar spray of 0.5% chelated Zn-EDTA at flowering and foliar spray of 0.5% chelated Zn-EDTA at active tillering + flowering + grain filling, respectively. Correlation analysis showed positive correlation between Zn uptake and grain yield.
Protected cultivation of ornamental flowers, as a commercial venture, becomes less profitable with excessive use of fertilizers. The present study examined the influence of microbial biofilm ...inoculants (Anabaena-Azotobacter, Anabaena-Trichoderma and Trichoderma-Azotobacter) on the availability of soil nutrients and structure of rhizosphere microbial communities in three varieties of chrysanthemum (var. White Star, Thai Chen Queen and Zembla). Varietal-specific responses in growth, enzyme activities, flower yield of plants and availability of soil nutrients were recorded. Dehydrogenase activity was highest in var. White Star treated with the Anabaena-Trichoderma biofilm inoculants. The Anabaena-Azotobacter inoculant enhanced the availability of nitrogen, phosphorus and micronutrients in the soil, besides 40-50% increase in soil organic carbon, as compared to carrier alone or no inoculation. PCR-DGGE profiling of the cyanobacterial communities and qPCR quantification of 16S rRNA abundance of bacteria, archaea and cyanobacteria in the rhizosphere soils, revealed the stronger influences of these inoculants, especially in var. Zembla. Principal Component Analysis (PCA) helped to illustrate that the enhanced microbe-mediated availability of soil macro-and micronutrients, except iron content (Fe), was the most influential factor facilitating improved plant growth and yield parameters. The Anabaena-Azotobacter, and Anabaena-Trichoderma biofilm inoculants, proved superior in all three chrysanthemum varieties.
Soil fertility and water use are two important aspects that influence rice productivity. This study was conducted to evaluate the performance of in-situ (sesbania and rice bean) and ex-situ (subabul) ...green manuring along with zinc fertilization on water productivity and soil fertility in rice under rice-wheat cropping system at Indian Agricultural Research Institute, New Delhi, India. Sesbania incorporation recorded higher total water productivity (2.20 and 3.24 kg ha
−1
mm
−1
), available soil nutrients, organic carbon, alkaline phosphatase activity, microbial biomass carbon and increased soil dehydrogenase activity by 39.6 and 26.8% over subabul and rice bean respectively. Among interaction of green manures and zinc fertilization, subabul × foliar application of chelated zinc-ethylenediaminetetraacetic acid at 20, 40, 60 and 80 days after transplanting recorded highest total water productivity (2.56 and 3.79 kg ha
−1
mm
−1
). Foliar application of chelated Zn-EDTA at 20, 40, 60 and 80 days after transplanting recorded significantly higher water productivity than other Zn treatments, however it was statistically similar with foliar application of zinc at active tillering + flowering + grain filling. Sesbania × 5 kg Zn ha
−1
through chelated Zn-EDTA, recorded highest available nitrogen, phosphorus, potassium, zinc, manganese, copper and iron than other green manure and Zn fertilization interactions, although it was statistically similar with rice bean × 5 kg Zn ha
−1
through chelated Zn-EDTA as soil application. Sesbania × foliar application of 5 kg Zn ha
−1
through chelated Zn-EDTA as soil application recorded highest soil enzymatic activities and microbial biomass carbon.
Direct-seeded rice (DSR) is an emerging resource-saving rice production practice. It can be alternative to input-intensive conventional transplanted puddled rice, which has encountered problems, ...relating to water, nutrients, energy, and environment. DSR can save water, labour, and energy, reduce greenhouse gases emission and improve soil properties. But, weeds are major constraint, which can cause complete failure of rice. Effective weed management is essential to achieve higher yield and resource-use efficiencies. Herbicide is a more effective and economical option than other weed control methods. But, its efficacy is influenced by herbicides and their use rates, and the weed species that vary across locations, depending on climate and soil. Therefore, this field experiment was carried out to evaluate the combinations of pre-emergence (~ PE) and post-emergence (~ PoE) herbicides as sequential applications, and their impacts on weeds, crops, economics, water productivity, and major nutrients-use efficiencies. It was observed that weed control treatments reduced weed density by 68–84.5% and weed dry weight by 71.6–86.7% at 60 days after sowing (DAS) compared to unweeded control (UWC). Among them, the pendimethalin 1000 g ha
–1
PE at 1 DAS followed by (~ fb) penoxsulam + cyhalofop-butyl 130 g ha
–1
(pre-mix) PoE at 25 DAS resulted in significant reduction in weed density (~ 84.5%) and weed dry weight (~ 86.7%) at 60 DAS. These sequential herbicides application increased effective tillers (233.3 m
–2
), grains weight per panicle (2.54 g), and grain yield (3.92 t ha
–1
) of rice, and irrigation (0.87 kg m
–3
) and total water productivity (0.31 kg m
–3
) by 288.2%, 75.2%, 378.9%, 378%, and 380%, respectively, than those in UWC. This resulted in 17.9% and 73.3% higher net returns and net benefit: cost, respectively, than even weed-free control (WFC) and was superior to all. Contrast analysis revealed that the brown manuring (BM) fb almix 20 g ha
–1
(pre-mix) applied at 40 DAS was similar to it, reducing weed density by 82.7% and dry weight by 83.3%. This study suggests that the sequential applications of herbicides or integration of herbicides with BM would provide broad-spectrum weed control and higher productivity and profitability in DSR. Controlling weeds may also reduce/economize water use and increase use efficiencies of N, P, and K in DSR.
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