Intensive Cropping Systems Research Articles

Understanding the physiological, genetic and molecular basis of nitrogen deficiency tolerance and their application in rice improvement

Nitrogen (N) is a major nutrient required for growth and yield of rice plants. Several factors including plant, edapic and climate conditions influence the criticle yield response curve of the plants. Apart from breeding for N responsive rice varieties, excessive use of nitrogenous fertilizers have become a general farmers practice to boost rice productivity under intensive cropping system. Now, it is imperative to orient the crop improvement programme for sustainable crop production strategy as well as to achieve the evergreen revolution through improving nitrogen use efficiency (NUE) under global climate change condition. To develop N-efficient rice varieties under crop breeding programs, it is crucial to comprehend the physiological, genetic and molecular features associated with tolerance to nitrogen deprivation. It has always been challenging for a rice breeders to develop rice varieties with high nitrogen use efficiency (NUE), as it is highly complex physiological trait involving several component traits and its dynamic interaction with environemental factor. NUE is a polygenic traits controlled by number of quantitative trait loci's at genomic level. Till date, researchers targeted component traits for increasing NUE such as, nitrogen uptake/absorption, transport from root to shoot, assimilation, utilisation, remobilisation, reasssssmilation and partitioning /redistribution. Here, we described a short summary of the physiological, genetic and molecular underpinnings of nitrogen deficit tolerance and how these prior art information can be used for improving NUE in rice. Insight from our discussions may facilitate the breeders to improve the NUE of rice plants in future.

Resource use efficiencies, environmental footprints and net ecosystem economic benefit of direct-seeded double-season rice in central China

Intensive cropping systems with two or three harvests per year are vital to produce sufficient food for the growing population. Improvements in the sustainability of these systems are critical for global food security. Transplanted double-season rice (TPD), an important cropping system in China, is seriously threatened by various challenges such as labor shortage, poor resource use efficiency, high environmental footprint, and low profitability. These challenges could be potentially alleviated by shifting TPD to direct-seeded double-season rice (DSD). Due to the limited thermal energy, ultrashort-duration cultivars matured within 95 days have to be used in DSD in central China. However, it is unknown whether DSD with ultrashort-duration cultivars (DSDS) can improve resource use efficiency and reduce environmental costs compared with TPD in this region. This study aimed to compare the resource use efficiency (energy, water, labor, and fertilizer), carbon and nitrogen footprints, and net ecosystem economic benefit of DSDS and TPD with ultrashort-duration (TPDS) and medium-duration cultivars (TPDM). Results showed that total energy output was 222.0 GJ ha−1 in DSDS, which was comparable to that of TPDM but was significantly increased by 9.5% compared with TPDS. Compared with TPD (i.e. both TPDS and TPDM), the total energy input, labor input, water input, and nitrogen surplus in DSDS reduced by 16.9%, 53.2%, 36.8%, and 31.4%, respectively, leading to significant increases in energy use efficiency, labor productivity, water use efficiency, and nitrogen use efficiency. Furthermore, DSDS decreased direct CH4 and NH3 emissions and indirect carbon emission and reactive nitrogen losses from agronomic inputs, and consequently reduced carbon footprint by 28.6–42.7% and nitrogen footprint by 12.9–14.8% compared with TPD. As a result, the net ecosystem economic benefit in DSDS was significantly increased by 65.9–188.2% relative to TPD. These findings suggest that DSDS is a highly promising strategy to maintain high productivity with less resource inputs and environmental pressures but high economic benefits in central China.

Reduced tillage and crop diversification can improve productivity and profitability of rice-based rotations of the Eastern Gangetic Plains.

Intensive rice (Oryza sativa)-based cropping systems in south Asia provide much of the calorie and protein requirements of low to middle-income rural and urban populations. Intensive tillage practices demand more resources, damage soil quality, and reduce crop yields and profit margins. Crop diversification along with conservation agriculture (CA)-based management practices may reduce external input use, improve resource-use efficiency, and increase the productivity and profitability of intensive cropping systems. A field study was conducted on loamy soil in a sub-tropical climate in northern Bangladesh to evaluate the effects of three tillage options and six rice-based cropping sequences on grain, calorie, and protein yields and gross margins (GM) for different crops and cropping sequences. The three tillage options were: (1) conservation agriculture (CA) with all crops in sequences untilled, (2) alternating tillage (AT) with the monsoon season rice crop tilled but winter season crops untilled, and (3) conventional tillage (CT) with all crops in sequences tilled. The six cropping sequences were: rice-rice (R-R), rice-mung bean (Vigna radiata) (R-MB), rice-wheat (Triticum aestivum) (R-W), rice-maize (Zea mays) (R-M), rice-wheat-mung bean (R-W-MB), and rice-maize-mung bean (R-M-MB). Over three years of experimentation, the average monsoon rice yield was 8% lower for CA than CT, but the average winter crops yield was 13% higher for CA than CT. Systems rice equivalent yield (SREY) and systems calorie and protein yields were about 5%, 3% and 6%, respectively, higher under CA than CT; additionally, AT added approximately 1% more to these benefits. The systems productivity gain under CA and AT resulted in higher GM by 16% while reducing the labor and total production cost under CA than CT. The R-M rotation had higher SREY, calorie, protein yields, and GM by 24%, 26%, 66%, and 148%, respectively, than the predominantly practiced R-R rotation. The R-W-MB rotation had the highest SREY (30%) and second highest (118%) GM. Considering the combined effect of tillage and cropping system, CA with R-M rotation showed superior performance in terms of SREY, protein yield, and GM. The distribution of labor use and GM across rotations was grouped into four categories: R-W in low-low (low labor use and low GM), R-M in low-high (low labor use and high GM), R-W-MB and R-M-MB in high-high (high labor use and high GM) and R-R and R-MB in high-low (high labor use and low GM). In conclusion, CA performed better than CT in different winter crops and cropping systems but not in monsoon rice. Our results demonstrate the multiple benefits of partial and full CA-based tillage practices employed with appropriate crop diversification to achieve sustainable food security with greater calorie and protein intake while maximizing farm profitability of intensive rice-based rotational systems.

Energy conservation prospects in water intensive Paddy-Wheat cropping system for groundwater pumping in the semi-arid region of Haryana.

The study was aimed at identifying the potential energy saving for groundwater pumping through enhanced efficiency of the pump sets. A total of 65 electrically powered tube wells were selected in the Sonipat district of the north Indian State of Haryana to study the energy use efficiency for groundwater pumping. The existing efficiency as well as the minimum expected overall efficiency of the tubewells were determined based on field survey, measurements, and applicable standard code of the Bureau of India Standards. The overall efficiencies of selected tube wells, computed based on actual measured power consumption, varied from 10.1% to 56.6% in the Sonipat block and 15.3% to 52.8% in the Rai block. The average energy requirement, for the selected tube wells, at the current efficiency level was 4,364.0 and 13,100.4 kWh for wheat and paddy crops, respectively, in the Sonipat block, while it was 3,424.8 and 10,280.9 kWh for wheat and paddy crops, respectively, in the Rai block. Analysis revealed that improving overall efficiency from the current level to the minimum expected level can lead to energy savings of 48.3% and 35.9% for tube wells in the Sonipat and Rai block, respectively. In the Rai block, where the groundwater level has declined significantly, the replacement of inefficient pumps should be done in tandem with crop diversification, improving water application efficiency and groundwater status by employing improved irrigation management practices and adopting groundwater recharge techniques.

Breeding and genomics approaches for improving phosphorus-use efficiency in grain legumes

Phosphorus (P) is an essential plant macronutrient, but P sources for plant growth are non-renewable, causing great concern for future sustainable agriculture and global food security. Thus, enhancing plant P-use efficiency (PUE) by improving P-acquisition and P-utilization efficiencies is urgently needed in various crops, including grain legumes, for intensive cropping systems. This review discusses how to harness the genetic variability in PUE traits across grain legume gene pools to improve PUE using various conventional breeding approaches and emerging breeding tools. The genetic architecture of PUE traits is complex, being quantitatively inherited and highly influenced by the environment. Thus, we discuss how the biparental QTL mapping approach has been used to dissect the genetic architecture of PUE traits. Unprecedented advances in legume genomics resources, especially high-throughput single nucleotide polymorphisms, have facilitated uncovering genomic regions related to PUE across the whole genome using a genome-wide association mapping approach. Likewise, the availability of complete genome sequence information, pangenome sequences, and the whole-genome resequencing approach have provided novel insights into structural variation, including presence/absence and copy number variations, underpinning PUE. Simultaneously, progress in functional genomics, including transcriptomics and computational biology, has facilitated the discovery of various underlying transcription factors and the corresponding downstream P signal perception genes and candidate gene(s) controlling PUE and conferring low-P tolerance in various legumes with putative function. We also discuss updated metabolomics and proteomics approaches that have improved our understanding of various gene networks, P-starvation signaling pathways, and P acquisition and utilization of molecular mechanisms important for PUE. Finally, we summarize how novel breeding schemes, including genomic selection, speed breeding, and emerging CRISPR/Cas9-based genome editing tools, will assist in designing P-use-efficient cultivars and adapting grain legumes to low-P environments. Thus, enhancing PUE by integrating various ‘omics’ approaches could improve P-acquisition and P-utilization efficiencies in various modern grain legume cultivars grown in intensive cropping systems to restrict P-fertilizer overuse and preserve the declining non-renewable global rock phosphate reservoir for securing an economical and sustainable future agriculture. • Phosphorus (P) is one of the most essential nutrients required for plant growth and development. • P fertilizers being non-renewable, judicious utilization of P fertilizer is urgently needed for sustaining legume yield for ensuring global food security. • Plants have evolved several molecular, physiological and biochemical mechanisms to sense, acquire and utilize soil P and adapt under P impoverished environments. • ‘Omics’ approach could greatly assist in unraveling the underlying genomic regions with their function contributing to improving phosphorus use efficiency in legume crops.

The potential impact of succeeding crops on soil carbon pools, carbon sequestration, beneficial microbes and enzyme activities under intensive sugarcane-based cropping systems

The potential impact of succeeding crops on soil carbon pools, carbon sequestration, beneficial microbes and enzyme activities under intensive sugarcane-based cropping systems

Is biochar a promising soil amendment to enhance perennial crop yield and soil quality in the tropics?

Soil quality improvement is crucial in tropical soils to enhance crop productivity. Organic matter incorporation is not a viable approach regarding perennials as it completely degrades within a year. Hence, biochar is a sustainable solution to boost crop productivity in the tropics. Biochar has been utilized in agriculture for decades due to its inherent properties that enhance the soil-mediated properties associated with soil fertility. The impact of biochar on tropical perennial intensive cropping systems has been understudied, possibly because of the high initial input demand. This paper highlights the facts related to soil chemical, physical, and biological property enhancement upon biochar incorporation relating to long-term impacts on perennial crops.

Significant reduction of ammonia emissions while increasing crop yields using the 4R nutrient stewardship in an intensive cropping system

Ammonia (NH3) emissions should be mitigated to improve environmental quality. Croplands are one of the largest NH3 sources, they must be managed properly to reduce their emissions while achieving the target yields. Herein, we report the NH3 emissions, crop yield and changes in soil fertility in a long-term trial with various fertilization regimes, to explore whether NH3 emissions can be significantly reduced using the 4R nutrient stewardship (4Rs), and its interaction with the organic amendments (i.e., manure and straw) in a wheat–maize rotation. Implementing the 4Rs significantly reduced NH3 emissions to 6 kg N ha–1 yr–1 and the emission factor to 1.72%, without compromising grain yield (12.37 Mg ha–1 yr–1) and soil fertility (soil organic carbon of 7.58 g kg–1) compared to the conventional chemical N management. When using the 4R plus manure, NH3 emissions (7 kg N ha–1 yr–1) and the emission factor (1.74%) were as low as 4Rs, and grain yield and soil organic carbon increased to 14.79 Mg ha–1 yr–1 and 10.09 g kg–1, respectively. Partial manure substitution not only significantly reduced NH3 emissions but also increased crop yields and improved soil fertility, compared to conventional chemical N management. Straw return exerted a minor effect on NH3 emissions. These results highlight that 4R plus manure, which couples nitrogen and carbon management can help achieve both high yields and low environmental costs.

Herbicide use history and weed management in Southeast Asia

Southeast Asia’s rich natural resources and favorable climatic conditions make it conducive for intensive rice-based, corn-based and perennial crops-based cropping systems. Regardless of the cropping system, weeds remain to be among the major factors that limit yields. The use of herbicides to manage weeds in these systems has been increasing through the years. The use of 2,4-D started in the late 1940s and remains as a major herbicide to control rice weeds. The 1980s saw the introduction of multiple [...]

Application of water-energy-food nexus approach for optimal tillage and irrigation management in intensive wheat-maize double cropping system

Demand for water, energy and food is increasing driven by a rising global population, changing diets, warming climate and economic growth. Wheat-maize double cropping system, as one of the best trials in ensuring sustainable food security, is experiencing various optimizing irrigation management and tillage practices in the North China Plain. However, previous studies mainly focused on their influences on crop yield and water use efficiency. Comprehensive analysis of water-energy-food for the practices was limited. Therefore, a life cycle assessments based water–energy–food (WEF) nexus analysis was conducted using data from a 7-year two-factor split-plot field experiments with four tillage (NT, no-tillage; RT, rotary tillage; PT, plow tillage; CT, local current tillage) and three irrigation managements (W1, pre-planting irrigation for wheat + pre-planting irrigation for maize; W2, pre-planting + jointing irrigation for wheat + pre-planting irrigation for maize; and W3, pre-planting + jointing + anthesis irrigation for wheat + pre-planting irrigation for maize; 75 mm each time). The results indicated that irrigation, fertilizer and diesels input were the top three items for water and energy consumption. Irrigation managements significantly altered wheat and annual yield but not for maize yield. Tillage practices primarily altered diesel input to affect energy mass and energy economic productivity. During wheat season, W3PT obtained the highest yield at 8.69 t ha−1 and highest net income at 8.27 ¥ ha−1. With the same tillage practice, W1 had the best performance in water and energy consumption and mass productivity, while W2 had the highest water and energy economic productivity. In terms of different tillage practices with the same irrigation amount, NT consumed lowest energy, but its lowest wheat yield offset its benefits as well. During maize season, the yields were insensitive for irrigation and tillage practices. NT and CT were substantially beneficial regarding energy input, which further resulted in good performance in terms of energy mass and economic productivity under the same irrigation treatment. Throughout the year, lower water and energy consumption and higher resource productivity offset the yield and income loss under W1CT to accomplish highest value of WEF nexus index. Thus it is the optimal tillage and irrigation management pattern in the wheat-maize double cropping system of the North China Plain achieving cleaner production. This study contributed a new case to using WEF nexus analysis and offered new reference data and effective suggestions for selecting proper filed management in the double cropping system to achieve sustainable development goals with carbon peaking and carbon neutrality.

Response of cadmium adsorption to three-year different agronomic managements in tropical soil: The role of P fractions and Fe oxides

The overuse of chemical fertilizers and intensive cropping systems often results in soil quality degradation in the tropical and subtropical regions and affects cadmium (Cd) availability to crops. Therefore, studying the impact of agronomic managements on soil Cd adsorption and related mechanisms is critical for sustainable agriculture in tropical regions. Here, a three-year field experiment was conducted with five different agronomic managements [corn-pepper rotation with NPK fertilizers as control treatment (NPK), corn-pepper rotation with NPK fertilizers and sheep manure (NPKM), continuous corn cropping (CC), corn-pepper intercropping, and then rotation with green manure (CPGM), and corn-pepper rotation and then fallow (CPRF)]. The chemical characterization of bulk soils and soil aggregates from different treatments was performed and the isotherm adsorption experiments of Cd on different bulk soils and soil aggregates were conducted to investigate the effects of agronomic managements on characters of bulk soil and soil aggregates and subsequent effects on Cd adsorption. The results revealed that the maximum adsorption of Cd by bulk soil and various soil aggregates in the five treatments ranged from 0.235 to 0.627 and 0.222–1.360 mg g−1, respectively. The change of maximum Cd adsorption with management was in the order of CPGM > CPPF > NPKM > CC > NPK, regardless of bulk soil and soil aggregates. Compared to the NPK treatments, total P and Fe contents were significantly increased in the bulk soil and various soil aggregates of the CPGM and CPRF treatments, respectively. Furthermore, SEM-EDS analysis implied that the micro-zone distribution of Cd in the bulk soil was closely related to P and Fe, especially in the CPGM treatment. Random forest model revealed that soil pH predominantly contributed to the Cd adsorption by both the bulk soil (8.7%) and 0.25–2.0 mm soil aggregates (10.8%) in the five treatments. However, the contribution of humic P, amorphous Fe oxide, labile inorganic P, labile organic P, and total P were significantly higher than soil pH for 0.053–0.25 mm and < 0.053 mm soil aggregates. Overall, corn-pepper intercropping with green manure rotation was promising for Cd immobilization by tropical soil because of the increased effective contents of P fractions and Fe oxides for Cd adsorption.

The genetic diversity-productivity effect in wheat cultivar mixtures at multiple levels

There is abundant evidence that biodiversity promotes ecosystem functions in various ecosystems, and recent syntheses stress the need to promote biodiversity in agroecosystems to enhance productivity and stability in a changing climate. Yet, how we can better manipulate genetic biodiversity to achieve these goals in intensive cropping systems is not well understood. Using a large-scale intensive wheat cropping experiment, we studied the effects of wheat genetic diversity on productivity at multiple levels. The results show that the overyielding effects were achieved in mixed cropping at the population, cultivar, and individual levels, which can be considered as a promising way to enhance food security. In addition, wheat cultivar mixtures were temporally more stable than the monocultures. These point to a combination of the positive and negative effects, including complementarity, selection, and competition, in mixtures that affect the cultivars' collective strategies, which are determined by both the complexity of the mixture and the environmental conditions. Furthermore, we found nonmonotonic genetic diversity-productivity relationships that are consistent at multiple levels, suggesting that increasing the number of cultivars in mixed cropping does not always promote productivity. Our results can be directly interpreted for policy and management in ecological cropping systems.

Editorial: Better management of phosphorus fertilizer in intensive cropping systems: An approach based on integrated agronomic, ecological and environmental compromises

Editorial: Better management of phosphorus fertilizer in intensive cropping systems: An approach based on integrated agronomic, ecological and environmental compromises

Performance of Diversified Legume Entailing Ultra High Intensity Rice based Cropping System Models for Higher Productivity, Profitability and Sustainability

Background: An intensive cropping system involving legume and vegetable crops not only highly productive and profitable but should also be stable over time and maintains soil health in present scenario. So, keeping this point in view the present investigation was carried out to evaluate the productivity, profitability and sustainability of legume entailing different ultra high intensity rice based cropping system models under irrigated sub-tropics. Methods: The field experiment was conducted at Research Farm, SKUAST-Jammu, Main Campus, Chatha for two consecutive years from kharif 2019 to summer season of 2021. The experiment consisting of five legume entailing rice based cropping system models of cropping intensity varying from 300-600% viz. T1: Rice (Basmati-370) - Wheat (HD-3086) - Cowpea (Lobia Super-60) having 300% cropping intensity, T2: Rice (Basmati-564) - Potato (Kufri Badshah) - Wheat (Raj-3765) - Mixed fodder (Maize+Cowpea+Charri in 2:2:1 ratio) having 400% cropping intensity, T3: Rice (SJR-129) - Knol khol (G-40) - Potato (Kufri Sindhuri) - Green gram (IPM 02-3) having 400% cropping intensity, T4: Rice (Pusa-1121) - Radish (CR-45) - Green onion (Nasik Red) - French bean (Anupama) - Okra (Seli special) having 500% cropping intensity in relay cropping from fourth crop onwards and T5: Rice (IET-1410) - Fenugreek (JF-07) - Knol khol (G-40) - Green onion (Nasik Red) - Dry onion (Selection-1) - Black gram (Pant U-19) having 600% cropping intensity in relay cropping from third crop onwards was laid out in a randomized block design with four replications. Result: The results obtained under two years research study revealed that treatment T4 recorded significantly highest basmati-370 rice equivalent system productivity followed by treatment T5. Further, treatment T4 also recorded highest system cost of cultivation, system gross returns and system net returns. System soil fertility status in terms of available NPK after completion of second crop cycle was significantly affected. Among different cropping systems, significantly higher available nitrogen and phosphorus were recorded in treatment T5 system which was at par with treatment T4.

Biochar-Induced Mitigation Potential of Greenhouse Gas Emissions Was Enhanced under High Soil Nitrogen Availability in Intensively-Irrigated Vegetable Cropping Systems

Intensive irrigation coupled with excessive nitrogen (N) fertilizer input has resulted in high soil greenhouse gas (GHG) emissions in vegetable cropping systems. Biochar as a soil amendment has been advocated as a desirable option to reduce GHG emissions in agricultural systems, but its interactive effects with soil N availability in vegetable systems have yet to be clarified. We performed a field study to examine how biochar interacts with N fertilizer in driving annual methane (CH4) and nitrous oxide (N2O) emissions from an intensively-irrigated greenhouse vegetable cropping system acting as both sources of atmospheric CH4 and N2O in subtropical China. Biochar amendment significantly increased soil CH4 emissions by 33% and 85%, while it decreased soil N2O emissions by 22% and 12% with and without N fertilizer input, respectively. Fertilizer N combination weakened the positive response of CH4 to biochar while it enhanced the mitigation potential of biochar for N2O. Annual direct emission factors of fertilizer N for N2O were estimated to be 1.35% and 1.94% for the fields with and without biochar amendment, respectively. Annual flux-sustained global warming potential (SGWP) and greenhouse gas intensity (GHGI) were significantly decreased by biochar amendment, and this mitigation effect was enhanced with fertilizer N combination. Altogether, we highlight that biochar can reconcile higher yield and lower climatic impact in intensive vegetable cropping systems in subtropical China, particularly in vegetable soils with high N availability.

Long-term nutrient management in an intensive rice-wheat cropping system improves the quantities, qualities, and availability of soil sulfur

In the last few decades, the deficiency of sulfur (S) has been noticed in the agricultural soils of India. Meanwhile, researchers reported that S plays a significant role in the productivity of the rice-wheat cropping system (RWCS). For the quantification of S response, a long-term field experiment was started at the Indian Council of Agricultural Research-Indian Institute of Farming Systems Research (ICAR-IIFSR), Modipuram, India. In total, 7 nutrient supply options were applied, i.e., organic, mineral fertilizer in the combination of integrated plant nutrition system (IPNS), and IPNS + berseem (B)/IPNS + cowpea (C) in the S availability of the soil in the RWCS. The results showed that the highest contribution in S availability by the total S (39%) is followed by the organic S (35%), sodium bicarbonate extractable sulfur (NaHCO3-ES; 7%), heat-soluble sulfur (SS; 7%), water-soluble sulfur (WSS; 4%), available S (4%), and inorganic S (4%) under different long-term nutrient supply options of RWCS. The continuous application of organic fertilizer and various IPNS options, such as the inclusion of pulses, significantly improved all S fractions in the soil and also offers an additional benefit in terms of sustainability of production and soil health as compared to the inorganic fertilizer fields. Overall, the results showed that IPNS showed its superiority over the rest of the treatment. The results also supported that the inclusion of pulses gives a further gain in terms of sulfur availability in soil systems under RWCS.

Microbes-mediated integrated nutrient management for improved rhizo-modulation, pigeonpea productivity, and soil bio-fertility in a semi-arid agro-ecology

Excessive dependence on chemical fertilizers and ignorance to organic and microbial inputs under intensive cropping systems are the basic components of contemporary agriculture, which evolves several sustainability issues, such as degraded soil health and sub-optimal crop productivity. This scenario urges for integrated nutrient management approaches, such as microbes-mediated integrated plant nutrition for curtailing the high doses as chemical fertilizers. Rationally, experiment has been conducted in pigeonpea at ICAR-IARI, New Delhi, with the aim of identifying the appropriate nutrient management technique involving microbial and organic nutrient sources for improved rhizo-modulation, crop productivity, and soil bio-fertility. The randomized block-designed experiment consisted nine treatments viz. Control, Recommended dose of fertilizers (RDF), RDF+ Microbial inoculants (MI), Vermicompost (VC), Farm Yard Manure (FYM), Leaf Compost (LC), VC + MI, FYM + MI, and LC + MI. Rhizobium spp., Pseudomonas spp., Bacillus spp., and Frateuria aurantia were used as seed-inoculating microbes. The results indicated the significant response of integration following the trend VC + MI > FYM + MI > LC + MI > RDF + MI for various plant shoot-root growth attributes and soil microbial and enzymatic properties. FYM + MI significantly improved the water-stable aggregates (22%), mean weight diameter (1.13 mm), and geometric mean diameter (0.93 mm), soil organic carbon (SOC), SOC stock, and SOC sequestration. The chemical properties viz. available N, P, and K were significantly improved with VC + MI. The study summarizes that FYM + MI could result in better soil physico-chemical and biological properties and shoot-root development; however; VC + MI could improve available nutrients in the soil and may enhance the growth of pigeonpea more effectively. The outcomes of the study are postulated as a viable and alternative solution for excessive chemical fertilizer-based nutrient management and would also promote the microbial consortia and organic manures-based agro-industries. This would add to the goal of sustainable agricultural development by producing quality crop produce, maintaining agro-biodiversity and making the soils fertile and healthy that would be a “gift to the society.”

Soil Acidification caused by excessive application of nitrogen fertilizer aggravates soil-borne diseases: Evidence from literature review and field trials

Modern high input–based intensive cropping systems often lead to the deterioration of the soil environment, which is one of the main driving factors for the build-up of soil-borne pathogens. However, soil chemical properties are complex and variable, and it is important to clarify the main factors driving soil-borne pathogens. In this study, meta-analysis and field experiment were used to determine the key soil chemical factors affecting soil-borne diseases. Our data demonstrated that a decrease in the soil pH was the key soil chemical factor that aggravated soil-borne diseases. Among the complex soil chemical factors, the increase in available nitrogen (AN) caused by excessive application of nitrogen fertilizer and the accumulation of phenolic acids were the main driving factors for the decrease in the soil pH value. Field experiments on Panax notoginseng, which is susceptible to nitrogen and suffers from serious soil-borne disease, showed that a high level of AN (≥350 mg kg−1) in soil caused by overuse of nitrogen fertilizer could decrease the pH and aggravate soil-borne disease. However, exogenous quicklime (600–1200 kg hm−2), calcium magnesium phosphate fertilizer (600–1200 kg hm−2), and organic fertilizer (1050–1500 kg hm−2) in acidic soil could effectively increase the soil pH value and alleviate soil-borne disease. Our results highlight that soil-borne disease can be aggravated by overuse of nitrogen fertilizer and can be alleviated by modifying soil to a suitable pH level.

Description of an Arabica Coffee Ideotype for Agroforestry Cropping Systems: A Guideline for Breeding More Resilient New Varieties.

Climate change (CC) is already impacting Arabica coffee cultivation in the intertropical zone. To deal with this situation, it is no longer possible to manage this crop using industrial agriculture techniques, which has been the main strategy implemented since the Green Revolution. Developing a more sustainable agriculture system that respects people and the environment is essential to guarantee future generations’ access to natural resources. In the case of Arabica coffee, the solution has been found. Agroforestry is proposed as an ecosystem-based strategy to mitigate and adapt to CC. At least 60% of Arabica coffee is produced in agroforestry systems (AFSs), which are the most sustainable way to produce coffee. Nevertheless, AFS coffee cultivation is currently uncompetitive partly because all modern varieties, selected for full-sun intensive cropping systems, have low yields in shaded environments. Here we review the reasons why agroforestry is part of the solution to CC, and why no breeding work has been undertaken for this cropping system. Based on the literature data, for breeding purposes we also define for the first time one possible coffee ideotype required for AFS coffee cultivation. The four main traits are: (1) productivity based on F1 hybrid vigor, tree volume and flowering intensity under shade; (2) beverage quality by using wild Ethiopian accessions as female progenitors and selecting for this criterion using specific biochemical and molecular predictors; (3) plant health to ensure good tolerance to stress, especially biotic; and (4) low fertilization to promote sustainable production. For each of these traits, numerous criteria with threshold values to be achieved per trait were identified. Through this research, an ecosystem-based breeding strategy was defined to help create new F1 hybrid varieties within the next 10 years.

Relationship between phosphorus uptake via indigenous arbuscular mycorrhizal fungi and crop response: A 32P-labeling study

Arbuscular mycorrhizal (AM) fungi form potentially symbiotic associations with most crop species and potentially increase crop phosphorus (P) uptake in intensive cropping systems. Their widespread use, however, remains restrained by our limited understanding of the processes that determine the outcome of the associations. Here, we have used 32P to quantify the delivery of P to maize (Zea mays L.) and wheat (Triticum aestivum L.) via indigenous AM fungi in compartmented pots under high- and low-P conditions. Soil P level was important in driving shoot P uptake via the direct root pathway (DP) or the mycorrhizal pathway (MP). The MP contribution reached 81.8 and 75.8%, respectively, in maize and wheat at low P status but declined to 40.6 and 9.1% at high P. The abundance of intraradical and extraradical colonization and the relative abundance of Rhizophagus and shoot P utilization efficiency (PUE) significantly impacted the MP contribution. Larger mycorrhizal P and growth responses were closely related to a higher MP contribution and shoot PUE in maize but only P response was significantly related to the latter in wheat. These results suggest that crops can acquire considerable amounts of P via the MP with indigenous AM fungi, especially at low P levels, and highlight the importance of plant and AM fungal identity in regulating the relationship between hidden P uptake and symbiotic outcomes. Therefore, manipulation of fertilizer P application rates to optimize the abundance and assemblage of the indigenous AM fungi and crop PUE to increase MP activity and symbiotic outcomes may contribute to the efficient utilization of AM fungi in intensive cropping systems.