Enhancing soil health and phosphorus use efficiency with modified biochar amendment.

Traditional agroforestry parkland systems in Burkina Faso are under threat due to human pressure and climate variability and change, requiring a better understanding for planning of adaptation. Field experiments were conducted in three climatic zones to assess Sorghum bicolor (L.) Moench (Sorghum) biomass, grain yield and harvest index in parklands under different rainfall pattern and compared to simulations of sorghum biomass and grain yield with the Water, Nutrient and Light Capture in Agroforestry Systems (WaNuLCAS) model for calibration and parametrisation. For planning adaptation, the model was then used to evaluate the effects of different management options under current and future climates on sorghum biomass and grain yield. Management options studied included tree densities, tree leaf pruning, mulching and changes in tree root patterns affecting hydraulic redistribution. The results revealed that sorghum biomass and grain yield was more negatively affected by Parkia biglobosa (Jacq.) Benth. (nere) compared to Vitellaria paradoxa C. F Gaertn (karite) and Adansonia digitata L. (baobab), the three main tree species of the agroforestry parkland system. Sorghum biomass and grain yield in different influence zones (sub-canopy, outside edge of canopy, open field) was affected by the amount of precipitation but also by tree canopy density, the latter depending itself on the ecological zone. The harvest index (grain as part of total biomass) was highest under the tree canopy and in the zone furthest from the tree, an effect that according to the model reflects relative absence of stress factors in the later part of the growing season. While simulating the effects of different management options under current and future climates still requires further empirical corroboration and model improvement, the options of tree canopy pruning to reduce shading while maintaining tree root functions probably is key to parkland adaptation to a changing climate.

Sorghum (Sorghum bicolor) is a well-known agronomic crop of global importance. The demand for sorghum as a food crop makes it the fifth most important cereal in the world. The grain of sorghum is utilized for food and feed, whereas the sorghum biomass may have many other uses such as for fodder, bioenergy or even for construction. Globally, sorghum is consumed as a food crop and used for home construction primarily in the developing world. The grain and biomass yield of sorghum is drastically reduced by the parasitic plant Striga hermonthica which is endemic to Sub-Saharan Africa. To date, only one sorghum gene, LGS1, has been characterized as a genetic mechanism that reduces S. hermonthica parasitism by altering the strigolactone composition of the host root exudates which results in a reduction of the parasites ability to germinate. To establish more durable resistance additional genetic variation needs to be identified that reduces the S. hermonthica parasitism in sorghum, but also reduces the parasitic weed seed bank by promoting suicidal germination. To that end, the PP37 multi-parent advanced generation inter-cross (MAGIC) population was developed, originally as a recurrent selection population that was developed to recombine sorghum accessions with different putative resistance mechanisms to S. hermonthica. Whole genome sequences were developed for approximately 1,006 individuals of the PP37 MAGIC population. The population was phenotyped for S. hermonthica resistance during the 2016 and 2017 growing season in Northwestern Ethiopia. There was significant spatial variation in the S. hermonthica natural infestations that were partially attenuated for with artificial inoculation. The data was used to conduct a genome-wide association study that detected several subthreshold peaks, including the previously mapped LGS1. The highly quantitative nature of S. hermonthica resistance confounded with the complex spatial variation in the parasite infestations across a given location make it difficult to detect highly heritable variation across years and environments. In addition to S. hermonthica resistance, the plant architecture of the PP37 MAGIC was also assessed at a location in Northwestern Ethiopia that is free of the parasite, as it significantly reduces plant height. To asses plant architecture the total plant height, the height of the panicle base, flag leaf height, and pre-flag leaf height were collected using a relatively high-throughput barcoded measurement system. Sorghum head exertion and panicle length were derived from this data. The actual measures of plant architecture and the derived traits were used to conduct a genome-wide association study. The high heritability of this trait demonstrated the statistical power of the PP37 mapping population. Highly significant peaks were detected that resolved the dwarf3 locus and an uncharacterized qHT7.1 that had only been previously resolved using a recombinant inbred line population. Furthermore, a novel significant locus was associated with exertion on chromosome 1. The random mating that was utilized to develop the PP37 MAGIC has broken the population structure that when present can hinder our ability associate regions of the genome to a given phenotype. As a result, novel candidate gene lists have been developed as an outcome of this research that refined the potential genes that need to be explored to validate qHT7.1 and the novel association on chromosome 1. This research demonstrated the power of MAGIC populations in determining the genomic regions that influence complex phenotypes, that facilitates future work in sorghum genetic improvement through plant breeding. This research however also demonstrates a large international research effort. The nuisances and lessons learned while conducting this international research project are also discussed to help facilitate and guide similar research projects in the future. The broader impacts of this research on the society at large are also discussed, to highlight the unique potential broader impacts of international research in the plant sciences. The broader impacts of this research include germplasm development and extensive human capacity building in plant breeding genetics for developing country students and aspiring scientists. Overall this research attempts to serve as a model for highlighting the interdisciplinary nature and complexity of conducting international plant science research, while also making significant strides in improving our understanding the genetic architecture of quantitative traits of agronomic importance in sorghum.

The objective of intercropping is to improve resource efficiencies for land, water and radiation. Few studies have focused on the interactive effects of water stress on radiation use efficiency (RUE) in an intercrop system. The study determines the effect of intercropping sorghum with either cowpea or bottle gourd on RUE and biomass accumulation in response to water stress. This was assessed using a split-plot design with crop sequences sole sorghum, sole cowpea, and sole bottle gourd and intercrop systems sorghum–cowpea and sorghum–bottle gourd assigned as sub-plots arranged in randomised complete blocks within main plots, water regimes: full irrigation, deficit irrigation and rainfed. We quantified specific leaf area, leaf area index as well as biomass accumulation and partitioning. Extinction coefficient, intercepted photosynthetic active radiation (IPAR) and RUE for biomass (RUEb) and grain (RUEg) were also determined. Under rainfed conditions, intercropping with either cowpea (26%) or bottle gourd (62%) improved sorghum leaf area. A reduction in specific leaf area was observed for sorghum when it was intercropped with either cowpea (−20%) or bottle gourd (−19%). Under full irrigation, sorghum stems constituted a larger proportion (62%) of final biomass in comparison to sorghum under deficit irrigation (52%) and rainfed conditions (50%). Intercropping sorghum with either cowpea or bottle gourd improved IPAR (38%), RUEb (93%) and RUEg (11%) under rainfed conditions. This study showed that under water-limited conditions intercropping reduced sorghum stem mass and increased canopy size, radiation interception, and grain yield and improved RUE. In agreement with our proposition, water availability was closely associated with radiation use efficiency. Intercropping can be recommended for semi-arid environments since it improves RUE and sorghum biomass and grain yield.

Adsorption and immobilization performance of pine-cone pristine and engineered biochars for antimony in aqueous solution and military shooting range soil: An integrated novel approach

Influence of tillage systems and seedbed types on sorghum yields and economics in northern Ghana

Converting sewage sludge to biochar to serve as soil amendment and nutrient supplement to cropland may be an environmental benign and value-added approach to recycle the waste. Potting experiments were conducted to examine the efficacy of sludge biochar amendments on enhancing soil health and crop productivity. Strongly acidic soil (pH=5.0) was amended with sludge biochar at three different concentrations: 0 (control), 1% and 2% of its dry weight, and packed into plastic buckets (9.45-L) to a bulk density of 1.1 g cm-3, and each treatment had three replicates. Winter wheat (Triticum aestivum L.), spinach (Spinacia oleracea), and Mung bean (Vigna radiata) were sequentially grown for nine months under greenhouse and field conditions (each crop cycle lasted three months). The above-ground biomass was collected, and oven dried at 65°C for 72 hours to assess plant biomass yield. Soil health parameters such as aggregates stability, pH, electric conductivity (EC), soil respiration, and microbial biomass C were measured. Soils amended with 2% biochar demonstrated higher biomass yield in winter wheat and spinach crops compared to those amended with 1% biochar and unamended control, on the other hand, mung bean did not present significant difference in all treatments. Similarly, 2% biochar demonstrated high aggregates stability (19.85%) followed by control (9%) and 1% biochar (8.3%). Soil acidity was neutralized in soils amended with 2% biochar (pH: 6.5) compared to control (pH: 5.8) and 1% biochar (pH: 5.5). EC was in the ideal level (<2.7 dS m-1) for all treatments. Soil respiration was not significantly different in all treatments. Microbial biomass C was higher in control and 2% biochar with significant differences towards 1% biochar. These findings provide additional evidence that sludge biochar promote plant growth and improve certain soil health parameters. However, the effect of sludge biochar in soil biological properties was not observed. Therefore, long-term field experiments are needed to assess the amendment effect of sludge biochar on microbial biomass C and soil respiration to validate the persistent efficacy of sludge biochar amendments on facilitating crop production, crop productivity, and soil health.

The dependency on rainfed agriculture and weak adaptability of the agricultural sector to climate change threaten food security in Sub-Saharan Africa (SSA). Biochar has widely been touted as a relatively easy means of increasing the soil water storage capacity of soils and thereby improving or maintaining crop yields. In this study we simulated the effect of biochar amendment on sorghum aboveground biomass and grain yield at a site in South Sudan. We used the model AquaCrop parameterized using site, soil, and cropping management data from a field experiment carried out at the site in 2011 and 2012, which were both wet years. Changes in soil hydraulic properties due to biochar were based on a published meta-analysis study. In order to investigate whether the response to biochar differed in dry years, simulations were also carried out for 1990, which was the driest year during the period 1979–2014. Measured and modelled biomass and yields with and without biochar for 2011 and 2012 were compared. Simulated and measured yields depended on growing season rainfall and distribution. The simulations showed that biochar amendment had an effect on rooting zone soil water content and sorghum biomass and grain yield in 1990, but not in 2011 and 2012. In view of expected climate change, the results have important implications for sorghum production and the potential use of biochar in SSA. Given the limited response of grain yield to biochar shown in our simulations, careful selection of sorghum variety and cultivar and consideration of planting date may be a more effective means of improving yields than applying biochar.

Soil is a powerful nonrenewable asset that embraces life on earth by furnishing nutrients to plant. Degradation of soil health due to indiscriminate use of chemical fertilizers and industrialization has become predominant environmental concern with high preeminence. In view of the present scenario, soil microbes are the most important candidates for improving soil fertility and health. The plant growth-promoting microbes are used for enhancing soil fertility under stressed and normal environment. Soil holds variety of microbial species such as fungi, bacteria, mosses and liverwort. The prevalence of microbes is an indicator of soil biological activities and regulates physical and chemical properties of soil. It enhances soil health and crop productivity by diverse mechanisms like biofortification of nutrients, bioremediation of soil, regulation of nutrient cycling, antibiosis, rhizosphere competence, secretion of enzymes, stimulation of systemic resistance in host plant, and production of metabolites, volatile compounds and antifungal toxins against pathogens. Interaction of plant and microorganisms results in plant growth promotion and disease control under fluctuating environment and enables sustainable agriculture without compromising ecosystem balance. Thus, the inclusive use of plant growth-promoting rhizobacteria promotes soil fertility that encourages sustainable agriculture production under extreme condition.

Soil health refers to its function as a living ecosystem. Food demand for the growing population necessitates boosting of crop productivity. Soil health and crop productivity are closely linked. Various chemicals are often added to the soil at higher doses in an effort to increase productivity, which in the long term deteriorates soil quality. The quality of soil is determined by the availability of essential nutrients. Healthy soil is vital for vibrant microbial diversity. An extensive range of microbes live in soil, which have a participatory contribution in modulating soil properties. The primary role of fungi in the soil ecosystem is decomposition, breakdown of complex substances, plant growth promotion, and biocontrol. Fungi have been extensively studied at pilot and field scale. Employing fungi for biocontrol is also a well-researched area and has a good representation of products in the market. The fungal role in plant growth promotion is relatively an emerging area. This chapter focuses on the role of fungi in defining various functions that impact soil quality. A detailed analysis of the assimilatory actions, dissimilatory reactions, remediatory roles, ecosystem, and regulatory functions of fungi has been discussed. The primary role of fungi is in the soil ecosystem. Additionally, this chapter provides information on commercial products derived from fungi that enhance soil health by way of nutrient acquisition, biocontrol, and bioremediation. The chapter also briefly describes the approaches through which fungi aid in restoring soil health.

A field study was conducted in Tanzania on a continuing five years old tillage trial to assess the residual effect of unmanured and manured tied ridges on some soil physical properties as well as on sorghum grain yield. Treatments tested were: no-till (NT), shallow tied ridges (STR), deep tied ridges (DTR) and annually made tied ridges (ADTR). The test crop was sorghum, variety, Tegemeo. There was no significant (P>0.05) difference in residual organic matter (OM) content among tillage treatments within unmanured and manured plots. Manure application significantly (P<0.05) affected sorghum grain yield. Compared to the control (No Primary Tillage with no FYM-NPT), yield was more than four times in the NPT+F (No Primary Tillage that received manure five years ago). Sorghum grain yield of the Control was significantly (P<0.05) increased by tillage methods. The annually made tied ridges had the highest grain yield of 2 t ha-1 while control plots had 0.4 t ha-1. In treatments referred to as having “residual tied ridges”, the tied ridges were established in 1996/97 season and have been under experiment as residual tied ridges with very limited repair since then. Grain yield of 1.9 t ha-1 under residual tied ridges after five seasons was statistically comparable to the yield from annually made tied ridges (ADTR). It was concluded that residual tied ridges could be utilized for up to five seasons for improved sorghum grain yield. The reduced tillage and the increased sorghum grain yield under the residual tied ridges are making the system attractive to farmers in semi-arid areas

Rapid urban expansion and a booming population are placing immense pressure on our agricultural systems, leading to detrimental impacts on soil fertility and overall health. Due to the extensive use of agrochemicals in agriculture, the necessity to meet the expanding demand for food has also resulted in unsustainable farming practices. Around the world, biochar, a multipurpose carbonaceous material, is being used to concurrently solve issues with enhancing soil fertility, plant growth, and development under both normal and stressful circumstances. It improves water retention, fosters nutrient absorption, and promotes microbial activity, creating a fertile environment that supports sustainable and resilient agriculture. Additionally, biochar acts as a carbon sink, contributing to long-term carbon sequestration and mitigating climate change impacts. The major benefit of biochar is that it helps the adsorption process with its highly porous structures and different functional groups. Understanding the elements involved in biochar formation that determine its characteristics and adsorptive capacity is necessary to assure the viability of biochar in terms of plant productivity and soil health, particularly biological activity in soil. This paper focuses on the development, composition, and effects of biochar on soil fertility and health, and crop productivity.

Modeling sorghum-cowpea intercropping for a site in the savannah zone of Mali: Strengths and weaknesses of the Stics model

Increased global food demand, as well as the need for an environmentally acceptable approach for a sustainable soil-plant-microbe-environmental system, necessitate special attention when it comes to agricultural productivity. Chemical fertilization is one approach to increase crop productivity as happened during the Green revolution. Food grain output in India increased from 115.6 million tonnes in 1960-61 to over 281.37 million tonnes in 2018-19 as a result of chemical fertilization. Similarly, yearly fertilizer use jumped from 0.07 million tonnes in 1951-52 to over 25.95 million tonnes in 2016-17.But due to injudicious use of chemical fertilizers soil, plant, human and animal health are at stake. Also, increased soil compaction and widespread multinutrient deficits have emerged as important restrictions limiting crop productivity and farm income. Because a major rise in fertilizer consumption is unlikely in the near future for economic and environmental reasons, there is a need to improve nutrient use efficiency through integrated and balanced fertilizer. On the other hand, organic manures, are unable to fulfill all of a crop's nutritional needs. Integrated nutrient management (INM) was created as a result of the aforesaid factors being taken into account. In this paper,role of INM in overcoming these difficulties is discussed, as it has been offered as a promising solution for tackling these issues. Plant performance and resource efficiency can be improved in a variety of ways with INM while also allowing for environmental and resource protection quality. With the use of advanced INM procedures, chemical fertilizer inputs are reduced, resulting in fewer human and environmental costs without any negative impact on crop production.Long-term research in various soil-crop situations have demonstrated the advantages of integrated nutrient management (INM), which includes the utilisation of organic and biological resources as well as fertilizers. The purpose of this article is to provide an overview of the effect of various INM components on Physical, chemical, and biological properties of soil, nutrient use efficiency, crop productivity and the role of these components in improving soil health. The majority of INM research has been done using dominant crop rotations of main field crops cultivated in the subtropical North Western states of India and most of the experiments revealed that INM leads to long term sustainable production along with providing nutritional security and also reduces pollution and enhances soil health by improving various physical, chemical and biological properties of soil.

Rain fed crop production in dryland areas is unreliable due to high evapo-transpiration, high run-off rates, delay onset, and early cessation of rains. So soil moisture deficiency is one of the primary factors that limit crop production in the area. Soil conservation is another important issue in dryland areas because high run-off rates leads to severe soil erosion. Due to shortage of soil moisture there have been attempts to optimize crop yield by planting drought-tolerant crops, particularly maize, sorghum and millet. This is not enough because crop failure due to water stress is still observed in dry lands. Therefore the proper use of soil moisture conservation structures like tied ridge helps to reduce the runoff rate, nutrient losses from soil and improve the soil moisture for plant growth which in turn, boost the productivity of land and plants. In addition to tied ridge mulching is a good practice used to reduce soil erosion and enhance water conservation. Tied ridge is one of the structures used to reduce water runoff and increase infiltration of rain water to the soil. It is a form of micro-basin tillage which consists of ridging the soil typically to heights of 0.20 to 0.30 m and is blocked with earth ties spaced considering slope of the land. Tied-ridging increased soil water by more than 25% compared to the traditional tillage practice in northern Ethiopia. It has been reported that tied ridging is beneficial for increasing crop yield. Tied-ridging increased sorghum grain yield by more than 40% compared to the traditional tillage practice in northern Ethiopia. It has beneficial effects of reducing runoff loss and soil loss. Mulching is also on the positive side of the balance in dry land. When adequate residues are available and conservation tillage is used, soil erosion is greatly reduced and water conservation is enhanced. Management of crop residues on the farm lands increased the grain yields of maize, sorghum and wheat crops both by improving soil fertility and conserving water at Haramaya area. Mulch conserved more water and led to higher dry matter and grain yields of maize compared to minimum tillage.

As blue water resources become increasingly scarce with more frequent droughts and overuse, irrigated agriculture faces significant challenges to reduce its water footprint while maintaining high levels of crop production. Building soil health has been touted as an important means of enhancing the resilience of agroecosystems to drought, mainly with a focus in rainfed systems reliant on green water through increases in infiltration and soil water storage. Yet, green water often contributes only a small fraction of the total crop water budget in irrigated agricultural regions. To scope the potential for how soil health management could impact water resources in irrigated systems, we review how soil health affects soil water flows, plant–soil–microbe interactions, and plant water capture and productive use. We assess how these effects could interact with irrigation management to help make green and blue water use more sustainable. We show how soil health management could (1) optimize green water availability (e.g., by increasing infiltration and soil water storage), (2) maximize productive water flows (e.g., by reducing evaporation and supporting crop growth), and (3) reduce blue water withdrawals (e.g., by minimizing the impacts of water stress on crop productivity). Quantifying the potential of soil health to improve water resource management will require research that focuses on outcomes for green and blue water provisioning and crop production under different irrigation and crop management strategies. Such information could be used to improve and parameterize finer scale crop, soil, and hydraulic models, which in turn must be linked with larger scale hydrologic models to address critical water-resources management questions at watershed or regional scales. While integrated soil health-water management strategies have considerable potential to conserve water—especially compared to irrigation technologies that enhance field-level water use efficiency but often increase regional water use—transitions to these strategies will depend on more than technical understanding and must include addressing interrelated structural and institutional barriers. By scoping a range of ways enhancing soil health could improve resilience to water limitations and identifying key research directions, we inform research and policy priorities aimed at adapting irrigated agriculture to an increasingly challenging future.