Sustainable Agroecosystems Research Articles

Agroecosystem Sustainability in Forest Dependent Tribal Villages in Odisha, Eastern India

The present study was carried out in Niyamgiri hills inhabited by primitive Dongaria tribes in Odisha to assess present state of socioeconomic components of village and efficiency and viability of production systems at the current level of natural resource dependency and to find out the linkage between human community and forest ecosystem. The study area comprises of eight villages where human population varies from 83 to 312 in uphill villages and 76 to 150 in foothill villages. The cultivated area ranges from 3.37% to 18.85% of the total village geographical area with per capita cultivated area 0.117 to 0.329 ha.. The quality of forest has been affected due to absolute dependency on resources which calls for taking appropriate step to enhance forest productivity. All villages depend on rain fed agriculture, natural stream water is used to cultivate paddy in valleys, shifting (Podu) cultivation practiced in uphill areas, mid hill orchards below the Podu area and home garden adjoining habitation. Cereals, pulses and oil seeds are grown together in Podu areas. Maize is a major cereal as staple food grown in uphill villages. The village productivity of Millets, legumes and paddy is much lower than other settled agriculture areas of the state. The home garden areas are grown with vegetables and cereals especially for domestic use. However, vegetables like Tomato, Brinjal, Bin, Sweet Potato, Chilly from foothill villages are marketed. Home garden provides variety of requirements to the tribal community round the year. The production of agriculture sub-system is not sufficient to meet the food requirement of villages and rice distributed to villagers meet this gap. However, crops grown as horticulture products (Jackfruit, Pine apple, Banana, Orange, Mango) and a few Millet crops in the uphill villages like minor Millets, are exported to markets for earning money as these are only assets recorded as high energy valued products. Odisha Millet Mission (OMM) may need to provide interventions to these villages with modern approach to increase Millet productivity including improvements in seed quality and health condition of the tribal community. To ensure sustainability of the traditional cultivation and livelihood system, involving the people of these villages in forest-based activities other than agriculture will lead to protecting the indigenous biodiversity of this region.

Elevated CO2, O3 and their interaction have differential impact on soil microbial diversity and functions in wheat agroecosystems

Elevated carbon dioxide (EC) and elevated ozone (EO) due to changing climate have a significant impact on the plant growth rate, primary productivity, and root turnover. EC and EO could have a differential impact on the structure and functioning of soil microbial communities in terrestrial ecosystems via modifications in the microbial population, soil enzyme activity, decomposition of organic compounds and cycling of nutrients. For the development of sustainable agroecosystems, soil microbial communities are essential due to their major roles in nutrient cycling, crop-microbe interplay and resistance towards biotic/abiotic factors. However, it remains difficult to project how multiple climate change factors would affect below-ground functions. Free-Air CO2 and O3 enrichment facility (FAOCE) was used to explore the effects of EC (550 ± 50 ppm) and EO (65 ± 10 ppb) along with their combined interactive treatment ECO on the structure and abundance of soil microbial community, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN) and microbes involved in N cycling in wheat crop (Triticum aestivum) under field conditions. The MBC increased by 20% in EC and declined by 5% in EO to ambient control. Treatments EC and ECO stimulated the growth of ammonia and nitrite-oxidizing bacteria. Heterotrophic microbial populations were favoured under EC and inhibited under EO. Treatments indirectly affected the soil microbial community structure by altering N-cycling microbes and modifying MBC and MBN which eventually changed soil fertility and biogeochemistry.

Análise multivariada como ferramenta na seleção de agroecossistemas sustentáveis de cultivo de meloeiro no Semiárido

ABSTRACT Soil management systems, including tillage and green manuring, are important for the control of nematodes and for the sustainable production. The objective was to select, through multivariate analysis, sustainable agroecosystems for yellow melon cultivated under irrigated conditions in the Brazilian semi-arid region. The long-term experiment is set up in Argissolo Vermelho- Amarelo (Ultisol) with six multifunctional agroecosystems, composed of the combination of three mixtures of cover crops (1 - 75% legumes + 25% grasses and oilseeds; 2 - 25% legumes + 75% grasses and oilseeds and 3 - spontaneous vegetation) and two types of soil management (no tillage-NT and tillage-T). The purpose was to evaluate the nutritional status of plants, soil fertility, nematode population in roots and soil, and the yield. Data were analyzed with multivariate techniques, allowing the grouping of the agroecosystems based on their similarities and complexity of functions. The incorporation of plant residues to the soil reduces nematode population, but their maintenance on the surface allows the improvement of fertility and yield, even under larger nematode populations. The agroecosystems that associate the nonincorporation of residues from cover crops with larger species diversity in composition constitute the most complex model, allowing different environmental functionalities. Thus, it is recommended not to incorporate the plant residues, planting the melon seedlings directly in the straw. However, considering that the results obtained with the non-incorporation of spontaneous vegetation were similar to those obtained with the incorporation of commercial cover crops, it is concluded that this practice is also viable and adapted to the semi-arid conditions.

Toward potential applications of the nitrogen nutrition index in Sweet basil (Ocimum basilicum L.) production under greenhouse conditions

The nitrogen nutrition index (NNI) as an effective indicator for monitoring crop nitrogen (N) status has multiple applications in agriculture, such as estimating in-season crop N requirement (NR), predicting crop biomass/yield, and improving N use efficiency. The present study was aimed to develop basil (Ocimum basilicum L.) NR and relative biomass (RB) prediction models based on the concept of critical N concentration. Two experiments were carried out with different N application rates in the research greenhouse of University of Tehran, Iran. Basil NNI values were calculated using the previously developed critical N dilution curve. Subsequently, the in-season basil NR estimation model was developed as a function of NNI, N recovery efficiency (NRE) and plant age. Additionally, basil RB was simulated as a function of the averaged and integrated NNI based on a linear-plateau model. Moreover, a theoretical relationship between N utilization efficiency (NUtE) and the NNI was established. The validation results of the developed NR-NNI model demonstrated a good performance with a root mean square error (RMSE) and a normalized root mean square error (NRMSE) less than 5.28 kg ha−1 and 4.72%, respectively. The results showed that crop biomass and NNI were the most significant explanatory factors for the variations in basil NUtE. Therefore, the crop NNI can serve as a practical in-season diagnostic tool for basil NR and RB prediction, while also contributing to the design of decision support systems and sustainable agro-ecosystems.

Potential soil organic carbon sequestration vis-a-vis methane emission in lowland rice agroecosystem.

Mitigating the atmospheric greenhouse effect while enhancing the inherent soil quality and productive capacity is possible through soil carbon (C) sequestration, which has a significant potential to counteract the adverse effects of agroecosystem level C emission through natural and anthropogenic means. Although rice is the most important food in India, feeding more than 60% of the country's population, it is commonly blamed for significant methane (CH4) emissions that accelerate climate change. Higher initial soil organic matter concentrations would create more CH4 under the flooded soil conditions, as reducible soil C is a prerequisite for CH4 generation. In India, rice is generally cultivated in lowlands under continuous flooding. Less extensive organic matter breakdown in lowland rice agroecosystems often significantly impacts the dynamics of soil active and passive C pools. Change from conventional to conservation agriculture might trap a significant quantity of SOC. The study aims to investigate the potential of rice-based soils to sequester C and reduce the accelerated greenhouse effects through modified farming practices, such as crop residue retention, crop rotation, organic farming, varietal selection, conservation agriculture, integrated nutrient management, and water management. Overall, lowland rice agroecosystems can sequester significant amounts of SOC, but this potential must be balanced against the potential for CH4 emissions. Management practices that reduce CH4 emissions while increasing soil C sequestration should be promoted and adopted to maximize the sustainability of rice agroecosystems. This review is important for understanding the effectiveness of the balance between SOC sequestration and CH4 emissions in lowland rice agroecosystems for adopting sustainable agricultural practices in the context of climate change.

Banka-Siphon Attached Eden-Canal of Damodar May be Develop as ‘Biodiversity-Biomedicines-Hub’ Improving World Policy

The oldest habitat of the ‘Damodar-River-Based-Kanchannagar’; the Banka-Siphon-Dam (BSD) of Banka River (BR) attached Eden Canal (EC) of Damodar River (DR), covering a 3-5 sq km area, enriched different flora- and faunal diversity with agricultural fields and dense vegetation forty-five years ago. But it was decreasing gradually up to December 2019 due to massive visitors or tourists, picnic parties with large sound systems, irregular fishing, killing wild animals, cutting the trees, disturbing and catching different animals including migratory birds, unethical human behaviors, and urbanization nearby. The Covid-lockdowns also impacted the ecosystem during the pandemic coronavirus-disease (COVID-19), it has faced social and economic challenges among the communities, and health systems-“the invisible patients”, due to hampering truism and education, and suspicious killing or catch or death of grey-colored water monitor lizards, fishing cats, civet cats, and barn owls, and even migratory birds also. And it has lost the ecological balance of water, land and vegetation (micro bio-climate) with an increased viper snake, rodent population, etc. And adversely affect the environment (Water, Sanitation and Ecology) and societal problems. To overcome, it is therefore, augments that propagation of the artificial nests, awareness, plantation of different fruits plants, and cultivations would be beneficial to do away with the rodent menace largely, and inhibit the damage and economic losses, without putting any severe implications on the sustainability of pisciculture-fishery agro-ecosystems of the “Banka-Siphon Eden-Canal of Damodar May be Develop as ‘Biodiversity-Biomedicines-Hub’ Improving World Policy”. And the perfect ecological balance of water, land and vegetation may develop any ‘Future-Socioeconomically-Ecological-Tourist-Hub’.

Carob as an Agrifood Chain Product of Cultural, Agricultural and Economic Importance in the Mediterranean Region

The carob tree (Ceratonia siliqua L.) is a typical Mediterranean species with over a 4000-year history. From ancient Egyptians to Cretans, carob products have been used as emergency food in the absence of basic goods. In the previous few decades, the global agricultural economy has replaced traditional crops with more profitable ones, which has led to soil degradation and a greater requirement for inputs. The rediscovery and use of plants that have best adapted to their growing territory is of crucial importance to preserve biodiversity and promote sustainable agricultural practices in a bioeconomy perspective. In recent years, carob’s commercial value has increased due to its use as a raw material in the food, pharmaceutical, cosmetic, and biofuel industries. This is expected to give a new impetus to the crop. Since the Mediterranean basin is the place of the origin of the carob tree, its cultivation will contribute to the sustainability of the Mediterranean agro-ecosystems and increase the socio-economic status of the local population.JEL Codes: Q570

The effect of rice residue management on rice paddy Si, Fe, As, and methane biogeochemistry

Rice production results in residues of straw and husk, and the management of these residues has implications for the sustainability of the rice agroecosystem. Rice straw is typically incorporated into soil either as fresh residue or is burned prior to incorporation. Rice husk is not typically returned to rice fields. However, rice husk contains high levels of silicon, which has been shown to decrease rice accumulation of arsenic. In this work, we studied the resulting biogeochemical changes in rice paddy soils when paddies were amended with either straw or burned straw and either no husk, husk, or burned husk over two years. Using a full-factorial design, we observed that the higher lability of rice straw carbon controlled redox-sensitive processes despite the application of husk and straw at similar carbon rates. Amending paddies with straw, rather than burned straw, increased porewater Fe and As, plant As, and methane emissions regardless of husk amendment. Husk addition provided insignificant Si to the plant despite its high concentration of Si, suggesting limited short-term mobility of Si and that long-term additions of husk or higher rates may need to be studied.

Impact of conservation tillage on wheat performance and its microbiome.

Winter wheat is an important cereal consumed worldwide. However, current management practices involving chemical fertilizers, irrigation, and intensive tillage may have negative impacts on the environment. Conservation agriculture is often presented as a sustainable alternative to maintain wheat production, favoring the beneficial microbiome. Here, we evaluated the impact of different water regimes (rainfed and irrigated), fertilization levels (half and full fertilization), and tillage practices (occasional tillage and no-tillage) on wheat performance, microbial activity, and rhizosphere- and root-associated microbial communities of four winter wheat genotypes (Antequera, Allez-y, Apache, and Cellule) grown in a field experiment. Wheat performance (i.e., yield, plant nitrogen concentrations, and total nitrogen uptake) was mainly affected by irrigation, fertilization, and genotype, whereas microbial activity (i.e., protease and alkaline phosphatase activities) was affected by irrigation. Amplicon sequencing data revealed that habitat (rhizosphere vs. root) was the main factor shaping microbial communities and confirmed that the selection of endophytic microbial communities takes place thanks to specific plant-microbiome interactions. Among the experimental factors applied, the interaction of irrigation and tillage influenced rhizosphere- and root-associated microbiomes. The findings presented in this work make it possible to link agricultural practices to microbial communities, paving the way for better monitoring of these microorganisms in the context of agroecosystem sustainability.

Intercropping increases soil macroaggregate carbon through root traits induced microbial necromass accumulation

Microbial necromass, as part of persistent soil organic matter, plays a significant role in maintaining soil fertility and sustainability of agroecosystems. Intercropping, planting multiple crop species in the same field at approximately the same time, has been demonstrated to increase soil organic matter through enhanced biomass input. Nonetheless, little is known as to how intercropping affects microbial necromass accumulation in soils and the underlying microbiological mechanisms, particularly about microbial life strategies and network stability. Here, we investigated the carbon (C) accumulation mechanism of microbe-aggregate interactions using aggregate fractionation combined with microbial biomarkers as well as high-throughput sequencing in an 11-year maize/peanut intercropping field experiment. We found that intercropping increased soil organic carbon (SOC) and microbial necromass C in macroaggregates (>250 μm) compared with sole crops, and it was mostly accounted for by fungal necromass C. Within small macroaggregates (250–2000 μm), bacterial necromass C was positively correlated with r-strategy bacteria, and fungal necromass C was positively correlated with K-strategy fungi. Microbial inter-kingdom co-occurrence network analysis showed higher proportions of positive links in intercropping system than in sole crops, and the proportions of positive links positively correlated with fungal necromass C in macroaggregates (>250 μm). Path analysis revealed that intercropping increased SOC mainly through root traits induced microbial life strategies and microbial network stability, resulting in increased microbial necromass. In conclusion, crop diversity-driven changes in root traits induced microbial traits promote microbial necromass accumulation. A new mechanism elucidating the positive crop diversity effect on soil C sequestration is proposed.

An increased dependence on agricultural policies led European grazing agroecosystems to an unsustainability trap

As all production processes, the agrifood system is driven by energy and materials. The origin and relative contribution of these resources to the system’s functioning determines its sustainability. Here we analyse the evolution of the sustainability of mountain grazing agroecosystems, which are often perceived as a better alternative for animal food production than industrial systems. Specifically, we use Emergy Accounting to assess the dependency of livestock farming on materials and energy in the Spanish Pyrenees along the last three decades, using data collected through face-to-face surveys in 1990, 2004 and 2018. We observe an increase of farm dependence on non-renewable resources, despite longer grazing periods and reduced use of off-farm animal feeds. The increasing inflow of public economic support and services from the socio-economic system (mainly driven by non-renewable sources) transfers its unsustainability to mountain grazing agroecosystems.

Can Entomopathogenic Nematodes and Their Symbiotic Bacteria Suppress Fruit Fly Pests? A Review.

Fruit flies (Diptera: Tephritidae) are serious pests that affect fruit production and marketing. Both third instar larvae and pupae are biological stages that persist in the soil until adult emergence. Entomopathogenic nematodes (ENs) are biological control agents that are used to control agricultural pests in greenhouse or field conditions. Several studies have been carried out under laboratory and field conditions showing how ENs can be applied within an area-wide integrated pest management approach to control fruit fly species in orchards and backyard fruit trees. In this review, we analyze how soil physical characteristics and biotic factors affect the performance of these biological control agents. Of the reviewed papers, more than half evaluated the influence of soil texture, humidity, temperature, and other factors on the performance of infective juveniles (IJs). Abiotic factors that significantly influence the performance of IJs are temperature, humidity, and texture. Among the biotic factors that affect IJs are fungi, bacteria, mites, insects, and earthworms. We conclude that ENs have the potential to be applied in the drip area of fruit trees that are infested by fruit flies and contribute to their suppression. This approach, in conjunction with an area-wide pest management approach, may contribute to pest suppression and increase the sustainability of agroecosystems.

Maize and Wheat Responses to the Legacies of Different Cover Crops under Warm Conditions

Cover crops (CC) have great potential to enhance the sustainability of agroecosystems. However, the wide range of possible rotations of CC and cash crops (CaC) means that important knowledge gaps persist on how CC affects CaC. We investigated the legacy effects of five common CC (three monocultures: vetch, melilotus, and barley, and two mixtures: barley-vetch and barley-melilotus) on two of the most important CaC, maize and wheat. A microcosm, semi-controlled experiment was established simulating warm, low-income Mediterranean conditions. After two cycles, soil physicochemical and microbial properties, as well as plant growth and nutrition variables, were measured at the CC early growth CaC stage. In maize, barley CC had the best soil microbial and nutritional legacy effects, which resulted in the highest biomass and nutrient status. In contrast, barley produced the worst results on wheat, showing the disadvantages of growing two crops from the same tribe consecutively. CC mixtures also did not offer a productive advantage over pure CC. Additionally, our findings suggest that archaea seem to play a role in increasing N and Zn content in maize shoots. Furthermore, shoot B contents showed highly significant regressions with the CaC biomass. These results can help select the appropriate CC in each case.

The Global Dilemma of Soil Legacy Phosphorus and Its Improvement Strategies under Recent Changes in Agro-Ecosystem Sustainability.

Phosphorus (P) is one of the six key elements in plant nutrition and effectively plays a vital role in all major metabolic activities. It is an essential nutrient for plants linked to human food production. Although abundantly present in both organic and inorganic forms in soil, more than 40% of cultivated soils are commonly deficient in P concentration. Then, the P inadequacy is a challenge to a sustainable farming system to improve the food production for an increasing population. It is expected that the whole world population will rise to 9 billion by 2050 and, therefore, it is necessary at the same time for agricultural strategies broadly to expand food production up to 80% to 90% by handling the global dilemma which has affected the environment by climatic changes. Furthermore, the phosphate rock annually produced about 5 million metric tons of phosphate fertilizers per year. About 9.5 Mt of phosphorus enters human food through crops and animals such as milk, egg, meat, and fish and is then utilized, and 3.5 Mt P is physically consumed by the human population. Various new techniques and current agricultural practices are said to be improving P-deficient environments, which might help meet the food requirements of an increasing population. However, 4.4% and 3.4% of the dry biomass of wheat and chickpea, respectively, were increased under intercropping practices, which was higher than that in the monocropping system. A wide range of studies showed that green manure crops, especially legumes, improve the soil-available P content of the soil. It is noted that inoculation of arbuscular mycorrhizal fungi could decrease the recommended phosphate fertilizer rate nearly 80%. Agricultural management techniques to improve soil legacy P use by crops include maintaining soil pH by liming, crop rotation, intercropping, planting cover crops, and the consumption of modern fertilizers, in addition to the use of more efficient crop varieties and inoculation with P-solubilizing microorganisms. Therefore, exploring the residual phosphorus in the soil is imperative to reduce the demand for industrial fertilizers while promoting long-term sustainability on a global scale.

Agricultural Greenhouse Gas Emissions and Mitigation Strategies for Promoting Sustainable Agroecosystems in Canada – A Review

Agricultural Greenhouse Gas Emissions and Mitigation Strategies for Promoting Sustainable Agroecosystems in Canada – A Review

IDENTIFIED RESILIENT FLAX GENOTYPES WITH IMPROVED AGRONOMIC CHARACTERISTICS FOR PRE-BREEDING

Genetic diversity evaluation in a breeding program is essential produce robust, resilient crop varieties with improved agronomic characteristics under environmental challenges in the sustainable agro-ecosystems. Knowledge and full potential on the impact of genotypes and growing conditions on flax yield traits still incomplete. The aim of this study was to evaluated the influence of hydrothermal conditions on the development of agronomic important traits of flax, analysed agronomic characteristics and identified perspective genotypes for pre-breeding. Field investigations were carried out from 2014 to 2017 for agronomically important traits of flax. In the study was evaluated flax population with Latvian origin in 24 fibre flax genotypes and ‘Vega 2’ (ST) as the standard variety of Lithuanian origin under Latvian meteorological conditions. Correlation between flax genotypes of the agronomically important yield traits and years of the hydrothermal coefficients during the growth period were analysed. According to the results obtained that most of genotypes the significant higher plants stem yield, total plant height, technical plant height, number of seed vessels per plant were measured in the growing seasons with high humidity. However, the higher seed yield and 1000 seed weight were measured in the driest year. The correlation between flax fibre content, seed number per seed-vessel, oil content and humidity level differed in dependence on genotype. The coefficient of variability between years was higher for of stem yield when compared with seed yield. The flax genotypes ‘S13/5-7/5-93’ exhibited more stable, highest stem yield (840.0 g m-2) and high seed yield (162.2 g m-2). The flax was identified 80% samples the short and 20% the medium vegetation period.

Spatiotemporal variations in the soil quality of agricultural land and its drivers in China from 1980 to 2018

Soil quality is essential for maintaining the sustainability of agroecosystems, especially under intensified agricultural activities and rapid land use change. The sampling and analysis of soil properties to assess the status of agricultural land is widely practiced at the field scale; however, the spatiotemporal variations in soil quality and its influencing factors at a large scale remain unclear. Here, we quantified spatiotemporal variations in the soil quality of agricultural land in China during 1980–2018 by using the soil quality index (SQI) area approach, and explored the drivers with a geographical detector method. The results showed that the distribution of the SQI in the two periods had a similar spatial trend, except for that in the southwest (SWC), and the SQI decreased from north to south regardless of land use type. The soil quality of woodland was comparatively good with mean SQI values of 1.55 and 1.53 in 1980 and 2018, respectively, followed by that in grassland and cropland. Soil organic carbon, total nitrogen and cation exchange capacity were the dominant soil indicators explaining the spatial heterogeneity of the SQI in all land uses; moreover, climatic factors (i.e., temperature and precipitation) showed a stronger effect on woodland. From 1980 to 2018, the SQI of grassland decreased deeply, especially in the SWC, which showed a severe decline of 12.5 %. The changes in precipitation and temperature were identified as the largest drivers of SQI temporal changes in woodland and grassland, respectively, and their interaction achieved the highest impact across all land uses. In addition, the bidirectional conversion between cropland and grassland in recent decades has aggravated the deterioration of soil quality. Therefore, quantifying spatiotemporal changes in the SQI and elucidating the role of factors influencing soil quality in agroecosystems can provide a guide for designing sustainable agriculture policies and improving environmental quality.

High-throughput soil health assessment to predict corn agronomic performance

Developing high-throughput methods to quantify soil health can support decision making to minimize soil constraints for crop growth and increase sustainability in agroecosystems. This study evaluated the ability of soil health assessment conducted at the beginning of the crop growing season to predict corn agronomic performance in nutrient fertilization trials. We compared different methods to assess soil health, from the most traditional approach of measuring individual soil biochemical indicators to more novel approaches using diffuse reflectance infrared Fourier transform spectroscopy (mid-DRIFTS). Soil health was quantified using: I) traditional and emerging biochemical soil health indicators (up to 20 soil indicators), II) mineral and organic functional groups abundances estimated as peak areas in mid-DRIFTS, and III) mid-DRIFTS with partitioned spectra and partial least squares regression. Corn response to fertilizer was evaluated in a) phosphorus, potassium, and sulfur omission trials (2016–2018; 41 sites across 17 Ohio counties) as well as in b) N rates trials (2016–2017; 25 fields across 14 Ohio counties). Modeling using either biochemical soil health indicators or mid-DRIFTS accurately predicted corn yield across nutrient treatments in omission trials (R2V=0.61–0.84 in validation sets) and unfertilized controls in N rates trials (R2V=0.68–0.81) as well as corn N-driven yield gap (i.e., delta yield defined as grain yield at agronomic optimum N rate minus grain yield of the control, R2V=0.64–0.76) in N rates trials. Mid-DRIFTS approaches equaled or outperformed the predictive ability of measured biochemical soil health indicators in estimating crop performance (up to 38 % improvement in R2V), unveiling a promising method to more efficiently assess soil health. Early season soil health assessment via mid-DRIFTS has potential to directly estimate corn agronomic performance.

Weed phyto-sociology and diversity in relation to conservation agriculture and weed management strategies in Northwestern Himalayas of India

To create weed management techniques capable of improving agroecosystem sustainability, it is essential to comprehend the different weed flora composition and diversification dynamics in conservation agriculture production systems. In North Western Himalaya from 2018 to 2020, evaluation of various tillage techniques with and without residue incorporation and weed management techniques on diverse weed flora composition was performed. Fifteen treatment amalgamations of five tillages viz. CT (conventional tillage) in maize-CT in wheat, CT-ZT (ZT, zero tillage), ZT-ZT, ZT-ZTR (ZTR, zero tillage in amalgamation with remainder integration) & ZTR-ZTR and three weed management practices viz. H (suggested herbicide in maize)-H (suggested herbicide in wheat), IWM-IWM (IWM, integrated weed supervision) & HW-HW; (HW, hand weeding) were calculated in strip plot design. Significant differences (p = 0.05) of weed density and total weed count were recorded during summer (maize) and winter (wheat) seasons. Among tillage treatments, lowest weed population and total weed population were recorded in conservation tillage (ZTR-ZTR) in summer and conservative tillage followed by zero tillage in winter season (CT-ZT), respectively. IWM-IWM and H-H had a least weed population and total weed population in summer and winter seasons, respectively. Highest important value index during summer and winter seasons was recorded in Echinochloa colona (55.90%) and Avena ludoviciana (76.99%), respectively. Higher Shannon Wiener index and Evenness were recorded for CT+HW-CT+HW (1.83, 0.91) and ZT+IWM-ZTR+IWM (1.73, 0.86) which indicate higher weed species diversity during summer and winter seasons, respectively. ZTR-ZTR led to less diverse weed diversity compared to intensive conventional tillage (CT-CT) practices. However, higher Simpson’s diversity was recorded for CT+HW-CT+HW, i.e. 0.83 and 0.82 for maize and wheat, respectively, compared to the other conventional tillage treatments. This study helps in understanding the crop-weed relation such that the implementation of sound and economic weeds management strategies. Further, long-term experiments are required in order to interpret the complicated relationships of diverse weed species under different tillage and weed management strategies for sustainable and adoptive conservation agriculture production system for North Western Himalayas.

Agricultural farming intensification significantly reduced earthworm abundance and diversity in Usangu agro-ecosystems, Tanzania

Earthworms an ecologically important group of invertebrates that are crucial to delivery of many ecosystem services, but also considered ecosystem engineers playing an important role in soil fertility and land productivity. Earthworms facilitate breakdown and decomposition of plant and animal materials releasing plant nutrients. Earthworm burrows allow air and water movement in the soil but also improve soil fertility and drainages. Earthworm population in agricultural soils is influenced by different factors i.e., tillage, farming activities, soil chemistry as well as chemical contaminants. Agricultural (paddy farming) intensification with increased and excessive use of agrochemicals (fertilizers, pesticides, and herbicides) may affect earthworm population in agricultural soils. Recently, there scant studies conducted to characterize earthworm abundance and diversity in Tanzania's agro-ecosystem. Therefore, the present study characterized earthworm population in agricultural soils of contrasting intensification in Usangu agro-ecosystem (UA) to understand influence of current land use on earthworm abundance and their diversity as they have a vital role in agro-ecosystem productivity and sustainability. This study found that current paddy farming and associated activities in UA negatively affect earthworm occurrence, distribution, and diversity. Where only four dominant earthworm species were determined (Apporectodea caliginosa (endogeic), Lumbricus terrestris (Anecic), Pontoscolex corentrurus (endogeic), Fimoscolex sporadochactus (Anecic)) compared to other tropical areas. But also, highly intensified paddy farming areas (i.e., Chimala, Igalako, Ihahi, Kapunga, Mahongole, and Uturo) were observed to have earthworm abundance <25 individuals/m2 an FAO recommended earthworm count/m2 in healthy soils compared to less intensified schemes (25-40 earthworm/m2). The earthworm abundance and biomass determined in UA was below global average of 78 individuals per m2 and 150 g/m2, indicating that UA is in deteriorating quality. Thus, current farming practices creates unfavourable environmental conditions which likely leads to migration of earthworm to other land use or death due to harsh environment created. High earthworm abundance and biomass improve land productivity via nutrient recycling, thus low earthworm counts and diversity in UA likely to threaten agro-ecosystem sustainability. The present study provides baseline information on earthworm abundance and their diversity in UA and Tanzania.