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1.
Proc Natl Acad Sci U S A ; 118(39)2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34556575

RESUMO

Hundreds of millions of smallholders in emerging countries substantially overuse nitrogen (N) fertilizers, driving local environmental pollution and global climate change. Despite local demonstration-scale successes, widespread mobilization of smallholders to adopt precise N management practices remains a challenge, largely due to associated high costs and complicated sampling and calculations. Here, we propose a long-term steady-state N balance (SSNB) approach without these complications that is suitable for sustainable smallholder farming. The hypothesis underpinning the concept of SSNB is that an intensively cultivated soil-crop system with excessive N inputs and high N losses can be transformed into a steady-state system with minimal losses while maintaining high yields. Based on SSNB, we estimate the optimized N application range across 3,824 crop counties for the three staple crops in China. We evaluated SSNB first in ca. 18,000 researcher-managed on-farm trials followed by testing in on-farm trials with 13,760 smallholders who applied SSNB-optimized N rates under the guidance of local extension staff. Results showed that SSNB could significantly reduce N fertilizer use by 21 to 28% while maintaining or increasing yields by 6 to 7%, compared to current smallholder practices. The SSNB approach could become an effective tool contributing to the global N sustainability of smallholder agriculture.

2.
Nutrients ; 13(7)2021 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-34371952

RESUMO

The distinct Tibetan regional diet is strongly influenced by the regional biogeography, indigenous traditions, popular religious beliefs and food taboos. In the context of the nutritional transition in Tibet, studies seldom report on the food consumption and dietary patterns of Tibetan residents. This is a cross-section study of 552 local adults (≥18 years old, 277 men and 275 women) living in 14 agricultural countries along the Yarlung Tsangpo River. Dietary intakes were assessed by a culturally specific FFQ and compared with the Chinese Dietary Pagoda (2016). Dietary Patterns were extracted by using PCA method. The binary logistic regression model was applied to assess the association between independent variables (genders, regions and age groups) and adherence to dietary patterns. With the exception of meat (100 ± 260 g/day) and soybean nuts (42 ± 12 g/day), which exceeded the recommended dietary intakes of CDP, the dietary intake of other foods were not up to the recommended value. In particular, the intake of aquatic products (2 ± 0.1 g/day), vegetables (90 ± 19 g/day), dairy products (114 ± 29 g/day), cereals (117 ± 27 g/day) and fruits (97 ± 25 g/day) were seriously inadequate, which were 95%, 70%, 62%, 53.2% and 51.5% lower than the recommended intakes, respectively. Four dietary patterns were identified. "Local traditional diet" was characterized by a high intake of tsampa (roasted highland barley flour), culturally specific beverages (sweet tea and yak buttered tea), potato and yak beef and was associated with female, rural and older adults (≥51 years old). The male, urban and 18~30 years old group had a higher adherence score with the "Han diet", which was comprised of rice, pork, dumplings, eggs, milk and cabbage. The "Beverage diet", which mainly include tsampa, chang (homemade barley wine) and sweet tea, was associated with the following group: female, urban and aged 18~30 years. The "Out-sourced diet" pattern, consisting of mainly rice, steam bread and some processed meat, was associated with being male, urban and 18-30 years of age. These findings indicate that the dietary practice of the Tibetan people still has strong local characteristics, but it is also undergoing a dietary transition with the penetration of the Chinese Han diet and the increased consumption of outsourced (processed) foods. The unbalanced dietary intake of Tibetan residents should be taken seriously by all parties.


Assuntos
Dieta , Comportamento Alimentar , Adolescente , Adulto , Fatores Etários , Bebidas , Estudos Transversais , Inquéritos sobre Dietas , Ingestão de Alimentos , Feminino , Frutas , Humanos , Masculino , Pessoa de Meia-Idade , Análise de Componente Principal , Recomendações Nutricionais , Rios , População Rural , Fatores Sexuais , Tibet , População Urbana , Verduras , Adulto Jovem
3.
Trends Ecol Evol ; 36(10): 899-906, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34246498

RESUMO

Increased anthropogenic nitrogen (N) deposition is driving N-limited ecosystems towards phosphorus (P) limitation. Plants have evolved strategies to respond to P limitation which affect N cycling in plant-soil systems. A comprehensive understanding of how plants with efficient P-acquisition or -use strategies influence carbon (C) and N cycling remains elusive. We highlight how P-acquisition/-use strategies, particularly the release of carboxylates into the rhizosphere, accelerate soil organic matter (SOM) decomposition and soil N mineralisation by destabilising aggregates and organic-mineral associations. We advocate studying the effects of P-acquisition/-use strategies on SOM formation, directly or through microbial turnover.


Assuntos
Fósforo , Solo , Carbono , Ecossistema , Nitrogênio , Microbiologia do Solo
4.
Sci China Life Sci ; 63(10): 1612-1614, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32710362
5.
Trends Plant Sci ; 25(10): 967-975, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32414603

RESUMO

We are facing unprecedented phosphorus (P) challenges, namely P scarcity associated with increasing food demand, and an oversupply of P fertilisers, resulting in eutrophication. Although we need a multidisciplinary approach to systematically enhance P-use efficiency, monodisciplinary studies still prevail. Here, we propose to tighten the P cycle by identifying P-efficient crop genotypes, integrating four plant strategies: increasing P-acquisition efficiency, photosynthetic P-use efficiency and P-remobilisation efficiency, and decreasing seed phytate P concentrations. We recommend P-efficient genotypes together with diversified cropping systems involving complementary P-acquisition strategies as well as smart P-fertiliser management to enhance P-use efficiency in agriculture dependent on soil P status. These strategies will reduce P-fertiliser requirements and offsite environmental impacts, while enhancing seed quality for human and livestock nutrition.


Assuntos
Fertilizantes , Fósforo , Agricultura , Genótipo , Humanos , Solo
6.
Sci Rep ; 7(1): 1422, 2017 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-28465551

RESUMO

Intensively managed grasslands are dominated by highly productive grass-clover mixtures. Increasing crop diversity by inclusion of competitive forbs may enhance biomass production and sustainable biofuel production. Here we examined if one or all of three forbs (chicory, Cichorium intybus L.; caraway, Carum carvi L.; plantain, Plantago lanceolata L.) included in ryegrass-red clover mixtures enhanced above- and below-ground productivity, and assessed their biofuel potentials, based on a three-year experiment with and without fertilisation as cattle slurry. We determined herbage yield, standing root biomass, and estimated methane energy output and greenhouse gas (GHG) emissions per energy unit using life cycle assessment. Results showed that plantain-containing grass-clover mixtures significantly increased herbage yield, while chicory- or caraway-containing mixtures maintained similar yields to the grass-clover mixture. Standing root biomass of the grass-clover mixture was enhanced by inclusion of caraway and plantain, with that of plantain further enhanced by fertilisation. The highest methane energy output was achieved in plantain-containing grass-clover mixtures. All unfertilised mixtures achieved the 60% reduction in GHG emissions compared to fossil fuel, whereas all fertilised mixtures did not meet the 60% reduction target. These findings suggest that including competitive forbs such as plantain in grass-clover mixtures enhances productivity, supporting low-carbon footprint bioenergy production.

7.
PLoS One ; 12(1): e0169208, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28046004

RESUMO

Plant species diversity may benefit natural grassland productivity, but its effect in managed grassland systems is not well understood. A four-year multispecies grassland experiment was conducted to investigate the effect of species diversity-legumes and non-leguminous forbs-on productivity, persistence and sward quality under cutting or grazing regimes and with or without slurry application. Three mixtures were established- 3-mix: grass, red and white clover, 10-mix: 3-mix plus birdsfoot trefoil and six non-leguminous forbs, and 12-mix: 10-mix plus lucerne and festulolium. Species diversity increased sward production and yield persistence under cutting regime. The 12-mix had the highest yield from the second year onwards and no statistically significant yield reduction over four years, while annual yields in the 3-mix and 10-mix decreased significantly with increasing grassland age. The higher yield in the 12-mix was mainly due to the inclusion of high-yielding lucerne. The 10-mix and 12-mix had lower proportions of unsown species than the 3-mix, the difference being dependent on grassland age. Generally, the 3-mix had higher concentrations of in-vitro organic matter digestibility (IVOMD), neutral detergent fiber (NDF) and crude protein (CP), and a lower concentration of ash than the 10-mix and 12-mix. Slurry application increased annual yield production by 10% and changed the botanical composition, increasing the proportion of grass and decreasing the proportion of legumes. Compared to cutting, grazing increased forage production by 9% per cut on average and lowered legume and forb proportions in the mixtures, but yields did not differ among the three mixtures. Overall, our results suggest that species diversity increases sward productivity and persistence only under an ungrazed cutting regime. We conclude that increasing species diversity by selecting appropriate species with compatible management is key to achieving both high yields and high persistence in managed grasslands.


Assuntos
Biodiversidade , Fabaceae/fisiologia , Poaceae/fisiologia , Biomassa , Pradaria , Especificidade da Espécie
8.
New Phytol ; 206(1): 107-117, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25866856

RESUMO

Intercropping is a farming practice involving two or more crop species, or genotypes, growing together and coexisting for a time. On the fringes of modern intensive agriculture, intercropping is important in many subsistence or low-input/resource-limited agricultural systems. By allowing genuine yield gains without increased inputs, or greater stability of yield with decreased inputs, intercropping could be one route to delivering 'sustainable intensification'. We discuss how recent knowledge from agronomy, plant physiology and ecology can be combined with the aim of improving intercropping systems. Recent advances in agronomy and plant physiology include better understanding of the mechanisms of interactions between crop genotypes and species ­ for example, enhanced resource availability through niche complementarity. Ecological advances include better understanding of the context-dependency of interactions, the mechanisms behind disease and pest avoidance, the links between above- and below-ground systems, and the role of microtopographic variation in coexistence. This improved understanding can guide approaches for improving intercropping systems, including breeding crops for intercropping. Although such advances can help to improve intercropping systems, we suggest that other topics also need addressing. These include better assessment of the wider benefits of intercropping in terms of multiple ecosystem services, collaboration with agricultural engineering, and more effective interdisciplinary research.


Assuntos
Agricultura/métodos , Conservação dos Recursos Naturais , Produtos Agrícolas/crescimento & desenvolvimento , Cruzamento , Produtos Agrícolas/genética , Produtos Agrícolas/fisiologia , Ecologia , Ecossistema , Fenômenos Fisiológicos Vegetais , Pesquisa , Solo
9.
Glob Chang Biol ; 21(4): 1715-26, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25216023

RESUMO

Intercropping, the simultaneous cultivation of multiple crop species in a single field, increases aboveground productivity due to species complementarity. We hypothesized that intercrops may have greater belowground productivity than sole crops, and sequester more soil carbon over time due to greater input of root litter. Here, we demonstrate a divergence in soil organic carbon (C) and nitrogen (N) content over 7 years in a field experiment that compared rotational strip intercrop systems and ordinary crop rotations. Soil organic C content in the top 20 cm was 4% ± 1% greater in intercrops than in sole crops, indicating a difference in C sequestration rate between intercrop and sole crop systems of 184 ± 86 kg C ha(-1) yr(-1). Soil organic N content in the top 20 cm was 11% ± 1% greater in intercrops than in sole crops, indicating a difference in N sequestration rate between intercrop and sole crop systems of 45 ± 10 kg N ha(-1) yr(-1). Total root biomass in intercrops was on average 23% greater than the average root biomass in sole crops, providing a possible mechanism for the observed divergence in soil C sequestration between sole crop and intercrop systems. A lowering of the soil δ(15) N signature suggested that increased biological N fixation and/or reduced gaseous N losses contributed to the increases in soil N in intercrop rotations with faba bean. Increases in soil N in wheat/maize intercrop pointed to contributions from a broader suite of mechanisms for N retention, e.g., complementary N uptake strategies of the intercropped plant species. Our results indicate that soil C sequestration potential of strip intercropping is similar in magnitude to that of currently recommended management practises to conserve organic matter in soil. Intercropping can contribute to multiple agroecosystem services by increased yield, better soil quality and soil C sequestration.


Assuntos
Agricultura/métodos , Carbono/química , Produtos Agrícolas/crescimento & desenvolvimento , Nitrogênio/química , Solo/química , Biomassa , Sequestro de Carbono , Ciclo do Nitrogênio , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Estações do Ano , Triticum/crescimento & desenvolvimento , Vicia faba/crescimento & desenvolvimento , Zea mays/crescimento & desenvolvimento
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