Phosphorus placement for annual crops in the tropics.

This article discusses principles for optimizing the placement of P in soils of the tropics?looking towards better agronomic, economic, environmental, and social outcomes. General guidelines are offered for short and long-term sustainability

Phosphorus acquisition by wheat from organic and inorganic sources labelled with P-32 and P-33 radioisotopes

Investment in soil phosphorus (P) capital in the tropics is often constrained by poor availability of mineral fertiliser to small-scale farmers. Consequently, new sustainable agricultural cropping strategies are required to maintain fertility and maximise crop yields. The co-application of Tithonia diversifolia (Tithonia) green manure and mineral fertiliser (KH2PO4) together (integrated nutrient management) in comparison to the addition of one or the other alone has been hypothesized to promote crop P uptake. The aim of this study was to critically evaluate the benefits of integrated nutrient management practices in laboratory experiments. Wheat was grown as a test crop in microcosms to which either 32P-labelled mineral fertiliser or 33P-labelled Tithonia was added either singly or in combination. Exclusion meshes were used to determine the role of arbuscular mycorrhizal (AM) fungi in P uptake from the different P sources. The rate of uptake of both 32P and 33P by mycorrhizas was similar, and the rate of mycorrhizal P capture was comparable to that of roots. Generally, there was little difference in wheat P acquisition under integrated nutrient management treatments in comparison to P acquisition from 32P-mineral fertiliser or the addition of 33P-Tithonia alone. Overall, Tithonia residues were not very effective in supplying P to wheat over a short time evaluation period, suggesting that mineral fertilisers will still be required to satisfy crop demand

Revealing soil legacy phosphorus to promote sustainable agriculture in Brazil

Exploiting native soil phosphorus (P) and the large reservoirs of residual P accumulated over decades of cultivation, namely "legacy P", has great potential to overcome the high demand of P fertilisers in Brazilian cropping systems. Long-term field experiments have shown that a large proportion (> 70%) of the surplus P added via fertilisers remains in the soil, mainly in forms not readily available to crops. An important issue is if the amount of legacy P mobilized from soil is sufficient for the crop nutritional demand and over how long this stored soil P can be effectively 'mined' by crops in a profitable way. Here we mapped the spatial-temporal distribution of legacy P over the past 50 years, and discussed possible agricultural practices that could increase soil legacy P usage by plants in Brazil. Mineral fertiliser and manure applications have resulted in ~ 33.4 Tg of legacy P accumulated in the agricultural soils from 1967 to 2016, with a current annual surplus rate of 1.6 Tg. Following this same rate, soil legacy P may reach up to 106.5 Tg by 2050. Agricultural management practices to enhance soil legacy P usage by crops includes increasing soil pH by liming, crop rotation, double-cropping, inter-season cover crops, no-tillage system and use of modern fertilisers, in addition to more efficient crop varieties and inoculation with P solubilising microorganisms. The adoption of these practices could increase the use efficiency of P, substantially reducing the new input of fertilisers and thus save up to 31.8 Tg of P fertiliser use (US$ 20.8 billion) in the coming decades. Therefore, exploring soil legacy P is imperative to reduce the demand for mineral fertilisers while promoting long-term P sustainability in Brazil

Map of total phosphorus content in native soils of Brazil

Knowledge of the distribution of total phosphorus (P) content in native soils provides information on the management of ecosystem, land capability for agriculture, environmental quality, and biodiversity conservation. We mapped the spatial distribution of total P concentrations in topsoils (0-30 cm) of uncultivated (native) areas in Brazil. We obtained data on native total P of the southern, south-eastern, and north-eastern regions from reports of exploratory projects developed between 1960s and 1970s by EMBRAPA and by the RADAM Brazil Project. We estimated data from the central-western and northern regions from the relationship between total P and soil properties (Fe, Al, C and clay content), based on the RADAM Brazil Project. Soil total P varied widely (< 25 to > 500 mg kg–1) in all regions in Brazil. Higher concentrations (> 500 mg kg–1) were observed in southern region compared to most of the rest of the country (< 200 mg kg–1), while the Cerrado (Central), Amazon (North) and Caatinga (Northeast) biomes are very poor in total P. This first national native soil total P map provides a valuable baseline for understanding the historical patterns of agriculture expansion in Brazil. It allows quantifying the effect of agriculture expansion and future cropping systems on soil available P content and legacy P, targeting regional soil-crop specific strategies for optimization of ecosystem services, and mitigating potential environmental risk due to P transference to water bodies

New insights into potocki-shaffer syndrome: Report of two novel cases and literature review

Potocki-Shaffer syndrome (PSS) is a rare non-recurrent contiguous gene deletion syndrome involving chromosome 11p11.2. Current literature implies a minimal region with haploinsufficiency of three genes, ALX4 (parietal foramina), EXT2 (multiple exostoses), and PHF21A (craniofacial anomalies, and intellectual disability). The rest of the PSS phenotype is still not associated with a specific gene. We report a systematic review of the literature and included two novel cases. Because deletions are highly variable in size, we defined three groups of patients considering the PSS-genes involved. We found 23 full PSS cases (ALX4, EXT2, and PHF21A), 14 cases with EXT2-ALX4, and three with PHF21A only. Among the latter, we describe a novel male child showing developmental delay, café-au-lait spots, liner postnatal overgrowth and West-like epileptic encephalopathy. We suggest PSS cases may have epileptic spasms early in life, and PHF21A is likely to be the causative gene. Given their subtle presentation these may be overlooked and if left untreated could lead to a severe type or deterioration in the developmental plateau. If our hypothesis is correct, a timely therapy may ameliorate PSS phenotype and improve patients’ outcomes. Our analysis also shows PHF21A is a candidate for the overgrowth phenotype

Exploitation of mitochondrial nad6 as a complementary marker for studying population variability in Lepidoptera

The applicability of mitochondrial nad6 sequences to studies of DNA and population variability in Lepidoptera was tested in four species of economically important moths and one of wild butterflies. The genetic information so obtained was compared to that of cox1 sequences for two species of Lepidoptera. nad6 primers appropriately amplified all the tested DNA targets, the generated data proving to be as informative and suitable in recovering population structures as that of cox1. The proposal is that, to obtain more robust results, this mitochondrial region can be complementarily used with other molecular sequences in studies of low level phylogeny and population genetics in Lepidoptera

Sistema Santanna: sistema integrado de produção de grãos e fibra (algodão-soja-milho) na Fazenda Planalto, Costa Rica, MS - estudo de caso.

Este trabalho descreve o modelo integrado de producao em SPD - o Sistema Santanna. São descritas acoes e operacoes que caracterizam os sistemas integrados e os seus efeitos sobre o solo e as especies vegetais que o compoem.bitstream/CPAO-2010/32430/1/BP200953.pdfDocumento on-line

Agroindústria familiar de produtos orgânicos: uma perspectiva para o mercado.

O presente estudo pretende enfatizar a importância da agroindustrialização familiar de orgânicos e os mercados que ela acessa

Qualidade físico-química de frutos de morangueiro em função da adubação potássica

A melhoria das características do morango é uma forma de garantir melhor aceitação pelo mercado consumidor e melhor rendimento no processamento e industrialização. Nesse contexto, a nutrição e adubação do morangueiro são fatores importantes a serem considerados para melhorar a produtividade, conservação  pós-colheita e propriedades físico-químicas do fruto. O presente trabalho teve como objetivo avaliar as características físico-químicas de frutos de duas cultivares de morangueiro, em função da adubação com diferentes doses de fertilizante potássico. Os tratamentos foram quatro doses de K2O (0,200, 400 e 600 kg ha-1) e duas cultivares de morangueiro (Camarosa e Sweet Charlie) produzidas em cultivo protegido. O delineamento experimental foi em blocos casualizados em esquema fatorial 4x2, com 3 repetições. Foram avaliados os teores de sólidos solúveis, pH, massa seca e acidez titulável nos frutos. Para as análises foram amostrados 20 frutos de cada parcela, colhidos e armazenados a baixas temperaturas (-5 oC). Os maiores teores de massa seca nos frutos de morango da cultivar Camarosa foram obtidos na dosagem de 332,5 kg ha-1 de K2O. A cultivar Sweet Charlie respondeu com maior acúmulo de massa seca e maiores teores de sólidos solúveis até a dose de 479 kg ha-1. Conforme esses resultados, doses de fertilizante potássico entre 300 e 500 kg ha-1 são consideradas ideais para a qualidade dos frutos do morangueiro