Rootstock and Nutrient Imbalance Leads to ‘‘Green Spot’’ Development in ‘WA 38’ Apples

‘WA 38’ is a new apple (Malus domestica Borkh.) cultivar, released by Washington State University (WSU) in 2017. An unknown disorder, ‘‘green spot’’ (GS), dark green halos in the epidermis, with necrotic, corky, and oxidated cortical tissue underneath the damaged epidermis, leads to unmarketable fruit and has become a threat to the adoption and profitability of ‘WA 38’, with young and mature orchards exhibiting up to 60% incidence in 2020. Given the apparent susceptibility of ‘WA 38’ to GS, this research investigated GS relation with nutrient levels in fruit. Research was carried out in 2018 and 2019 in a ‘WA 38’ apple block planted in 2013, on ‘Geneva 41’ (‘G.41’) and ‘M.9-Nic 29’ (‘M.9’) rootstocks. In both years, fruit number per tree, fruit weight, and fruit diameter were evaluated in 18 trees per treatment, from both rootstocks. From each tree, fruit were classified for presence or absence of GS, and subsequently analyzed for nutrient concentration in the peel and in the flesh, nutrient extraction, and total nutrient content, on an individual apple basis. Apples with GS had higher nitrogen (N) and magnesium (Mg) levels in the peel, regardless of year and rootstock. Apples grown on ‘G.41’ rootstock exhibited higher GS incidence and reduced crop load in both years; reduced size and fruit diameter were exhibited only in 2018. Fruit on ‘G.41’ had higher N, potassium (K), and Mg in the flesh and higher N and Mg in the peel, with lower levels of calcium (Ca) in the flesh and peel; however, only in 2018, with no differences in 2019. GS in ‘WA 38’ apples appears to be another Ca-related disorder in which excessive vigor, rootstock, and N and Mg excess are predisposing factors for its development.

Supplementary Nitrogen Fertilization in Sugarcane

In Brazil, sugarcane (Saccharum spp.) is considered one of the most economically important crops. Nitrogen (N) is one of the most required elements in sugarcane cultivation. Nevertheless, the information about the soil and foliar applications of this nutrient in crops are discrepant. Therefore, the importance of this study is evident. Given the above, this study aimed to evaluate the soil-applied and foliar N fertilization of sugarcane. The experiment was conducted at the Araporã Bioenergia S.A. power plant, located at Fazenda Santa Rita, in the municipality of Itumbiara-GO. The 5 × 5 factorial design was adopted, with four repetitions, including five doses of soil-applied ammonium nitrate and five doses of foliar Amidic N polymer. The nutrient extraction, the experiment’s initial and final total chlorophyll content, the biometric indexes and the industrial quality indexes were analyzed for sugarcane. The ammonium nitrate doses caused differences in fiber, sacarose content, total recoverable sugar, sugar cane Brix, magnesium, and zinc, which was statistically different for the foliar polymer doses. There was no increment of the production variables with the increase of the nitrogen supply in the soil. On the other hand, the levels of zinc and magnesium in the leaves increased 12% and 27%, respectively, reflecting the importance of this fertilization in sugarcane cultivation.

Ecological and Edaphic Drivers of Yam Production in West Africa

Yam is an important food and cash crop in West Africa (the yam belt) whose production is traditionally nonsedentary due to its substantial nutrient demand. Population growth, urbanization, and existing soil degradation have made nonsedentary farming virtually impossible. Despite the numerous research invested in yam production within and outside the yam belt, some gaps remain to be filled owing to changing climate events and global developments. Alarmingly, the yam belt is facing sharp yield declines despite increasing production areas. The key edaphic and ecological drivers of yam production in the global yam belt were reviewed. The implications for yam production were discussed along with prospects for future research, sustainable production, and soil management. The main findings are that (1) agroecological zone, postplanting cultural practices, and climate change and variability ecological drivers, while (2) tillage, soil type, texture, and fertility were the edaphic factors. The most critical among the drivers, principally, soil fertility, entails the biological and chemical through which nutrients are released lude, and physical soil fertility which enhances low bulk density, porosity, and water retention for free yam tuber expansion. Soil fertility was the most cited driver, which explains why yam is often the first crop in the cropland cultivation cycle in the yam belt. Data show that yam yields decline with time under native fertility and mineral fertilizer application due to the voracious nutrient extraction by tubers. Conversely, yields increase chronologically under organic fertilizer application due to the additive effects of the latter on soil properties. Thus, a yam fertilizer program to develop specific yam fertilizer formulations and the adoption of the Terra Preta Model are proposed to sustain future yam production.

Monitoring soil nutrients using a simple cafetiere-based extraction with paper-based readout.

<p>Routine monitoring of available soil nutrients is required to better manage agricultural land<sup>1</sup>, especially in many lower and middle income countries (LMICs). Analysis often still relies on laboratory-based equipment, meaning regular monitoring is challenging.<sup>2</sup> The limited number of in situ sensors that exist are expensive or have complex workflows, thus are not suitable in LMICs, where the need is greatest.<sup>3</sup> We aim to develop a simple-to-use, low-cost analysis system that enable farmers to directly monitor available nutrients and pH on-site, thus making informed decisions about when and where to apply fertilisers.</p><p>We combine nutrient extraction via a cafetiere-based filtration system with nutrient readout on a paper microfluidic analysis device (PAD) employing colour producing reactions that can be captured via a smartphone camera through an app. Image analysis of colour intensity permits quantitation of analytes. We initially focus on key nutrients (phosphate, nitrate) and pH analysis.</p><p>For extraction of phosphate, we mixed soil and water in the cafetiere and quantified the extracted phosphate via phosphomolybdenum blue chemistry. For example, for 5 g of soil, a water volume of about 160 mL led to optimum extraction. Active mixing, by pushing coffee filter plunger up and down, aided extraction. A mixing period of 3 min yielded maximum extraction; this time period was deemed suitable for an on-site workflow.</p><p>Following nutrient extraction, a simple-to-use readout system is required. For this, we developed colourimetric paper-based microfluidic devices; these are simply dipped into the decanted soil supernatant from the cafetiere and wick fluids based on capillary forces. Chemical reagents are pre-stored in reaction zones, created by patterning cellulose with wax barriers. Our devices contain multiple paper layers with different reagents; these are folded, laminated and holes cut for sample entry. Following the required incubation time, the developed colour is captured using a smartphone. This constitutes a portable detector, already available to envisaged end users, even in LMICs. We have previously developed an on-paper reaction for monitoring phosphates in fresh water in the mg L<sup>-1</sup> working range, with readout after an incubation period of 3 min. This method was adapted here to enable storage at ambient temperatures up to 1 week by incorporating additional acidic reagents. Further pad devices were developed in our group for colour-based readout of nitrate, involving a two-step reaction chemistry. Within a relatively short incubation period (≤8 min) a pink coloured was formed following reduction of nitrate to nitrite with zinc and subsequent reaction to form an azo-dye. This system achieved detection in the low mg L<sup>-1</sup> range. Moreover, a pad to monitor pH was developed, employing chlorophenol red indicator, with linear response achieved over the relevant pH 5-7 range.  </p><p>Our analysis workflow combines a simple-to-use cafetiere-based extraction method with paper microfluidic colour readout and smart-phone detector. This has the potential to enable farmers to monitor nutrients in soils on-site. Future work will aim at integrating multiple analytes into a single analysis card and to automate image analysis.</p><p>[1] <em>Europ. J. Agronomy</em>, 55, 42–52, <strong>2014.</strong></p><p>[2] <em>Nutr. Cycling Agroecosyst.,</em> 109, 77-102, <strong>2017.</strong></p><p>[3] Sens Actuators B, 30, 126855, <strong>2019.</strong></p>

Justus von Liebig Makes the World

Just as capitalism’s exchange of commodities between disparate locations requires a singular referent of value, so does the movement of ideas and practices necessitate consolidations of meaning through complex fields of people, landscapes, and things. Introducing key innovations in agricultural and chemical science, Justus von Liebig’s chemical model of soil fertility involved a profound reenvisioning of organic development, distilling complex processes to a series of chemical relationships easily recognized in any geographic context. Drawing on Henri Lefebvre’s (1984) arguments about the production of abstract space, this article argues that Liebig’s assessment of nutrient extraction was essential to a broader midcentury reconsideration and reorganization of capitalist agricultural production, an example of what world ecologist Jason Moore calls an “organizational revolution,” allowing global capitalism to overcome past limits and thus move through systemic crises.

Nutrient Extraction Lowers Postprandial Glucose Response of Fruit in Adults with Obesity as well as Healthy Weight Adults

Fruit consumption is recommended as part of a healthy diet. However, consumption of fruit in the form of juice is positively associated with type 2 diabetes risk, possibly due to resulting hyperglycemia. In a recent study, fruit juice prepared by nutrient extraction, a process that retains the fiber component, was shown to elicit a favorable glycemic index (GI), compared to eating the fruit whole, in healthy weight adults. The current study expanded on this to include individuals with obesity, and assessed whether the nutrient extraction of seeded fruits reduced GI in a higher disease risk group. Nutrient extraction was shown to significantly lower GI, compared to eating fruit whole, in subjects with obesity (raspberry/mango: 25.43 ± 18.20 vs. 44.85 ± 20.18, p = 0.034 and passion fruit/mango (26.30 ± 25.72 vs. 42.56 ± 20.64, p = 0.044). Similar results were found in those of a healthy weight. In summary, the current study indicates that the nutrient-extraction of raspberries and passionfruit mixed with mango lowers the GI, not only in healthy weight individuals, but also in those with obesity, and supports further investigation into the potential for nutrient extraction to enable increased fruit intake without causing a high glycemic response.

Dry matter and macronutrient extraction curves of potato varieties in the Alto Paranaíba region, Brazil

ABSTRACT Information on plant nutrient extraction is of utmost importance for the management of fertilization in crops. The objective of the study was to determine the accumulation of dry matter mass in the tubers and aerial parts of the plants and to generate absorption curves of macronutrients N, P, K, Ca and Mg for the potato varieties Ágata, Asterix, Atlantic and Taurus. The shoot and tuber samples were collected at 6, 13, 54, 66, 70, 82 and 97 days after planting. The highest accumulation of dry matter was observed in the Asterix and Atlantic varieties. The varieties Asterix and Atlantic showed higher N and K extraction and, consequently, higher productivity, while Taurus and Ágata presented lower yields and nutrient extraction. The period of greatest demand for macronutrients for the varieties studied is during the tuber filling phase (40 days after plantation). The variation between potato varieties in macronutrient extraction indicates a need for differential management fertilization of the plants.