Agriculture2015, 5(3), 713-722; doi:10.3390/agriculture5030713 (registering DOI) - published 27 August 2015 Show/Hide Abstract
Abstract: Farmers are increasingly demanding rapid, cost-effective, easy-to-use and non-destructive methods for monitoring changes in the physical and chemical characteristics of crops and plants from the early stages of crop development until harvest. Remote and proximal sensor tools have been used recently to monitor different aspects of cereal production (e.g., fertilization, crop diseases). Most of these tools are characterized as non-destructive, non-invasive and easy-to-use, and most of them are based in near-infrared (NIR) spectroscopy. This article reviews recent and potential applications for the use of proximal sensors based on NIR spectroscopy to monitor dry matter (DM), yield, nitrogen and diseases in different cereal crops.
Abstract: Pig manure is an excellent fertilizer and rich source of organic carbon and nitrogen compounds such organic nitrogen (O-N) (95% of total nitrogen) that is plant-unavailable-nitrogen (PUN) and mineralized nitrogen (about 1% of total nitrogen) such as ammonium (NH4+) and nitrate (NO3) that are plant-available-nitrogen (PAN). In addition, manure also contains two forms of estrogens: (i) poorly estrogenic thus essentially nontoxic conjugated estrogens (cEs) such as estrone (cE1), estradiol (cE2) and estriol (cE3); and (ii) highly estrogenic and toxic free estrogens (fEs) such as fE2, fE1 and fE3. This study showed that aerobic processing reduced concentrations of total carbon (TC), O-N, PAN and NH4+/NH3 ratio, transiently hydrolyzed cEs (cE2 > cE1 > cE3) into corresponding fEs, transiently increased estrogenic activity and potential toxicity, and rapidly degraded fEs (fE2, fE1 > fE3), thus reducing the estrogenic activity in manure. Unlike aerobic processing, anaerobic processing stabilized and increased PAN and NH4+/NH3 ratio, thus increasing the manure’s fertilizer value. However, anaerobic processing, relative to aerobic processing, poorly hydrolyzed cEs (reducing transient toxicity and increasing reserve toxicity potential) and poorly degraded fEs (increasing toxicity) in manure. Thus, aerobic and anaerobic environments have distinct effects on manures’ PAN and estrogenic activity, presenting an interesting dilemma: anaerobic incubation that increases manures’ PAN does not effectively degrade estrogens, while aerobic incubation that effectively degrades estrogens (after transiently increasing their estrogenic activity) also decreases PAN, thus making manure less profitable. New techniques are need to fully use manure as organic fertilizer.
Abstract: Leaf length is a key factor in the economic value of different grass species and cultivars in forage production. It is also important for the survival of individual plants within a sward. The objective of this paper is to discuss the basis of within-species variation in leaf length. Selection for leaf length has been highly efficient, with moderate to high narrow sense heritability. Nevertheless, the genetic regulation of leaf length is complex because it involves many genes with small individual effects. This could explain the low stability of QTL found in different studies. Leaf length has a strong response to environmental conditions. However, when significant genotype × environment interactions have been identified, their effects have been smaller than the main effects. Recent modelling-based research suggests that many of the reported environmental effects on leaf length and genotype × environment interactions could be biased. Indeed, it has been shown that leaf length is an emergent property strongly affected by the architectural state of the plant during significant periods prior to leaf emergence. This approach could lead to improved understanding of the factors affecting leaf length, as well as better estimates of the main genetic effects.
Abstract: Biochars are produced by low-oxygen gasification or pyrolysis of organic waste products, and can be co-produced with energy, achieving waste diversion and delivering a soil amendment that can improve agricultural yields. Although many studies have reported the agronomic benefits of biochars produced from pyrolysis, few have interrogated the ability of gasified biochars to improve crop productivity. An earlier study described the ability of a biochar that was derived from gasified Kentucky bluegrass (KB) seed screenings to impact the chemistry of acidic agricultural soils. However, that study did not measure the effects of the biochar amendment on plant growth or on nutrient acquisition. To quantify these effects we conducted a greenhouse study that evaluated wheat grown in agricultural soils amended with either the KB-based biochar or a biochar derived from a blend of woody mixed-waste. Our studies indicated that biochar amended soils promoted the growth of wheat in these agricultural alfisols. Our elemental analysis indicated that an attenuation of metal toxicity was likely responsible for the increased plant growth. The results of our study are placed in the context of our previous studies that characterized KB-sourced biochar and its effects on soil chemistry.
Abstract: Wheat is increasingly used as a dual-purpose crop (for forage and grain production) worldwide. Plants encounter low temperatures in winter, which commonly results in sugar accumulation. High sugar levels might have a positive impact on forage digestibility, but may also lead to an increased risk of bloat. We hypothesized that cultivars with a lower capacity to accumulate sugars when grown under cold conditions may have a lower bloat risk than higher sugar-accumulating genotypes, without showing significantly lower forage digestibility. This possibility was studied using two wheat cultivars with contrasting sugar accumulation at low temperature. A series of experiments with contrasting temperatures were performed in controlled-temperature field enclosures (three experiments) and growth chambers (two experiments). Plants were grown at either cool (8.1 °C–9.3 °C) or warm (15.7 °C–16.5 °C) conditions in field enclosures, and at either 5 °C or 25 °C in growth chambers. An additional treatment consisted of transferring plants from cool to warm conditions in the field enclosures and from 5 °C to 25 °C in the growth chambers. The plants in the field enclosure experiments were exposed to higher irradiances (i.e., 30%–100%) than those in the growth chambers. Our results show that (i) low temperatures led to an increased hemicellulose content, in parallel with sugar accumulation; (ii) low temperatures produced negligible changes in in vitro dry matter digestibility while leading to a higher in vitro rumen gas production, especially in the higher sugar-accumulating cultivar; (iii) transferring plants from cool to warm conditions led to a sharp decrease in in vitro rumen gas production in both cultivars; and (iv) light intensity (in contrast to temperature) appeared to have a lower impact on forage quality.
Abstract: Data on fresh fruit and vegetable shrink in supermarkets is important to help understand where and how much shrink could potentially be reduced by supermarkets to increase their profitability. This study provides: (1) shrink estimates for 24 fresh fruits and 31 fresh vegetables in U.S. supermarkets in 2011 and 2012; and (2) retail-level food loss. For each covered commodity, supplier shipment data was aggregated from a sample of 2900 stores from one national and four regional supermarket retailers in the United States, and this sum was then compared with aggregated point-of-sale data from the same stores to estimate the amount of shrink by weight and shrink rates. The 2011–2012 average annual shrink rates for individual fresh vegetables varied from 2.2 percent for sweet corn to 62.9 percent for turnip greens and for individual fresh fruit ranged from 4.1 percent for bananas to 43.1 percent for papayas. When these shrink estimates were used in the Loss-Adjusted Food Availability data series, annual food loss for these commodities totaled 5.9 billion pounds of fresh fruit and 6.1 billion pounds of fresh vegetables. This study extends the literature by providing important information on where and how much shrink could potentially be reduced. Precise comparisons across studies are difficult. This information, combined with information on available and cost-effective technologies and practices, may help supermarkets target food loss reduction efforts though food loss will never be zero.