Increase In Planted Area Research Articles

First report of alfalfa root rot caused by Trichothecium roseum in China.

Alfalfa (Medicago sativa L.) is perennial leguminous forage, which is cultivated throughout the world due to its high yield, high quality, satisfactory palatability, and wide adaptability. With the increase of planting area in China, root diseases caused by Fusarium spp., Sclerotium rolfsii, Phytophthora spp. (Yang et al. 2022), and new pathogens have been found that reduce the yield and quality of alfalfa and cause economic losses (Li at al. 2019). In 2021, an alfalfa disease occurred under conditions of high temperature and high humidity at the Jiaozhou Experimental Base of Qingdao Agricultural University (Jiaozhou Modern Agricultural Science and Technology Demonstration Park, 36.33°N 120.40°E, Qingdao, Shandong, China), and about 2 ha of alfalfa were infected. The disease affected up to 35% of the plants and caused grass spots. Infected plants developed black-brown lesions with irregular shapes on roots with yellowing of the foliage; the leaves of the whole plant turned yellow. In the late stage of the disease, defoliation occurred and the plants stopped growing, wilted and died. Ten infected plants with typical symptom were collected for isolation and identification of pathogen. The infected roots were cut into 3-5 mm2 sections and then soaked in 75% ethanol for 30 s, followed by a 3-minute immersion in 2% sodium hypochlorite for surface sterilization. Next, the tissues were rinsed in sterile water five times and then placed on potato dextrose agar (PDA) medium. After three subcultures and subsequent single spore isolation, one representative strain named as DC1 was isolated from the infected roots. Based on morphological observation, the colony of DC1 was flat, granular, and powdery in appearance. Four days after inoculation on PDA medium, the size of the colony were 2.1-2.6 cm. After 8 to 20 days, the colonies were initially white and gradually change a light pink to peach color. The conidia are two-celled (Hamid et al. 2014), elliptic to pear-shaped, colorless or translucent, smooth to slightly rough with thick walls. The size of conidia ranged from 11.3 to 23.5 μm long × 6.1 to 12.7 μm wide (n =30). For the identification, the rDNA--ITS gene of the fungus was amplified using the primers ITS1/ITS4 (White et al.1990), and the EF1α gene was amplified using primers EF1-983F/EF1-2218R (Rehner and Buckley 2005). Then the PCR amplicons were cloned into the pCE2 TA/Blunt-Zero vector. The results of the rDNA-ITS (OM049197.1, 515 bp) and EF1α (OM069381.1, 926 bp) sequences were deposited in GenBank. DNA analysis showed that the two sequences were 100% similar to the rDNA-ITS sequence (MN882763.1) and EF1α sequence (DQ676610.1) of Trichothecium roseum, respectively. A pathogenicity test was done by placing one piece (0.5 cm in diameter) of fungal culture (PDA plug) 1cm below the crown of 40-day-old healthy alfalfa (cv. Zhongmu No.3) plants, 3 replicates and 20 plants in each replicate. PDA plug without the pathogen were used for control. All plants were cultivated in a growth chamber at 25±1°C with a light cycle of 15 h (90% relative humidity). After 18 days, the roots of inoculated plants had dark brown lesions and the leaves of their plants turn yellow, while those control plants had no symptoms. To fulfilling Koch's postulates, the same pathogen was re-isolated from necrotic root tissue of inoculated plants and confirmed by morphology and the rDNA-ITS and EF1-α sequences. Based on disease symptoms, morphological characteristics DNA sequences and pathogenicity, the pathogen of alfalfa disease in Jiaozhou Experimental Base of Qingdao Agricultural University was identified as T. roseum. To our knowledge, this is first report of T. roseum causing alfalfa root rot. The newly emerging disease may pose threat to alfalfa production of central and southern China in future.

Proposal for Integrated Management of Verticillium Wilt Disease in Avocado Cultivar Hass Crops

The area planted with avocado crops in Colombia has been growing rapidly in recent years, especially for export varieties such as Hass. The increase in planted area coincided with increased phytosanitary problems, where pathogens such as fungi of the genus Verticillium spp. are becoming of economic importance. The objective of this study was to evaluate different control strategies for avocado wilt disease caused by Verticillium spp., under in vitro, net house, and field conditions. Strategies tested included fungicides (benomyl, azoxystrobin, captan, and carbendazim), beneficial and antagonistic microorganisms (Trichoderma sp., and Rhizoglomus fasciculatum), and physical and cultural practices such as solarization, drainage and removal of diseased tissues. Treatments T7fi (pruning-solarization-Trichoderma-mycorrhiza-sucrose-organic matter-drainage) and T8fi (fungicide-pruning-solarization-Trichoderma-mycorrhiza-sucrose-organic matter-drainage), showed the greatest reduction in the area under disease progress curve and Verticillium dahliae inoculum in soil and plant tissues under field conditions. Fruit with extra quality increased 120.8% with T7fi and 108% with T8fi, compared to the control with diseased trees. The highest costs were identified for T7fi and T8fi; however, these treatments also showed the best cost/benefit relationship. Integrated approaches as in T7fi and T8fi showed the best results for Verticillium wilt control. As no fungicides of chemical synthesis are included in T7fi (pruning-solarisation-Trichoderma-mycorrhiza-sucrose-organic matter-drainage), it should be preferred to T8fi, which does include them, to avoid their negative impacts on avocado production.

Analysis of the Production Components in the Soybean Crop in the Last Two Decades in the State of Parana and Brazil

Introduction: Soy is an agricultural crop that has great economic importance. The analysis considering the cultivated area, the production and the yield of grains contributes to research and transfer of technology to the producers.
 Aims: To adjust the mathematical model using simple linear regression analysis and correlation between the variables of planted area, production and productivity, in the state of Paraná and Brazil, in the last two decades.
 Study Design: Data collection and research of information on the cultivation of soybeans in the state of Paraná and in Brazil on official websites
 Place and Duration of Study: State University of Western Paraná, Post-Graduation in Agronomy, between July 2018 and December 2018.
 Methodology: Data were obtained from the Portal of the Brazilian Institute of Geography and Statistics between 1997 and 2017. Simple linear regression analysis and Pearson correlation analysis were used.
 Results: By analyzing the results, it is possible to observe significant increases in soybean production in both Paraná and Brazil over this 20-year period. Paraná achieved a 205% increase in planted area, 290% in production and 141% in average yield.
 Conclusion: The simple linear regression and correlation analysis showed an adjustment between the cultivated area, the production and the average productivity in the soybean crop in the period from 1997 to 2017.

English

The millet crop in recent decades has shown an increase in planted area, mainly in the Cerrado region. However, there are few studies related to the management and phytossociology of weeds in this culture. Thus, the objective of this research was to perform a phytosociological survey in millet under different soil managements in Savanna Sul-Mato-Grossense region. The experiment was conducted in the experimental area of Universidade Estadual de Mato Grosso do Sul – Unit of Aquidauana (UEMS/UUA), in Aquidauana-MS. The area is cultivated to five years with soybeans in first crop and corn in second. The experimental design was randomized complete block in a split-plot design consisting of four blocks with four replications. In the plots were used soil preparation systems (minimum tillage and no-tillage) and in the subplots was utilized the nitrogen fertilization at 50 kg ha -1 and absence of nitrogen on millet at 25 days after emergence (DAE). Were evaluated the parameters number of species (NS), total number and dry mass of weeds (TN and DMW, respectively), dry mass of millet (DMM) and frequency (F), density (D), abundance (A) and Importance Value (IV) of weeds. The no-tillage system provided greater dry mass of weeds, whereas the nitrogen resulted in a smaller total number of weeds (TN). Cynodon dactylon and Commelina benghalensis were the most predominant species on area.

Impact of agricultural development on variation in surface runoff in arid regions: a case of the Aksu River Basin

Located in the south of Xinjiang Uygur autonomous region, the Tarim River is the longest inland river in China. Agricultural development, excessive exploitation and low surface water use efficiency in the headstream regions have led to a marked decrease in the water supply to the mainstream. This, in turn, has resulted in the drying-up of the watercourse in the lower reaches of the Tarim River and serious deterioration of the eco-environment. The Aksu River Basin, the most important headstream of the Tarim River, was selected as the research area in this study. Taking elastic coefficient, water demand coefficient and water utilization intensity as the indices, we studied the impact of agricultural development on decreasing surface runoff since the 1950s. The re- sults indicated that (1) the increasing rate of consumption of surface runoff outstripped the rate of increase meas- ured in the natural catchment discharge, resulting in ever diminishing stream discharge into the Tarim River. Agri- cultural irrigation and seepage loss in irrigation canal systems were the major sources for runoff consumption, tak- ing 63.72% of the overall runoff consumption. What's more, agricultural water consumption took up more than 97% of the water used for long-term production; (2) the expansion of cultivated land, change of planting structure and comparatively low agricultural irrigation efficiency all contributed to the decrease in surface runoff of the Aksu River. The elasticity coefficient of surface runoff reduction corresponding to the increase in planted area was 0.34 in the 1950s, while in the 2000s it had increased to 7.87. This reflected a more sensitive response of runoff decrease to cultivated land expansion. The increase in cotton and fruit production, without widely-used scientific irrigation methods and water-saving technology, led to considerable waste of the water resources. Meanwhile, the irrigation efficiency was still quite low, characterized by the waste of water resources, and the decrease of surface runoff; (3) in different stages, cultivated land area, planting structure and agricultural water use efficiency exerted different effects on runoff decrease. In the early stage, agricultural development showed no obvious effect on runoff de- crease. Since the 1960s, the expansion in cultivated land resulted in large consumption of surface runoff; since the 1990s, not only expansion in cultivated land expansion, but also planting structure exerted significant impact on the consumption of surface runoff. Recently, though agricultural water use efficiency has improved in some regions to reduce the consumption of runoff to a certain extent, overall agricultural water use efficiency is still quite low; (4) during the investigation period, water consumption by agricultural development reflected the unbalanced relation- ship between human activities and water resources.

Impactos na produção de políticas "desacopladas" na agricultura norte-americana: o papel do risco

Nos últimos anos, esforços têm sido feitos no sentido de modificar as políticas de apoio à agricultura para minimizar os efeitos distorcivos sobre a produção e o comércio internacional. Ênfase tem sido dada às políticas desacopladas de preços e/ou produção, sobretudo às transferências diretas de renda aos agricultores, consideradas neutras em relação às decisões de produção corrente. O argumento é de que estas políticas têm efeitos mínimos na produção atual, pois não influenciam os retornos marginais da cultura, já que seus pagamentos independem da produção corrente. Este estudo mostra que, ao contrário, as decisões de produção correntes são afetadas pelas políticas de transferência de renda, especialmente através dos efeitos diretos sobre a percepção de risco dos agricultores. Estes efeitos, divididos em efeito-renda e efeito-segurança, estimulam o aumento da área plantada e assim, têm efeitos sobre a produção e os preços.