2. A new hoe share design for weed control: measurements of soil movement and
draught forces during operation
Liubava Znovaa, Bo Melanderb, Aleksander Lisowskic, Jacek Klonowskic, Jaroslaw Chlebowskic, Gareth T. C. Edwardsa, Søren Kirkegaard Nielsena and Ole Greena
aAgro Intelligence Aps, Aarhus N, Denmark; bDepartment of Agroecology, Research Centre Flakkebjerg, Aarhus University, Slagelse, Denmark; cDepartment of Agricultural and Forest Machinery, Faculty of Production Engineering, Warsaw University of Life Sciences, Warsaw, Poland
ABSTRACT
This research introduces a new share design (L-share) that reduces the undesired random soil movement, providing a more controlled disturbance of the upper soil layer. Purpose: The aim of this study was to evaluate draught forces and soil movements when operating the new share.
Materials and Methods: Experiments were conducted in a laboratory set-up using a soil bin with a fine loamy soil texture. The soil was compacted to a bulk density of 1500 kg m −3, with a penetration index of 486 kPa and a mean water content of 10%. The cultivation depths were 30, 50 and 70 mm and the operation speeds were 0.84, 1.67 and 2.31 m s −1 . Cubes were used to measure soil movement by recording the displacement from their initial positions. The soil surface and furrow profile were measured by using a 2D laser range scanner. Results: The results showed that increasing operation speed and cultivation depths generally increased draught forces and soil movement. Changing the cultivation depth from 30 to 50 mm resulted in a 63% greater longitudinal force (Fx), and 71% greater Fx when increasing the cultivation depth from 50 to 70 mm.
Conclusion: The study showed that the new L-share mounted on a modified spring tine only causes minor soil movement and thereby minimising the undesirable soil movement.
KEYWORD S
Soil disturbance; soil movement; draught force; sweep; share; soil bin
Changes induced by plastic film mulches on soil temperature and their relevance in growth and fruit yield of pickling cucumber
Vicente Torres-Olivar, Luis Ibarra-Jiménez , Antonio Cárdenas-Flores, Ricardo Hugo Lira-Saldivar, José Humberto Valenzuela-Soto and Marco Antonio Castillo-Campohermoso
Departamento de Plásticos en la Agricultura, Centro de Investigación en Química Aplicada, Saltillo, Mexico
ABSTRACT
Purpose: The aim of this study was to realize whether soil mulching, with different plastic mulch colors, is a suitable practice for the culture of pickling cucumber.
Materials and Methods: The crop was cultured or not with black, silver/black, white/black, and aluminum/black plastic films, treatments were evaluated in randomized complete block design, to determine their effect on soil temperature, gas exchange, nutrient concentration, growth, and fruit yield.
Results and Conclusions: Black, silver/black, and aluminum/black plastic mulches were higher (p ≤ 0.05) in plant height, leaf area, and shoot dry weight than bare soil at 15 days after sowing, whose results were similar than using white/black film. Maximum, minimum, and mean soil temperatures were higher with all plastic mulches except for aluminum/black, in which the maximum soil temperature was similar to the one in bare soil. There was no difference in net photosynthesis and there was very little difference in nutrient concentration between plants in plastic mulches and plants in bare soil; however, early and total yield showed a higher ( p ≤ 0.05) yield in all plastic mulches, and lower with bare soil and white/black plastic mulch. Our results confirm that soil mulching impacts the pickling cucumber yield. We suggest a carefull selection of the color plastic mulch.
KEYWORD S
Plasticulture; Cucumis sativus; photosynthesis; leaf area; plant dry weight
Diversity assessment of sweetpotato germplasm collections for yield and yield-related traits in western Tanzania
Filson Mbezi Kagimboa,b, Hussein Shimelisa and Julia Sibiyaa
aAfrican Centre for Crop Improvement, School of Agricultural, Earth and Environmental Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal, Pietermaritzburg, South Africa; bDepartment of Research and Development (Root and Tuber Crops), Tumbi Agricultural Research Institute, Tabora, Tanzania
ABSTRACT
The experimental system: Sweetpotato ( Ipomoea batatas [L.] Lam.) is an important food crop widely grown under low input production systems and harsh growing environments. It is a relatively drought tolerant crop attaining higher biomass production per unit area. Genetic diversity present in breeding populations is a raw material for selection of parental genotypes with desirable and complementary traits. The objective of this study was to determine the genetic diversity present among Tanzania grown sweetpotato germplasm to select promising breeding parents with enhanced yield and yield-related traits and dry matter content.
Procedures: Seventy six sweetpotato accessions collected from Tanzania and 20 sweetpotato accessions received from International Potato Centre (CIP) in Lima/Peru were characterized in two seasons. The study was conducted using a 16 x 6 triple lattice design. The data collected included 16 morphological traits using CIPs standard descriptors. Data were analysed using multivariate procedure including cluster analysis and principle component analysis.
Results and conclusions: The tested sweetpotato collections differed significantly for storage root yield, dry matter content (DMC) and number of roots per plot. Genotypes New Kawogo, Kiti cha Nyerere and Kisu cha Masai had the highest root yields whereas genotypes Ngw’anangusa, Rugomoka and Secondary had significantly higher mean DMC. Traits considered in the study revealed positive and significant correlations. The first four principal components accounted for 69.33% of the variations present in the tested sweetpotato genotypes. Cluster analysis grouped the studied genotypes into two major classes with genetic diversity of 0.54. The selected genotypes can be recommended for future breeding programs to bolster yield and dry matter content of sweetpotato under western Tanzania conditions.
KEYWORD S
Dry matter content; genetic diversity; morphological traits; sweetpotato; western Tanzania
Efficacy of fresh fruit from Cucumis myriocarpus as Nemarioc-AL phytonematicide on suppression of root-knot nematodes in tomato plant production
P. E. Tseke and P. W. Mashela
Green Biotechnologies Research Centre of Excellence, University of Limpopo, Sovenga, Republic of South Africa
ABSTRACT
Experimental System: Fermented dried fruit of wild cucumber ( Cucumis myriocarpus Naude.) Had been successfully used as Nemarioc-AL phytonematicide in managing plant-parasitic nematodes in various cropping systems. However, the specialised oven-drying equipment are inaccessible to most resource-poor smallholder farmers in marginalised communities.
Procedures: The objective of this study was to determine the efficacy of fermented crudes extracts of C. myriocarpus fruit when used in fresh form as Nemarioc-AL phytonematicide on management of population densities of root-knot (Meloidogyne species) nematodes and growth of tomato (Solanum lycorpersicum L.) plants. Seedlings at five leaf-stage were transplanted into pots containing 2700 ml steam-pasteurised river sand and Hygromix at 3:1 (v/v) ratio. Each seedling was inoculated with approximately 3000 eggs and second-stage juveniles (J2) at transplanting. The phytonematicide was applied at 0%, 2%, 4%, 8%, 16%, 32% and 64%, arranged in a randomised complete block design, with five replications and validated in time.
Results: At 56 days after treatment, nematode variables and phytonematicide concentrations exhibited negative quadratic relations, with coeffients of determination (COD) ranging from 93% to 97%. Similarly, plant variables and phytonematicide concentrations exhibited positive quadratic relations, with COD from 96% to 98%.
Conclusions: In conclusion, when prepared from fresh fruit of C. myriocarpus, Nemarioc-AL phytonematicide was suitable for use in managing nematode population densities of Meloidogyne species in tomato production.
KEYWORD S
Cucurbitacin A; effective microorganisms; fermented crude extracts; methyl bromide; nematicide
Inoculant rhizobia suppressed root-knot disease, and enhanced plant
productivity and nutrient uptake of some field-grown food legumes
Mujeebur Rahman Khana, Fayaz A. Mohiddinb and Faheem Ahamada
aDepartment of Plant Protection, Aligarh Muslim University, Aligarh, India; bDivision of Plant Pathology, SKUAST, Srinagar, India
ABSTRACT
The potential effect of rhizobial inoculation on root knot nematodes in chickpea, mungbean and pigeonpea were studied under field condition. The seed treatment with respective rhizobium strains increased the nodulation, leghemoglobin content, bacteriod population, plant growth, yield and nitrogen uptake of three three food legumes compared to the plants without the rhizobium treatment. The nematode (1500 juveniles/kg soil) incited oval galls on the roots of the three legumes, and suppressed plant growth and yield. The galling, egg mass production and soil population of the nematode was greater on the plants without the rhizobium treatment. The pure culture and culture filtrate of the rhizobium strains suppressed the egg hatching and induced mortality to the juveniles of M. incognita over control. The nematode infection reduced the nodulation, bacteroid population and leghemoglobin contents of the nodules and NPK uptake by the plants. Hence, the rhizobia treatment shall be integrated to common agronomic practice of food legume cultivation so as to enhance crop productivity and to protect roots from nematode attack.
KEYWORD S
Pulses; Meloidogyne incognita; leghemoglobin; NPK uptake; bacteriod population
Low-P solution culture can be used for screening root growth vigor in soil for high nutrient uptake of spring wheat varieties
Yaosheng Wang a,b, Lars Stoumann Jensen b and Jakob Magid b
aInstitute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, People’s Republic of China; bDepartment of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
ABSTRACT
Purpose: Root and root hairs of plants have been intensively studied in solution culture; however, correlation of such measurements in solution culture with development in soil is poorly understood. Therefore, the aim of this study is to study whether root and root hairs grown in solution culture can predict their behavior in soil and their correlation with macro- and micronutrients uptake of wheat genotypes.
Materials and methods: The growth of roots and root hairs as well as uptake of macro- and micronutrients of six spring wheat varieties was compared in solution culture under P stress and P abundance and in a low fertility soil.
Results and conclusions: Root length and surface area under P stress were significantly positively correlated with that in the low fertility soil, while no such correlation was apparent for root hair length and density. In absolute terms, the root length, surface area, root hair length and density of spring wheat varieties were substantially higher in soil than in solution culture, while the concentration and uptake of macro- and micronutrients in soil differed from solution culture in a complex way. The early uptake of macro- and micronutrients was intimately associated with root length and surface area as well as root hair length and density in soil but not in solution culture. Therefore, root length rather than root hair traits in low-P solution may be used to screen early root growth vigor in soil and thereby high nutrient uptake of wheat in low fertility soil.
KEYWORD S
Macronutrient; micronutrient; phosphorus; root length; root hair
Meta-analysis of experimental warming on soil invertase and urease activities
Yinping Baia,b*, Feng Lic*, Gang Yanga, Shengwei Shid, Faqin Donge, Mingxue Liua, Xiaoqin Niee and Jiangbo Haib
aSchool of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, People’s Republic of China; bCollege of Agronomy, Northwest A&F University, Yangling, People’s Republic of China; cDongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Hunan, People’s Republic of China; dPlant Science and Technology College, Beijing University of Agriculture, Beijing, People’s Republic of China; eKey Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Southwest University of Science and Technology, Mianyang, People’s Republic of China
ABSTRACT
Soil enzymes are regulate terrestrial carbon (C) and nitrogen (N) cycles, and how the activity of these enzymes are affected by soil warming duration is unclear. In the study, the effect of experimental soil warming duration (<2 years and >2 years) on invertase and urease activities were examined by meta-analysis. Soil warming increased invertase activity by 22% (<2 years) and 16% (>2 years), respectively, while they increased urease by 29% and 9%. Meta-analysis of soil warming experiments found that warming by less than 1.5°C increased invertase by 22%, while warming it by more than 1.5°C increased invertase by 29%; the corresponding increases in urease were 16% and 8%. These effects of experiment warming differed among ecosystem types, with warming-induced increases being greatest in forest ecosystem. The results of this meta-analysis suggest that invertase and urease become less responsive to warming over longer periods and
invertase with greater warming-responsiveness than urease activity.
KEYWORD S
Soil enzyme activity; soil warming; carbon cycles; nitrogen pool
Resistance breeding and biocontrol of Striga asiatica (L.) Kuntze in maize: a review
Admire Tichafa Shayanowako, Mark Laing, Hussein Shimelis and Learnmore Mwadzingeni
School of Agricultural, Earth and Environmental Sciences, African Centre for Crop Improvement, University of KwaZulu-Natal, Pietermaritzburg, South Africa
ABSTRACT
Purpose: The aims of this article are to highlight pre-breeding procedures for identifying primary sources of Striga-resistance genes and to summarize complimentary breeding techniques that enhance partial resistance of maize varieties against Striga species.
Materials and methods: The paper presented a comprehensive account of Striga screening and controlling techniques and highlighted the potential of integrating partial resistance with FOS to boost maize production and productivity in SSA.
Results: Striga infestation is a major constraint to maize production and productivity in Sub-Saharan Africa (SSA). A lack of Striga-resistant maize varieties and the limited adoption of other control methods hinder effective and integrated control of the parasitic weed in maize and related cereal crops globally. Genetic resistance of maize should be complemented with the use of Fusarium oxysporum f.sp. strigea (FOS), a biocontrol agent known to suppress Striga.
Conclusions: A combined use of genetic resistance and FOS has remained largely unutilized in controlling Striga in Africa. A combination of conventional and molecular Striga-resistance breeding tools as well as the use of FOS are promising methods to effectively control Striga in SSA.
KEYWORD S
Biocontrol; F. oxysporum f.sp. strigea; screening techniques; Striga asiatica (L.) Kuntze; Zea mays. L
Soil microbial communities changed with a continuously monocropped processing tomato system
Yalong Kang, Feng Jing, Wenqinq Sun, Jianguo Liu and Guiying Jiang
The Key Laboratory of Oasis Ecology Agriculture of Xinjiang Bingtuan, Shihezi University, Shihezi, People’ s Republic of China
ABSTRACT
To reveal the regulatory mechanisms underlying the productivity of long-term continuous cropping of processing tomato, a multi-year study was carried out to understand the effects of long-term continuous cropping on the community structures of the root zone microbes. Soil samples collected from continuous cropping of processing tomato after 3, 5 and 7 years were used for this study. Results showed that soil microbial biomass C (SMBC), N (SMBN) and microbial quotient (qMB) significantly decreased with longer cropping. After seven years of continuous cropping, the SMBC and SMBN contents, and qMB respectively significantly decreased by 52.3%, 78.8% and 48.2% ( p < 0.01). In contrast, soil microbial biomass P (SMBP) increased during the first three years of continuous cropping, peaking to up to 1.6 times higher than that of the control, which also declined in the succeeding years. Continuous cropping significantly increased the PLFA of fungi, whereas the opposite trend was observed for bacteria, total PLFAs biomass, and the ratios of bacteria and fungi. The PLFA of actinomycetes have no change throughout.
This suggests that fungi were better adapted to nutrient poor conditions than bacteria. Microbial diversity indices reached the highest after three years of continuous cropping, with the lowest observed after seven years. This indicated that microbial community diversity and uniformity decreased with increasing number of planting years. Furthermore, our results revealed that the microbial community structure in processing tomato soils changed with extended cropping, resulting to a decline in soil microbial biomass, which may be both a cause and a reflection of the poor soil quality.
KEYWORD S
Processing tomato; continuous cropping; soil microbial biomass; community structure; phospholipid fatty acid biomarker
Yield and water use efficiency of dryland potato in response to plastic film
mulching on the Loess Plateau
Qiang Lia,b*, Hongbing Lia,b* and Suiqi Zhanga,b
aState Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, People’s Republic of China; bUniversity of Chinese Academy of Sciences, Beijing, People’s Republic of China
ABSTRACT
Water shortage is a key factor limiting potato yield in dryland farming regions, and the practice of soil mulching with plastic film has proven to be effective for increasing crop yield and improving soil and water conservation. This study investigated the effects of plastic mulching on potato yield and water use efficiency (WUE) on the Loess Plateau of China based on a synthesis of 44 publications (1987–2016) from 17 sites. Our results indicated that relative to no mulching, plastic mulching significantly increased the yield and WUE by 29.2% and 31.7%, respectively. The effects on yield under different mulching methods were ranked as follows: ridge-furrow mulching (RFM) > flat mulching (FM), and the effects on yield with different mulching extents were ranked full-area mulching (FAM) > partial-area mulching (PAM). The effects of plastic mulching on the yield using different colors of film were ranked as white plastic mulching (WPM) > black plastic mulching (BPM) and under different rainfall levels as (precipitation < 400 mm) > (precipitation > 400 mm). The rankings of the effects of plastic mulching on WUE were the same as for potato yield. The yield-evapotranspiration (ET) relationship could be described using a quadratic polynomial, and the yield response curve to ET under plastic mulching fell above the no-mulching curve, indicating that plastic mulching can result in higher yields than no mulching when ET is equal. The yield-ET relationship indicated that potatoes required an ET of 334 and 360 mm to achieve the highest yield under plastic mulching and no mulching, respectively, and potato WUE increased linearly with yield under both plastic mulching and no mulching. This study indicated that RFM, FAM and WPM are better potato management measures and that there is potential to improve the yield and WUE on the Loess Plateau.
KEYWORD S
Plastic film mulching; Loess Plateau; yield; water use efficiency; potato; economic benefits
