Corn Rows Research Articles

This Land: An American Portrait by Jack Spencer

Reviewed by: This Land: An American Portrait by Jack Spencer Kat Krutak-Bickert This Land: An American Portrait. By Jack Spencer. Foreword by Jon Meacham. Austin: University of Texas Press, 2017. vii + 268 pp. Illustrations. $45.00 cloth. Jack Spencer's This Land: An American Portrait is a collection of photographs spanning from the West Coast to the East, the Great Plains to the Gulf. The book is Spencer's relevant and critical depiction of the changing landscape of the lower forty-eight. Spencer captures a range of activities from wild animals grazing in their undisturbed habitats to lonely storefronts—seemingly abandoned—and children wading in ankle deep beachfronts. Spencer dazzles us with his visual poetry while at the same time guiding us to look beyond his images. He explores the delicate balance struck with what our culture demands and what truly is important to lead a fulfilling life. One cannot be blamed for opening this book solely to marvel at the photographs and the wonder they elicit. Nonetheless, I urge all who gaze upon these images to read Spencer's prologue. In Spencer's written word the truth of his dissolution of the American population comes into full view. "This society," Spencer writes, "has a deepening, narcissistic, and consumer-driven neurosis that urges it members to buy something—anything—in order to fill some unidentified hole in their lives, and to get someplace—anywhere—as quickly as possible." It is here that Spencer is imploring us to slow down, to watch out for the undercurrent by which so many of us are swept away. This book is not a collection of glossy travel photos of America's most treasured attractions. It is a deeper look at our attitudes and the mental health of our society. It is a juxtaposition of the natural world, the manufactured world, and all the worlds that lie in between. Through [End Page 326] Spencer's words and his lens, he explores the implications of an apathetic and greedy culture—a culture that takes without asking and reaps with no consequences. The images taken in the Great Plains are as varied as the region itself. There are rolling hills of short, tall, and mixed prairie grasses, small wooden frame homes, long dirt roads enclosed by rows of corn, and flora and fauna specific to this beautiful part of the country. Much of my own youth and early adulthood was spent chasing some of these same images. With my first ever camera, an old Canon AE-1, I would ride my bike outside the city limits to try and capture an old barn or even just a single fencepost. I, like Spencer, was searching for a portal into the past. Now, more often than not, our society takes the natural world for granted, or even worse, ignores it completely. Spencer reminds us what lies outside our cities and towns while also pleading for better stewardship, conservation, and maybe even a trip to Amish Country! Kat Krutak-Bickert Great Plains Cooperative Ecosystems Studies Unit University of Nebraska–Lincoln Copyright © 2018 Center for Great Plains Studies, University of Nebraska-Lincoln

Pengaruh Penggunaan Mulsa Jerami Pada Sistem Tumpang Sari Tanaman Jagung Manis (Zea Mays saccharata Sturt) dan Kacang Kedelai (Glycine max (L) Merill) Terhadap Pertumbuhan dan Produksi

Influence of Straw Mulch on intercropping system Crop Sweet Corn (Zea mays saccharata Sturt) and Soybean (Glycine max (L) Merrill) on Growth and Production. The aim of research to determine the effect of mulching straw on intercropped plants sweet corn (Zea mays saccharata Sturt.) And soybean (Glycine max (L) Merrill) on the growth and production. Research dilakanakan for 4 months starting from May to August of 2010, starting from land preparation to harvest. Location of research carried out in the village of Muara Bengkal ngayau East Kutai. This study was conducted using the Draft Plots Separated (RPT) with analysis of 2 x 5 and each -masing treatment was repeated 4 times. As the main plot (main plot) is a straw mulch consisting of two levels, namely: mo = without straw mulch, m1 = with straw mulch. Meanwhile, as the subplots (sub plot) is the use of intercropping systems (P) consists of 5 levels:: p1 = soybean monoculture, p2 = sweet corn monoculture, p3 = intercropping soybean + maize dibarisan middle, p4 = intercropping 3 lines corn among soybean, p5 = intercropping two rows of corn beside the left and right of the soybean crop. The results showed a significant effect of straw mulching treatment. Treatment cropping system significantly. Combination treatment with straw mulching intercropping system had no significant effect.

Long-term no-till as a means to maintain soil surface structure in an agroecosystem transformed into irrigation

The aim of this study was to determine the most appropriate soil management to reduce the structural degradation of soils susceptible to crusting in Mediterranean areas recently transformed into irrigation. A long-term field experiment (LTE) under rainfed conditions was established in 1996 in NE Spain to compare three tillage systems (no-tillage, NT; reduced tillage, RT; conventional tillage, CT). The experiment was transformed to irrigated corn in 2015. In 2015, an adjacent experiment with the same layout was created (short-term experiment, STE) in an area previously managed under long-term NT. The study was carried out during the second corn growing season (i.e. year 2016). Soil samples were collected from 0 to 5cm depth at different dates during corn season. Dry and water-stable macroaggregates and their C concentration, soil organic carbon (SOC) and labile C concentration, soil respiration, bulk density, penetration resistance (PR), water infiltration, macroporosity, microporosity, amount of crop residues and ground cover, corn development, aerial biomass, and grain yield were measured. In LTE and STE tillage led to a breakdown of dry sieved aggregates (of 2–4 and 4–8mm size) in RT and CT, being slowly reconsolidated throughout the corn growing season. However, macroaggregate water-stability did not increase in CT and RT compared to NT due to a lower SOC concentration, making the soil more susceptible to its degradation by the action of water. SOC differences between treatments were more pronounced in LTE than STE given the long-term differential management in the first, which allowed greater accumulation of SOC under NT. In LTE, PR between corn rows was greater under NT than CT and RT and non-significantly different between treatments within the row. In the case of STE, PR increased over time after tillage (CT and RT) to match NT in the last sampling. Crop establishment was slower in CT than NT in LTE highlighting the impact of soil surface degradation on crop development. However, contrarily to the differences in corn yield in 2015, a careful planting in 2016 led to a lack of differences between tillage systems on corn yield. Our results indicate that in areas transformed into irrigation intensive tillage leads to greater susceptibility to soil structural degradation. Thus, in these areas the adoption of conservation agriculture practices such RT and NT enhances soil resilience to degradation processes and ensures an adequate development of the crop.

Improving Sample Collection, Sample Processing, and Laboratory Analyses for Corn Stalk Nitrate Test

Core Ideas Corn stalk nitrate test results can help corn growers fine‐tune N management. Adoption of corn stalk nitrate test use can be enhanced with more practical field sampling protocols. Laboratory processing of corn stalk nitrate test samples can be simplified for reduced analytical cost. The corn (Zea mays L.) stalk nitrate test (CSNT) is a site‐specific, after‐the‐fact, diagnostic tool for N management of corn. Although considered effective, widespread adoption of CSNT is limited due to somewhat impractical sample collection, handling, and laboratory sample processing protocols. Five studies were conducted to evaluate the impact of alternative sampling, sample handling, and laboratory processing protocols on CSNT outcomes. Study 1 evaluated the effect of stalk length and position on CSNT values. In Study 2 timing of sampling or growth stage was evaluated. In Study 3 several sampling patterns within a field (samples taken within a corn row vs. perpendicular or under an angle to rows) were analyzed. Study 4 tested if (a) quartering of stalks, (b) delay in mailing of stalks to the laboratory, and (c) temperature during storage (refrigerator, freezer, room temperature) affected CSNT‐N. Laboratory grinding, extraction, and determination procedures were compared in Study 5. The results suggest that sampling protocols can be adjusted to include shorter stalk samples, taken within 5 d after silage harvest. Direction of sampling within a field did not impact CSNT‐N, eliminating the need for more labor‐intensive sampling. Also, quartering of stalks and different temperature during storage did not change CSNT‐N. Laboratories can use 2‐mm grinding, extraction with distilled water, and a nitrate specific ion electrode or flow injection analysis. We conclude that adjustments in sampling protocols and sample processing can be made, possibly increasing farmer acceptance of the test, and reducing the cost of sampling, sample processing, and laboratory analyses.

Optimizing Agronomic Practices for Clover Persistence and Corn Yield in a White Clover–Corn Living Mulch System

Core Ideas Living mulch cover crops help stabilize erosive soils during corn production. Wide rows enable the living mulch cover crop to re‐establish for subsequent cropping. Herbicide bands must be kept to a minimum width to permit living mulch. Removal of crop residue is essential for white clover to perenniate in the living mulch system. White clover can supply over 100 kg ha−1 N to corn in the living mulch system. The area dedicated to corn (Zea mays L.) production increased 50% in the southeastern United States between 2006 and 2016, but producers need to find production systems that mitigate environmental impacts on erosive soils. Utilizing a perennial legume in a living mulch system may help stabilize the soil. The objectives of this study were to identify the most successful herbicide banding pattern (20 or 40 cm), corn row spacing (75 or 90 cm), and corn population density (60,000 or 90,000 plants ha−1) to optimize potentially mineralizable nitrogen (PMN) from white clover (Trifolium repens L.) and maximize clover regrowth in a living mulch system. Plots were established at Floyd and Oconee Counties, Georgia, and tested over 2014 and 2015. Clover persistence and regrowth was best when initial clover suppression used a 20‐cm band and corn was planted on 90‐cm rows. Herbicide‐induced PMN was greater for the wide herbicide band width, but shade‐induced PMN was greater from the narrow band width. Corn shaded the clover at approximately 40 d after planting (DAP) and clover responded by senescing biomass as shading increased. Shading resulted in the majority of PMN regardless of other treatments variables. Corn grain yields were greater in the high population treatments, but there was a year × location × herbicide band width interaction. Considering clover persistence, PMN, and corn grain yield, we conclude that corn planted on 90‐cm rows in 20‐cm wide herbicide bands of dead clover is the best treatment for the living mulch system.

Crop canopy sensor orientation for late season nitrogen determination in corn

ABSTRACTIncreasing nitrogen use efficiency (NUE) in irrigated corn production is of great importance to overall agricultural sustainability. Studies have shown that crop canopy sensors can aid in this pursuit as they allow for the determination of nitrogen (N) requirements in split applications later in the growing season. Fertigation can also increase NUE as many split applications can be conducted. If crop canopy sensors could be used to direct N fertigation rates, overall NUE may be increased even further. However, in some cases, N differences may need to be determined later in the growing season after corn has tasseled, which can cause issues with crop canopy sensor readings. Therefore, a study was initiated to evaluate the potential of a crop canopy sensor to differentiate between N levels at two corn (Zea mays) growth stages (R1 and R3) after the corn had tasseled. The sensor was placed in three orientations to evaluate which orientation best determined the corn N status across two sensor-calculated indices while avoiding taking measurements involving the corn tassel. These orientations were (1) nadir, between corn rows (above canopy), (2) 45° off nadir within the corn canopy (below corn tassel), and (3) 90° off nadir within the corn canopy (below corn tassel). The results of this study show that N differences in late season corn can be determined by utilizing crop canopy sensors in an inter-row orientation. Results also show that the red edge normalized difference vegetation index (ReNDVI) index is superior to the normalized difference vegetation index (NDVI) index for late season N determinations in corn. These results suggest that crop canopy sensors could be an effective tool for determining N requirements of corn late in the growing season.

Factors Influencing Corn Canopy Throughfall at the Row Scale in Northeast China

Core Ideas Throughfall was statistically different among five measurement locations. Cumulative throughfall of 24 to 36 cm from row exceeded that of 0 to 12 cm and 48 to 60 cm by 46 to 88%. Coefficient of variation of throughfall decreased with rainfall amount and increased with leaf area index and plant height. Understanding throughfall (TF) and its influencing factors at crop row scale is a key step to reveal the mechanisms of soil water recharging, soil erosion, and evaporation of intercepted rainfall. The objective of this study was to determine the amount and the variation of TF in relation to plant canopy and rainfall. In this study, TF was measured by a rectangular plexiglass collector at five measurement locations (MLs) with the distances of the (A) 0 to 12 cm, (B) 12 to 24 cm, (C) 24 to 36 cm, (D) 36 to 48 cm, and (E) 48 to 60 cm from corn (Zea mays L.) row during the period of corn plant height growth (HT) approximately from 50 to 250 cm when the leaf area index (LAI) increases from 0.4 to 4.0 in 2013 and 2014. Throughfall increased with total rainfall amount (RA) but decreased with LAI and HT values. The lowest TF values were recorded at the MLs of 0 to 12 cm and 48 to 60 cm near the corn row, and the highest TF values occurred at the ML of 24 to 36 cm at the center of between row areas. The cumulative TF at the ML of 24 to 36 cm exceeded that at the MLs of 0 to 12 cm and 48 to 60 cm by approximately 88 and 46% in 2013 and 2014, respectively. These results have potential values in irrigation scheduling and agrochemical application in the Corn Belt of Northeast China (CBNC).

English

Intercropping is a technique which consists of cultivating two or more species in the same area. In these systems, planning and management should be carried out in order to avoid interspecies competition for water, light, and nutrients. This paper aimed to evaluate macronutrient content and accumulations in corn (Zea mays L.) intercropped with dwarf pigeon pea (Cajanus cajan L.) in different plant arrangements. The experimental design adopted was one of randomized blocks, with six treatments and four repetitions. The treatments consisted of different arrangements of dwarf pigeon pea intercropped with corn: corn in monoculture, dwarf pigeon pea sown in the same rows as the corn, one row of dwarf pigeon pea sown between the rows of corn, dwarf pigeon pea sown in the same rows and in a row between the corn, and dwarf pigeon pea sown in the same rows and in two rows between the corn. The following variables were evaluated: dry matter (t ha-1), macronutrient content and accumulations (g kg-1), total chlorophyll in the corn leaves (FCI) and grain yield of corn, as well as dry matter production (t ha-1) and macronutrient content in the aerial part of the dwarf pigeon pea (g kg-1). The arrangement with dwarf pigeon pea sown in the same rows and in two rows between the corn increased N content in the corn plants, in relation to the other arrangements and the corn in monoculture. Ca content and accumulations were higher in corn in monoculture and in the arrangement with dwarf pigeon peas sown in the same rows as the corn. Key words: Zea mays L., Cajanus cajan, interspecies competition, plant nutrition.

Corn yield, forage production and quality affected by methods of intercropping corn and Panicum maximum

Abstract: The objective of this work was to evaluate methods of intercropping corn and Panicum spp. forages and their effects on corn yield and forage development. Two experiments with Panicum spp. were conducted, one with 'Tanzania' and other with 'Massai' in the municipality of Piracicaba, in the state of São Paulo, Brazil, in the 2012/2013 growing season. In both experiments, the treatments were: broadcast seeding of Panicum spp. at the same time of corn sowing; corn with Panicum spp. between rows; Panicum spp. sown with fertilizer; Panicum spp. sown between corn rows after corn establishment; broadcast seeding of Panicum spp. after corn establishment; and sole corn sowing. For corn, leaf nitrogen content, ear height, and grain yield were evaluated. For Panicum spp. cultivars, height, dry mass, tiller density, and leaf:stem ratio were evaluated. The intercropping establishment methods used do not affect corn growth, grain yield, and N leaf content. The seeding of both cultivars of Panicum spp. when corn plants had four expanded leaves reduces forage dry mass production and increases the leaf:stem ratio. The Panicum spp. broadcast method, performed after corn was established, does not allow appropriate establishment, with few plants in the area.

We Were Never Here

We Were Never Here Catherine Prescott (bio) A short tree with exalted branchesstretched its canopy in all directionslike an ambitious captain. Overripe melons hung like lanternsinches above a dust-whorled ground.We walked through a field with no moon— pitched as a shadow’s center savebillions of stars buttoning the night sky.We found rows of peppers and corn standing like sentinels among tentsof climbing peas, walls of cucumbersand lines of wild carrot tails. We found the angels rumored to lifteach plant a little further toward its end.As we crushed garnet melon flesh into sweet nectar, juice rivered from our lips.Under the light of an absent moon,we feasted until our tongues burned numb with sugar. Then the garden adoptedus, by which I mean the four cornersof our feet shot roots into the earth. Dear reader, there was nothing we could dobut grow as our arms vined forever north,our fingers vied for stars, and our earth-bound bodies burst into bloom. [End Page 144] Catherine Prescott Catherine Prescott is the author of the chapbook The Living Ruin (Finishing Line Press, 2012). Her work has appeared in Bellevue Literary Review, MiPOesias and Poetry East. Copyright © 2017 Pleiades and Pleiades Press

Atrazine Reduces the Critical Period of Weed Interference on Narrow Row Corn

ABSTRACT The objective was to determine whether a change occurs in the critical period of weed interference prevention in narrow row corn with the use of atrazine and whether there is influence of the herbicide on crop yield components. The treatments consisted of periods without or with an initial weed control (0, 21, 35, 49, 63, 77, and 91 days after emergence), with or without application of atrazine in spikely post-emergence. The experiment was carried out in a 2 x 7 randomized blocks design (with and without weed control and seven periods with three replications). The use or not of atrazine was arranged in a split plot design. The most important weed species were Senecio brasiliensis, Urochloa plantaginea, Conyza bonariensis, Sida rhombifolia, and Solanum spp. Corn yield reduced by 15% and 18% with and without application of atrazine, respectively. The number of grains per spike and corn yield were negatively influenced by coexistence with weeds, while the number of rows per spike, the diameter and length of spike were not affected. Corn yield components were not affected by the use of atrazine. The critical period of weed interference prevention was 35 days without atrazine and 23 days with application of atrazine. There is a reduction of the critical period of weed interference prevention on narrow row corn by using atrazine, with no influence of the herbicide on crop yield.

Corn Response to Row Spacing and Seeding Rate Varies by Hybrid and Environment in Kentucky

There has been recent interest in growing corn in narrow rows (<30 inches wide) and at dense plant populations to increase grain yields. The purpose of this study was to evaluate three corn hybrids adapted to the midsouthern United States at multiple row spacings and seeding rates. Studies were established at Lexington and Hodgenville, KY during the 2011 and 2012 growing season. The corn hybrids were planted in 15‐inch rows, twin 8‐inch rows on 30‐inch centers, and 30‐inch rows at seeding rates of 30,000; 35,000; 40,000; and 45,000 seeds/acre. Plant stands, stalk diameter, intercepted photosynthetically active radiation, and grain yield were evaluated for all hybrid × row spacing × seeding rate combinations. Stalk diameter decreased with increasing seeding rates, but no lodging was observed. At Hodgenville in 2011, corn planted in twin rows yielded 6.7% more than corn in 30‐inch rows, but row spacing did not affect yield in the other site‐years. Under favorable growing conditions at Lexington in 2011, grain yield increased by 1.5 bu/acre per 1000 seed increase in seeding rate; however, under hot and dry conditions in 2012, grain yield decreased 0.87 bu/acre for every 1000 seed increase in seeding rate. At Hodgenville in 2012, a hybrid × seeding rate interaction was observed in which one hybrid responded positively, one responded negatively, and one was unresponsive to seeding rate. Corn producers considering decreasing row widths or increasing plant population density should ensure that they choose hybrids appropriate for their management systems and environmental conditions.

CORN-TREE PROXIMITY EFFECTS IN AGROFORESTRY EXPERIMENTS

ABSTRACT In agroforestry systems, annual plants closest to trees may behave differently from plants in rows that are more distant. This study evaluated the proximity effects of Mimosa caesalpiniifolia (sabiá) and Gliricidia sepium (gliricidia) on corn yield under the taungya and alley cropping systems. The two species were evaluated, in randomised blocks with five replications, in 2010 and 2011, under taungya and alley cropping, respectively. Three rows of corn (left, middle, and right) were grown between two rows of trees. Sabiá trees grew higher than gliricidia trees. The difference in crown diameter between species depended on plant age. There was a linear relationship between plant age and plant height and between plant age and crown diameter for both sabiá and gliricidia trees. In the taungya system, left rows produced more green ears than middle and right rows, but grain yield was higher in middle rows. In the alley system, green ear yield was also higher in left rows than in middle and right rows, but grain yield was unaffected by row position. In both agroforestry systems, there were no differences in corn yield for corn grown between sabiá or gliricidia trees.

Weed Mortality Caused by Row-Crop Cultivation in Organic Corn–Soybean–Spelt Cropping Systems

To assess the effectiveness of interrow cultivation, counts were taken before and after cultivation of corn and soybean during the first two crop rotations in a corn–soybean–spelt organic grain cropping systems experiment. Overall control per cultivation event in soybean was 73%, about equal to the 67% of the interrow area actually covered by cultivator tools. Weed control per cultivation event in corn was higher, and exceeded 91% at later cultivations. The greater weed control in corn relative to soybean, particularly at later cultivations, was probably due to more soil being thrown into the corn row, burying a greater proportion of the weeds. Perennial weeds emerging from roots and rhizomes were less controlled by cultivation events than weeds emerging from seeds. Relatively poor control of perennials was due both to rapid resprouting during the few days between cultivation and assessment and to a lower probability of death in the zone indirectly disturbed by cultivator tools. Seedlings of perennial species suffered greater mortality from cultivation than annual weeds, probably because the low relative growth rate of perennials resulted in small seedlings that were susceptible to cultivation. Common ragweed was less controlled by cultivation than other annual weeds, probably because its heavier seeds produced larger seedlings at the time of cultivation. These larger seedlings were less likely to be buried during hilling-up operations at later cultivations. Counts of weeds before and after individual cultivation events provide insight into the processes affecting weed mortality during mechanical management.

A mowing strategy to convert red clover to annual crops in organic farming

AbstractOrganic producers are interested in no-till cropping systems. In this study, we found that perennial clover can be converted to corn without tillage. Conversion tactics involved fall mowing in the third year of red clover, followed by between-row mowing of weeds and volunteer red clover in corn grown during the fourth year. Corn yielded 85% of the weed-free control with mowing conversion. In contrast, weed interference in tillage-based conversion and between-row tillage reduced corn yield 53%. Weed emergence was sixfold greater in the tilled conversion. Weeds were present in the corn row with mowing, but recently developed implements could control these weeds and further support a no-till conversion method.

The long-term effects of tillage practice and phosphorus fertilization on the distribution and morphology of corn root

Relevant soil properties and nutrient distributions influencing crop root growth might be different under no-till (NT) and mouldboard plough (MP) management. The possible different root systems within different managements might have key impact on crop nutrient uptake and consequently crop production. Our objective was to assess the long-term combined effects of tillage and phosphorus (P) fertilization on corn (Zea mays L.) root distribution and morphology. Corn root and soil samples were collected during the silking stage at five depths (0–5, 5–10, 10–20, 20–30 and 30–40 cm) and three horizontal distances perpendicular to the corn row (5, 15 and 25 cm) under MP and NT with three P fertilizations (0, 17.5, and 35 kg P ha−1) for a long-term (22 years) experiment in eastern Canada. Root morphology and soil properties were determined. NT practice decreased corn root biomass by −26 % compared to MP, mainly by decreasing the primary and secondary roots. Additionally, corn roots in NT tend to be more expansive on the surface layer with higher root length and surface densities for the depth of 0–5 cm at two sampling distances of 15 and 25 cm. The 35 kg P ha−1 rate increased the root biomass by 26 and 41 % compared to the 0 and 17.5 kg P ha−1 rates. No-tillage practice and low rates of P fertilization reduce corn roots. This is probably caused by the weed competition in NT and the continued downward P status with low P rates over 22 years.

Sampling Position under No-Tillage System Affects the Results of Soil Physical Properties

Understanding the spatial behavior of soil physical properties under no-tillage system (NT) is required for the adoption and maintenance of a sustainable soil management system. The aims of this study were to quantify soil bulk density (BD), porosity in the soil macropore domain (PORp) and in the soil matrix domain (PORm), air capacity in the soil matrix (ACm), field capacity (FC), and soil water storage capacity (FC/TP) in the row (R), interrow (IR), and intermediate position between R and IR (designated IP) in the 0.0-0.10 and 0.10-0.20 m soil layers under NT; and to verify if these soil properties have systematic variation in sampling positions related to rows and interrows of corn. Soil sampling was carried out in transect perpendicular to the corn rows in which 40 sampling points were selected at each position (R, IR, IP) and in each soil layer, obtaining undisturbed samples to determine the aforementioned soil physical properties. The influence of sampling position on systematic variation of soil physical properties was evaluated by spectral analysis. In the 0.0-0.1 m layer, tilling the crop rows at the time of planting led to differences in BD, PORp, ACm, FC and FC/TP only in the R position. In the R position, the FC/TP ratio was considered close to ideal (0.66), indicating good water and air availability at this sampling position. The R position also showed BD values lower than the critical bulk density that restricts root growth, suggesting good soil physical conditions for seed germination and plant establishment. Spectral analysis indicated that there was systematic variation in soil physical properties evaluated in the 0.0-0.1 m layer, except for PORm. These results indicated that the soil physical properties evaluated in the 0.0-0.1 m layer were associated with soil position in the rows and interrows of corn. Thus, proper assessment of soil physical properties under NT must take into consideration the sampling positions and previous location of crop rows and interrows.

Inter-row Robot Navigation using 1D Ranging Sensors

Abstract: In this paper a fuzzy logic navigation controller for an inter-row agricultural robot is developed and evaluated in laboratory settings. The controller receives input from one-dimensional (1D) ranging sensors on the robotic platform, and operated on ten fuzzy rules for basic row-following behavior. The control system was implemented on basic hardware for proof of concept and operated on a commonly available microcontroller development platform and open source software libraries. The robot platform used for experimentation was a small tracked vehicle with differential steering control. Fuzzy inferencing and defuzzification, step response and cross track error were obtained from the test conducted to characterize the transient and steady state response of the controller. Controller settling times were within 4 seconds. Steady state centering errors for smooth barrier navigation were found to be within 3.5% of center for 61 cm wide solid barrier tests, and within 38% for simulated 61 cm corn row tests.

Control of Two Spotted Spider Mite, Sweetpotato Whitefly, and Melon Thrips with Predatory Mites, Metharhizium, and Insecticides on Eggplant, 2014

Spider mites are important and consistent pests of eggplant in south Florida where feeding damage often causes decline in the overall health of the plant, leading to lower yields. Sweetpotato whitefly can often build up extremely dense populations in eggplant, leading to plant decline and problems for other crops in the area. Melon thrips feeding can cause fruit scarring and flecking, leading to a reduction in fruit quality. For this trial, two single rows separated with a row of corn were prepared at the Southwest Florida Research and Education Center in Immokalee, FL, on raised beds. Granular fertilizer (10-2-10 N-P-K) was incorporated, and two drip tapes with emitters spaced at 8 inches and a flow rate of 0.67 gpm/100 ft were laid before covering with black polyethylene film mulch and fumigating through the drip with 300 lb/acre PicClor 60 EC. Greenhouse-raised plants were transplanted on 6 Mar at 24-inch spacing, and the remaining 50% required nutrients were delivered by drip irrigation as liquid 7-2-7. Plots contained …

Grain yield of corn at different population densities and intercropped with forages

ABSTRACT The no-tillage system optimizes agricultural areas, maintaining the supply of straw and promoting crop rotation and soil conservation. The aim of the present study was to evaluate sowing quality and grain yield of corn intercropped with three forage species of the Urochloa genus associated with two corn population densities. The experiment was conducted at the São Paulo State University (UNESP), in Jaboticabal-SP, Brazil. The experimental design was randomized blocks in a 2 x 3 factorial scheme with four replicates. The treatments consisted of two corn densities (55,000 and 75,000 plants ha-1) intercropped with three forages (Urochloa brizantha, Urochloa decumbens and Urochloa ruziziensis) sown between rows of corn in the V4 stage. The following corn variables were analysed: mean number of days for emergence, longitudinal distribution, grain yield, initial population and final population. There were differences between corn populations (p < 0.1) and the intercropping of corn with the species U. brizantha and U. ruziziensis promoted the best results, which permitted concluding that the cultivation of corn at the population density of 75,000 plants ha-1 intercropped U. brizantha and U. ruziziensis promoted better sowing quality and, consequently, higher grain yields.