4 pp. / Wheat Production on Lettuce Beds / In 2009, over 56,000 acres were planted to wheat in Arizona, all of which following either a lettuce or cotton crop. For wheat grown in the region, the conventional tillage sequence prior to planting can be tied to as many as seven field operations that consume valuable time, labor, and resources. In this study, our aim was to determine the effectiveness of reducing the number tillage (minimum till) operations in fields immediately following lettuce harvest. And demonstrate to Southwest wheat producers a means for conserving time, fuel, and resources. Growing wheat on lettuce beds immediately following lettuce harvest did not significantly reduce grain yield or quality. Although the regrowth of the previous crop can have significant implications for Durum grown with minimum tillage if not managed effectively, lodging was not a significant factor in this study as the degree of lodging was similar in both growing systems. The significant savings in fuel, labor and time, with no apparent reduction in Durum yield or quality, may be a significant benefit to wheat producers who incorporate minimum tillage practices following a lettuce crop.

No description available.

Exposure of bare soil for long periods and onsite compaction create soil and water problems in asparagus production. This project aims to develop a cost effective and practical runoff and soil erosion management system. Two field trials (Phase 1 running from April - July 2012 and Phase 2 running from May - November 2013) tested different combinations of shallow soil disturbance (SSD) and mulch (straw and compost) application for soil erosion control. Cranfield University’s soil bin was used to test the effect of different tine configurations on soil disturbance. The results of this research corroborated observations that asparagus production can result in levels of unsustainable soil loss that will contribute to the degradation of the existing soil resource. The field trials demonstrated that a straw mulch applied at 6 t ha- 1 significantly improved key performance indicators (KPIs, i.e. runoff initiation, volume and rate; total soil loss; sediment concentration; total oxides of nitrogen; orthophosphate-P; and sediment-bound P) as compared with the Non-SSD Control. In general, SSD (irrespective of tine configuration) was ineffective at improving key performance indicators as compared with the Non-SSD Control. In the soil bin work, different tine configurations generated varying degrees and extent of SSD, with the modified para-plough giving the greatest soil disturbance for the least draught force. However, the differences in SSD observed in the soil bin had no effect on the KPI’s tested in the Phase 2 field trial. The effective treatments observed in the field trials only yielded cost savings to the farmer/grower when a high level of soil loss occurred. This research highlights the need to develop erosion control measures in asparagus fields, with wider implications to other row crops. However caution is needed, given the observed variation in effectiveness and reliability of in-field mitigation measures, especially during ‘extreme’ rainfall events.

Doctor of Philosophy / Department of Agronomy / Dorivar Ruiz Diaz / The appropriate management for phosphorus (P) fertilizer can have significant agronomic, economic, as well as environmental impact. Studies in Kansas have evaluated different management systems to determine best management practices (BMP). The first component of this dissertation is a comprehensive review of tillage system and P fertilizer placement interaction. This review included studies completed in the U.S. Midwest. Results of this review showed greater corn yields with conventional tillage and broadcast applications when soil test P levels (STP) were below 20 mg P kg⁻¹. However, soybean yield was highest in no-till systems with broadcast P fertilizer applications. The second component if this dissertation was a long-term study conducted in Kansas to evaluate the effect of P fertilizer placement on corn and soybean production. Results showed that under strip-tillage, P fertilizer placement significantly affected corn growth, but, seldom resulted in yield response difference among placement methods. Phosphorus application as starter fertilizer at planting showed the most consistent yield response. In addition to the agronomic aspect of this study, the third component of this dissertation consisted of an economic analysis using partial budgets calculated using both fixed and varying prices and costs to compare management practices. With decreased application costs associated with deep banding in strip-tillage system, net returns are greater than broadcast applications. The highest net responses were observed with starter P fertilizer applications. The fourth component of this dissertation included a study evaluating the effects of chelated fertilizer on nutrients, such as P, Fe, Mn, and Zn in soybean. Results from our study showed that both ethylenediamine tetraacetic acid (EDTA)+P and hydroxyethyl ethylenediamine tetraacetic acid (HEDTA)+P resulted in greater concentrations and uptake of Fe and lower Mn uptake in soybean. However, the application of glucoheptonate (GCH)+P had no negative effect on Mn uptake compared to EDTA+P and HEDTA+P. Across locations, EDTA+P and HEDTA+P showed higher yield than GCH+P. The use of long-term studies and comprehensive reviews can provide a unique perspective and better understanding of the most appropriate BMPs for P fertilizer management. Many agronomic and environmental implications of P fertilizer management and the interactions with tillage systems and soils may only become noticeable after multiple years or in a variety of conditions.

Master of Science / Agronomy / Dorivar A. Ruiz Diaz Suarez / The effect of tillage on crop yield, early growth, and soil nutrient stratification can be influenced by fertilizer placement. In addition, deeper root systems can enhance the crop ability to uptake water and nutrients. A thorough understanding of how these factors interact can result in increased grain yields and profitability for the producer. Three studies were completed to describe and evaluate different aspects of crop root system and response to fertilizer placement and tillage. The objective of the first study was to characterize the root system of two genotypes of corn (Zea mays) and soybean (Glycine max (L.) Merr.) using image analysis in the greenhouse and in the field, as well as evaluate dry weight accumulation and nutrient uptake patterns by shoot and root plant parts for both crops. Two different genotypes of each crop were sampled during the growing season to access root characteristics such as biomass, length, surface area, average diameter and volume. Significant differences were found in corn where the P1151 AM hybrid had greater root length, surface area and volume than the P1105 AM hybrid. In soybean, the differences were found in nutrient uptake with overall greater nutrient uptake values for the poor drainage variety (PD) compared to the good drainage variety (GD). The objective of the second study was to evaluate the effect of fertilizer placement and tillage system on corn with different genotypes. Three fertilizer treatments were combined with two different corn genotypes selected based on contrasting root systems and two different tillage systems. The three fertilizer placements were sub-surface band, broadcast, and control. The two hybrids of corn used were a P1151 AM hybrid and P1105 AM hybrid. The two tillage systems were no-till (NT) and strip-till (ST). Corn hybrids showed different response in root biomass but did not show a consistent response in other characteristics evaluated. Broadcast and sub-surface band increased nutrient uptake and grain yields over the control but were not significantly different from each other. Tillage showed no difference in corn response. The objective of the third study was to evaluate the effect of fertilizer placement and tillage system on contrasting soybean genotypes. Three fertilizer treatments were combined with two different genotypes selected based on contrasting root systems and two different tillage operations. The three fertilizer placements were sub-surface band, broadcast, and control. The two varieties of soybean used were one recommended for poor drainage (PD) and one recommended for good drainage (GD). The two tillage operations were NT and ST. Soybean root biomass differences were observed by varieties. Sub-surface band treatment favored early soybean growth, biomass and P uptake at the V3 growth stage, but it did not turn into yield increase. Soybean grain yields did not respond to fertilization in this study. Yield was affected significantly by variety selection and response varies by site-year.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Typescript, etc. / Digitized by Kansas Correctional Industries

While many spring and winter wheat (Triticum aestivum) varieties have been evaluated for yield characteristics under Utah's conventional dryland cropping systems, little is known about these same varieties under new conservation tillage farming management techniques. Farmers are rapidly adopting various reduced tillage systems and need information regarding proper varieties, fertility practices, weed control , etc. A two year field study, in Box Elder County, Utah on a DeJarnet Gravelly silt loam (Loamy-skeletal, mixed, mesic, Calcic Pachic Haploxeroll) and on a Mendon silt loam (fine-silty, mixed, mesic, Calcic Pachic Argixeroll) examined total dry matter, grain yield, percent protein, kernel weight, kernel volume, and average bushel weight responses to four fertility treatments superimposed upon five spring wheat and four winter wheat varieties. Also compared were one spring wheat variety "Komar" and one winter wheat variety "Weston" in a conventional verses conservation tillage dryl and c ropping system. Soi 1 moisture and soi 1 temperature (20 em and 10 em, respectively bel ow the soi 1 surface) readings were compared between the conventional and conservation tillage planting systems. The conservation tillage plantings were done with an air-seeding tillage planter and the conventional plantings were done with standard deep-furrow drills. Dry granular fertilizer (27 -12-0-4 sulfur) was applied to both deepfurrow and conservation tillage plots with the air-seeder. Rates were 0, 168, 224, 280 kg/ha fertilizer material applied. Significant differences were obtained for all spring wheat varieties. Conservation-tilled "Komar" yielded significant yield increases ove r conventio na l- tilled "Komar". The opposite held true for "Weston" , with the conventional-tilled plots yielding a slightly significant increase in grain over conservation-tillage "Weston". No relative difference in soil water or soil temperature were observed in either variety through time. However, at certain growth stages the differences were clearly discernable. Very littl e significant differences were established amoung the winter wheat varieties. Because of heavy infestations of snowmold (Calonectria graminicola) on all winter wheat plots, the true potential yield characteristics of conservation verses conventional tillage remain unproven on these winter wheat varieties.

Includes bibliographical references (leaves 11-1-11-26). / xv, 222 leaves : ill. (some col.) : 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Adelaide University, Dept. of Agronomy and Farming Systems, 2001