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Abstract
Peach trees [Prunus persica (L.) Batsch cvs. Loring/Halford] were grown in boxes 100 × 60 × 36 cm (length × width × depth) to evaluate the effect of K-31 tall fescue sod (Festuca arundinacea Schreb.) on peach root growth and development. The entire soil surface was kept bare in one treatment, while a fescue sod was established in one-third of the box for the second treatment. Trees were planted 17 cm from one edge of the box in bare soil in both treatments. Sod reduced tree growth. The length of roots ≥1 mm in diameter was unaffected by the sod at any position in the box. The length of roots <1 mm in diameter was reduced beneath the sod and in the area between the sod and tree compared to the bare soil treatment. The plant resistance to water flow/cm root (Rp) was unaffected by the presence of grass under both stressed and nonstressed conditions. Rp was relatively constant (9.4 × 109 s cm-1) over a range of transpiration flux levels until the flux dropped below 0.3 cm3 s-1. Below 0.3 cm3 s-1 Rp increased due to soil resistance to water flow.
Abstract
Peach [Prunus persica (L.) Batsch] trees were planted in four soil management systems (cultivated, herbicide, mowed sod, and killed sod) in 1982 and grown through 1984. A companion study was established in 1984 with three systems (cultivated, herbicide, and killed sod). Tree growth and fruit yield were greatest when trees were planted and managed in a killed sod system. Establishing a living sod before planting the trees, and then killing the sod with herbicides, prevented the depletion of soil organic matter and increased water infiltration rates, aggregate stability, macroporosity, and microbial respiration rates compared to conventional systems. The changes in soil structure persisted for 2 to 3 years.
Abstract
The purpose of this study was to assess the effect of four soil management systems: herbicide strip (H), cultivated strip (C), mowed sod (MS), and killed sod strip (KS) on rainfall infiltration in two young peach [Prunus persica (L.) Batsch] orchards. Soil water content (0- to 0.90-m depth) was measured immediately before a rainfall event and then as soon as possible after the rain. During the first growing season, MS captured more rainfall than KS, H, or C in the spring and summer months. In the fall, when soil water levels were reduced, all of the soil management systems were equally effective in reducing rainfall runoff. During the second and third growing seasons, the KS system often captured as much rainfall as MS and more than H and C, when killed sod residue covered 50% or more of the surface. When < 10% soil cover remained in the KS treatment, it was no more effective in reducing runoff than the H or C treatments. Growth and yield parameters were lowest in the MS due to sod interference. KS generally provided greater growth and yield than the C and H.
Several orchard floor management strategies were evaluated beginning in Fall 1993 in a `Limoneira 8A Lisbon' lemon (Citrus limon) grove on the Yuma Mesa in Yuma, Ariz. and in a `Valencia' orange (Citrus sinensis) grove at the University of Arizona Citrus Agricultural Center, Waddell, Ariz. At Yuma, disking provided acceptable weed control except underneath the tree canopies where bermudagrass (Cynodon dactylon), purple nutsedge (Cyperus rotundus), and other weed species survived. Mowing the orchard floor suppressed broadleaf weed species allowing the spread of grasses, primarily bermudagrass. Preemergence (norflurazon and oryzalin) and postemergence (glyphosate and sethoxydim) herbicides were used to control weeds in the clean culture treatment in Yuma. After three harvest seasons (1994-95 through 1996-97), the cumulative yield of the clean culture treatment was 385 kg (848.8 lb) per tree, which was significantly greater than the 332 kg (731.9 lb) and 320 kg (705.5 lb) per tree harvested in the disking and mowing treatments, respectively. In addition, the clean culture treatment had a significantly greater percentage of fruit in the 115 and larger size category at the first harvest of the 1995-96 season than either the disk or mow treatments. At Waddell, the management strategies compared were clean culture (at this location only postemergence herbicides were used), mowing of resident weeds with a vegetation-free strip in the tree row, and a `Salina' strawberry clover (Trifolium fragiferum) cover crop with a vegetation-free strip. The cumulative 3-year yield (1994-95 through 1996-97) of the clean culture treatment was 131 kg (288.8 lb) per tree, which was significantly greater then the 110 kg (242.5 lb) per tree yield of the mowed resident weed treatment. The yield of the strawberry clover treatment, 115 kg (253.5 lb) of oranges per tree, was not significantly different from the other two treatments. The presence of cover crops or weeds on the orchard floor was found to have beneficial effects on soil nitrogen and soil organic matter content, but no effect on orange leaf nutrient content. The decrease in yield in the disked or mowed resident weed treatments compared to the clean culture treatment in both locations was attributed to competition for water.
In several regions of the United States, waste and “tag” wool are readily available, inexpensive, and considered low-quality because of weed seed contamination and stains from defecation. Because of an overabundance of waste and tag wool, some are landfilled. Previous research has indicated that wool or hair incorporated in potted plants can improve the water-holding capacity of the soil and act as a slow-release fertilizer. Furthermore, compost trials have demonstrated that wool produces a high-quality compost product. This study aimed to evaluate the market potential of wool-based compost to determine its commercial viability. To address this, we conducted in-depth interviews with lead user gardeners (n = 10) who used 1 yard of wool-based compost in their gardens over the course of 10 weeks and distributed a quantitative survey instrument to both lead users and general gardeners recruited from garden centers, nurseries, and horticulture classes (n = 256). Lead users responded positively to the wool-based compost and reported they would be willing to pay $6 to $7 per ft3. General gardeners who were less familiar with the product reported they were willing to pay at least a similar amount as that for typical market composts, but they suggested that they would pay more if characteristics such as “increases drought tolerance” were used in advertising. Our analysis indicated that the target audience for the wool-based compost is male gardeners older than 25 years who are concerned about the environment.
Two unpruned willow leaf and two unpruned standard leaf peach [Prunuspersica(L.) Batsch.] selections were evaluated for physiological components related to water use efficiency (WUE). The purpose of the study was to assess the value of willow leaf phenotypes to improve water use efficiency in peach and separate the environmental from the genetic components. The willow leaf characteristic itself did not confer improved water use efficiency. Light interception was a key determinant of WUE in these genotypes and the relationship of WUE with intercepted photosynthetically active radiation (PAR) by the entire canopy indicated a significant negative correlation. Internal shading of the tree by excessive leaf area reduced WUE and canopies that intercept more than 60% of the PAR have reduced WUE. While WUE is improved by reducing the amount of PAR interception of the canopy, productivity is reduced. Neither of the willow leaf genotypes had a significant correlation of WUE with yield (leaf and fruit weight); however, the standard leaf type cultivars, `Bounty' and `Redhaven', had significantly different regressions that indicate greater productivity in `Bounty' for a given level of WUE. `Redhaven' was the least productive cultivar; `Bounty' was the most productive, and the two willow leaf genotypes were intermediate in the relationship of intercepted PAR with yield. Therefore, genetic differences in peach growth types can be selected for both increased WUE as well as increased productivity. Future work in peach breeding to improve WUE and productivity must take into consideration light interception, productivity, and WUE in an integrated manner to make progress in the efficient use of water and light.
A management expert system that enables producers to fully assess the integrated resource requirements, management risks, and profit potential for growing muskmelon was developed. The expert system environment Guru was used as the development software.