Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: Steve Smith x
Clear All Modify Search

Abstract

A range of techniques are used to preserve postharvest quality of fruit, vegetables, and other perishable produce. Refrigeration is the principal technique used but, in some instances, low temperature alone may be insufficient to retard ripening of fruit and prevent detrimental quality changes. Moreover, low temperatures for prolonged periods may lead to physiological damage, e.g., low temperature breakdown in apples (14). Pioneering work of Kidd and West (23) led to the development of controlled atmosphere (CA) storage, a sophisticated technique that extends the life of some produce more than refrigeration alone. CA storage is used mainly for apples (40), although recommendations for other fruits (15) and vegetables (16) can be found. Where CA techniques are applied, the concentrations of CO2 and O2 are controlled at optima specific for each cultivar, facilitated by the recent development of automatic control systems (22). However, both refrigeration and application of CA techniques are expensive, requiring large capital outlay for installation and maintenance and high energy inputs, especially for cooling. Moreover, it is not practical to provide equipment for CA control or refrigeration for small quantities of produce or individual fruit. Thus, once produce is harvested or removed from storage, it is subject to ambient conditions during marketing, which often lead to rapid quality deterioration.

Open Access

Growers in the Salinas Valley are not able to rotate away from lettuce to other crops such as broccoli, as often as would be desirable due to economic pressures such as high land rents and lower economic returns for rotational crops. This aggravates problems with key soilborne diseases such as Sclerotinia minor, Lettuce Drop. Mustard cover crops (Brassica juncea and Sinapis alba) are short-season alternative rotational crops that are being examined in the Salinas Valley for the potential that they have to reduce soilborne disease and weeds. Mustard cover crops have been have been shown to suppress various soilborne diseases and there are also indications that they can provide limited control of some weed species. However, no studies have shown the impact of mustard cover crops under field conditions on S. minor. In 2003 we conducted preliminary studies on the incidence of S. minor and weeds following mustard cover crops in comparison with a bare control or an area cover cropped to Merced Rye (Secale cereale). There was a slight, but significant reduction of S. minor infection in one of three trials following mustard cover crops. Mustard cover crops also reduced emergence of Shepherd's Purse (Capsella bursa-pastoris) and Common Purslane (Portulaca oleracea) these studies. Mustard cover crops have distinct nitrogen cycling characteristics. They were shown to reach a peak of release of nitrogen in 30 to 50 days following incorporation into the soil. The levels of nitrogen that are released by mustard cover crops were substantial and could be useful in nitrogen fertilizer programs for subsequent vegetable crops.

Free access

This article summarizes the current status of organic vegetable production practices in California. The production of vegetables organically is growing rapidly in California, led in large part by growth in the market demand for organically grown produce. Key aspects of organic vegetable production operations such as certification and farm production planning, soil management, weed management, insect management, and plant disease management involve special practices. Many practices have not been thoroughly researched and the scientific base for some practices is still being developed.

Full access

Watermelon growers are advised to grow melons in a given field no more than 1 year out of 4. Bermudagrass pastures are abundant in the southern U.S., but ranchers are reluctant to destroy a pasture for 1 year and plant it with melons if they must then re-establish a sod. A project was designed to develop a system for growing watermelon in a permanent pasture with only a minimal amount of tillage, and without destroying the established forages in the pasture. The approach is to compare and evaluate several techniques for growing watermelons in strip-tilled areas within a permanent pasture. These techniques include cultivation, plastic mulches, and herbicides applied to 2-m strips separated by untilled bermudagrass. Research was done in 1996 at two university research centers in Oklahoma and Texas. The treatments with greatest watermelon yields, in decreasing order, were black polyethylene mulch, hand-weeded control, photodegradable mulch, biodegradable mulch, cultivation plus sethoxydim, sethoxydim alone, cultivation alone, and the weedy check. At harvest, 63% of the area in the cultivation alone treatment, 40% of the area in the plastic mulch treatment, and 1% of the area in the sethoxydim treatment were covered with a regrowth of bermudagrass. Forage was also collected from row areas of plots. Forage amounts, in decreasing order, were from cultivation alone, weedy check, sethoxydim alone, photodegradable mulch, polyethylene mulch, biodegradable mulch, cultivation plus sethoxydim, and the clean control.

Free access