The practice of composting mixed green wastes from community collection programs has been on the increase as a means to reduce organic debris to landfills. Recent reports of plant injury have appeared and were attributed to residues of the herbicide clopyralid in compost. Phytotoxicity issues with compost have been reported previously to result from other factors, including heavy metal content, soluble salts, organic acids and oxygen deprivation related to incomplete decomposition. The recent reports of plant injury due to clopyralid-contaminated compost were also associated with very heavy applications of compost, yet few of these reports included observations of herbicide symptomology. Since immature compost may contain sufficient degradation intermediates, soluble salts and other contaminants to cause phytotoxicity, particularly when applied at heavy rates, an effort must be made to distinguish confounding factors. Complete composting normally allows for the degradation of phytotoxic intermediates and synthetic compounds, such as herbicides, as well as allowing for leaching of salts. Absence of compost completeness standards within the compost industry leaves such factors to the guesswork of the end-user. Recommended compost use rates have established a relationship between compost maturity, application rate and use pattern, based on compost quality metrics. Greater attention to the use of high-quality compost, properly designated as to completeness of composting and applied at appropriate use rates, would minimize the potential for phytotoxic effects, irrespective of the contributing source.

In Ghana, studies on the use of organic materials to increase soil productivity have focused on crop-residue management, use of green and animal manures, and legume cover cropping. Few studies have assessed the use of human waste for agriculture, even though this is widely practiced by farmers in the northern part of the country. This study was carried out to investigate the stakeholders in the use of faecal sludge (FS) for crop production in Tamale and Bolgatanga municipalities in the guinea savanna agroecological zone of Ghana. The aim was to determine the driving factors, constraints and potentials for this practice. Field survey and focus group discussions were carried out among 90 farmers who use FS, and officials of the Municipal Sanitation Unit were interviewed. Sixty-four percent of farmers interviewed used FS as a cost-effective way to improve soil fertility and increase yields of maize and sorghum. Sludge is discharged by spreading it on the soil surface, or it is stored and dried in pits during the dry season and incorporated into the soil at the onset of the rainy season. The high temperatures of the savanna climate and this long period of drying allow sludge to be handled easily. Although this treatment is perceived to reduce the number of pathogens in dried sludge, 22% of farmers complained of itching feet and foot rot after working with FS, which is done without wearing protective foot covering. This constraint is coupled with the foul smell, transport problem and public mockery associated with the use of human waste for agriculture. In spite of these problems, there is competition for FS among farmers, due to benefits derived from its use. Further investigation is required to ascertain the causes of itching feet and foot rot, and there is a need for education on proper handling and appropriate hygiene practices when working with FS. Information regarding optimal FS application rates is also required.

We compared soil characteristics, runoff water quantity and nutrient fluxes, energy use and productivity of three farm types in an unusually dry farming season: conventional (continuous corn and deep tillage), rotation (5-year corn–soybean–oats/alfalfa–alfalfa–alfalfa rotation with tillage 2/5 years) and no-till (corn–soybean with no cultivation). Soil organic matter content was highest on the rotation farm, followed by the no-till farm, and lowest on the conventional farm. Nitrate content of the soil did not differ significantly among the three farms, although the conventional farm had a much higher input of fertilizer nitrogen. Soil penetrometer resistance was lower and percent soil moisture was higher in the no-till and rotation systems compared to the conventional farm. Soil macroinvertebrate abundance and diversity were highest on the no-till farm, followed by the rotation farm. No invertebrates were found in the soil of the conventional farm. The conventional farm had the highest runoff volume per cm rain and higher nitrogen (N) loss in runoff when compared to the rotation and no-till farms, as well as a higher phosphorus (P) flux in comparison to the no-till farm. These results indicate that perennial close-seeded crops (such as alfalfa) used in crop rotations, as well as plant residue left on the surface of no-till fields, can enhance soil organic content and decrease runoff. The lower soil penetrometer resistance and higher soil moisture on the rotation and no-till farms show that conservation tillage can increase soil aggregation and water infiltration, both of which prevent erosion. Furthermore, crop rotation, and particularly no-till, promote diverse invertebrate populations, which play an important role in maintaining nutrient cycling and soil structure. Crop rotation and no-till agriculture are less fossil-fuel intensive than conventional agriculture, due to decreased use of fertilizers, pesticides and fuel. In this unusually dry year they provided superior corn and soybean yields, most likely due to higher soil moisture as a result of greater water infiltration and retention associated with cover crops (rotation farm) and crop residue (no-till farm).

Pesticide Free Production (PFP) is a pesticide reduction system that removes in-crop pesticide use on a yearly basis. A long-term study was established in 2000 to investigate the effect of crop rotation and frequency of inclusion on the success of PFP, as well as the effect of PFP on subsequent crops in the rotation. The crop rotations being compared were linola–oat–canola–wheat and linola–oat–alfalfa–alfalfa. PFP occurred either once in the rotation (oat) or twice (linola–oat). Weed density and yield were measured in the crops that followed PFP. Oat was a more successful PFP crop than linola because it was better able to compete with weeds. Furthermore, PFP oat had a higher weed density when it followed PFP linola, but this did not influence PFP oat yield. Under the conditions of this study, PFP linola was more successful in the annual crop rotation. Inclusion of alfalfa hay crops in the crop rotation was not effective in lowering weed pressure and, in fact, may have contributed to an increase in weed density. It is concluded that weed species present influenced the effectiveness of alfalfa in facilitating PFP, because major weeds in the study are not effectively controlled by alfalfa. PFP did not have a negative effect on following crops in the rotation (i.e. canola–wheat or alfalfa), regardless of whether one or two consecutive years of PFP occurred in the rotation. No additional herbicide was necessary for weed control in the crops that followed PFP; however, alfalfa hay was weedier for the first year following PFP. This study indicates that PFP is a viable way to reduce herbicide use in a cropping system and that attention needs to be paid to PFP crop selection and crop rotation, particularly when the PFP crop is less competitive with weeds.

Production of some organic commodities, such as apples, is heavily concentrated in the United States (US), with Washington State being the leading US producer of organic apples. In 2003, there were 4047 ha of certified organic apple orchards in Washington State, an all-time high and a more than tenfold increase since 1989. But this growth has not occurred without difficulties. Washington State's organic apple growers have encountered international supply and demand pressures forcing them to seek new markets, such as the European Union (EU). In this paper, we explore the complexities of the international marketing of organic fruit, using organic apple production in Washington State and market opportunities for this organic fruit in the EU, as a case study. We find that as a result of the expansion of organic apple plantings in Washington State, there has been a decrease in the price premiums, which traditionally offset the greater costs of organic production and which originally motivated many Washington growers to certify their apple orchards. We also find that increased demand for organic fruits in the EU has been outpacing supply, making EU member states the most important export market for Washington's organic apples. However, despite the unification of US standards by the US Department of Agriculture (USDA) and an overriding EU standard, an entanglement of regulatory bodies from around the world is involved in the certification of organic products. For example, growers and marketers may have to interact with as many as six different regulatory bodies in order to export organic produce from the US to the EU. This study shows that while the EU market remains a promising destination for US organic apples, organic growers and marketers must plan ahead and thoroughly understand the multitude of regulations involved in the international trade of organic fruits.

In anticipation of the Philippines being a major producer of organic bananas, this study was conducted to provide a quantitative basis for certain practices in organic farming. The nutrient supplying capacity of banana residues in combination with leguminous materials and chicken manure was investigated in composting studies. Changes in the chemical composition of ten formulations of banana residue-based compost involving leguminous plants (Sesbania rostrata, Flemingia macrophylla, Arachis hypogea) and chicken manure were analyzed periodically during a composting period of 16 weeks. Results showed that combinations of banana residues (BnR) and chicken manure or leguminous plants were highly decomposed compared to untreated BnR. The use of leguminous plants and/or chicken manure enhanced the composting process significantly compared to the effect of Bioquick. The compost piles were characterized by increases in pH, total N and total P, and decreases in total K, total carbon and C/N ratio with time. Notably, BnR+chicken manure attained a C/N ratio of 15 at 4 weeks, while the BnR+leguminous materials reached such a low C/N ratio at 8–16 weeks. An incubation study was conducted under greenhouse conditions for 24 weeks. It was designed to follow the dynamics of nitrogen (N), phosphorus (P) and potassium (K) availability in two clay soils (Antipolo and Lipa) amended with five compost formulations (BnR alone, BnR+Sesbania prunings, BnR+Flemingia prunings, BnR+peanut stover and BnR+chicken manure) and with uncomposted banana residue at an application rate of 20 Mg ha−1. Results showed that net N mineralization occurred in soils amended with BnR+chicken manure and BnR+leguminous materials, which had C/N ratios ranging from 12 to 16. Net N immobilization during the earlier period of incubation was observed in uncomposted and composted banana residues with a C/N ratio of 68 and 24, respectively. Significantly higher net P mineralization was obtained only in soils amended with BnR+chicken manure. An abrupt increase in exchangeable K was observed in all treatments 2 weeks after the incorporation of organic residues. Higher available K in pure BnR treatments (uncomposted or composted) exhibits the inherently high K content of banana residues.