No-Till Production of Irish Potato on Raised Beds

INTRODUCTION In an extensive review of organic mulches applied on conventionally tilled (plow-disk) fields, Dutton (1957) concluded: 1) that organic mulches such ashay and straw often increasedboth yield and quality of Irish potato (Solanum tuberosum L.) and 2 ) that improved soil physical properties under the mulch, particularly lower soil temperatures and conservation of soil moisture, were responsible for the yield and quality enhancement. In these mulching studies, highest yield increases generally occurred in hot climates where temperatures were above optimum during tuber development and where soil moisture deficits are prevalent. Thus, applying organic mulches in hot, dry climates normally results in increased potato yield (Dutton, 1957). Although mulchinggenerallyretards growth and reduces tuber yield in cool, wet climates, yield of potato often increases in hot, humid regions, if provisions are made to assure adequate soil drainage. Under conditions of adequate soil moisture in hot climates, reduced soil temperatures under organic mulches can increase tuber yield and quality. However, many potato mulch experiments (Dutton, 1957) have clearly shown that, when heavy (thick) mulches are prematurely applied (at or soon after planting), slow emergence, poor stands, and stunted early growth often result. Because applying thick layers of organic mulches is economically prohbitive on large-scale commercial farms, researchers have assessed the potential of reducedtillage systems for production of Irish potato (Midmore, 1991;Lanfranconi et al., 1993; Hoyt and Monks, 1996). Although the results of reduced tillage systems have been encouraging, in most cases potato planted in flat, untilled, or strip-tilled soils have required conventional hilling practices to achieve yields equal to that of conventional tillage systems (Lanfranconi et al., 1993; Hoyt and Monks, 1996). In such cases, organic residues were either incorporated or buried, leaving bare soil which minimizes or even negates potential soil-cooling and moisture-conserving effects during tuber bulking.