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High rates of N fertilizers and limited crop uptake of N during the growing season can result in excessive accumulation of soil nitrate (NO−3). Soil NO−3 can be decreased with efficient cropping systems. Experiments were conducted in Connecticut from 1987 through 1990 on a Paxton fine sandy loam soil (coarse‐loamy, mixed, mesic Typic Dystrochrept) to determine the effects of N rate and cropping system on soil NO−3. Orchardgrass (Dactylis glomerata L.), red clover (Trifolium pratense L.), a double‐crop system of oat (Avena sativa L.) followed by tyfon [Brassica rapa L. × B. pekinensis (Lour.) Rupr.], maize (Zea mays L.) followed by a cover crop of winter rye (Secale cereale L.), and a fallow system received preplant N at 0, 112, 224, 336, and 448 kg ha−1. Each system was evaluated for two consecutive growing seasons and repeated three times. Nitrogen was applied only in the first growing season. Soil NO−3 at the first autumn sampling generally increased for all systems as N rate increased. Mean spring soil NO−3 levels were only 23% of previous autumn NO−3 levels. By the second autumn sampling, soil NO−3 values were near background levels except in the fertilized fallow system. At the two highest N rates, oat‐tyfon produced the smallest overwinter change in soil NO−3 storage. An oat‐tyfon double crop, orchardgrass, or red clover system should decrease soil NO−3 more effectively than maize or a noncropped fallow when soil NO−3 accumulations are greater than those produced from N inputs equivalent to 224 kg ha−1.

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Excessive application of N‐containing fertilizers may result in high concentrations of soil nitrate. Soil nitrate levels can be reduced with cropping systems that best utilize N. Split‐plot design experiments were conducted in Connecticut from 1987 through 1990 on a Paxton fine sandy loam soil (coarse‐loamy, mixed, mesic Typic Dystrochrept) to determine the effectiveness of various cropping systems in utilizing N. Orchardgrass (Dactylis glomerata L.), red clover (Trifolium pratense L.), a doublecrop system of oat (Avena sativa L.) followed by the forage brassica tyfon [Brassica rapa L. × B. pekinensis (Lour.) Rupr.], and maize (Zea mays L.) followed by a cover crop of winter rye (Secale cereale L.) received preplant N at 0, 112, 224, 336, and 448 kg ha−1. Cropping systems were tested three times for two consecutive growing seasons, with N applied only in the first season. Dry matter yield (DMY), N uptake (NUP), apparent N recovery (NREC), and N use efficiency (NUE) were determined. Maize‐rye produced the greatest DMY (18.3 to 22.8 Mg ha−1), followed by oat‐tyfon (9.8 to 16.5 Mg ha−1). Highest NUP (121 to 329 kg N ha−1) and NREC (46.5 to 81.7%) were obtained by oat‐tyfon. The greatest NUE was produced by maize‐rye and oat‐tyfon at 112 kg N ha−1. The oat‐tyfon double crop provides the most effective means for preventing N loss among the systems evaluated for N rates > 112 kg ha−1.

Kura or Caucasian clover (Trifolium ambiguum Bieb.) is a perennial, rhizomatous legume indigenous to Caucasian Russia and adjacent regions (Kannenberg & Elliott,1962; Bryant, 1974). Those agronomic characteristics that lend it potential significance, namely an extensive root-rhizome system, winter-hardiness, resistance to numerous and serious clover pests, and the production of nectar-rich flowers, were enumerated by Parker & Allen (1952). These authors also pointed out that usage of kura clover was hampered by ineffective nodulation. However, in recent years commercial and effective inoculant preparations have become available. Consequently, it has been suggested that kura clover could have potential as a pasture legume and for soil conservation purposes (Bryant, 1974; Spencer et al.1975). Pertinent literature on kura clover is scanty. The present study evaluated the nutritional characteristics of kura clover relative to otherforage legumes.