Effects of row spacing, seeding rate and nitrogen on yield of barley and wheat under zero-till management

Abstract

Adopting water-conserving tillage practices on the Canadian prairies will protect the soil against erosion while conserving soil water. The use of tall-standing stubble to conserve water creates a dilemma for producers because maximum yields can only be obtained with narrow rows, and tall stubble may limit the use of narrow row spacings. A 4-yr study on a thin Black clay soil investigated the effects of three row spacings (10, 20 and 30 cm), six seeding rates (34, 67, 100, 134, 168 and 202 kg ha−1 for wheat and 27, 54, 81, 108, 134 and 161 kg ha−1 for barley) and two rates of N (low and high) in hard red wheat (Triticum aestivum L.), durum (Triticum durum L.) and barley (Hordeum vulgare L.) using a continuous cropping, zero-till production system. The yields of cereals were maintained with 30-cm row spacing over a wide range of growing conditions under zero-till management. Durum had a 5.8% yield advantage and barley a 2.4% advantage for the 30-cm row spacing over the 10-cm row spacing. The number of plants established and the number of spikes produced decreased as row spacing increased for all crops. But wider row spacing resulted in more kernels produced per spike, which, in the case of barley and durum, more than compensated for the lower number of spikes. Increasing seeding rates significantly improved grain yield in all crops and years because more spikes were produced. Grain yield was related to the reciprocal of seeding rate. The few row spacing × seeding rate interactions observed in 2 of 12 cases suggest that seeding rates need not be adjusted for changes in row spacing. The results obtained have important implications for equipment design and the ability to more easily handle high-crop-residue situations. Key words: Yield components, seeding rate, row spacing, yield compensation