Reduced tillage increases residue groundcover in subsequent dry pea and winter wheat crops in the Palouse region of Idaho

Abstract

Crop management practices are needed that increase crop residue groundcover and reduce soil erosion after winter wheat ( Triticum aestivum L. emend. Thell.) planting in the Palouse region of northern Idaho and eastern Washington. This experiment investigates if reduced tillage leaves more residue groundcover from two spring small grain crops following different tillage practices and increases crop performance in subsequent dry pea ( Pisum sativum L. subsp. sativum) crops, and into winter wheat crops. In 1996 and 1997, two 3-year trials (spring cereal–dry pea–winter wheat rotation) were seeded to spring wheat and barley ( Hordeum vulgare L.) crops as sub-plot treatments. Plow, chisel, and paratill tillage, and no-till main-plot tillage treatments were applied to silt loam soils after the spring small grain crops. Spring small grain residue persisted from fall tillage through pea planting with little change over winter averaging 44% groundcover in 1997 and 74% groundcover in 1998 for the no-till treatment after pea planting. In 1998 pea yield in no-till was highest (1835 kg ha −1), whereas pea yield was lowest in the plow treatment (1605 kg ha −1). Pea residue mass collected after harvest was not different across treatments, but the carryover spring small grain residue mass was highest in no-till at 3010 kg ha −1 for barley and 2160 kg ha −1 for wheat. After winter wheat seeding in 1997, only the no-till treatment had over the minimum 30% groundcover recommended for erosion control. In 1998, all reduced tillage treatments left more than 30% groundcover and the next year no-till had 46% groundcover after winter wheat seeding. Winter wheat yields were not different in 1998, but in 1999 were highest in the chisel and paratill treatment and averaged 5150 kg ha −1. Residue groundcover can be increased by reduced tillage and good yields can be obtained if plant stand is achieved and pest problems are well managed.