Dual-purpose use of winter wheat in western China: cutting time and nitrogen application effects on phenology, forage production, and grain yield

Abstract

Conventional rainfed mixed crop–livestock systems of western China lack high-quality forage and restrict livestock production. This study explored the forage potential from wheat and its effects on subsequent grain yield. Different cutting times were imposed on winter wheat (Triticum aestivum) at Qingyang, Gansu Province, in two growing seasons, and the effect of nitrogen (N) topdressing rates (0, 60, and 120 kg N/ha) on grain yield recovery was explored. Results showed the potential to produce 0.8–1.6 t DM/ha of wheat forage with high nutritive value when cut before stem elongation (GS 30). In the wetter year, cutting before stem elongation did not delay crop development significantly (<3 days at anthesis and 5 days at maturity), but grain yields were reduced by 17–28% compared with the uncut crop (5.8 t DM/ha), mainly due to reductions in number of spikes per m2 and, consequently, number of grains per m2. In both seasons, more forage biomass was available if crops were cut later than GS 32, but this came with large reductions (>62%) in grain yield and delays in crop development (>9 days or 131 degree-days). Crops cut later than GS 30 had greatly reduced harvest index, tillers per m2, and total N uptake but higher grain protein content. There was no significant effect of N topdressing rate on grain yield, although provided the crop was cut before GS 30, higher rates of N increased maturity biomass and crop N uptake by replacing N removed in cut biomass. This study showed that physiological delay of wheat due to cutting was not significant. The forage harvested from winter wheat before stem elongation could be a valuable feed resource to fill the feed gap in western China.

Nitrogen Fertilizer and Seeding Rate Influence on Grain and Forage Yield of Dual‐Purpose Barley

“…This is why plants in grain-only systems are more likely to escape damage from hot winds, drought, and rust, which normally are experienced during later growing stages of wheat and barley in this region. Other researchers have found similar results about delaying in phenological development of cereals as a consequence of forage removal (Royo et al, 1997;Tian et al, 2012;Virgona et al, 2006). The extent of delay in crop phenology was dependent on the time of forage removal; cutting or grazing before stem elongation (GS30) resulted in only small delays (0-5 d) in crop phenology (Tian et al, 2012;Virgona et al, 2006), whereas defoliation at later growth stages resulted in greater delays (Royo et al, 1997).…”

“…It has been found that N availability plays an important role in crop regrowth after defoliation (Pandey, 2005;Tian et al, 2012). Using supplementary N fertilizer after forage removal, therefore, is a common practice in dual-purpose systems in many areas (Pandey, 2005;Tian et al, 2012).…”

“…F eed shortages during late winter and early spring are among the major constraints of livestock production in many areas (Afshar et al, 2012(Afshar et al, , 2014Sadeghpour et al, 2013;Tian et al, 2012). Clipping and/or grazing fall-sown cereals, mostly wheat (Triticum aestivum L.) and barley, provides a good source of high-quality forage in the feed gap period in many countries, such as the United States, Canada, Argentina, Morocco, Pakistan, Syria, Uruguay, Australia, and Mediterranean countries (Harrison et al, 2012).…”

“…In their study, wheat grain yield increased as N rate increased. Tian et al (2012) evaluated the effect of N topdressing rates (0, 60, and 120 kg N ha -1 ) on grain yield recovery of wheat after forage removal. They reported no significant effect of N topdressing rate on grain yield of wheat.…”

Dual-purpose cropping – capitalising on potential grain crop grazing to enhance mixed-farming profitability

“…The previous success with dual-purpose crops in higher rainfall regions of south-eastern Australia has increased interest in the potential of dual-purpose crops in new regions of Australia, and the world, including exploration of winter wheat for grazing in north-west China (Tian et al 2012). Capitalising on dual-purpose crops in existing areas and expanding their use in new areas requires underpinning research to understand crop responses to grazing, crop agronomic and grazing management to maximise the benefits and whole-farm integration to optimise the synergies at the farm level.…”