[Responses of water consumption characteristics and grain yield of maize to different nitrogen form ratios with full film mulching on double ridges and planting in furrows]. / å ¨è†œåŒåž„æ²Ÿæ’­çŽ‰ç±³è€—æ°´ç‰¹æ€§å’Œç±½ç²’äº§é‡å¯¹ä¸åŒæ°®ç´ å½¢æ€é æ¯”çš„å“åº”.

To optimize the effects of nitrate (NO3--N) to ammonium (NH4+-N) ratios on water consumption characteristics, grain yield and water use efficiency (WUE) of maize under full film mulching on double ridges, a field experiment was conducted at semi-arid Loess Plateau of Gansu Province, China during 2015 to 2017 cropping seasons. The treatments with different ratios of NO3--N to NH4+-N included: N1 (1:0), N2 (1:1), N3 (1:3) and N4 (3:1). The results showed that different NO3--N/NH4+-N ratios had significant impacts on soil water storage in 0-200 cm soil layer. Treatment N3 had the lowest soil water storage. Treatment N4 significantly increased total water consumption by 2.9%, 1.9% and 0.9% in 2015, and 2.3%, 1.4%, and 2.2% in 2017, compared with N1, N2 and N3 treatments, respectively. Compared with the other treatments, treatment N4 increased grain yield by 3.3%-9.9%, 3.5%-24.2% and 8.3%-36.1% and improved WUE by 1.6%-6.8%, 4.9%-21.8%, and 6.6%-32.9% in 2015, 2016 and 2017, respectively. Treatment N4 had the highest partial productivity of nitrogen fertilizer, followed by N2, N3 and N1, respectively. We recommended treatment N4 as the best nitrate and ammonium ratio to improve water use efficiency, N partial productivity, and grain yield of maize in arid and semi-arid Loess Plateau.

Effects of different mulching modes on soil nitrate concentration and grain yield of Linum usitatissimum in dry land.

To investigate soil NO3--N dynamics and yield increasing effect of mulching planting for Linum usitatissimum (oil flax) in semi-arid Loess Plateau, we examined the effects of three mul-ching modes (whole field plastic mulching and micro ridges with soil cover and bunch-seeding; whole field plastic mulching with soil cover and bunch-seeding; and straw mulching with strips) on seed yield and distribution of soil NO3--N during the main growth periods of oil flax, with the conventional planting model as control (CK) in 2015 and 2016. Results showed that the average yield under mulching modes was increased by 56.1% (2015) and 22.7% (2016). The treatment of whole field plastic mulching with soil cover and bunch-seeding had the highest grain yield. Mulching treatments significantly increased soil water content. Soil water content was increased first and then reduced in the whole growth stage of oil flax. The soil NO3--N content was gradually decreased during the oil flax growth process. In both years, NO3--N content in 0-40 cm soil depth under mul-ching treatments were increased by 3.1%-18.6% (2015) and 5.1%-16.4% (2016) at budding stage of oil flax, respectively. The whole field plastic mulching with soil cover and bunch-seeding treatment showed the larges increases across all treatments. In 2015, NO3--N accumulation in 0-100 cm soil depth between the flowering and maturity stages of oil flax were increased by 10.2%-22.2% and 8.6%-21.4%, respectively. Especially during the more rainfall period of maturity stage, NO3--N accumulation in 0-40 cm soil depth was significantly enhanced by 3.3%-4.9% than that in 40-100 cm soil depth. It indicated that more rainfall could slow down the migration of NO3--N to the lower layer under the mulching modes in the maturity stage. In 2016, high temperature and drought at late growth stages had a great influence on oil flax growth. The NO3--N accumulation in 0-100 cm soil depth at the maturity stage was increased by 6.6%-18.0%. There was significant correlation between NO3--N content and grain yield during the main growth stages of oil flax. In conclusion, the whole field plastic mulching with soil cover and bunch-seeding treatment was the most appropriate way of oil flax production in arid and semi-arid area.