Alfalfa Water Use and Yield under Different Sprinkler Irrigation Regimes in North Arid Regions of China

Abstract

Alfalfa (Medicago sativa) is one of the major crops grown in Northern China in recent years, however, the current serious water shortage conditions present a challenge to the growth of this crop, especially if efficient use of water is considered in forage production for sustainability. This study aimed to evaluate alfalfa productivity and water use efficiency (WUE) under different sprinkler irrigation levels. This experiment was conducted at Shiyanghe Experimental Station for Water-Saving in Agriculture and Ecology of China Agricultural University in Wuwei, Gansu, China, over a period of two years. There were three irrigation treatments: A1: 100% measured evapotranspiration (ETc) of alfalfa; A2: irrigation amount was 66% of A1; A3: irrigation amount was 33% of A1; and a control of A4: no irrigation during the growing season. A randomized block design with three replications were applied. The results showed that the ETc and forage yield of alfalfa decreased, while WUE and crude protein (CP) increased with the decreasing irrigation amounts. The seasonal average ETc and yield ranged from 412 mm to 809 mm and from 11,577 to 18,636 kg/ha, respectively, under different irrigation levels. The highest yields were obtained from the first growth period in all treatments in both years, due to the winter irrigation and the longest growth period. Alfalfa grown under lesser irrigation treatment conditions had higher variability in ETc and yield, mainly due to the variability in the amount of rainfall during the growth period. The seasonal average WUE of treatments ranged from 22.78 to 26.84 kg/(mm·ha), and the highest WUE was obtained at the first growth period, regardless of treatments. Seasonal average CP content ranged from 18.99% to 22.99%. A significant linear relationship was found between yield and ETc or irrigation amount, and the fitting results varied between growth periods and years. The present results also implied that winter irrigation provided the space for saving water and should be applied at the end of each growing season to fill the soil profile, and to maintain a greater yield in the next growing season. During the growing season, more irrigation should be concentrated in the early growth period, especially in the second growth period.

Phenotypic Diversity and Productivity of Medicago sativa Subspecies from Drought-Prone Environments in Mediterranean Type Climates

“…This could be explained by the rainfall conditions during the 2019 growing season, since South Australia recorded the driest year in more than a decade, with 170 mm less than the long-term average (528.3 mm). Similar response to irrigation was reported by Li and Su [43] in alfalfa grown under a gradient of water treatments in Northern China. Additionally, forage yield throughout locations and years was significantly related to the amount of rainfall or water added to the experiments (Figure 5), which is the typical agronomic responses of crops grown in Mediterranean environments [8,44,45].…”

The Dynamic Yield Response Factor of Alfalfa Improves the Accuracy of Dual Crop Coefficient Approach under Water and Salt Stress

“…It has been three years since alfalfa was sown in 2017, and the K cb was 0.3 in initial stage, 1.15 in mid-season stage and 1.1 in late-season stage, respectively, which was consistent with the proposed value of FAO-56; and the annual average K c of 2018 and 2019 were 1.09 and 1.08, respectively, indicating a similar growth state. In the same region with this study, the K c of alfalfa in the 2nd and 3rd year under subsurface drip irrigation were 1.03 and 0.84 [46], while 1.13 and 1.31 under sprinkler irrigation in the same period, respectively [7]. In arid Northern Australia, the K c of alfalfa were 1.04 and 0.97 during two consecutive years [47].…”

Yield, nutrient quality and water and phosphorus recovery efficiencies of alfalfa under different drip irrigation and phosphorus levels in Northern Xinjiang, China

“…Previous studies have shown that there are synergistic effects between water and fertiliser and that fertilisation has an obvious water‐regulating effect. In this study, although the WUE was highest in the W 1 P 2 treatments (Table 6), the alfalfa hay yield of W 1 P 2 treatments was relatively low (Table 4), which was mainly due to N nutrition of alfalfa was severely depress by water stress, and lower plant N nutrition will lead to lower plant P nutrition, which will reduce alfalfa hay yield (Lemaire et al, 2019; Li & Su, 2017; Rathore et al, 2017; Tandoh et al, 2019). At the early stage of alfalfa growth, under drought conditions, increasing irrigation can promote the water absorption and plant growth of alfalfa, but excessive irrigation increases alfalfa lodging, which is not conducive to alfalfa photosynthesis or dry matter accumulation, and ultimately reduces the hay yield of alfalfa.…”