Effects Of Different Water And Fertilizers Treatment On Water Use Efficiency And Nutrient Absorption Characteristics Of Asparagus Lettuce

The field experiment was conducted to study the effects of different moistureconditions (75%,65%and55%of field capacity) and different fertilizing amount(local fertilizing amount,85%local fertilizing amount,70%local fertilizing amount)on growth, yield, quality, nutrient absorption (N, P and K) of plant, physical andchemical properties of soil and water use efficiency of asparagus lettuce. It willprovide theoretical basis for establishing an appropriate irrigation and fertilizationsystem of asparagus lettuce grown in Yongchang county, Gansu Province.The mainresults showed follows:1. Treatment of medium watering and high fertilization (W2F1) significantlyincreased the root length and diameter of asparagus lettuce in seedling stage, rootlength in the mature period and aboveground dry matter accumulating of asparaguslettuce during the whole period of duration.2. The Vc and soluble solid content of edible part of asparagus lettuce undertreatment of medium watering and high fertilization (W2F1) were significantly higherthan other treatments, while its nitrate and soluble sugar content were significantlylower than low watering and high fertilization treatment(W3F1).3. The asparagus lettuce absorbed potassium most, then nitrogen, and phosphorusleast. The order of nitrogen content in different organs of asparagus lettuce wereleaf>stem>root. The order of phosphorus content were stem>leaf>root. The potassimcontent was least in root, while stem and leaf showed different competitiveness underdifferent irrigation and nutrient condition. Among them, nitrogen uptake amount indifferent organs of asparagus lettuce were largest under medium watering and highfertilization treatment (W2F1); Phosphorus content of root and stem reachedmaximum under high watering and high fertilization treatment (W1F1), whilephosphorus content of leaf were largest under medium watering and high fertilizationtreatment (W2F1). Unexpected, low watering and low fertilization treatment (W3F3)was beneficial to potassium absorption of root and stem.4. With the development of growth period of asparagus lettuce, soil available N changed gently, available P firstly rised, then declined, and available K reducedgradually. After harvest, soil bulk density (1.28g cm-3) was least under treatment ofmedium watering and low fertilization (W2F3), which was not significantly differentform of medium watering and high fertilization (W2F1) treatment. The soil bulkdensity of these both treatments was lower than initial value (1.35g cm-3).5. The yield (87019.06kg·hm-2) of asparagus lettuce under treatment of highwatering and high fertilization (W1F1) was the highest, which was not significantlydifferent from the yield (85777.28kg·hm-2) of medium watering and high fertilization(W2F1) treatment. The yield of these two treatments increase by20.40%and18.68%,compared to low watering and medium fertilization (W3F2) treatments.6. Along with the fertilizing amount reducing, water use efficiency of mediumwatering treatment was higher than high and low watering treatments. As a whole, thewater use efficiency (30.41kg m-3) of medium watering and high fertilization (W2F1)treatment was highest, which was not significantly different from high watering andhigh fertilization (W1F1) treatment.7. In short, the medium watering and high fertilization amount treatment (totalirrigation volume:2820.11m3hm-2; fertilizing amount: N296.7kg hm-2, P2O570.2kg hm-2, K2O171.6kg hm-2) are the appropriate irrigation and fertilization scheme forasparagus lettuce grown in Yongchang area of Gansu Province.