No abstract

The objective of this study was to investigate the effects of applying different amounts of water and nitrogen on yield, fruit quality, water use efficiency (WUE), irrigation water use efficiency (IWUE) and nitrogen use efficiency (NUE) of drip-irrigated greenhouse tomatoes in northwestern China. The plants were irrigated every seven days at various proportions of 20-cm pan evaporation (E p). The experiment consisted of three irrigation levels (I1, 0.5 E p ; I2, 0.75 E p ; and I3, 1.0 E p) and three N application levels (N1, 150 kg N ha-1 ; N2, 250 kg N ha-1 ; and N3, 350 kg N ha-1). Tomato yield increased with the amount of applied irrigation water in I2 and then decreased in I3. WUE and IWUE were highest in I1. WUE was 16.5% lower in I2 than I1, but yield was 26.6% higher in I2 than I1. Tomato yield, WUE, and IWUE were significantly higher in N2 than N1 and N3. NUE decreased with increasing N levels but NUE increased with increase the amount of water applied. Increasing both water and N levels increased the foliar net photosynthetic rate. I1 and I2 treatments significantly increased the contents of total soluble solids (TSS), vitamin C (VC), lycopene, soluble sugars (SS), and organic acids (OA) and the sugar:acid ratio in the fruit and decreased the nitrate content. TSS, VC, lycopene, and SS contents were highest in N2. The harvest index was highest in I2N2. I2N2 provided the optimal combination of tomato yield, fruit quality, and WUE. The irrigation and fertilisation regime of 0.75 E p and 250 kg N ha-1 was the best strategy of water and N management for the production of drip-irrigated greenhouse tomato.

No abstract

The effect of n on soil enzyme activity and microbial a ated irrigation conditions was explored. The experim levels under aerated irrigation (n0, 0 kg n ha-1 ; n150, 1 200 kg n ha-1 ; n250, 250 kg n ha-1) and a control tre tional irrigation with 250 kg n ha-1). Soil bacteria, fun abundance as well as catalase and phosphatase activi then decreased with increasing n application, with ma n200 treatment. Soil nitrifier and denitrifier microbia as urease activity increased with increasing n levels a n250 treatment. Compared with the Ck treatment, enhanced soil microbial abundance by approximately and increased soil enzyme activity by 16.67 to 22.92% tion significantly promoted plant n uptake, and the n2 the highest uptake levels. Compared with Ck, celery (n uptake in the n200 and n250 treatments were si (P < 0.05). The celery yield, n agronomic efficiency, n p cy and n recovery efficiency in the n200 treatment wer and 16.07% higher compared with the n250 treatment factor productivity in the n150 treatment was 10.35% n200 treatment yet yields decreased by 20.82%. The n2 maximum yield value, net income and ratio of output 200 kg n ha-1 application with aerated irrigation effe biological environments, increases the n utilization rat n to dry matter. Abbreviations: AE, agronomic efficiency; CK, conventional irriga DAT, days after transplant; N0, aerated irrigation with 0 kg irrigation with 150 kg N ha-1 ; N200, aerated irrigation with 200 k irrigation with 250 kg N ha-1 ; PE, physiological efficiency; PFP, p of applied N; RE, recovery efficiency. I ncreasing N application is one of the main agricultura crop yield and dry matter accumulation (Guo et al., 201 The application of synthetic N to agricultural crops via cess has aided in providing foods to an estimated half of t since the Green Revolution (Erisman et al., 2008).

No abstract

No abstract

No abstract

No abstract