Experimental Study on the Optimal Threshold of Water and Nitrogen Quantities for Tomato Growth under the Irrigation with Biogas Slurry in Greenhouse

Abstract

HighlightsApplication of biogas slurry can significantly improve the integrated growth, yield, quality of tomatoes.Water-nitrogen coupling model was established based on multi-index evaluation system of tomatoes.The optimal application quantitative range of water and nitrogen was obtained based on the water-nitrogen coupling model.Abstract. Biogas slurry, a liquid organic fertilizer, has been widely used in agricultural production. However, the characteristics of high water content and low fertility make it always applied empirically and a scientific and reasonable application of biogas slurry is urgent needed in practical agricultural production. This study aims to explore the effects of various biogas slurry concentrations on the yield, comprehensive nutritional quality (CNQ), irrigation water use efficiency (IWUE) and partial factor productivity of nitrogen (PFPN) of tomatoes in a greenhouse. Seven treatments, including T1(BS1:4; 0.8Ep), T2 (BS1:6; 0.8Ep), and T3(BS1:8; 0.8Ep), T4(BS1:4; 0.6Ep), T5(BS1:4; 1.0Ep), CK (no fertilization; 1.0Ep), CF (conventional chemical fertilization; 1.0Ep) were set up, where BS1:4, BS1:6,and BS1:8 are the volume ratio of biogas slurry to water, 0.6, 0.8, and 1.0 were crop dish coefficients, respectively. Ep is the evaporation amount of a 20 cm standard evaporating dish. The results showed that appropriate application of biogas slurry had a positive impact on crop growth such as total dry biomass, plant height, stem diameter and finally increased the yields, in which T1 treatment was the best. The fruit yield increased with the increase of biogas slurry ratio for treatments at the same irrigation level of 0.8Ep and the maximum yield of single tomato can reach 5.174 kg. The IWUE increased with the decrease of irrigation for treatments at the same biogas slurry ratio of BS1:4 and T4 treatment had the highest IWUE. The CNQ first increased and then decreased with the increase of biogas slurry ratio under the same irrigation level of 0.8Ep and T2 treatment obtained the highest CNQ; but the PFPN decreased with the increase of biogas slurry ratio and T3 treatment acquired the largest PFPN. Within an 80% confidence interval, when the irrigation amount was in a range of 39.233~43.134 L and the nitrogen quantities was 7.983~8.426 g, the yield, IWUE, CNQ, and PFPN can reach =80% of their maximums at the same time. Taking into account the growth, yield, fruit quality, and water and fertilizer use efficiency, T1 treatment was the best fertigation strategy for a higher production and better quality. The results can provide some help for scientific management of biogas slurry application in greenhouse. Keywords: Biogas slurry, Quality, Spatial analysis method, Tomato (Lycopersicum esculantum Mill), Yield.

Effects and evaluation of biogas slurry/water integrated irrigation technology on the growth, yield and quality of tomatoes

“…This is consistent with the relevant results obtained by Du et al [39] , Wang et al [40] , and by Zheng et al [11] . TOPSIS method has been proven to be a good evaluation method in agricultural production [10] .…”

“…Studies have shown that the application of biogas slurry in agriculture production can significantly increase soil organic matter content [7] , improve crop quality [8] , maintain soil fertility [9] , and facilitate the formation of soil aggregate structure. Nevertheless, biogas slurry is a mass with high water content and low fertility [10] , making it easy to produce surface runoff or deep leakage when applied by traditional irrigation methods, which will reduce the water and fertilizer use efficiency.…”

A 15N-Tracing Study to Explore the Coupling Effects of Biochar and Nitrogen Fertilizer on Tomato Growth, Yield, Nitrogen Uptake and Utilization, and the Rhizosphere Soil Environment under Root-Divide Alternative Irrigation

“…The consistency test coefficients were CR < 0.1, indicating that the consistency met the requirements. In Table 10, the objective weights of each evaluation indicator were calculated using the entropy weight method (EWM) based on the tomato quality indicators, nitrogen utilization, and growth benefits, while the indicator matrix was constructed [25]. Simultaneously, to achieve more scientific and reasonable weights, the combined weights were calculated using AHP and EWM.…”