分根交替滴灌施肥下根区土壤水氮时空变化规律及对番茄水氮利用效率的影响研究

Alternate partial root-zone drip fertigation is the combination of alternate partial root-zone irrigation and drip fertigation. It is a technique to save water, and enhance water and fertilizer use efficiency simultaneously, which makes full use of crop biological characteristics and precision fertigation. The key to successful application of the technique is reasonable alternately drying and wetting and the precise distribution of water and fertilizer in root-zone. The objectives of the project are to investigate the effects of fertigation frequency and nitrogen fertilizer amount on the spatial and temporal change of water and nitrogen in the soil, and the growth of tomato under alternate partial root-zone drip fertigation. The main research contents are below: (1) The spatial and temporal distribution and movement of water and nutrient in the soil under different partial root-zone drip fertigation. (2) Responses characteristics of tomato growth, yield, quality, and water and fertilizer use efficiency to alternate drip fertigation. (3) The appropriate water and fertilizer regulation method for better fruit quality and higher yield of tomato will be raised based on the experimental data. The research achievement will help improve the yield, quality, water and fertilizer use efficiency in greenhouse tomato production. On the other hand, it can provide a scientific guidance for further enriching the theory of partial irrigation and improving water and fertilizer utilization in farmland.

分根交替滴灌施肥技术将分根交替灌溉和滴灌施肥相结合，可充分利用作物生物学特性和精准灌溉施肥技术，实现节水和提高水肥利用效率。合理的根区干湿交替和水肥在根区的精准分布是分根交替滴灌施肥技术能够成功应用的关键，因此，本项目通过调整滴灌施肥频率，实现水肥在根区的动态调控，结合分根交替技术，研究该模式下不同滴灌施肥频率和施氮量对番茄根区土壤水氮时空变化规律和作物生长响应规律的影响机理。主要内容包括：（1）分根交替滴灌施肥条件下不同根区土壤水分养分的时空分布和运移规律；（2）交替滴灌施肥对番茄生长、产量、果实品质以及水氮利用效率的影响机理；（3）建立基于作物产量和品质响应的交替滴灌水肥调控模型，提出优质高效的分根交替滴灌施肥方法。该研究一方面将有助于在番茄生产中提高果实产量品质及水肥利用效率；另一方面也有助于进一步丰富局部根区灌溉理论，为农田水肥高效利用提供科学依据。

分根交替滴灌施肥（ADF）是一种结合了交替灌溉和滴灌施肥优点的精准灌溉施肥技术，具有节水和提高氮肥利用率的潜力。但目前有关ADF不同施肥频率对土壤水分和养分状况以及作物生长的影响研究尚不深入。本项目通过连续3年的田间试验，设置不同施肥频率和施氮量的水肥调控处理，研究了ADF条件下土壤水分养分的时空分布和运移规律，结果表明高频灌溉引起土层0-40cm水分养分含量较高；在相同灌溉频率下，ADF处理（F6）在0-20和20-40cm土层氮素含量比传统滴灌处理分别增加21.0%和29.0%，而在40-60cm土层降低23.0%。分根交替灌溉在灌水量减少40%条件下能够保持番茄茎粗、株高，却显著降低植株生物量和吸氮量。F3处理番茄产量比F12显著增加23.3%，但F3与F6差异不显著；与常规滴灌施肥相比，F6可以保持番茄高产；N75、N100和N125处理番茄产量之间无显著性差异，但其显著高于N0处理。综合考虑作物产量和水肥高效利用，建议将分根交替灌溉条件下灌溉频率6天1次和施氮量135kg/ha作为温室番茄生产的水氮管理措施。该研究成果完善了温室番茄分根交替滴灌水肥一体化技术，进一步发展和丰富局部根区灌溉理论，为分根交替灌溉水肥综合高效利用提供科学依据。