基于单片机技术的露播种子区微气候评价

[目的]露播是免耕种植及套作的重要农艺技术模式之一，露播的种子萌发及成苗与种子所处微小空间尺度范围内的温度和湿度条件相关。[方法]将种子所处的微小尺度空间内的温、湿度环境定义为种子区微气候，并构建以微小温湿度传感器作检测单元的单片机种子微气候检测系统，检测与定量露播全量秸秆覆盖（M1）、露播半量秸秆覆盖（M2）和露播免覆盖（CK）小麦种子所处的微气候条件及其对种子萌发及立苗的影响。[结果]田间试验表明：所构建的种子区微气候测试系统能够获取露播种子所处微域空间的温、湿度动态，稻茬麦免耕露播的播前灌水保障了种子前期萌发，但是后续的种子微气候动态是决定立苗的关键。不同的秸秆覆盖处理对种子微气候影响显著，秸秆覆盖在白天具有降温效应，夜间具有保温效应，且秸秆覆盖层可以有效阻碍地表水蒸气向空气中扩散。对比发现：M1的小麦出苗率最高，为58.75%，M2次之（48.15%），而对照组（CK）因无秸秆覆盖其出芽率仅为34.49%。播后20 d的立苗统计则发现CK立苗率为0。[结论]田间条件的种子区微气候是决定种子萌发及立苗的关键性条件，微型温湿度传感器技术是检测露播种子微气候的手段。稻茬田小麦免耕露播农艺所需保障的3个关键措施分别是播前灌水、种土接触以及合理的秸秆覆盖量，但鉴于露播无法提供良好的种土接触，因此需要适当加大播量。
[Objectives] Surface seeding is an important agronomic technology for no-till seeding and inter-cropping systems. Seed germination and seedling establishment is closely related to the seed-zone micro-climate which affects seed germination and seedling establishment. [Methods] Seed-zone heat and humid status was defined as‘seed-zone microclimate’. A micro-chip measurement system for seed-zone microclimate was fabricated with micro-sensor units for heat and humidity sensing. Seed-zone micro-climate was monitored for surface seeding+full straw mulching(M1),surface seeding+half straw mulching(M2) and surface seeding with no straw mulching(CK). [Results] Field experiment showed that the constructed measurement system was suitable for registering the heat and humid dynamics within the seed-zone for no-till surface seeding. Irrigation before seeding guarantees seed germination,but the seed-zone microclimate plays a key role for seedling establishment. Straw mulching affects seed-zone microclimate significantly. Being covered straw layer reduces temperature in the day time and maintains heat in the night. Mulching also keeps surface soil moisture from evaporating to the atmosphere. Seedling establishment rate of M1 was 58.75%,which was the highest as compared with other treatments,and that for M2 was 48.15%. The lowest seed germination rate was found for CK,which was only 34.49%. Twenty days after seeding,a statistical counting was performed for seedling establishment,revealing that seedling establishment of the CK was 0. [Conclusions] Field state seed-zone microclimate plays a decisive role in determining seed germination and seeding establishment. The constructed micro-sensor measurement system is a suitable tool for seed-zone microclimate detection. A proper agronomic technology for no-till surface seeding in paddy soil requires 3 key treatments:irrigation before seeding,full seed-soil contact and appro-priate amount straw mulching. However,as no effective measure can be provided for desirable