A long-term study to increase water use efficiency, grain yield and the profit of growers in the Western region in a no-till system. Mingenew Site.

The main principles of conservation agriculture are permanent soil cover, minimal soil disturbance and diverse crop rotations, yet these are often absent from our no-till systems. This project was designed to test and further develop high quality no-till systems based on these conservation principles. The project commenced in 2006 and completed twelve years of cropping in 2018. An additional year was completed in 2019 with the whole trial seeded to wheat. The overall objective of the project was to determine the benefits of diverse rotations, high residue and minimal disturbance no-till systems on soil quality, weeds, diseases as well as crop water use efficiency, economics, and yield. \nLineage: Two long-term conservation agriculture cropping system experiments were started in 2007, one on a farm near Mingenew (115°17´E, 28°56´S) and the other at the Cunderdin College of Agriculture (117°14´E, 31°38´S) in Western Australia. The soil at Mingenew was deep yellow sand with a soil pH (0.01M CaCl2) ranging from 5.4 to 5.0. The Cunderdin soil was red sandy clay loam with pH of 6.6, increasing with depth to 7.9.\nThe treatments were based on four different cropping philosophies/rotations titled "P1-maximum carbon input/continuous cereals", "P2-maximum diversity/diverse rotation", "P3-controls/monoculture wheat and permanent pasture" and "P4-maximum profit/farmer rotation" (Appendix 1). There was a total of 11 crop sequences each replicated three times in a randomised complete block design: the P1, P2 and P4 philosophies had a three-year rotation with each phase presented every year, giving nine crop sequences, while P3 had two sequences, being continuous crop and pasture. The crop types grown at the two sites were selected according to the particular philosophies/treatments but differed in some instances between the two sites because of soil type and local experience. Crops were only changed, to ensure they were relevant to farmers after three years (still within the 'philosophy') and when all phases of the rotation were complete.\nPlots in the same phase within a rotation (i.e. the replicates) were given the same sequence number. The three sequences for the cereal rotation were S1-S3, those for the diverse rotation were S4-S6, monoculture wheat S7, pasture S8 and the farmer rotation were S9-S11. Therefore, there were a total of 33 plots, comprising 11 sequences, each replicated three times. In addition, four "farmer controls" that consists of geo-located positions within adjacent paddocks (that have sheep in the system), were monitored for soil properties, yield and quality of grain providing an additional two sequences. From 2010 onwards plots in the cereal, diverse and farmer rotations were split for different residue amounts. In the cereal and diverse rotations, the crop residue was either fully retained and spread behind the harvester (spread) or laid in a narrow windrow and then just the windrow burnt before seeding (windrow burn). In the farmer rotation, whole plots were windrow burnt from 2010 to 2012, then in 2013 were split for windrow burn and lightly tilled with a harrow (to a depth of about 15 cm, which buried most of the crop residue). The monoculture wheat plots were not split and maintained full residue retention (i.e. spread).\n\n

保护性农业（conservation agriculture）的核心原则为永久土壤覆盖、最小化土壤扰动与多样化作物轮作，但当前多数免耕（no-till）系统往往未遵循这些原则。本项目旨在基于上述保护性农业原则，测试并优化高质量免耕系统。项目于2006年启动，2018年完成了为期12年的作物种植试验，2019年追加一轮试验：全部试验小区均播种小麦。本项目的总体目标为明确多样化轮作、高残茬覆盖与低扰动免耕系统对土壤质量、杂草、病害、作物水分利用效率、经济效益以及产量的影响。
试验溯源：2007年启动了两项长期保护性农业种植系统试验，一项位于西澳大利亚州明格纽（Mingenew）附近的农场（经度115°17′E，纬度28°56′S），另一项位于昆达丁农业学院（Cunderdin College of Agriculture，经度117°14′E，纬度31°38′S）。明格纽试验点的土壤为深黄色砂土，土壤pH（0.01M CaCl₂浸提）介于5.4至5.0之间；昆达丁试验点的土壤为红色砂质粘壤土，初始pH为6.6，随土层深度增加升至7.9。
试验处理基于四种不同的种植理念/轮作模式，分别命名为“P1-最大碳输入/连续谷物种植”、“P2-最高多样性/多样化轮作”、“P3-对照/单作小麦与永久草地”、“P4-最高收益/农户常规轮作”（详见附录1）。试验采用随机完全区组设计（randomised complete block design），共包含11种作物种植序列，每种序列重复3次：其中P1、P2与P4组采用三年轮作模式，每年均覆盖所有轮作阶段，对应9种种植序列；P3组包含2种序列，即连作与永久草地。两个试验点的种植作物类型根据对应种植理念/处理设置，但因土壤类型与当地种植习惯差异，部分作物类型在两个试验点有所不同。作物每三年更换一次（仍符合对应种植理念框架），且需完成轮作的全部阶段，以确保试验结果与农户实际种植场景相符。
同一轮作阶段内的重复小区（即重复组）使用相同的序列编号。谷物轮作的三个序列编号为S1-S3，多样化轮作的三个序列为S4-S6，单作小麦为S7，永久草地为S8，农户常规轮作为S9-S11。因此总计33个试验小区，涵盖11种序列，每种序列重复3次。此外，在相邻牧场（包含肉羊养殖系统）中选取4个地理定位的农户对照地块，监测其土壤属性、产量与籽粒品质，对应新增2种序列。
自2010年起，谷物轮作、多样化轮作与农户常规轮作的小区按残茬管理方式拆分处理：在谷物与多样化轮作组中，作物残茬要么完全保留并由收割机抛撒还田（简称抛撒处理），要么被集合成窄条带，播种前仅焚烧条带内残茬（简称条带焚烧处理）。农户常规轮作组在2010-2012年期间，全部小区均采用条带焚烧处理；2013年起拆分为两组：一组保持条带焚烧，另一组使用耙进行浅耕（耕深约15cm，可掩埋大部分作物残茬）。单作小麦小区未拆分，始终保持残茬全量抛撒还田。