How the productivity of crops in organic arable farming may be sustainably increased remains a key issue. We combined measurements of crop yield, total aboveground biomass (AGB) and light interception over a 4-year crop rotation cycle from 2015 to 2018 in a long-term experiment in Denmark with arable organic and conventional cropping systems. These cropping systems comprise one conventional (CGL) and two organic (OGL and OGC) crop rotations, where CGL and OGL had three spring cereal and one grain legume crop (faba bean) in the rotation, and the faba bean was in OGC replaced with grass-clover. All crop rotations were grown with and without the use of cover crops, and the organic systems were grown with and without the manure application. The light interception was calculated from measurements of spectral reflectance, and this allowed the AGB to be decomposed into accumulated intercepted PAR (AIPAR) and radiation use efficiency (RUE).

The conventional cropping system (CGL) had significantly greater AGB, AIPAR and RUE compared with the corresponding organic, grain legume-based system (OGL). AIPAR of the organic grass-clover-based cropping system (OGC) was greater than CGL, although the contrary conclusion was found in AGB and RUE. Across crops, RUE was greatest for cereals and smallest for faba bean and grass-clover. AIPAR was consistently greatest for grass-clover, and both grass-clover and faba bean had smaller variability in AIPAR between years and treatments than the cereal crops. Cover crops significantly increased AGB and AIPAR in the organic cropping systems but not in CGL. RUE was not significantly affected by the inclusion of cover crops. The use of manure in the organic systems increased AGB, AIPAR and RUE. The results show that AIPAR can be higher in organic cropping systems compared with conventional cropping systems, but this is not translated into a greater yield of cereal crops. There is, therefore, a need for novel approaches to management and the use of biomass in organic cropping systems for increasing yields for feed and food, and which sustains soil fertility.

如何可持续地提高有机耕作作物的生产力仍然是一个关键问题。我们在丹麦的一项长期试验中结合了作物产量、总地上生物量 (AGB) 和 2015 年至 2018 年 4 年作物轮作周期内的光截获量，并采用有机耕作和传统耕作系统进行了长期试验。这些种植系统包括一种常规 (CGL) 和两种有机 (OGL 和 OGC) 轮作，其中 CGL 和 OGL 轮作中有 3 种春季谷物和一种谷物豆类作物（蚕豆），而 OGC 中的蚕豆被替换为草三叶草。所有轮作都在使用和不使用覆盖作物的情况下种植，有机系统在使用和不使用肥料的情况下种植。光拦截是根据光谱反射率的测量值计算的，

与相应的有机谷物豆类系统 (OGL) 相比，传统种植系统 (CGL) 具有显着更高的 AGB、AIPAR 和 RUE。尽管在 AGB 和 RUE 中发现了相反的结论，但有机三叶草种植系统 (OGC) 的 AIPAR 大于 CGL。在所有作物中，谷物的 RUE 最大，蚕豆和三叶草的 RUE 最小。草三叶草的 AIPAR 一直是最大的，而且草三叶草和蚕豆在年份和处理之间的 AIPAR 变异性小于谷类作物。覆盖作物在有机种植系统中显着增加了 AGB 和 AIPAR，但在 CGL 中没有。RUE 没有受到包含覆盖作物的显着影响。有机系统中粪便的使用增加了 AGB、AIPAR 和 RUE。结果表明，与传统种植系统相比，有机种植系统中的 AIPAR 可以更高，但这并没有转化为更高的谷类作物产量。因此，需要在有机种植系统中管理和使用生物量的新方法，以提高饲料和食物的产量，并维持土壤肥力。