ABSTRACT

Soil biology influences soil nutrient cycling and crop nutrition, and yet, the use of synthetic fertilizers supersedes the need for crop producers to improve soil biological health. A big reason is that soil biology is complex and is difficult for the farmers to assess the biological health of their own soils. Two separate studies were designed to test a novel protocol to study soil biology that can easily be carried out by the farmers. We used cotton strip weight loss (CWL) and microbial pigmentation on the cotton strip buried in soil to assess soil microbial communities. In NPKZn experiment, we evaluated how the exclusion of nitrogen (N), phosphorus (P), potassium (K), and zinc (Zn) from crop nutrition affects the microbial community. The second experiment, CCNR, evaluated the effects of cover crop mixes as either grass, broadleaf, or blend (50% grass + 50% broadleaf), alone or in combination with four corn N rates, 0, 45, 90, 180 kg N ha⁻¹, on microbial communities in the soil. We found that P and K are limiting factors, while exclusion of N was beneficial to microbial communities. N rate higher than 90 kg ha⁻¹ was detrimental to microbes; however, cover crops modify this effect. We also found that in the CCNR experiment, brown pigmentation (r = 0.40***) was significantly correlated with CWL. These research conclusions should provide a better understanding of the relationship between pigmentation and soil microbial activity, while this protocol is simple, efficient, and easy to carry out by the farmers.

摘要

土壤生物学影响土壤养分循环和作物营养，然而，合成肥料的使用取代了作物生产者改善土壤生物健康的需要。一个很大的原因是土壤生物学很复杂，农民很难评估自己土壤的生物健康状况。两项独立的研究旨在测试一种新的协议，以研究农民可以轻松进行的土壤生物学研究。我们使用棉条失重 (CWL) 和埋在土壤中的棉条上的微生物色素沉着来评估土壤微生物群落。在 NPKZn 实验中，我们评估了从作物营养中排除氮 (N)、磷 (P)、钾 (K) 和锌 (Zn) 对微生物群落的影响。第二个实验 CCNR 评估了覆盖作物混合物作为草、阔叶、^-1，关于土壤中的微生物群落。我们发现 P 和 K 是限制因素，而排除 N 有利于微生物群落。N 比率高于 90 kg ha ^-1对微生物有害；然而，覆盖作物会改变这种效果。我们还发现，在 CCNR 实验中，棕色色素沉着 (r = 0.40***) 与 CWL 显着相关。这些研究结论应该可以更好地理解色素沉着与土壤微生物活动之间的关系，而该协议简单、高效且易于农民执行。