周年氮磷钾配施模式对砂姜黑土麦玉轮作体系籽粒产量和养分利用效率的影响

【目的】探讨周年不同氮磷钾配施对砂姜黑土麦玉轮作体系产量及养分利用效率的影响,明确适宜豫东南砂姜黑土麦玉一体化种植的氮磷钾配施模式。【方法】于2012—2014年连续两年在河南省周口市商水县典型砂姜黑土区设置氮磷钾不同配施大田定位试验,研究磷钾肥总用量不变、2种氮用量投入水平下麦玉两季磷钾配施模式对冬小麦-夏玉米轮作种植体系氮、磷、钾养分吸收利用及产量的调控效应。其中,氮肥设全年用量360.00kg·hm~(-2)和540.00 kg·hm~(-2)两个梯度,磷钾肥总量不变,设计4种配施方式,即麦季全磷玉米全钾(磷肥和钾肥分别全部施用于小麦季和玉米季)、麦季全磷玉米重钾(磷肥全部施用于小麦季,钾肥按麦玉两季42﹕58的比例分配)、麦季重磷玉米全钾(磷肥按麦玉两季64﹕36的比例分配,钾肥全部施用于玉米季)、麦季重磷玉米重钾(磷肥按麦玉两季64﹕36的比例分配,钾肥按麦玉两季42﹕58的比例分配)。【结果】高氮水平下麦玉两季磷钾肥分施能促进作物产量三要素的协调发展,显著提高冬小麦的穗数和夏玉米的穗长与行粒数,且两年度单季作物和全年籽粒产量均以麦季重磷且玉米季重钾P8处理最高,周年产量分别达21 274.2 kg·hm~(-2)和20 219.1 kg·hm~(-2)。砂姜黑土区冬小麦和夏玉米地上部养分含量大小均表现为氮钾磷。与低氮水平相比,高氮水平有利于提高植株地上部总氮、磷、钾的含量,然而氮素的偏生产力(NPFP)、吸收效率(NUPE)、利用效率(NUE)有所降低。磷钾肥分施不仅能促进冬小麦和夏玉米对氮素的吸收,还可有效防止元素的流失,提高作物对磷素和氮素的吸收和利用,显著提高磷钾两类元素的偏生产力(PFP)、吸收效率(UPE)。而磷钾全施在麦玉某一季作物上,由于磷肥易固定、钾肥易流失的原因,造成肥料后效减小,下茬作物因养分供给不平衡而影响作物对氮磷钾的吸收利用,致使产量降低。低氮水平下麦季重磷、玉米季重钾P4处理的氮磷钾养分利用较其他处理表现较优;高氮水平下麦季重磷、玉米季重钾P8处理的单季和周年氮素偏生产力及吸收效率均显著高于其他处理。【结论】综合考虑养分利用效率和籽粒产量,在本试验条件下,麦季重磷、玉米季重钾配施模式有利于养分效率和产量的同步提高,可作为豫东南砂姜黑土及相似生态类型区冬小麦-夏玉米轮作种植高产高效施肥的优选模式。

Effects of the Year-Round Management Model of N,P and K Combined Application on Grain Yield and Nutrient Efficiency of Wheat-Maize Rotation System in Lime Concretion Black Soil

【Objective】This research was conducted to explore the effect of different year-round management models of combined application of nitrogen (N), phosphorus (P) and potassium (K) nutrients on grain yields and nutrient efficiency of wheat-maize rotation system in lime concretion black soil and identify an optimal model for the use efficiency of the combined N, P, and K fertilizers in integrated wheat and maize planting system in the lime concretion black soil in the southeast area of Henan province.【Method】A field experiment of combined application of N, P, and K fertilizers was persistently performed in a typical lime concretion black soil area located in Shangshui country, Zhoukou city of Henan province during two continuous wheat-maize growing seasons (2012.09-2013.08 and 2013.09-2014.08). In this experiment, a wheat-maize rotation system was designed, in which the amounts of total P and K fertilizers were not changed while two different amounts of N fertilizers and different application methods of P and K fertilizers were applied. And the effects of this rotation on absorbance and utilization of N, P, and K fertilizers by wheat and maize crops were studies. In this study, two different amounts of N fertilizers were applied at two levels of 360.00 kg·hm^-2 and 540.00 kg·hm^-2 in every year. The amounts of total P and K fertilizers were not changed, whereas these two fertilizers were applied with four different ways: all P and K fertilizers were applied in wheat and maize growing seasons, respectively; all P fertilizers were applied in wheat growing seasons, and K fertilizers were applied in both wheat and maize seasons and the ratio of K fertilizer applied in these two seasons was 42:58; all K fertilizers were applied at maize growing season and P fertilizers were applied in both wheat and maize seasons with 64:36 ratio for these two crops; P and K fertilizers were simultaneously applied into soil in both wheat and maize seasons and the ratios of P and K fertilizers applied in these two seasons were 64:36 and 42:58, respectively. The aim of this study is to find an optimal combined mode of application of N, P and K fertilizers in wheat/maize rotation system in the lime concretion black soil.【Result】Results of the experiment indicated that under large amount of the applied N fertilizer condition, simultaneous application of P and K fertilizers in both wheat and maize crops could promote the coordinated development of three key components of wheat and maize yields, and significantly improved the spike number of wheat and the lengths as well as row grains of maize spikes. Of all treatments in these two continuous crop growing seasons, P8 treatment (a larger amount of P fertilizer applied to wheat and a larger amount of K fertilizer applied to maize) harvested the highest grain yields in both a single or two seasons, and year-round yields were respectively 21 274.2 kg·hm^-2 and 20 219.1 kg·hm^-2 in two growing seasons (2012.09-2013.08 and 2013.09-2014.08). The nutrient contents in aboveground tissues of wheat and maize crops showed N>K>P in lime concretion black soil. Compared with low amounts of the applied N fertilizer condition, large amounts of the applied N fertilizers were helpful to improvement of the contents of total N, P and K nutrients in the aboveground tissues of these two crops, whereas reduced nitrogen partial factor productivity (NPFP), nitrogen uptake efficiency (NUPE) and nitrogen use efficiency (NUE). Simultaneous application of P and K fertilizers to both wheat and maize crops in one growing year improved the absorbance of N fertilizers, prevented the loss of major nutrients, improved the absorption and utilization of P and K fertilizers of both wheat and maize crops, and significantly increased partial productivity (PFP) and uptake efficiency (UPE) of P and K fertilizers. However, application of total P or K fertilizers in single wheat or maize resulted in the reduced use efficiency of major nutrients and the decreased yields of the subsequently planted crops for unbalanced nutrient supply and the reduced absorbance of N, P and K fertilizers, because P fertilizer is easily immobilized into soil and K fertilizer is easily washed away from soil, respectively. The yield of subsequently planted crops would decrease in this way, because the crops could not absorb and utilize N, P and K in the soil environment of unbalanced nutrient supply. Under small amount of the applied N fertilizer condition, absorbance and utilization of N, P and K nutrients in P4 treatment (a larger amount of P fertilizer applied to wheat and a larger amount of K fertilizer applied to maize) were the highest among all treatments. Under large amount of the applied N fertilizer condition, however, NPFP of N fertilizer in single season or year-round in P8 treatment was the highest among all treatments.【Conclusion】 Based on the efficiency of nutrient utilization and yields of wheat and maize crops, a larger amount of P and K fertilizers separately applied in wheat and maize crops could help synchronously to improve the utilization efficiency of three main nutrients and yields of wheat and maize crops. This can be an optimal model of main nutrient application for wheat and maize yields and use efficiency of fertilizers in wheat/maize rotation system in lime concretion black soil area of southeast Henan province or other similar ecological regions.